Patent Publication Number: US-2022220475-A1

Title: Method for controlling microrna expression

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority of US patent application No. 62/922,198, filed 2 Aug. 2019, the contents of it being hereby incorporated by reference in its entirety for all purposes. 
    
    
     FIELD OF THE INVENTION 
     The present invention generally relates to molecular biology. In particular, the present invention relates to means of controlling microRNA processing and expression. 
     BACKGROUND OF THE INVENTION 
     microRNAs (miRNAs) play important roles in gene regulation and are involved in many essential cellular processes. Their importance is exemplified by the many diseases that are associated with aberrations in miRNAs. Therefore, it would be imperative to control the levels of miRNAs expression in cells so as to restore normal levels of miRNA expression, especially in diseased cells. 
     Conventional methods of gene editing include mediating microRNA (miRNA) expression in cells by knocking-out or knocking-down target miRNA sequences. However, these methods contain inherent disadvantages, such as the production of unexpected miRNA sequences, off-target gene expression, and difficulty in controlling the level of miRNA expression. In addition, it is also not possible to increase the level miRNA expression using conventional methods. 
     In view of the above, there is a need to provide alternative methods that address some of the above problems. 
     SUMMARY 
     In one aspect, there is provided a method of producing single cut precursor microRNA (pre-miRNA) in a host cell from a primary microRNA (pri-miRNA) comprising the following structure: 
     
       
         
         
             
             
         
       
         
         
           
             wherein [B] to [b] is in the 5′ to 3′ directionality to form a stem loop structure, and wherein:
           motifs [B] and [b] each constitute a cleavage site in the stem region;   motif [C] constitute a loop region;   
         
             the method comprising:
 
introducing one or more mutations in a region upstream of motif [B] and/or downstream of motif [b] to produce a genetically modified primary microRNA (pri-miRNA) comprising the following structure:
 
           
         
       
    
     
       
         
         
             
             
         
       
         
         
           
              wherein motifs [A] and [a] constitute the asymmetric internal loop (AIL) region in the stem region; 
             a) transfecting the genetically modified primary microRNA (pri-miRNA) from step b) to the host cell;
 
wherein the single cut precursor microRNA (pre-miRNA) is produced from cleaving at motif [B].
 
           
         
       
    
     In another aspect, there is provided a method of producing single cut precursor microRNA (pre-miRNA) in a host cell from a primary microRNA (pri-miRNA) comprising the following structure: 
     
       
         
         
             
             
         
       
         
         
           
             wherein [A] to [a] is in the 5′ to 3′ directionality to form a stem loop structure, and wherein:
           motifs [A] and [a] constitute the asymmetric internal loop (AIL) region in the stem region;   motifs [B] and [b] each constitute a cleavage site in the stem region;   motif [C] constitute a loop region;   
         
             the method comprising: 
             a) introducing one or more mutations at one or both of motifs [A] and [a] to modulate the size of the asymmetric internal loop (AIL) region; 
             b) transfecting the primary microRNA (pri-miRNA) from step b) to the host cell;
 
wherein the single cut precursor microRNA (pre-miRNA) is produced from cleaving at motif [B].
 
           
         
       
    
     In yet another aspect, there is provided a method of increasing production levels of single cut precursor microRNA (pre-miRNA) and decreasing production levels of double cut precursor microRNA (pre-miRNA) in a host cell from a primary microRNA (pri-miRNA) comprising the following structure: 
     
       
         
         
             
             
         
       
         
         
           
             wherein [B] to [b] is in the 5′ to 3′ directionality to form a stem loop structure, and wherein:
           motifs [B] and [b] each constitute a cleavage site in the stem region;   motif [C] constitute a loop region;   
         
             the method comprising: 
             a) introducing one or more mutations in a region upstream of motif [B] and/or downstream of motif [b] to produce a genetically modified primary microRNA (pri-miRNA) comprising the following structure: 
           
         
       
    
     
       
         
         
             
             
         
       
         
         
           
             wherein motifs [A] and [a] constitute the asymmetric internal loop (AIL) region in the stem region; 
             b) transfecting the genetically modified primary microRNA (pri-miRNA) from step b) to the host cell; 
             c) producing one or both single cut precursor microRNA (pre-miRNA) and double cut precursor microRNA (pre-miRNA) by controlling cleaving at one or both motifs [B] and [b]; 
             wherein the single cut precursor microRNA (pre-miRNA) is produced from cleaving at motif [B];
 
wherein the double cut precursor microRNA (pre-miRNA) is produced from cleaving at motifs [B] and [b].
 
           
         
       
    
     In yet another aspect, there is provided a method of increasing production levels of single cut precursor microRNA (pre-miRNA) and decreasing production of double cut precursor microRNA (pre-miRNA) in a host cell from a primary microRNA (pri-miRNA) comprising the following structure: 
     
       
         
         
             
             
         
       
         
         
           
             wherein [A] to [a] is in the 5′ to 3′ directionality to form a stem loop structure, and wherein:
           motifs [A] and [a] constitute the asymmetric internal loop (AIL) region in the stem region;   motifs [B] and [b] each constitute a cleavage site in the stem region;   motif [C] constitute a loop region;   
         
             the method comprising: 
             a) introducing one or more mutations at one or both of motifs [A] and [a] to modulate the size of the asymmetric internal loop (AIL) region; 
             b) transfecting the primary microRNA (pri-miRNA) from step b) to the host cell; 
             c) producing one or both single cut precursor microRNA (pre-miRNA) and double cut precursor microRNA (pre-miRNA) by controlling cleaving at one or both motifs [B] and [b]; 
             wherein the single cut precursor microRNA (pre-miRNA) is produced from cleaving at motif [B]; 
             wherein the double cut precursor microRNA (pre-miRNA) is produced from cleaving at motifs [B] and [b]. 
           
         
       
    
     In yet another aspect, there is provided a method of decreasing production levels of single cut precursor microRNA (pre-miRNA) and increasing production of double cut precursor microRNA (pre-miRNA) in a host cell from a primary microRNA (pri-miRNA) comprising the following structure: 
     
       
         
         
             
             
         
       
         
         
           
             wherein [A] to [a] is in the 5′ to 3′ directionality to form a stem loop structure, and wherein:
           motifs [A] and [a] constitute the asymmetric internal loop (AIL) region in the stem region;   motifs [B] and [b] each constitute a cleavage site in the stem region;   motif [C] constitute a loop region;   
         
             the method comprising: 
             a) introducing one or more mutations at one or both of motifs [A] and [a] to modulate the size of the asymmetric internal loop (AIL) region; 
             b) transfecting the primary microRNA (pri-miRNA) from step b) to the host cell; c) producing one or both single cut precursor microRNA (pre-miRNA) and double cut precursor microRNA (pre-miRNA) by controlling cleaving at one or both motifs [B] and [b];
           wherein the single cut precursor microRNA (pre-miRNA) is produced from cleaving at motif [B];
 
wherein the double cut precursor microRNA (pre-miRNA) is produced from cleaving at motifs [B] and [b].
   
         
           
         
       
    
     In yet another aspect, there is provided a method of modulating expression levels of microRNA (miRNA) in a host cell comprising modulating expression levels of one or both of single cut precursor microRNA (pre-miRNA) and double cut precursor microRNA (pre-miRNA) using the methods as disclosed herein. 
     In yet another aspect, there is provided a method of modulating expression levels of microRNA (miRNA) in a subject comprising modulating expression levels of one or both of single cut precursor microRNA (pre-miRNA) and double cut precursor microRNA (pre-miRNA) using the methods as disclosed herein. 
     In yet another aspect, there is provided a method of treating a disease in a subject, comprising:
         a) detecting the presence or absence of a mutation in a microRNA related to the disease, wherein the mutation alters or disrupts expression of microRNA;   b) modulating expression levels of one or both of single cut precursor microRNA (pre-miRNA) and double cut precursor microRNA (pre-miRNA) in a host cell using the methods as disclosed herein.       

     In yet another aspect, there is provided a genetically modified primary microRNA (pri-miRNA) comprising the following structure: 
     
       
         
         
             
             
         
       
         
         
           
             wherein [A] to [a] is in the 5′ to 3′ directionality to form a stem loop structure, and wherein:
           motifs [A] and [a] constitute an asymmetric internal loop (AIL) region in the stem region;   motifs [B] and [b] each constitute a cleavage site in the stem region;   motif [C] constitute a loop region;
               wherein one or both motifs [A] and [a] comprise 0-9 nucleotides;
                   wherein motif [A] comprises at least 1 nucleotide that does not match to any nucleotide in motif [a]; or
 
wherein motif [a] comprises at least 1 nucleotide that does not match to any nucleotide in motif [A].
   
                   
               
         
           
         
       
    
     In yet another aspect, there is provided a genetically modified primary microRNA (pri-miRNA) comprising SEQ ID NO: 1. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be better understood with reference to the detailed description when considered in conjunction with the non-limiting examples and the accompanying drawings, in which: 
         FIG. 1  shows 2 cartoons illustrating the structure of a primary microRNA (pri-miRNA) and an example of the downstream pathways of primary microRNA (pri-miRNA) using the method as described herein.  FIG. 1A  illustrates the structure of an exemplary primary microRNA (pri-miRNA) comprising a stem and loop structure, wherein the stem region can further comprise an upper stem and lower stem. The apical and basal junctions are identified by the dotted arrows, and the cleavage sites are identified by the white and black arrowheads. The lower stem region is the area wherein an asymmetrical internal loop (AIL) region can exist.  FIG. 1B  shows the following: (left) a modified primary microRNA (pri-miRNA) without an asymmetric internal loop (AIL) region is cleaved at the cleavage site on the 5′ stem of the primary microRNA (pri-miRNA) (denoted by white arrowhead) and the cleavage site on the 3′ stem of the primary microRNA (pri-miRNA) (denoted by black arrowhead), resulting in the production of a double cut precursor microRNA (pre-miRNA) that is exported out of the cell nucleus to be further processed into a microRNA (miRNA); (right) a modified primary microRNA (pri-miRNA) with a large asymmetric internal loop (AIL) region is cleaved at the cleavage site on the 5′ stem of the primary microRNA (pri-miRNA) (denoted by white arrowhead) only, resulting in the production of a single cut precursor microRNA (pre-miRNA) that is trapped in the cell nucleus and degraded; (center) a modified primary microRNA (pri-miRNA) with a small asymmetric internal loop (AIL) region is cleaved at the cleavage site on the 5′ stem of the primary microRNA (pri-miRNA) (denoted by white arrowhead) and the cleavage site on the 3′ stem of the primary microRNA (pri-miRNA), wherein the levels of cleaving in the cleavage site on the 3′ stem of the primary microRNA (pri-miRNA) is less than that in the scenario depicted on the left (denoted by a smaller black arrowhead), resulting in the production of both double cut precursor microRNA (pre-miRNA) that is exported out of the cell nucleus to be further processed into a microRNA (miRNA) and single cut precursor microRNA (pre-miRNA) that is trapped in the cell nucleus and degraded. 
         FIG. 2  shows representative images of primary microRNA (pri-miRNA) and images of RNA bands visualized on Urea polyacrylamide gel electrophoresis (Urea PAGE) gels and verification of the single cut product by NGS (Next Generation Sequencing).  FIG. 2A  shows 11 images of exemplary primary microRNA (pri-miRNA) pri-mir-92a-1, pri-mir-216a, pri-mir-217, pri-mir-654, pri-mir-200b, pri-let-7e, pri-mir-100, pri-mir-29a, pri-mir-367, pri-mir-181a-1 and pri-mir-19b-1. The sequences of the exemplary primary microRNA (pri-miRNA) are shown in each image, wherein the sequence of the resulting double cut precursor microRNA (pre-miRNA) region is shown in capital letters. The black arrowheads indicate the cleavage sites that would result in the double cut precursor microRNA (pre-miRNA). The white arrowheads indicate the cleavage site that would result in the 5′ single cut product (single cut precursor microRNA (pre-miRNA)).  FIG. 2B  shows 5 images of RNA bands visualized on Urea polyacrylamide gel electrophoresis (Urea PAGE) gels of pri-miRNA processing assays of pri-mir-92a-1, pri-mir-216a, pri-mir-217, pri-mir-654, pri-mir-200b by wild type (WT) Microprocessor, or TN1 mutant Microprocessor that cleaves pri-miRNA only at its 5′ strand. The band representing single cut products (single cut precursor microRNA (pre-miRNA)) align to the white arrowhead. The bands representing double cut products (double cut precursor microRNA (pre-miRNA)) align to the black arrowhead named F2. F1 represents the fragment from 5′ end to 5′ cleavage site; F2 represents the fragment between 5′ and 3′ cleavage sites, which is the (double cut precursor microRNA (pre-miRNA)); and F3 represents the fragment from 3′ cleavage site to 3′ end.  FIG. 2C  shows 1 image of RNA bands visualized on Urea polyacrylamide gel electrophoresis (Urea PAGE) gels of pri-miRNA processing assays of pri-let-7e, pri-mir-100, pri-mir-654, pri-mir-204, pri-mir-29a, pri-mir-367, pri-mir-181a-1 and pri-mir-19b-1 by Microprocessor (WT).  FIG. 2C  (lower panel) shows the single cut products (single cut precursor microRNA (pre-miRNA)) (indicated by white arrow heads in  FIG. 2C  upper panel) were cut from the gel and cloned, after which next-generation sequencing (NGS) reads were aligned with pri-miRNA sequences. The single-cut products (single cut precursor microRNA (pre-miRNA)) were selected and visualized by IGV software. Thus,  FIG. 2  illustrates that Microprocessor exhibit single cut activity on investigated pri-miRNAs. 
         FIG. 3  shows representative images of primary microRNA (pri-miRNA) of pri-mir-92a-1 and its variants with the different AIL sizes and images of RNA bands visualized on Urea polyacrylamide gel electrophoresis (Urea PAGE) gels.  FIG. 3A  shows 6 images of primary microRNA (pri-miRNA) pri-mir-92a-1, including wild-type AIL3/6, and the mutated variants AIL3/8, AIL3/9, AIL3/3, AIL2/2 and AIL1/l. The sequence of each primary microRNA (pri-miRNA) is shown in each image, wherein the underlined nucleotides are exemplary mutation in the variants by insertion or substitution. Each dash represents the space created by one extra nucleotide on the opposing strand. The sequence of the resulting double cut precursor microRNA (pre-miRNA) region is shown in capital letters. The black arrowheads indicate the cleavage sites that would result in the double cut precursor microRNA (pre-miRNA). The white arrowheads indicate the cleavage site that would result in the 5′ single cut product (single cut precursor microRNA (pre-miRNA)).  FIG. 3B  shows 1 image of RNA bands visualized on Urea polyacrylamide gel electrophoresis (Urea PAGE) gels of pri-miRNA processing assays of the six pri-mir-92a-1 (wild-type AIL3/6, the mutated variants AIL3/8, AIL3/9, AIL3/3, AIL2/2 and AIL1/1) by wild type (WT) Microprocessor. The band representing single cut products (single cut precursor microRNA (pre-miRNA)) align to the white arrowhead. The bands representing double cut products (double cut precursor microRNA (pre-miRNA)) align to the black arrowhead named F2. F1 represents the fragment from 5′ end to 5′ cleavage site; F2 represents the fragment between 5′ and 3′ cleavage sites, which is the (double cut precursor microRNA (pre-miRNA)); and F3 represents the fragment from 3′ cleavage site to 3′ end. Thus,  FIG. 3  illustrates that larger AIL size leads to increased production of single cut products (single cut precursor microRNA (pre-miRNA)) from pri-mir-92a-1. 
         FIG. 4  shows representative images of primary microRNA (pri-miRNA) of pri-mir-133a-1, pri-mir-217, pri-mir-204, pri-mir-181a-1 and their variants with the different AIL sizes and images of RNA bands visualized on Urea polyacrylamide gel electrophoresis (Urea PAGE) gels.  FIG. 4A  shows 4 images of primary microRNA (pri-miRNA) pri-mir-133a-1, including wild-type AIL3/3, and the mutated variants AIL0/0, AIL7/3 and AIL3/7.  FIG. 4B  shows 1 image of RNA bands visualized on Urea polyacrylamide gel electrophoresis (Urea PAGE) gels of pri-miRNA processing assays of the four pri-mir-133a-1 (wild-type AIL3/3, the mutated variants AIL0/0, AIL7/3 and AIL3/7) by wild type (WT) Microprocessor.  FIG. 4C  shows 3 images of primary microRNA (pri-miRNA) pri-mir-217, including wild-type AIL3/3, and the mutated variants AIL0/0 and AIL5/3.  FIG. 4D  shows 1 image of RNA bands visualized on Urea polyacrylamide gel electrophoresis (Urea PAGE) gels of pri-miRNA processing assays of the three pri-mir-217 (wild-type AIL3/3, the mutated variants AIL0/0 and AIL5/3) by wild type (WT) Microprocessor.  FIG. 4E  shows 3 images of primary microRNA (pri-miRNA) pri-mir-204, including wild-type AIL3/3, and the mutated variants AIL1/1 and AIL3/5.  FIG. 4F  shows 1 image of RNA bands visualized on Urea polyacrylamide gel electrophoresis (Urea PAGE) gels of pri-miRNA processing assays of the three pri-mir-204 (wild-type AIL3/3, the mutated variants AIL1/1 and AIL3/5) by wild type (WT) Microprocessor.  FIG. 4G  shows 3 images of primary microRNA (pri-miRNA) pri-mir-181a-1, including wild-type AIL2/2, and the mutated variants AIL0/0 and AIL2/5.  FIG. 4H  shows 1 image of RNA bands visualized on Urea polyacrylamide gel electrophoresis (Urea PAGE) gels of pri-miRNA processing assays of the three pri-mir-181a-1 (wild-type AIL2/2, the mutated variants AIL0/O and AIL2/5) by wild type (WT) Microprocessor. In  FIGS. 4A, 4C, 4E and 4G , the sequence of each primary microRNA (pri-miRNA) shown in each image, wherein the underlined nucleotides are exemplary mutation in the variants by insertion or substitution. Each dash represents the space created by one extra nucleotide on the opposing strand. The sequence of the resulting double cut precursor microRNA (pre-miRNA) region is shown in capital letters. The black arrowheads indicate the cleavage sites that would result in the double cut precursor microRNA (pre-miRNA). The white arrowheads indicate the cleavage site that would result in the 5′ single cut products (single cut precursor microRNA (pre-miRNA)). In  FIGS. 4B, 4D, 4F and 4H , the band representing single cut products (single cut precursor microRNA (pre-miRNA)) align to the white arrowhead. The bands representing double cut products (double cut precursor microRNA (pre-miRNA)) align to the black arrowhead named F2. F1 represents the fragment from 5′ end to 5′ cleavage site; F2 represents the fragment between 5′ and 3′ cleavage sites, which is the (double cut precursor microRNA (pre-miRNA)); and F3 represents the fragment from 3′ cleavage site to 3′ end. Thus,  FIG. 4  illustrates that larger AIL size leads to increased production of single cut products (single cut precursor microRNA (pre-miRNA)) from mir-133a-1, pri-mir-217, pri-mir-204, pri-mir-181a-1. 
         FIG. 5  shows representative images of primary microRNA (pri-miRNA) of pri-mir-216a-1 and its variants with the different AIL sizes and images of RNA bands visualized on Urea polyacrylamide gel electrophoresis (Urea PAGE) gels.  FIG. 5A  shows 5 images of primary microRNA (pri-miRNA) pri-mir-216a-1, including wild-type AIL2/1, and the mutated variants AIL0/0, AIL2/2, AIL6/2 and AIL8/2. The sequence of each primary microRNA (pri-miRNA) is shown in each image, wherein the underlined nucleotides are exemplary mutation in the variants by insertion or substitution. Each dash represents the space created by one extra nucleotide on the opposing strand. The sequence of the resulting double cut precursor microRNA (pre-miRNA) region is shown in capital letters. The black arrowheads indicate the cleavage sites that would result in the double cut precursor microRNA (pre-miRNA). The white arrowheads indicate the cleavage site that would result in the 5′ single cut product (single cut precursor microRNA (pre-miRNA)).  FIG. 5B  shows 1 image of RNA bands visualized on Urea polyacrylamide gel electrophoresis (Urea PAGE) gels of pri-miRNA processing assays of the five pri-mir-216a-1 (wild type and the mutated variants AIL0/0, AIL2/2, AIL6/2 and AIL8/2) by wild type (WT) Microprocessor. The band representing single cut products (single cut precursor microRNA (pre-miRNA)) align to the white arrowhead. The bands representing double cut products (double cut precursor microRNA (pre-miRNA)) align to the black arrowhead named F2. F1 represents the fragment from 5′ end to 5′ cleavage site; F2 represents the fragment between 5′ and 3′ cleavage sites, which is the (double cut precursor microRNA (pre-miRNA)); and F3 represents the fragment from 3′ cleavage site to 3′ end. Thus,  FIG. 5  illustrates that the introduction of larger AIL leads to increased production of single cut products (single cut precursor microRNA (pre-miRNA)) from pri-mir-216a-1. 
         FIG. 6  shows a cartoon illustrating an example of the experimental setup of the method as described herein, and a column graph.  FIG. 6A  shows an experimental scheme of estimating the miRNA expression altered by AILs. The DNA sequence encoding for wild type or mutant pri-miRNA was cloned in the pcDNA3 vector. Each cloned vector was co-transfected with pcDNA3 expressing pri-mir-16-1 into HCT116 cells as described in the Method section. The RNA transcription in human cells was carried out under the CMV promoter of the pcDNA3 vector. The expression of miRNAs was quantified by real time quantitative polymerase chain reaction (RT-qPCR) and normalized against that of miR-16-1.  FIG. 6B  is a column graph that shows the expression of miRNAs was quantified by RT-qPCR and normalized against that of miR-16-1. Thus,  FIG. 6  illustrates that miRNA expression in human cells can be modulated by increasing the size of AILs. 
         FIG. 7  shows two cartoons illustrating an example of the experimental setup of the method as described herein, and a column graph.  FIG. 7A  shows an experimental scheme of modulating miRNA expression in human cell by changing AIL sizes using CRISPR-Cas9 technique. The CRISPR-Cas9 technique is employed to modify the genomic DNA sequence encoding for the AIL at the lower stem of a pri-miRNA. The single cut activity of Microprocessor resulting in single cut products is correlated with the size of the AILs, and is anti-correlated with the miRNA expression.  FIG. 7B  shows the authenticity of the pri-mir-92a-1 AIL3/9 knock-in cells. The genomic DNA region covering the knock-in site in pri-mir-92a-1 was amplified by polymerase chain reaction (PCR), and after which the PCR products were sequenced by both Sanger sequencing and next generation sequencing (NGS). Three knock-in cell lines were generated.  FIG. 7C  is a column graph that shows the expression of miR-92a-1 and 8 other miRNAs in HCT116 (parental cells) and pri-mir-92a-1 AIL3/9 knock-in cells which were quantified by RT-qPCR and normalized against that of U6. Thus,  FIG. 7  illustrates that miRNA expression can be modulated using gene editing techniques. 
     
    
    
     DETAILED DESCRIPTION 
     Human cells produce ˜2500 microRNAs (miRNAs) that are small and non-coding ribonucleic acids (RNAs) of ˜21-22 nucleotides (nt). miRNAs play important roles in gene regulation and they are involved in most essential cellular processes. The malfunction of miRNAs is associated with various human diseases. 
     During miRNA biogenesis, Microprocessor and DICER sequentially process primary miRNA transcripts (pri-miRNAs) to generate miRNAs. As used herein, the terms “primary microRNA” and “pri-miRNA” are used interchangeably and in their broadest sense refer to a small ribonucleic acids (RNAs) consisting of a chain of nucleotides in which the sugar is ribose (or variations thereof) and the bases are adenine, cytosine, guanine, and uracil. A typical pri-miRNA usually has a stem and loop structure that contains a double-stranded RNA (dsRNA) stem of about 35 base pairs (bp), an apical loop (also known as a loop region), and two basal single-stranded RNA (ssRNA) segments. The dsRNA-ssRNA junction between the stem and the apical loop, and between the stem and basal segments are called apical and basal junctions, respectively ( FIG. 1A ). Specifically, the dsRNA-ssRNA junction between the 5′ stem and the apical loop is the 5′ apical junction; the dsRNA-ssRNA junction between the 3′ stem and the apical loop is the 3′ apical junction; the dsRNA-ssRNA junction between the 5′ stem and the basal loop is the 5′ basal junction; and the dsRNA-ssRNA junction between the 3′ stem and the basal loop is the 3′ basal junction. In one example, the dsRNA-ssRNA junction pri-miRNAs are processed by Microprocessor to generate miRNA precursors (pre-miRNAs), wherein the stem of the pri-miRNAs is divided by Microprocessor cleavage sites into lower and upper stems ( FIG. 1A ). In one example, the pri-microRNA comprises the following structure: 
     
       
         
         
             
             
         
       
     
     wherein [B] to [b] is in the 5′ to 3′ directionality to form a stem loop structure, and wherein: motifs [B] and [b] each constitute a cleavage site in the stem region; motif [C] constitute a loop region. In another example, the pri-microRNA comprises the following structure: 
     
       
         
         
             
             
         
       
     
     wherein [A] to [a] is in the 5′ to 3′ directionality to form a stem loop structure, and wherein: motifs [A] and [a] constitute the asymmetric internal loop (AIL) region in the stem region; motifs [B] and [b] each constitute a cleavage site in the stem region; motif [C] constitute a loop region. In one example, the primary microRNA is selected from a group consisting of pri-mir-92a-1, pri-mir-216a, pri-mir-217, pri-mir-654, pri-mir-200b, pri-mir-133a-1, pri-mir-16a-1, pri-mir-19b, pri-mir-17 and pri-mir-20a. 
     Microprocessor refers to a complex comprising the RNase III enzyme Drosha and the double-stranded RNA-binding protein DGCR8 (DiGeorge syndrome critical region 8 gene). The Microprocessor recognizes various features of pri-miRNAs to interact and place the 3′ cleavage site and a 5′ cleavage site on the pri-miRNA. As used herein, the terms “3′ cleavage site” and “5′ cleavage site” refer to the cleavage sites of DROSHA RIIIDa and DROSHA RIHDb, wherein the cleavage sites of DROSHA RIIIDa and DROSHA RIIIDb are located approximately 11 and 13 nucleotides (nt) from the 3′ basal junction and the 5′ basal junction respectively. The 3′ cleavage site and a 5′ cleavage site on the pri-miRNA are represented by motifs [b] and [B] respectively. In the nucleus, the Microprocessor may cleave pri-miRNAs at both 3′ cleavage site and a 5′ cleavage sites to produce double cut precursor miRNAs (pre-miRNAs), which are then exported to the cytoplasm. Subsequently, cytoplasmic DICER creates double cuts on the double cut pre-miRNAs to generate miRNAs, which leads to the expression of the mature miRNAs. The Microprocessor may also cleave pri-miRNAs at the 5′ cleavage site only to produce single cut precursor miRNAs (pre-miRNAs), which are trapped in the nucleus. The single cut pre-miRNAs are then degraded, therefore no miRNA would be expressed ( FIG. 1B ). 
     Due to the complexities of the miRNA biogenesis processes, it is not a surprise that abnormal miRNA expression commonly occurs. Abnormal miRNA expression is associated with numerous human diseases, for example, cancer, viral diseases, immune-related diseases, and neurodegenerative diseases. Specific and accurate manipulation of miRNA biogenesis is essential to correct aberrant miRNA expression in such diseases. Presently, different methods are available to correct aberrant miRNA expression. For example, the use of oligonucleotides complementary to miRNA sequences, for example small interfering RNAs (siRNAs), to knockdown aberrant miRNA expressions. However, this method has proven challenging as it is difficult to control the extent of knockdown of miRNA expression. In addition, this method is time consuming and may not be effective, as repeated treatment of the oligonucleotides that are complementary to miRNA sequence, for example siRNAs, to the cells would be required to obtain an acceptable level of knockdown of miRNA expression. Another example includes the use of gene editing technology to mutate the genomic DNA region that encodes for miRNA sequences, thereby knocking out or blocking miRNA synthesis. However, this method might lead to the production of unexpected or unwanted miRNA sequences that leads to off-target gene expression. In addition, this method might also lead to complete removal of miRNA expression that would be required for normal cellular processes. Furthermore, both of the aforementioned methods cannot be used to increase miRNA expression. 
     In view of the above problems, the inventors of the present disclosure have set out to provide alternative methods to control miRNA expression and preserve normal cellular functions of miRNAs by targeting the AIL region, wherein controlling the size of the AIL region may control the single cut activity or double cut activity of the Microprocessor on primary miRNA transcripts (pri-miRNAs) to produce single cut pre-miRNAs or double cut pre-miRNAs. The alternative methods also do not cause a complete knock-out of miRNA expression like those in the conventional gene editing techniques. Instead, the alternative methods can increase or reduce miRNA expression to a different level. As the AIL region does not form part of a miRNA sequence, it does not lead to the synthesis of unexpected miRNA sequences and avoids any off-target effects, therefore the alternative methods would not affect the miRNA expression for the essential normal cellular functions in a cell. 
     As used herein, the terms “precursor microRNA” and “pre-miRNA” are used interchangeably and in their broadest sense refer to a hairpin precursor of a miRNA formed by the cleavage of a primary miRNA by the Microprocessor. The cleavage may occur at the 5′ and 3′ cleavage sites, otherwise known as a double cut activity, to produce a double cut pre-miRNA, or may occur at the 5′ cleavage site to produce a single cut pre-miRNA. As used herein, the term “double cut pre-miRNA” refers to a pre-miRNA that is cleaved at the 5′ and 3′ cleavage sites, which is then exported to the cytoplasm where it would be further cleaved by DICER and processed to form a miRNA. As used herein, the term “single cut pre-miRNA” refers to a pre-miRNA that is cleaved only at the 5′ cleavage site, which results in an incompletely cleaved pre-miRNA that would be retained in nucleus and degraded. Therefore, no miRNA would be produced from single cut pre-miRNA. 
     The pri-miRNA basal junction recognition is crucial for the Microprocessor activity. The lower stem of pri-miRNAs is usually an almost perfect dsRNA region that may only accept few mismatches or small bulges. As shown in the present disclosure, the asymmetric internal loop (AIL) at the lower stem of pri-miRNAs stimulated the single cut activity of Microprocessor which cleaves only one strand of these pri-miRNAs. Consequently, this activity reduced miRNA synthesis. Therefore, the introduction or removal of the AIL region from the lower stem of pri-miRNA could control the expression of miRNAs in human cells. In addition, modulating the size of the AIL region could also modulate miRNA expression. 
     As used herein, the terms “asymmetric internal loop”, “asymmetric internal loop region”, “AIL” and “AIL region” are used interchangeably and in their broadest sense refer to a secondary structure on the lower stem region of the pri-miRNA that resembles a bulge. As used herein, the term “bulge” refers to a protrusion or swelling from an otherwise flat surface of the pri-miRNA. Formation and size of the bulge is the result of the size of the AIL region. The size of the AIL region is dependent on the number of nucleotides on motifs [A] and [a]. In one example, the number of nucleotides on either one of motifs [A] or [a] may be 0-15. In another example, the number of nucleotides on motif [A] or [a] may be 0-9. In another example, the number of nucleotides on motif [A] or [a] may be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15. As used herein, the term “AILx/y” refers to a pri-miRNA that comprises an AIL region, wherein “x” and “y” refer to the numbers of nucleotides on the 5′ and 3′ strands of the AIL region respectively. In one example, “x” or “y” may be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15. In one example, the pri-miRNA that comprises an AIL region may be AIL0/0, AIL0/1, AIL0/2, AIL0/3, AIL0/4, AIL0/5, AIL0/6, AIL0/7, AIL0/8, AIL0/9, AIL0/10, AIL0/11, AIL0/12, AIL0/12, AIL0/13, AIL0/14, AIL0/15, AIL1/0, AIL1/1, AIL1/2, AIL1/3, AIL1/4, AIL1/5, AIL1/6, AIL1/7, AIL1/8, AIL1/9, AIL1/10, AIL1/11, AIL1/12, AIL1/12, AIL1/13, AIL1/14, AIL1/15, AIL2/0, AIL2/1, AIL2/2, AIL2/3, AIL2/4, AIL2/5, AIL2/6, AIL2/7, AIL2/8, AIL2/9, AIL2/10, AIL2/11, AIL2/12, AIL2/12, AIL2/13, AIL2/14, AIL2/15, AIL3/0, AIL3/1, AIL3/2, AIL3/3, AIL3/4, AIL3/5, AIL3/6, AIL3/7, AIL3/8, AIL3/9, AIL3/10, AIL3/11, AIL3/12, AIL3/12, AIL3/13, AIL3/14, AIL3/15, AIL4/0, AIL4/1, AIL4/2, AIL4/3, AIL4/4, AIL4/5, AIL4/6, AIL4/7, AIL4/8, AIL4/9, AIL4/10, AIL4/11, AIL4/12, AIL4/12, AIL4/13, AIL4/14, AIL4/15, AIL5/0, AIL5/1, AIL5/2, AIL5/3, AIL5/4, AIL5/5, AIL5/6, AIL5/7, AIL5/8, AIL5/9, AIL5/10, AIL5/11, AIL5/12, AIL5/12, AIL5/13, AIL5/14, AIL5/15, AIL6/0, AIL6/1, AIL6/2, AIL6/3, AIL6/4, AIL6/5, AIL6/6, AIL6/7, AIL6/8, AIL6/9, AIL6/10, AIL6/11, AIL6/12, AIL6/12, AIL6/13, AIL6/14, AIL6/15, AIL7/0, AIL7/1, AIL7/2, AIL7/3, AIL7/4, AIL7/5, AIL7/6, AIL7/7, AIL7/8, AIL7/9, AIL7/10, AIL7/I1, AIL7/12, AIL7/12, AIL7/13, AIL7/14, AIL7/15, AIL8/0, AIL8/1, AIL8/2, AIL8/3, AIL8/4, AIL8/5, AIL8/6, AIL8/7, AIL8/8, AIL8/9, AIL8/10, AIL8/11, AIL8/12, AIL8/12, AIL8/13, AIL8/14, AIL8/15, AIL9/0, AIL9/1, AIL9/2, AIL9/3, AIL9/4, AIL9/5, AIL9/6, AIL9/7, AIL9/8, AIL9/9, AIL9/10, AIL9/11, AIL9/12, AIL9/12, AIL9/13, AIL9/14, AIL9/15, AIL10/0, AIL10/1, AIL10/2, AIL10/3, AIL1/4, AIL10/5, AIL1/6, AIL10/7, AIL1/8, AIL10/9, AIL10/10, AIL10/11, AIL10/12, AIL10/12, AIL10/13, AIL10/14, AIL10/15, AIL11/0, AIL11/1, AIL11/2, AIL11/3, AIL11/4, AIL11/5, AIL11/6, AIL11/7, AIL11/8, AIL11/9, AIL11/10, AIL11/11, AIL11/12, AIL11/12, AIL11/13, AIL11/14, AIL11/15, AIL12/0, AIL12/1, AIL12/2, AIL12/3, AIL12/4, AIL12/5, AIL12/6, AIL12/7, AIL12/8, AIL12/9, AIL12/10, AIL12/11, AIL12/12, AIL12/12, AIL12/13, AIL12/14, AIL12/15, AIL13/0, AIL13/1, AIL13/2, AIL13/3, AIL13/4, AIL13/5, AIL13/6, AIL13/7, AIL13/8, AIL13/9, AIL13/10, AIL13/11, AIL13/12, AIL13/12, AIL13/13, AIL13/14, AIL13/15, AIL14/0, AIL14/1, AIL14/2, AIL14/3, AIL14/4, AIL14/5, AIL14/6, AIL14/7, AIL14/8, AIL14/9, AIL14/10, AIL14/11, AIL14/12, AIL14/12, AIL14/13, AIL14/14, AIL14/15, AIL15/0, AIL15/1, AIL15/2, AIL15/3, AIL15/4, AIL15/5, AIL15/6, AIL15/7, AIL15/8, AIL15/9, AIL15/10, AIL15/11, AIL15/12, AIL15/12, AIL15/13, AIL15/14 or AIL15/15. The number of nucleotides on motif [A] or [a] in AIL region may be identical or different. 
     An AIL region may be located upstream or downstream of a cleavage site of the pri-miRNA. In one example, motif [A] may be upstream of motif [B]. In one example, motif [a] may be downstream of motif [b]. In one example, motif [A] may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15 nucleotides upstream of motif [B]. In another example, motif [A] is 3-8 nucleotides upstream of motif [B]. In another example, motif [a] may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15 nucleotides downstream of motif [b]. In another example, motif [a] is 3-8 nucleotides downstream of motif [b]. 
     An AIL may be formed due to mismatched base pairing of nucleotides in the AIL region, or when there is a different number of nucleotides on motifs [A] and [a] in the AIL region. In one example, mismatched pairing of nucleotides in the ALL region may be formed when at least 1 nucleotide on motif [A] is not complementary to at least 1 nucleotide on motif [a]. It is generally known that when one nucleotide on motif [A] is not complementary to one nucleotide on motif [a], it is the same as when one nucleotide on motif [a] is not complementary to one nucleotide on motif [A]. Complementary pairing of nucleotides on a double stranded RNA occurs when a uracil (U) on one RNA strand binds to a arginine (A) on the other RNA strand; or when a cytosine (C) or uracil (U) on one RNA strand binds to a guanine (G) on the other RNA strand. Therefore, mismatched pairings occur when uracil (U) on one RNA strand binds to cytosine (C) on the other RNA strand. Mismatched pairings also occur when adenine (A) on one RNA strand binds to cytosine (C) or guanine (G) on the other RNA strand. In another example, mismatched pairing of nucleotides in the AIL region may be formed when 1-15 nucleotides on motif [A] are not complementary to the nucleotide on motif [a]. In another example, mismatched pairing of nucleotides in the AIL region may be formed when 1-9 nucleotides on motif [A] are not complementary to the nucleotide on motif [a]. In another example, mismatched pairing of nucleotides in the AIL region may be formed when 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 nucleotides on motif [A] are not complementary to the nucleotide on motif [a]. 
     As mentioned above, a different number of nucleotides on motifs [A] and [a] also give rise to an AIL region. In one example, the difference in the number of nucleotides between motifs [A] and [a] may be 1-15. In another example, the difference in the number of nucleotides between motifs [A] and [a] may be 1-9. In another example, the difference in the number of nucleotides between motifs [A] and [a] may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15. In a preferred example, the difference in the number of nucleotides between motifs [A] and [a] is 6. 
     The inventors of the present disclosure have found a method of producing single cut precursor microRNA (pre-miRNA) in a host cell from a primary microRNA (pri-miRNA) as disclosed herein. Increasing the size of the AIL region increases the single cut activity of the Microprocessor, which leads to the production of single cut pre-miRNA. In one example, the method comprises: a) introducing one or more mutations in a region upstream of motif [B] and/or downstream of motif [b] to produce a genetically modified primary microRNA (pri-miRNA) comprising the following structure: 
     
       
         
         
             
             
         
       
     
     wherein motifs [A] and [a] constitute the asymmetric internal loop (AIL) region in the stem region; b) transfecting the genetically modified primary microRNA (pri-miRNA) from step b) to the host cell; wherein the single cut precursor microRNA (pre-miRNA) is produced from cleaving at motif [B]. In another example, the method comprises: a) introducing one or more mutations at one or both of motifs [A] and [a] to modulate the size of the asymmetric internal loop (AIL) region; b) transfecting the primary microRNA (pri-miRNA) from step b) to the host cell; wherein the single cut precursor microRNA (pre-miRNA) is produced from cleaving at motif [B]. In another example, the method of producing single cut precursor microRNA (pre-miRNA) in a host cell from a primary microRNA (pri-miRNA) comprising the following structure: 
     
       
         
         
             
             
         
       
     
     wherein [B] to [b] is in the 5′ to 3′ directionality to form a stem loop structure, and wherein: motifs [B] and [b] each constitute a cleavage site in the stem region; motif [C] constitute a loop region; the method comprising: a) introducing one or more mutations in a region upstream of motif [B] and/or downstream of motif [b] to produce a genetically modified primary microRNA (pri-miRNA) comprising the following structure: 
     
       
         
         
             
             
         
       
     
     wherein motifs [A] and [a] constitute the asymmetric internal loop (AIL) region in the stem region; b) transfecting the genetically modified primary microRNA (pri-miRNA) from step b) to the host cell; wherein the single cut precursor microRNA (pre-miRNA) is produced from cleaving at motif [B]. In another example, the method of producing single cut precursor microRNA (pre-miRNA) in a host cell from a primary microRNA (pri-miRNA) comprising the following structure: 
     
       
         
         
             
             
         
       
     
     wherein [A] to [a] is in the 5′ to 3′ directionality to form a stem loop structure, and wherein: motifs [A] and [a] constitute the asymmetric internal loop (AIL) region in the stem region; motifs [B] and [b] each constitute a cleavage site in the stem region; motif [C] constitute a loop region; the method comprising: a) introducing one or more mutations at one or both of motifs [A] and [a] to modulate the size of the asymmetric internal loop (AIL) region; b) transfecting the primary microRNA (pri-miRNA) from step b) to the host cell; wherein the single cut precursor microRNA (pre-miRNA) is produced from cleaving at motif [B]. 
     Controlling the size of the AIL region may also control the single cut activity and the double cut activity of the Microprocessor on primary miRNA transcripts (pri-miRNAs). This modulates the production of single cut precursor miRNAs (pre-miRNAs) and/or double cut precursor miRNAs (pre-miRNAs), which controls the expression of miRNA ( FIG. 1B ). 
     The inventors of the present disclosure have found a method of increasing production levels of single cut precursor microRNA (pre-miRNA) and decreasing production levels of double cut precursor microRNA (pre-miRNA) in a host cell from a primary microRNA (pri-miRNA) as disclosed herein. In one example, the method comprises: a) introducing one or more mutations in a region upstream of motif [B] and/or downstream of motif [b] to produce a genetically modified primary microRNA (pri-miRNA) comprising the following structure: 
     
       
         
         
             
             
         
       
     
     wherein motifs [A] and [a] constitute the asymmetric internal loop (AIL) region in the stem region; b) transfecting the genetically modified primary microRNA (pri-miRNA) from step b) to the host cell; c) producing one or both single cut precursor microRNA (pre-miRNA) and double cut precursor microRNA (pre-miRNA) by controlling cleaving at one or both motifs [B] and [b]; wherein the single cut precursor microRNA (pre-miRNA) is produced from cleaving at motif [B]; wherein the double cut precursor microRNA (pre-miRNA) is produced from cleaving at motifs [B] and [b]. In another example, the method comprises: a) introducing one or more mutations at one or both of motifs [A] and [a] to modulate the size of the asymmetric internal loop (AIL) region; b) transfecting the primary microRNA (pri-miRNA) from step b) to the host cell; c) producing one or both single cut precursor microRNA (pre-miRNA) and double cut precursor microRNA (pre-miRNA) by controlling cleaving at one or both motifs [B] and [b]; wherein the single cut precursor microRNA (pre-miRNA) is produced from cleaving at motif [B]; wherein the double cut precursor microRNA (pre-miRNA) is produced from cleaving at motifs [B] and [b]. In another example, the method of increasing production levels of single cut precursor microRNA (pre-miRNA) and decreasing production levels of double cut precursor microRNA (pre-miRNA) in a host cell from a primary microRNA (pri-miRNA) comprising the following structure: 
     
       
         
         
             
             
         
       
     
     wherein [B] to [b] is in the 5′ to 3′ directionality to form a stem loop structure, and wherein: motifs [B] and [b] each constitute a cleavage site in the stem region; motif [C] constitute a loop region; the method comprising: a) introducing one or more mutations in a region upstream of motif [B] and/or downstream of motif [b] to produce a genetically modified primary microRNA (pri-miRNA) comprising the following structure: 
     
       
         
         
             
             
         
       
     
     wherein motifs [A] and [a] constitute the asymmetric internal loop (AIL) region in the stem region; b) transfecting the genetically modified primary microRNA (pri-miRNA) from step b) to the host cell; c) producing one or both single cut precursor microRNA (pre-miRNA) and double cut precursor microRNA (pre-miRNA) by controlling cleaving at one or both motifs [B] and [b]; wherein the single cut precursor microRNA (pre-miRNA) is produced from cleaving at motif [B]; wherein the double cut precursor microRNA (pre-miRNA) is produced from cleaving at motifs [B] and [b]. In another example, the method of increasing production levels of single cut precursor microRNA (pre-miRNA) and decreasing production of double cut precursor microRNA (pre-miRNA) in a host cell from a primary microRNA (pri-miRNA) comprising the following structure: 
     
       
         
         
             
             
         
       
     
     wherein [A] to [a] is in the 5′ to 3′ directionality to form a stem loop structure, and wherein: motifs [A] and [a] constitute the asymmetric internal loop (AIL) region in the stem region; motifs [B] and [b] each constitute a cleavage site in the stem region; motif [C] constitute a loop region; the method comprising: a) introducing one or more mutations at one or both of motifs [A] and [a] to modulate the size of the asymmetric internal loop (AIL) region; b) transfecting the primary microRNA (pri-miRNA) from step b) to the host cell; c) producing one or both single cut precursor microRNA (pre-miRNA) and double cut precursor microRNA (pre-miRNA) by controlling cleaving at one or both motifs [B] and [b]; wherein the single cut precursor microRNA (pre-miRNA) is produced from cleaving at motif [B]; wherein the double cut precursor microRNA (pre-miRNA) is produced from cleaving at motifs [B] and [b]. 
     The AIL region in the pri-miRNA may be naturally occurring, or may be genetically inserted by introducing one or more mutations to result in a genetically modified pri-miRNA. As used herein, the term “genetically modified pri-miRNA” refers to a pri-miRNA as described herein that has modifications made to the AIL region by gene editing techniques. The inventors of the present disclosure have also found a genetically modified primary microRNA (pri-miRNA) comprising the following structure: 
     
       
         
         
             
             
         
       
     
     wherein [A] to [a] is in the 5′ to 3′ directionality to form a stem loop structure, and wherein: motifs [A] and [a] constitute an asymmetric internal loop (AIL) region in the stem region; motifs [B] and [b] each constitute a cleavage site in the stem region; motif [C] constitute a loop region; wherein one or both motifs [A] and [a] comprise 0-9 nucleotides; wherein motif [A] comprises at least 1 nucleotide that does not match to any nucleotide in motif [a]; or wherein motif [a] comprises at least 1 nucleotide that does not match to any nucleotide in motif [A]. In one example, the genetically modified primary microRNA (pri-miRNA) comprises the structure of the pri-miRNA as disclosed herein. In another example, the genetically modified primary microRNA (pri-miRNA) has motif [a] comprising 1-15 nucleotides, 1-14 nucleotides, 1-13 nucleotides, 1-12 nucleotides, 1-11 nucleotides, 1-10 nucleotides, 1-9 nucleotides, 1-8 nucleotides, 1-7 nucleotides, 1-6 nucleotides, 1-5 nucleotides, 1-4 nucleotides, 1-3 nucleotides, or 1-2 nucleotides more than motif [A] to create a larger bulge on motif [a]. In a preferred example, the genetically modified primary microRNA (pri-miRNA) has motif [a] comprising 1-9 nucleotides more than motif [A] to create a larger bulge on motif [a]. In another example, the genetically modified primary microRNA (pri-miRNA) has motif [A] comprising 1-15 nucleotides, 1-14 nucleotides, 1-13 nucleotides, 1-12 nucleotides, 1-11 nucleotides, 1-10 nucleotides, 1-9 nucleotides, 1-8 nucleotides, 1-7 nucleotides, 1-6 nucleotides, 1-5 nucleotides, 1-4 nucleotides, 1-3 nucleotides, or 1-2 nucleotides more than motif [a] to create a larger bulge on motif [A]. In a preferred example, the genetically modified primary microRNA (pri-miRNA) has motif [A] comprising at least 1-9 nucleotides more than motif [a] to create a larger bulge on motif [A]. In another example, the genetically modified primary microRNA (pri-miRNA) has motif [A] comprising 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 nucleotides more than motif [a] to create a larger bulge on motif [A]. In another example, the genetically modified primary microRNA (pri-miRNA) has motif [a] comprising 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 nucleotides more than motif [A] to create a larger bulge on motif [a]. In a preferred example, the genetically modified primary microRNA (pri-miRNA) has motif [a] comprising 6 nucleotides more than motif [A] to create a larger bulge on motif [a]. In another example, the genetically modified primary microRNA (pri-miRNA) comprises SEQ ID NO: 1. In another example, the genetically modified primary microRNA (pri-miRNA) can be produced by any one of the methods as disclosed herein. 
     The method of the present invention uses the gene editing techniques to modulate the size of asymmetric internal loop (AIL) at the lower stem region of pri-miRNA. The gene editing techniques comprises those that are commonly used, for example, mutagenesis, cloning, CRISPR-Cas9, Cre-Lox technique, and Transcription activator-like effector nucleases (TALEN). Such gene editing techniques may also be employed to modulate the size of the AIL region. In one example, the size of the AIL region may be increased or decreased by introducing one or more mutations. 
     As used herein, the term “mutation” refers to a natural or artificial modification, or genetic alteration of the genome or part of a pri-miRNA sequence of any biological organism, virus or extra-chromosomal genetic element. This mutation can be induced artificially using, but not limited to, chemicals and radiation, but can also occur spontaneously during nucleic acid replication in cell division. Mutations may or may not produce discernible changes in the observable characteristics (phenotype) of an organism. There are various types of mutations known, which can either be small-scale mutations or large-scale mutations. Examples of small-scale mutations are, but are not limited to, substitution mutations, silent mutations, missense mutations, nonsense mutations, insertions, and deletions. Examples of large-scale mutations are, but are not limited to, amplifications, deletions, chromosomal translocations, interstitial deletions, chromosomal inversions and mutations that result in a loss of heterozygosity. Mutations can also be grouped by their effect on the function of the resulting product. These include, but are not limited to, loss-of-function (inactivating) mutations, gain-of-function (activating) mutations, dominant-negative (antimorphic) mutations, lethal mutations and back or reverse mutations. Insertion, for example, is a mutation wherein one or more nucleotides are inserted into a new region along the sequence. Substitution, for example, is a mutation that exchanges one nucleotide base for another (for example, switching an A to a G). Deletion, for example, is a mutation wherein one or more nucleotides are removed from the sequence. 
     The one or more mutations can increase the size of the AIL region. In one example, the one or more mutations comprises insertion and/or substitution of at least one nucleotide to increase the size of one or both motifs [A] and [a]. Insertion of at least one nucleotide to motif [A] and/or [a] may either increase the bulge of the AIL region, or result in a different number of nucleotides on motifs [A] and [a]. Substitution of at least one nucleotide in motif [A] and/or [a] can create mismatched base pairing of nucleotides in the AIL region. In another example, the one or more mutations comprises insertion and/or substitution of at least 2 nucleotides, at least 3 nucleotides, at least 4 nucleotides, at least 5 nucleotides, at least 6 nucleotides, at least 7 nucleotides, at least 8 nucleotides or at least 9 nucleotides to increase the size of one or both motifs [A] and [a]. In another example, the one or more mutations comprises insertion of 1 to 15 nucleotides, 1 to 14 nucleotides, 1 to 13 nucleotides, 1 to 12 nucleotides, 1 to 11 nucleotides, 1 to 10 nucleotides, 1 to 9 nucleotides, 1 to 8 nucleotides, 1 to 7 nucleotides, 1 to 6 nucleotides, 1 to 5 nucleotides, 1 to 4 nucleotides, 1 to 3 nucleotides, or 1 to 2 nucleotides in one or both motifs [A] and [a] to increase the size of one or both motifs [A] and [a]. In a preferred example, the one or more mutations comprises insertion of 1-9 nucleotides in one or both motifs [A] and [a] to increase the size of one or both motifs [A] and [a]. In another example, the one or more mutations comprises insertion of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 nucleotides in one or both motifs [A] and [a] to increase the size of one or both motifs [A] and [a]. In a preferred example, the one or more mutations comprise insertion of 1 to 9 nucleotides in motif [A] to increase the size of motif [A]. In another preferred example, the one or more mutations comprise insertion of 1 to 9 nucleotides in motif [a] to increase the size of motif [a]. In another example, the one or more mutations comprise substitution of at least one nucleotide in one or both motifs [A] and [a] to produce at least one mismatched pair in the asymmetric internal loop (AIL) region to increase the size of one or both motifs [A] and [a]. In one example, the one or more mutations comprises substitution of at least 2 nucleotides, at least 3 nucleotides, at least 4 nucleotides, at least 5 nucleotides, at least 6 nucleotides, at least 7 nucleotides, at least 8 nucleotides or at least 9 nucleotides to increase the size of one or both motifs [A] and [a]. In another example, the one or more mutations comprises substitution of 1 to 15 nucleotides, 1 to 14 nucleotides, 1 to 13 nucleotides, 1 to 12 nucleotides, 1 to 11 nucleotides, 1 to 10 nucleotides, 1 to 9 nucleotides, 1 to 8 nucleotides, 1 to 7 nucleotides, 1 to 6 nucleotides, 1 to 5 nucleotides, 1 to 4 nucleotides, 1 to 3 nucleotides, or 1 to 2 nucleotides in one or both motifs [A] and [a] to increase the size of one or both motifs [A] and [a]. In a preferred example, the one or more mutations comprise substitution of 1-9 nucleotides in motif [A] to increase the size of one or both motifs [A] and [a]. In another preferred example, the one or more mutations comprise substitution of 1-9 nucleotides in motif [a] to increase the size of one or both motifs [A] and [a]. In another example, the one or more mutations comprises substitution of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 nucleotides in one or both motifs [A] and [a] to increase the size of one or both motifs [A] and [a]. 
     The inventors of the present disclosure have also found a method of decreasing production levels of single cut precursor microRNA (pre-miRNA) and increasing production of double cut precursor microRNA (pre-miRNA) in a host cell from a primary microRNA (pri-miRNA) as disclosed herein. In one example, the method comprises: a) introducing one or more mutations at one or both of motifs [A] and [a] to modulate the size of the asymmetric internal loop (AIL) region; b) transfecting the primary microRNA (pri-miRNA) from step b) to the host cell; c) producing one or both single cut precursor microRNA (pre-miRNA) and double cut precursor microRNA (pre-miRNA) by controlling cleaving at one or both motifs [B] and [b]; wherein the single cut precursor microRNA (pre-miRNA) is produced from cleaving at motif [B]; wherein the double cut precursor microRNA (pre-miRNA) is produced from cleaving at motifs [B] and [b]. In another example, the method of decreasing production levels of single cut precursor microRNA (pre-miRNA) and increasing production of double cut precursor microRNA (pre-miRNA) in a host cell from a primary microRNA (pri-miRNA) comprising the following structure: 
     
       
         
         
             
             
         
       
     
     wherein [A] to [a] is in the 5′ to 3′ directionality to form a stem loop structure, and wherein: motifs [A] and [a] constitute the asymmetric internal loop (AIL) region in the stem region; motifs [B] and [b] each constitute a cleavage site in the stem region; motif [C] constitute a loop region; the method comprising: a) introducing one or more mutations at one or both of motifs [A] and [a] to modulate the size of the asymmetric internal loop (AIL) region; b) transfecting the primary microRNA (pri-miRNA) from step b) to the host cell; c) producing one or both single cut precursor microRNA (pre-miRNA) and double cut precursor microRNA (pre-miRNA) by controlling cleaving at one or both motifs [B] and [b]; wherein the single cut precursor microRNA (pre-miRNA) is produced from cleaving at motif [B]; wherein the double cut precursor microRNA (pre-miRNA) is produced from cleaving at motifs [B] and [b]. 
     The one or more mutations can decrease the size of the AIL region. In one example, the one or more mutations comprises deletion and/or substitution of at least one nucleotide to decrease the size of one or both motifs [A] and [a]. Deletion of at least one nucleotide to motif [A] and/or [a] may remove any extra nucleotides to result in a decreased number of nucleotides on motifs [A] and [a], thereby decreasing the bulge of the AIL region, or even eliminating the AIL region entirely. Substitution of at least one nucleotide in motif [A] and/or [a] can correct and remove any mismatched base pairing of nucleotides in the AIL region. In another example, the one or more mutations comprises deletion and/or substitution of at least 2 nucleotides, at least 3 nucleotides, at least 4 nucleotides, at least 5 nucleotides, at least 6 nucleotides, at least 7 nucleotides, at least 8 nucleotides or at least 9 nucleotides to decrease the size of one or both motifs [A] and [a]. In another example, the one or more mutations comprises deletion of 1 to 15 nucleotides, 1 to 14 nucleotides, 1 to 13 nucleotides, 1 to 12 nucleotides, 1 to 11 nucleotides, 1 to 10 nucleotides, 1 to 9 nucleotides, 1 to 8 nucleotides, 1 to 7 nucleotides, 1 to 6 nucleotides, 1 to 5 nucleotides, 1 to 4 nucleotides, 1 to 3 nucleotides, or 1 to 2 nucleotides in one or both motifs [A] and [a] to decrease the size of one or both motifs [A] and [a]. In a preferred example, the one or more mutations comprises deletion of 1-9 nucleotides in one or both motifs [A] and [a] to decrease the size of one or both motifs [A] and [a]. In another example, the one or more mutations comprises deletion of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 nucleotides in one or both motifs [A] and [a] to decrease the size of one or both motifs [A] and [a]. In a preferred example, the one or more mutations comprise deletion of 1 to 9 nucleotides in motif [A] to decrease the size of motif [A]. In another preferred example, the one or more mutations comprise deletion of 1 to 9 nucleotides in motif [a] to decrease the size of motif [a]. In another example, the one or more mutations comprise substitution of at least one nucleotide in one or both motifs [A] and [a] to produce at least one matched pair in the asymmetric internal loop (AIL) region to decrease the size of one or both motifs [A] and [a]. In one example, the one or more mutations comprises substitution of at least 2 nucleotides, at least 3 nucleotides, at least 4 nucleotides, at least 5 nucleotides, at least 6 nucleotides, at least 7 nucleotides, at least 8 nucleotides or at least 9 nucleotides to decrease the size of one or both motifs [A] and [a]. In another example, the one or more mutations comprises substitution of 1 to 15 nucleotides, 1 to 14 nucleotides, 1 to 13 nucleotides, 1 to 12 nucleotides, 1 to 11 nucleotides, 1 to 10 nucleotides, 1 to 9 nucleotides, 1 to 8 nucleotides, 1 to 7 nucleotides, 1 to 6 nucleotides, 1 to 5 nucleotides, 1 to 4 nucleotides, 1 to 3 nucleotides, or 1 to 2 nucleotides in one or both motifs [A] and [a] to decrease the size of one or both motifs [A] and [a]. In a preferred example, the one or more mutations comprise substitution of 1-9 nucleotides in motif [A] to decrease the size of one or both motifs [A] and [a]. In another preferred example, the one or more mutations comprise substitution of 1-9 nucleotides in motif [a] to decrease the size of one or both motifs [A] and [a]. In another example, the one or more mutations comprises substitution of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 nucleotides in one or both motifs [A] and [a] to decrease the size of one or both motifs [A] and [a]. 
     The inventors of the present disclosure have found a method of modulating expression levels of microRNA (miRNA) in a host cell comprising modulating expression levels of one or both of single cut precursor microRNA (pre-miRNA) and double cut precursor microRNA (pre-miRNA) using the methods as described herein. As used herein, the term “host cell” refers to a cell derived from an animal including, but not limited to, a mammal or a bird. “Mammal” includes humans and both domestic animals such as laboratory animals and household pets, (e.g. cats, dogs, swine, cattle, sheep, goats, horses, rabbits), and non-domestic animals such as wildlife, fowl, birds and the like. In one example, the host cell is a cell from a cell line that is derived from an animal. In one example, the host cell is a human cell. In one example, increasing the expression levels of single cut precursor microRNA (pre-miRNA) decreases the expression levels of microRNA (miRNA) in a host cell. In another example, increasing the expression levels of double cut precursor microRNA (pre-miRNA) increases the expression levels of microRNA (miRNA) in a host cell. 
     The inventors of the present disclosure have also found a method of modulating expression levels of microRNA (miRNA) in a subject comprising modulating expression levels of one or both of single cut precursor microRNA (pre-miRNA) and double cut precursor microRNA (pre-miRNA) using the methods as described herein. In one example, the method further comprises a step of detecting the absence or presence of a microRNA (miRNA) of a sample obtained from the subject. As used herein, the term “subject” refers to an animal, preferably a mammal or a bird. “Mammal” includes humans and both domestic animals such as laboratory animals and household pets, (e.g. cats, dogs, swine, cattle, sheep, goats, horses, rabbits), and non-domestic animals such as wildlife, fowl, birds and the like. In a preferred example, the mammal is a human. As used herein, the term “sample” refers to a specimen taken, obtained or derived from an organism. The sample can be obtained or derived from an animal. 
     The methods as disclosed herein can be used on its own, or in combination with other methods. In one example, the methods as disclosed herein can be included in a method to generate a stable cell line, wherein the expression levels of miRNA can be controlled to examine cellular functions of miRNAs. The methods as disclosed herein can be used in vitro, in vivo or ex vivo. 
     As the methods as disclosed herein only targets the lower stem region of pri-miRNA that does not make up the miRNA sequences, the methods would not interfere with miRNA sequences. This prevents the production of abnormal or unwanted miRNA sequences, which might lead to unwanted off-target gene expressions that causes aberrant functions. Therefore, the methods as disclosed herein can also be used to treat different diseases caused by aberrant miRNA expressions, without the disadvantage of unwanted off-target gene expressions. The inventors of the present disclosure have found a method of treating a disease in a subject, comprising: a) detecting the presence or absence of a mutation in a microRNA related to the disease, wherein the mutation alters or disrupts expression of microRNA; b) modulating expression levels of one or both of single cut precursor microRNA (pre-miRNA) and double cut precursor microRNA (pre-miRNA) in a host cell using the method. In one example, the disease is selected from the group consisting of cancer, viral diseases, immune-related diseases, and neurodegenerative diseases. 
     As used in this application, the singular form “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. For example, the term “a genetic marker” includes a plurality of genetic markers, including mixtures and combinations thereof. 
     As used herein, the terms “increase” and “decrease” refer to the relative alteration of a chosen trait or characteristic in a subset of a population in comparison to the same trait or characteristic as present in the whole population. An increase thus indicates a change on a positive scale, whereas a decrease indicates a change on a negative scale. The term “change”, as used herein, also refers to the difference between a chosen trait or characteristic of an isolated population subset in comparison to the same trait or characteristic in the population as a whole. However, this term is without valuation of the difference seen. 
     As used herein, the term “about” in the context of concentration of a substance, size of a substance, length of time, or other stated values means+/−5% of the stated value, or +/−4% of the stated value, or +/−3% of the stated value, or +/−2% of the stated value, or +/−1% of the stated value, or +/−0.5% of the stated value. 
     Throughout this disclosure, certain embodiments may be disclosed in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the disclosed ranges. Accordingly, the description of a range should be considered to have specifically disclosed all the possible sub-ranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range. 
     The invention illustratively described herein may suitably be practiced in the absence of any element or elements, limitation or limitations, not specifically disclosed herein. Thus, for example, the terms “comprising”, “including”, “containing”, etc. shall be read expansively and without limitation. Additionally, the terms and expressions employed herein have been used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by preferred embodiments and optional features, modification and variation of the inventions embodied therein herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention. 
     The invention has been described broadly and generically herein. Each of the narrower species and subgeneric groupings falling within the generic disclosure also form part of the invention. This includes the generic description of the invention with a proviso or negative limitation removing any subject matter from the genus, regardless of whether or not the excised material is specifically recited herein. 
     Other embodiments are within the following claims and non-limiting examples. In addition, where features or aspects of the invention are described in terms of Markush groups, those skilled in the art will recognize that the invention is also thereby described in terms of any individual member or subgroup of members of the Markush group. 
     EXPERIMENTAL SECTION 
     Material and Methods 
     Preparation of the Substrates 
     The pri-miRNAs were synthesized by in vitro transcription (IVT) in 20 μl reaction mixture containing 200 ng of double-stranded DNA templates using MEGAscript T7 Kit (Invitrogen). The DNA templates were prepared by polymerase chain reaction (PCR) with the proper primers. The PCR templates are either the genomic DNAs or pri-miRNA-containing vectors. The IVT mixture was incubated at 37° C. overnight. The reaction was stopped by adding 20 μl of 2×TBE-Urea sample buffer [20 mM Tris-HCl (pH 7.5), 20 mM EDTA, 8 M Urea], heated at 75° C. for 5 min, and separated by 10% urea polyacrylamide gel electrophoresis (Urea-PAGE) gel. The RNAs were gel-eluted overnight, precipitated by Isopropanol, washed by 80% ethanol, dried, and finally dissolved in distilled water. The RNA concentration was measured by Nanodrop and the RNA quality was assessed by 10% Urea-PAGE before usage. The purified RNAs were stored at −80° C. 
     Pri-miRNA Processing Assay 
     The pri-miRNA processing assay was carried out at 37° C. in 10 μl of a buffer containing 50 mM Tris-HCl (pH 7.5), 150 mM NaCl, 10% glycerol, 0.2 μg/μl BSA, 1 mM DTT and 2 mM MgCl2. Five pmol of each pri-miRNA were incubated with 6 pmol of Microprocessor for 2 hours at 37° C. ( FIGS. 2C, 4F and 4H ). Five pmol of each pri-miRNA were incubated with 8 pmol of Microprocessor for 2 hours at 37° C. ( FIGS. 2B, 3B, 4B, 4D and 5B ). The reaction was stopped by adding 10 μl of 2×TBE-Urea sample buffer, and immediately chilled on ice. The stopped reaction mixture was treated with 20 μg of Proteinase K for 15 min at 37° C. followed by 15 min at 50° C. Finally, the reaction mixture was heated at 95° C. for 10 min and quickly chilled on ice before loading onto a pre-run 12% Urea-PAGE in 1×TBE buffer. Gel running condition was at 300 V for 40 min. The gel was finally stained with SYBR™ Green II RNA Gel Stain for 5 min and captured by Bio-Rad Gel Doc XR+ system. RNA band intensities were estimated using the Image Lab 3.0 program. 
     Vector Construction, Transfection, and Quantitative Reverse Transcription PCR (RT-qPCR) 
     The DNA regions encoding for the pri-miRNA sequences were cloned in the pcDNA3 vector. The cloning detail information is presented in Table 1. The sequence of the cloned pcDNA3 vectors was confirmed by Sanger sequencing. Two micrograms of wild-type (WT) or mutant pri-miRNA vector was co-transfected with 0.5 μg of pcDNA3-pri-mir-16-1 in one well of HCT116 cells in 6-well plate using Lipofectamine 3000 transfection reagent (Thermo Scientific). The total RNAs were extracted from the transfected cells two days after transfection using miRNeasy Mini Kit (Qiagen). 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Cloning printer list 
               
            
           
           
               
               
               
               
            
               
                   
                   
                   
                 Inserted 
               
               
                 Backbone 
                 Primer 
                 Primer 
                 sequence 
               
               
                 vector 
                 name 
                 sequences 
                 name 
               
               
                   
               
               
                 pcDNA3 
                 F-miR92a 
                 CGCCTCGAGCTGTGGTAGTGAAAAGTCTGTAG 
                 Pri-mir- 
               
               
                   
                 XhoI 
                 AAAAG 
                 92a-1 WT 
               
               
                   
                   
                 (SEQ ID NO: 109) 
                 and 
               
               
                   
                   
                   
                 Pri-mir- 
               
               
                   
                   
                   
                 92a-1 
               
               
                   
                   
                   
                 AIL3/9 
               
               
                   
                 R-92a XbaI 
                 GGCTCTAGACAGTGGAAGTCGAAATCTTCAGT 
                 Pri-mir- 
               
               
                   
                 (WT, and 
                 AA 
                 92a-1 WT 
               
               
                   
                 AIL3/9) 
                 (SEQ ID NO: 110) 
                 and 
               
               
                   
                   
                   
                 Pri-mir-92a-1 
               
               
                   
                   
                   
                 AIL3/9 
               
               
                   
                 F-mir216a- 
                 AGACCCAAGCTTGGGTAACACGGATGGCTGT 
                 Pri-mir- 
               
               
                   
                 HindIII 
                 G 
                 216a WT; 
               
               
                   
                   
                 (SEQ ID NO: 111) 
                 Pri-mir- 
               
               
                   
                   
                   
                 216a 
               
               
                   
                   
                   
                 AIL6/2 
               
               
                   
                   
                   
                 and 
               
               
                   
                   
                   
                 Pri-mir- 
               
               
                   
                   
                   
                 216a 
               
               
                   
                   
                   
                 AIL8/2 
               
               
                   
                 R-mir216a- 
                 ACTAGTGGATCCTAGGAAATTGCTCTGTTTAG 
                 Pri-mir-216a WT 
               
               
                   
                 BamHI 
                 C 
                   
               
               
                   
                   
                 (SEQ ID NO: 112) 
                   
               
               
                   
                 R- 
                 ACTAGTGGATCCTAGGAAATTGCTCTGTTTTA 
                 Pri-mir-216a 
               
               
                   
                 mir216a2M 
                 GC 
                 AIL6/2 
               
               
                   
                 M-BamHI 
                 (SEQ 1D NO: 113) 
                 and 
               
               
                   
                 (AIL6/2 
                   
                 Pri-mir-216a 
               
               
                   
                 and 
                   
                 AIL8/2 
               
               
                   
                 AIL8/2) 
                   
                   
               
               
                   
                 F-mir217- 
                 AGACCCAAGCTTGGGATTACATAGTTTTTGAT 
                 Pri-mir- 
               
               
                   
                 HindIII 
                 GTCGC 
                 217 WT 
               
               
                   
                   
                 (SEQ ID NO: 114) 
                 and Pri- 
               
               
                   
                   
                   
                 mir-217 
               
               
                   
                   
                   
                 AIL5/3 
               
               
                   
                 R-mir217- 
                 ACTAGTGGATCCGGTGCTTGTTTAGATGCTGA 
                 Pri-mir- 
               
               
                   
                 BamHI 
                 (SEQ ID NO: 115) 
                 217 WT 
               
               
                   
                 (WT and 
                   
                 and Pri- 
               
               
                   
                 AIL5/3) 
                   
                 mir-217 
               
               
                   
                   
                   
                 AIL5/3 
               
               
                   
                 F-mir654- 
                 AGACCCAAGCTTGGGAGCCCTCCAGGGTAAG 
                 Pri-mir-654 WT 
               
               
                   
                 HindIII 
                 TGG 
                   
               
               
                   
                   
                 (SEQ ID NO: 116) 
                   
               
               
                   
                 F-mir654 
                 AGACCCAAGCTTGGGAGCCCTCCAGGGTAAA 
                 Pri-mir654 
               
               
                   
                 AIL8/3- 
                 AG 
                 AIL8/3 
               
               
                   
                 HindIII 
                 (SEQ ID NO: 117) 
                   
               
               
                   
                 R-mir654- 
                 ACTAGTGGATCCCTCAGCGAAAGGGGGCTTCT 
                 Pri-mir- 
               
               
                   
                 BamHI 
                 AAAG 
                 654 WT 
               
               
                   
                   
                 (SEQ ID NO: 118) 
                 and Pri- 
               
               
                   
                   
                   
                 mir654 
               
               
                   
                   
                   
                 AIL8/3 
               
               
                   
                 F- 
                 AGACCCAAGCTTGGGCTAGCAGCACTACAAT 
                 Pri-mir- 
               
               
                   
                 mir133a1- 
                 GC 
                 133a-1 
               
               
                   
                 HindIII 
                 (SEQ ID NO: 119) 
                 WT, Pri-mir-133a- 
               
               
                   
                   
                   
                 1 AIL7/3 
               
               
                   
                   
                   
                 and Pri- 
               
               
                   
                   
                   
                 mir-133a- 
               
               
                   
                   
                   
                 1 AIL3/7 
               
               
                   
                 R- 
                 ACTAGTGGATCCAGTAATCAATGCATAGCTAC 
                 Pri-mir- 
               
               
                   
                 mir133a1- 
                 AGC 
                 133a-1 
               
               
                   
                 BamHI 
                 (SEQ ID NO: 120) 
                 WT and 
               
               
                   
                 (WT and 
                   
                 Pri-mir- 
               
               
                   
                 AIL7/3) 
                   
                 133a-1 
               
               
                   
                   
                   
                 AIL7/3 
               
               
                   
                 R-mirl33a1 
                 ACTAGTGGATCCAGTAATCAATGCATAAAAA 
                 Pri-mir-133a-1 
               
               
                   
                 AIL3/7- 
                 GCTACAGC 
                 AIL3/7 
               
               
                   
                 BamHI 
                 (SEQ ID NO: 121) 
               
               
                   
               
            
           
         
       
     
     Fifty nanograms of total RNA were used in the reverse transcription (RT) step using stem-loop RT primers that were designed for each miRNA. The stem-loop RT primers were bound to miRNA and are reverse transcribed to form cDNA. cDNA was quantified by qPCR using common miRNA reverse primer and miRNA-specific forward primer. The qPCR for miRNAs was performed using iTaq Universal SYBR Green Supermix (Bio-Rad). 
     Experimental Result 
     The Single Cut Activity of the Microprocessor is Exhibited on Pri-miRNAs Containing the Asymmetric Internal Loops (AIL) at the Lower Stem 
     Primary microRNA (pri-miRNA) processing activity of the Microprocessor was examined on several pri-miRNAs containing the asymmetric internal loop (AIL) at their lower stem. It was observed that the Microprocessor showed a single cut and double cut activities on all these tested pri-miRNAs ( FIGS. 2A-C ). The single cut occurred on the 5′-strand of the stem of the pri-miRNA, resulting in the production of a single cut product. This single cut pre-miRNA is similarly produced by the mutant TN1-Microprocessor, wherein the mutation causes the enzyme to cleave only at the 5′-strand of pri-miRNAs. The TN1 mutant Microprocessor contains an E1045Q mutation wherein the catalytic glutamic acid residue at positions 1045 of DROSHA is mutated to a glutamine residue. This mutation blocks the catalysis of RNAseIII a of DROSHA, making DROSHA only can use RNAseIII b to carry out the 5′-strand cleavage. Since the Microprocessor displayed the single cut activity on pri-miRNAs that possess the asymmetric internal loops (AIL), various sizes of the AIL were generated in the lower stem of pri-mir-92a-1, and their effects on the Microprocessor were tested in the processing assays ( FIGS. 3A and 3B ). A pri-miRNA variant is labelled as “AILx/y”, in which x and y refer to the numbers of nucleotides in the AIL region on the 5′- and 3′-strands respectively. It was observed that the different AIL sizes at the lower stem showed distinct ratios of the single cut to double-cut (sc/dc) activity ( FIGS. 3A and 3B ). The introduction of a few additional nucleotides on the 3′-strand to enlarge the size of the AIL region significantly increased the single cut activity. This is exemplified by pri-mir-92a-1 variant AIL3/8 AIL3/9, wherein 2 and 3 additional uracil nucleotides were added to the AIL region on the 3′-strand of the pri-miRNA. In these examples, the sc/dc ratio was observed to be increased by about 2 and 3.75 times (AIL3/8 and AIL3/9, respectively) compared to that in AIL3/6 (WT) (Table 2)-. In contrast, the removal or decrease of the size of the AIL region significantly decreased the sc/dc ratio. This is exemplified by the pri-mir-92a-1 variant AIL3/3, wherein 3 nucleotides, in this case ugg, were deleted from the AIL region on the 3′-strand of the pri-miRNA. In these examples, the sc/dc ratio was observed to be decreased by 6.5 times (Table 2). In addition, the pri-mir-92a-1 variants containing only 1 (AIL1/1) or 2 (AIL2/2) mismatches almost lost the single cut activity ( FIGS. 3A and 3B ). pri-mir-92a-1 variant AIL1/1 is produced by deleting ugg and substituting two uracil nucleotides with two guanine nucleotides on the AIL region on the 3′-strand of the pri-miRNA. AIL2/2 is produced by deleting the nucleotides ugg, and substituting a uracil with a guanine on the AIL region on the 3′-strand of the pri-miRNA. This suggests that the large AIL at the lower stem stimulates the single cut activity of Microprocessor. 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 sc/dc ratio of pri-mir-92a-1 wildtype and variants 
               
            
           
           
               
               
               
            
               
                   
                   
                 Compared to WT 
               
            
           
           
               
               
               
               
            
               
                   
                   
                 Increased fold 
                   
               
               
                 Pri-mir-92a-1 
                 sc/dc ratio 
                 change 
                 Decreased fold change 
               
               
                   
               
               
                 AIL3/6 (WT) 
                 1.1 
                 1 
                   
               
               
                 AIL3/8 
                 2.19 
                 1.990909091 
                   
               
               
                 AIL3/9 
                 4.13 
                 3.754545455 
                   
               
               
                 AIL3/3 
                 0.17 
                   
                  6.470588235 
               
               
                 AIL2/2 
                 0.02 
                   
                 55 
               
               
                 AIL1/1 
                 0.07 
                   
                 15.71428571 
               
               
                   
               
            
           
         
       
     
     It was then examined whether the presence and the size of the AIL region would impact the Microprocessor cleavage pattern on different pri-miRNAs containing the AIL region at the lower stem, like pri-mir-92a-1. Consistent with the pri-mir-92a-1 results, it was observed that the removal of or the reduction in size of the AIL in, for example, pri-mir-133a-1 variant AIL0/0, pri-mir-217 variant AIL0/0, pri-mir-181a-1 AIL0/0 and pri-mir-204 AIL1/1 markedly reduced the single cut activity but enhanced the double-cut activity of the Microprocessor on pri-mir-133a-1, pri-mir-217, pri-mir-181a-1 and pri-mir-204 ( FIGS. 4A-4H ). In contrast, the addition of nucleotides to increase the size of the AIL region in, for example, pri-mir-133a-1 variants AIL7/3 and AIL3/7, pri-mir-217 variant AIL5/3, pri-mir-204 variant AIL3/5, and pri-mir-181a-1 variant AIL2/5 significantly increased the single cut activity but abated the double-cut activity of the Microprocessor ( FIGS. 4A-4H ). 
     The Large AIL Facilitates the Single Cut Activity of the Microprocessor on Various Pri-miRNAs 
     The effect of adding an AIL region to the lower stem of the pri-miRNAs that are resistant to the single cut activity of the Microprocessor complex was examined. pri-mir-216a was selected as an exemplary pri-miRNAs that are resistant to the single cut activity of the Microprocessor complex. pri-mir-216a has less than 3 unmatched nucleotides on each strand of the lower stem ( FIG. 5A ). The Microprocessor generated a negligible amount of the single cut product (single cut pre-miRNA) from pri-mir-216a ( FIGS. 5A and 5B ). The removal (AIL0/0) or the introduction of a mismatch (AIL2/2) altered the 5′-strand single cleavage level. For example, when compared with the WT (AIL2/1), pri-mir-216a-AIL0/0 resulted in less while pri-mir-216a-AIL2/2 led to marginally more single cleavage product (single cut pre-miRNA). In contrast, the addition of a large AIL profoundly enhanced the single cleavage products of Microprocessor, but largely diminished its double-cut products (double cut pre-miRNA) from pri-mir-216a-AIL6/2 and AIL8/2. The increase in size of the AIL region by additional nucleotides profoundly facilitated the Microprocessor&#39;s single cut activity resulting in an increase in the levels of single cut products, while largely diminished its double-cut activity on pri-mir-216a-AIL6/2 and AIL8/2 ( FIGS. 5A and 5B ) reflected by an increase in sc/dc ratio by 9.94 and 11.49 times (Table 3), respectively. Consistent with the pri-mir-92a-1 results in  FIGS. 3A and 3B , the increase in size of the AIL region in pri-mir-216a considerably increased the ratios of single cut over double-cut cleavages ( FIGS. 5A and 5B ). 
     
       
         
           
               
             
               
                 TABLE 3 
               
             
            
               
                   
               
               
                 sc/dc ratio of pri-mir-216a wildtype and variants 
               
            
           
           
               
               
               
            
               
                   
                   
                 Compared to WT 
               
            
           
           
               
               
               
               
            
               
                   
                 sc/dc 
                 Increased fold 
                 Decreased fold 
               
               
                 Pri-mir-216a 
                 ratio 
                 change 
                 change 
               
               
                   
               
               
                 AIL2/1 (WT) 
                 0.09 
                  1 
                   
               
               
                 AIL0/0 
                 0.05 
                   
                 1.8 
               
               
                 AIL2/2 
                 0.1 
                  1.11 
                   
               
               
                 AIL6/2 
                 0.895 
                  9.94 
                   
               
               
                 AIL8/2 
                 1.034 
                 11.49 
               
               
                   
               
            
           
         
       
     
     Modulate miRNA Expression in Human Cells by Changing the Size of AIL at Lower Stem of pri-miRNAs 
     The addition of an AIL region or the increase in size of the AIL region to the lower stem of pri-miRNAs does not affect the miRNA region, and can reduce double cut pre-miRNA production in vitro. Therefore, it would be possible to modulate the size of the AIL region at the lower stem of pri-miRNA so as to modulate the level of miRNA expression. pCDNA3 vectors expressing pri-miRNA with small or large AIL regions were generated. Based on the various AIL sizes that were tested on the different pri-miRNAs, AILx/y with x&lt;3 and y&lt;3 would be considered as a small AIL region; whereas AILx/y with x&gt;3 and y&gt;3 or x+y≥6 would be considered as a large AIL region. Two vectors expressing one of the pri-miRNA variants and pri-mir-16-1 were co-transfected. miRNA expression in the transfected cells was measured by real time quantitative polymerase chain reaction (RT-qPCR) as described in the Material and Methods section. The miRNA expression from the different pri-miRNA variants was normalized to the level of miR-16-1. The data in  FIG. 6  showed that the AILs significantly reduced the miRNA expression of all tested pri-miRNAs ( FIGS. 6A and 6B ). This was consistent with the in vitro processing data ( FIGS. 3B, 4B, 4D, 4F, 4H and 5B ) showing that the AIL-containing pri-miRNAs generated less pre-miRNA than the wild-type pri-miRNA. This data suggests that the addition of an AIL region or the increase in size of the AIL region would be alternative methods to knockdown miRNA expression in human cells. 
     In addition, based on the data, it was suggested that it would be possible to modulate the AIL region to manipulate the expression of a certain clustered miRNA without affecting neighboring miRNAs in the same cluster, for example, miR-92a-1 of the miR-17/92 cluster. The specificity in targeting clustered miRNA without affecting other neighboring miRNAs in the same cluster and outside of cluster is shown in  FIG. 7C . 
     Modulate miRNA Expression Using Gene Editing Technique that Targets AIL 
     After validating the effect of the AIL on the Microprocessor&#39;s single cut activity in vitro and miRNA expression in human cells using the transfection system, an experiment was designed to edit the genome region encoding for the AIL region using CRISPR-Cas9 technique ( FIG. 7A ). Single guide RNA (sgRNA) that guides Cas9 to cut the genomic site at proximity of the AIL region will be synthesized. The sgRNA will be synthesized using T7 RNA polymerases. Subsequently, the resulting Cas9-sgRNA complex will be reconstituted in vitro. Donor ssDNAs (˜150 nt) containing the mutant DNA region that adds or deletes nucleotides from the AIL region will be used. The mixture of Cas9-sgRNA and donor ssdDNA will be transfected into human cells using electroporation. After that, the single cell that contains the expected knock-in sequence in the genome will be isolated. 
     The above can be summarized as a three-step experiment: 
     Step 1: Examine the effects of pri-miRNA with AIL regions of various sizes using the pri-miRNA processing assay, and select the pri-miRNA with the appropriate size of the ALL region that produce the outcome of your choice (either to increase or decrease the single cut product).
 
Step 2: Transfect the plasmid containing pri-miRNA with the appropriate size of the ALL region to human cells, and confirm that the outcome of your choice (either to increase or decrease the single cut product) is also produced in human cells.
 
Step 3: Perform the gene-editing experiments with sgRNA and proper donor ssDNAs to generate the pri-miRNA with the appropriate size of the AIL region that were selected and confirmed from steps 1 and 2. Finally, evaluate the effect of the pri-miRNA with the appropriate size of the AIL region in the edited cells.
 
     Description of SEQ ID 
     Table 4 below details the SEQ ID NOs referenced herein and their corresponding sequences. A brief description of the sequences is also provided. F1 represents the fragment from 5′ end to 5′ cleavage site; F2 represents the fragment between 5′ and 3′ cleavage sites, which is the (double cut precursor microRNA (pre-miRNA)); and F3 represents the fragment from 3′ cleavage site to 3′ end. 
     
       
         
           
               
               
               
             
               
                   
               
               
                 SEQ ID 
                   
                   
               
               
                 NO 
                 Sequence (5′ to 3′) 
                 Description 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                 1 
                 GGGAAACUCAAACCCCUUUCUACACAGGUUGGGAUC 
                 Pri-mir-92a-1; 
               
               
                   
                 GGUUGCAAUGCUGUGUUUCUGUAUGGUAUUGCACU 
                 Pri-mir-92a-1 
               
               
                   
                 UGUCCCGGCCUGUUGAGUUUGGUGGGGAUUGUGA 
                 AIL3/6 (WT) 
               
               
                   
               
               
                 2 
                 GGGAAACUCAAACCCCUUUCUACAC 
                 Pri-mir-92a-1 
               
               
                   
                   
                 F1; Pri-mir- 
               
               
                   
                   
                 92a-1 AIL3/6 
               
               
                   
                   
                 (WT) F1; Pri- 
               
               
                   
                   
                 mir-92a-1 
               
               
                   
                   
                 AIL3/8 F1; 
               
               
                   
                   
                 Pri-mir-92a-1 
               
               
                   
                   
                 AIL3/9 F1; 
               
               
                   
                   
                 Pri-mir-92a-1 
               
               
                   
                   
                 AIL3/3 F1; 
               
               
                   
                   
                 Pri-mir-92a-1 
               
               
                   
                   
                 AIL2/2 F1; 
               
               
                   
                   
                 Pri-mir-92a-1 
               
               
                   
                   
                 AIL1/1 F1 
               
               
                   
               
               
                 3 
                 AGGUUGGGAUCGGUUGCAAUGCUGUGUUUCUGUAU 
                 Pri-mir-92a-1 
               
               
                   
                 GGUAUUGCACUUGUCCCGGCCUGU 
                 F2; Pri-mir- 
               
               
                   
                   
                 92a-1 AIL3/8 
               
               
                   
                   
                 F2; Pri-mir- 
               
               
                   
                   
                 92a-1 AIL3/9 
               
               
                   
                   
                 F2; Pri-mir- 
               
               
                   
                   
                 92a-1 AIL3/6 
               
               
                   
                   
                 (WT) F2; Pri- 
               
               
                   
                   
                 mir-92a-1 
               
               
                   
                   
                 AIL3/3 F2; 
               
               
                   
                   
                 Pri-mir-92a-1 
               
               
                   
                   
                 AIL2/2 F2; 
               
               
                   
                   
                 Pri-mir-92a-1 
               
               
                   
                   
                 AIL1/1 F2 
               
               
                   
               
               
                 4 
                 UGAGUUUGGUGGGGAUUGUGA 
                 Pri-mir-92a-1 
               
               
                   
                   
                 F3; Pri-mir- 
               
               
                   
                   
                 92a-1 AIL3/6 
               
               
                   
                   
                 (WT) F3 
               
               
                   
               
               
                 5 
                 GGGUAACAGGAUGGCUGUGAGUUGGCUUAAUCUCA 
                 Pri-mir-216a; 
               
               
                   
                 GCUGGCAACUGUGAGAUGUUCAUACAAUCCCUCACA 
                 Pri-mir-216a 
               
               
                   
                 GUGGUCUCUGGGAUUAUGCUAAACAGAGCAAUUUCC 
                 AIL2/1 (WT) 
               
               
                   
                 UA 
                   
               
               
                   
               
               
                 6 
                 GGGUAACAGGAUGGCUGUGAGUUGGCU 
                 Pri-mir-216a 
               
               
                   
                   
                 F1; Pri-mir- 
               
               
                   
                   
                 216a A IL2/1 
               
               
                   
                   
                 (WT) F1; Pri- 
               
               
                   
                   
                 mir-216a 
               
               
                   
                   
                 AIL2/2 F1 
               
               
                   
               
               
                 7 
                 UAAUCUCAGCUGGCAACUGUGAGAUGUUCAUACAAU 
                 Pri-mir-216a 
               
               
                   
                 CC CUCACAGUGGUCUCUGGGAUUAU 
                 F2; Pri-mir- 
               
               
                   
                   
                 216a AIL2/1 
               
               
                   
                   
                 (WT) F2; Pri- 
               
               
                   
                   
                 mir-216a 
               
               
                   
                   
                 AIL0/0 F2; 
               
               
                   
                   
                 Pri-mir-216a 
               
               
                   
                   
                 AIL2/2 F2; 
               
               
                   
                   
                 Pri-mir-216a 
               
               
                   
                   
                 AIL6/2 F2; 
               
               
                   
                   
                 Pri-mir-216a 
               
               
                   
                   
                 AIL8/2 F2 
               
               
                   
               
               
                 8 
                 GCUAAACAGAGCAAUUUCCUA 
                 Pri-mir-216a 
               
               
                   
                   
                 F3; Pri-mir- 
               
               
                   
                   
                 216a AIL2/1 
               
               
                   
                   
                 (WT) F3 
               
               
                   
               
               
                 9 
                 GGGAUUACAUAGUUUUUGAUGUCGCAGAUACUGCA 
                 Pri-mir-217; 
               
               
                   
                 UCAGGAACUGAUUGGAUAAGAAUCAGUCACCAUCAG 
                 Pri-mir-217 
               
               
                   
                 UUCCUAAUGCAUUGCCUUCAGCAUCUAAACAAGCAC 
                 AIL3/3 (WT) 
               
               
                   
                 C 
                   
               
               
                   
               
               
                 10 
                 GGGAUUACAUAGUUUUUGAUGUCGCAGA 
                 Pri-mir-217 
               
               
                   
                   
                 F1; Pri-mir- 
               
               
                   
                   
                 217 AIL3/3 
               
               
                   
                   
                 (WT) F1; Pri- 
               
               
                   
                   
                 mir-217 
               
               
                   
                   
                 AIL0/0 F1 
               
               
                   
               
               
                 11 
                 UACUGCAUCAGGAACUGAUUGGAUAAGAAUCAGUCA 
                 Pri-mir-217 
               
               
                   
                 CCAUCAGUUCCUAAUGCAUUGCC 
                 F2; Pri-mir- 
               
               
                   
                   
                 217 AIL3/3 
               
               
                   
                   
                 (WT) F2; Pri- 
               
               
                   
                   
                 mir-217 
               
               
                   
                   
                 AIL0/0 F2; 
               
               
                   
                   
                 Pri-mir-217 
               
               
                   
                   
                 AIL5/3 F2 
               
               
                   
               
               
                 12 
                 UUCAGCAUCUAAACAAGCACC 
                 Pri-mir-217 
               
               
                   
                   
                 F3; Pri-mir- 
               
               
                   
                   
                 217 AIL3/3 
               
               
                   
                   
                 (WT) F3; Pri- 
               
               
                   
                   
                 mir-217 
               
               
                   
                   
                 AIL5/3 F3 
               
               
                   
               
               
                 13 
                 GGGAUUACAUAGUUUUUGAUGUCGCAGAUACUGCA 
                 Pri-mir-217 
               
               
                   
                 UCAGGA 
                 unproductive 
               
               
                   
                   
                 product 1; Pri- 
               
               
                   
                   
                 mir-217 
               
               
                   
                   
                 AIL3/3 (WT) 
               
               
                   
                   
                 unproductive 
               
               
                   
                   
                 product 1; Pri- 
               
               
                   
                   
                 mir-217 
               
               
                   
                   
                 AIL0/0 
               
               
                   
                   
                 unproductive 
               
               
                   
                   
                 product 1 
               
               
                   
               
               
                 14 
                 ACUGAUUGGAUAAGAAUCAGUCACCAUCAGUUC 
                 Pri-mir-217 
               
               
                   
                   
                 unproductive 
               
               
                   
                   
                 product 2; Pri- 
               
               
                   
                   
                 mir-217 
               
               
                   
                   
                 AIL3/3 (WT) 
               
               
                   
                   
                 unproductive 
               
               
                   
                   
                 product 2; Pri- 
               
               
                   
                   
                 mir-217 
               
               
                   
                   
                 AIL0/0 
               
               
                   
                   
                 unproductive 
               
               
                   
                   
                 product 2; Pri- 
               
               
                   
                   
                 mir-217 
               
               
                   
                   
                 AIL5/3 
               
               
                   
                   
                 unproductive 
               
               
                   
                   
                 product 2 
               
               
                   
               
               
                 15 
                 CUAAUGCAUUGCCUUCAGCAUCUAAACAAGCACC 
                 Pri-mir-217 
               
               
                   
                   
                 unproductive 
               
               
                   
                   
                 product 3; Pri- 
               
               
                   
                   
                 mir-217 
               
               
                   
                   
                 AIL3/3 (WT) 
               
               
                   
                   
                 unproductive 
               
               
                   
                   
                 product 3; Pri- 
               
               
                   
                   
                 mir-217 
               
               
                   
                   
                 AIL5/3 
               
               
                   
                   
                 unproductive 
               
               
                   
                   
                 product 3 
               
               
                   
               
               
                 16 
                 GGGAGCCCUCCAGGGUAAGUGGAAAGAUGGUGGGCC 
                 Pri-mir-654 
               
               
                   
                 GCAGAACAUGUGCUGAGUUCGUGCCAUAUGUCUGCU 
                   
               
               
                   
                 GACCAUCACCUUUAGAAGCCCCCUUUCGCUGAG 
                   
               
               
                   
               
               
                 17 
                 GGGAGCCCUCCAGGGUAAGUGGAAAGA 
                 Pri-mir-654 
               
               
                   
                   
                 F1 
               
               
                   
               
               
                 18 
                 UGGUGGGCCGCAGAACAUGUGCUGAGUUCGUGCCAU 
                 Pri-mir-654 
               
               
                   
                 AUGUCUGCUGACCAUCACCUU 
                 F2 
               
               
                   
               
               
                 19 
                 UAGAAGCCCCCUUUCGCUGAG 
                 Pri-mir-654 
               
               
                   
                   
                 F3 
               
               
                   
               
               
                 20 
                 GGGAGCCCUCCAGGGUAAGUGGAAAGAUGGUGGGCC 
                 Pri-mir-654 
               
               
                   
                 GCAG 
                 unproductive 
               
               
                   
                   
                 product 1 
               
               
                   
               
               
                 21 
                 AACAUGUGCUGAGUUCGUGCCAUAUGUCU 
                 Pri-mir-654 
               
               
                   
                   
                 unproductive 
               
               
                   
                   
                 product 2 
               
               
                   
               
               
                 22 
                 GCUGACCAUCACCUUUAGAAGCCCCCUUUCGCUGAG 
                 Pri-mir-654 
               
               
                   
                   
                 unproductive 
               
               
                   
                   
                 product 3 
               
               
                   
               
               
                 23 
                 GGGCGGACCCAGCUCGGGCAGCCGUGGCCAUCUUAC 
                 Pri-mir-200b 
               
               
                   
                 UGGGCAGCAUUGGAUGGAGUCAGGUCUCUAAUACUG 
                   
               
               
                   
                 CCUGGUAAUGAUGACGGCGGAGCCCUGCACGCAGC 
                   
               
               
                   
               
               
                 24 
                 GGGCGGACCCAGCUCGGGCAGCCGUGGCC 
                 Pri-mir-200b 
               
               
                   
                   
                 F1 
               
               
                   
               
               
                 25 
                 AUCUUACUGGGCAGCAUUGGAUGGAGUCAGGUCUCU 
                 Pri-mir-200b 
               
               
                   
                 AAUACUGCCUGGUAAUGAUGA 
                 F2 
               
               
                   
               
               
                 26 
                 CGGCGGAGCCCUGCACGCAGC 
                 Pri-mir-200b 
               
               
                   
                   
                 F3 
               
               
                   
               
               
                 27 
                 GGGCCCUCCCCCUCAUCCCUGGUCCUCCUGGUCCCUG 
                 Pri-let-7e 
               
               
                   
                 UCUGUCUGUCUGUCGGGUCUGUCCACCUGCCGCGCC 
                   
               
               
                   
                 CCCCGGGCUGAGGUAGGAGGUUGUAUAGUUGAGGA 
                   
               
               
                   
                 GGACACCCAAGGAGAUCACUAUACGGCCUCCUAGCU 
                   
               
               
                   
                 UUCCCCAGGCUGCGCCCUGCACGGGACGGGGCCCGG 
                   
               
               
                   
                 CGGGGACCCCCAGCCCCA 
                   
               
               
                   
               
               
                 28 
                 GGGCCCUCCCCCUCAUCCCUGGUCCUCCUGGUCCCUG 
                 Pri-let-7e F1 
               
               
                   
                 UCUGUCUGUCUGUCGGGUCUGUCCACCUGCCGCGCC 
                   
               
               
                   
                 CCCCGGGC 
                   
               
               
                   
               
               
                 29 
                 UGAGGUAGGAGGUUGUAUAGUUGAGGAGGACACCC 
                 Pri-let-7e F2 
               
               
                   
                 AAGGAGAUCACUAUACGGCCUCCUAGCUUUCC 
                   
               
               
                   
               
               
                 30 
                 CCAGGCUGCGCCCUGCACGGGACGGGGCCCGGCGGG 
                 Pri-let-7e F3 
               
               
                   
                 GACCCCCAGCCCCA 
                   
               
               
                   
               
               
                 31 
                 GGGUUGGAUUAAUGGUUGUAAUAUUUUAUUUUCAG 
                 Pri-mir-100 
               
               
                   
                 ACAUGUCACAGCCCCAAAAGAGAGAAGAUAUUGAGG 
                   
               
               
                   
                 CCUGUUGCCACAAACCCGUAGAUCCGAACUUGUGGU 
                   
               
               
                   
                 AUUAGUCCGCACAAGCUUGUAUCUAUAGGUAUGUGU 
                   
               
               
                   
                 CUGUUAGGCAAUCUCACGGACCUGGGGCUUUGCUUA 
                   
               
               
                   
                 UAUGCCAUUCA 
                   
               
               
                   
               
               
                 32 
                 GGGUUGGAUUAAUGGUUGUAAUAUUUUAUUUUCAG 
                 Pri-mir-100 
               
               
                   
                 ACAUGUCACAGCCCCAAAAGAGAGAAGAUAUUGAGG 
                 F1 
               
               
                   
                 CCUGUUGCCACA 
                   
               
               
                   
               
               
                 33 
                 AACCCGUAGAUCCGAACUUGUGGUAUUAGUCCGCAC 
                 Pri-mir-100 
               
               
                   
                 AAGCUUGUAUCUAUAGGUAUG 
                 F2 
               
               
                   
               
               
                 34 
                 UGUCUGUUAGGCAAUCUCACGGACCUGGGGCUUUGC 
                 Pri-mir-100 
               
               
                   
                 UUAUAUGCCAUUCA 
                 F3 
               
               
                   
               
               
                 35 
                 GGGAAAGAGCCCAAUGUAUGCUGGAUUUAGUAAGA 
                 Pri-mir-29a 
               
               
                   
                 UUUGGGCCCUCCCAACCCUCACGACCUUCUGUGACC 
                   
               
               
                   
                 CCUUAGAGGAUGACUGAUUUCUUUUGGUGUUCAGA 
                   
               
               
                   
                 GUCAAUAUAAUUUUCUAGCACCAUCUGAAAUCGGUU 
                   
               
               
                   
                 AUAAUGAUUGGGGAAGAGCACCAUGAUGCUGACUGC 
                   
               
               
                   
                 UGAGAGGAAAUGUAU 
                   
               
               
                   
               
               
                 36 
                 GGGAAAGAGCCCAAUGUAUGCUGGAUUUAGUAAGA 
                 Pri-mir-29a 
               
               
                   
                 UUUGGGCCCUCCCAACCCUCACGACCUUCUGUGACC 
                 F1 
               
               
                   
                 CCUUAGAGGAUG 
                   
               
               
                   
               
               
                 37 
                 ACUGAUUUCUUUUGGUGUUCAGAGUCAAUAUAAUU 
                 Pri-mir-29a 
               
               
                   
                 UUCUAGCACCAUCUGAAAUCGGUUA 
                 F2 
               
               
                   
               
               
                 38 
                 UAAUGAUUGGGGAAGAGCACCAUGAUGCUGACUGCU 
                 Pri-mir-29a 
               
               
                   
                 GAGAGGAAAUGUAU 
                 F3 
               
               
                   
               
               
                 39 
                 GGGUGUUUGAGUGUGGUGGUUCCUACCUAAUCAGCA 
                 Pri-mir-367 
               
               
                   
                 AUUGCGUUAACGCCCACACUGUGUGCAGUUCUUGGC 
                   
               
               
                   
                 UACAGGCCAUUACUGUUGCUAAUAUGCAACUCUGUU 
                   
               
               
                   
                 GAAUAUAAAUUGGAAUUGCACUUUAGCAAUGGUGA 
                   
               
               
                   
                 UGGAUUGUUAAGCCAAUGACAGAAUUUAAACCACAG 
                   
               
               
                   
                 ACUUACUUUGAUAG 
                   
               
               
                   
               
               
                 40 
                 GGGUGUUUGAGUGUGGUGGUUCCUACCUAAUCAGCA 
                 Pri-mir-367 
               
               
                   
                 AUUGCGUUAACGCCCACACUGUGUGCAGUUCUUGGC 
                 F1 
               
               
                   
                 UACAGGCCAUU 
                   
               
               
                   
               
               
                 41 
                 ACUGUUGCUAAUAUGCAACUCUGUUGAAUAUAAAU 
                 Pri-mir-367 
               
               
                   
                 UGGAAUUGCACUUUAGCAAUGGUGA 
                 F2 
               
               
                   
               
               
                 42 
                 UGGAUUGUUAAGCCAAUGACAGAAUUUAAACCACAG 
                 Pri-mir-367 
               
               
                   
                 ACUUACUUUGAUAG 
                 F3 
               
               
                   
               
               
                 43 
                 GGGUUUCUGUCUCCCAUCCCCUUCAGAUACUUACAG 
                 Pri-mir-181a-1; 
               
               
                   
                 AUACUGUAAAGUGAGUAGAAUUCUGAGUUUUGAGG 
                 Pri-mir-181a-1 
               
               
                   
                 UUGCUUCAGUGAACAUUCAACGCUGUCGGUGAGUUU 
                 AIL2/2 (WT) 
               
               
                   
                 GGAAUUAAAAUCAAAACCAUCGACCGUUGAUUGUAC 
                   
               
               
                   
                 CCUAUGGCUAACCAUCAUCUACUCCAUGGUGCUCAG 
                   
               
               
                   
                 AAUUCGCUGAAGACA 
                   
               
               
                   
               
               
                 44 
                 GGGUUUCUGUCUCCCAUCCCCUUCAGAUACUUACAG 
                 Pri-mir-181a- 
               
               
                   
                 AUACUGUAAAGUGAGUAGAAUUCUGAGUUUUGAGG 
                 1 F1; Pri-mir- 
               
               
                   
                 UUGCUUCAGUG 
                 181a-1 
               
               
                   
                   
                 AIL2/2 (WT) 
               
               
                   
                   
                 F1; Pri-mir- 
               
               
                   
                   
                 181a-1 
               
               
                   
                   
                 AIL0/0 F1; 
               
               
                   
                   
                 Pri-mir-181a- 
               
               
                   
                   
                 1 AIL2/5 F1 
               
               
                   
               
               
                 45 
                 AACAUUCAACGCUGUCGGUGAGUUUGGAAUUAAAA 
                 Pri-mir-181a- 
               
               
                   
                 UCAAAACCAUCGACCGUUGAUUGUACC 
                 1 F2; Pri-mir- 
               
               
                   
                   
                 181a-1 
               
               
                   
                   
                 AIL2/2 (WT) 
               
               
                   
                   
                 F2; Pri-mir- 
               
               
                   
                   
                 181a-1 
               
               
                   
                   
                 AIL0/0 F2; 
               
               
                   
                   
                 Pri-mir-181a- 
               
               
                   
                   
                 1 AIL2/5 F2 
               
               
                   
               
               
                 46 
                 CUAUGGCUAACCAUCAUCUACUCCAUGGUGCUCAGA 
                 Pri-mir-181a- 
               
               
                   
                 AUUCGCUGAAGACA 
                 1 F3; Pri-mir- 
               
               
                   
                   
                 181a-1 
               
               
                   
                   
                 AIL2/2 (WT) 
               
               
                   
                   
                 F3 
               
               
                   
               
               
                 47 
                 GGGAAGUACUGCUAGCUGUAGAACUCCAGCUUCGGC 
                 Pri-mir-19b-1 
               
               
                   
                 CUGUCGCCCAAUCAAACUGUCCUGUUACUGAACACU 
                   
               
               
                   
                 GUUCUAUGGUUAGUUUUGCAGGUUUGCAUCCAGCUG 
                   
               
               
                   
                 UGUGAUAUUCUGCUGUGCAAAUCCAUGCAAAACUGA 
                   
               
               
                   
                 CUGUGGUAGUGAAAAGUCUGUAGAAAAGUAAGGGA 
                   
               
               
                   
                 AACUCAAACCCCUUU 
                   
               
               
                   
               
               
                 48 
                 GGGAAGUACUGCUAGCUGUAGAACUCCAGCUUCGGC 
                 Pri-mir-19b-1 
               
               
                   
                 CUGUCGCCCAAUCAAACUGUCCUGUUACUGAACACU 
                 F1 
               
               
                   
                 GUUCUAUGGUU 
                   
               
               
                   
               
               
                 49 
                 AGUUUUGCAGGUUUGCAUCCAGCUGUGUGAUAUUCU 
                 Pri-mir-19b-1 
               
               
                   
                 GCUGUGCAAAUCCAUGCAAAACUGA 
                 F2 
               
               
                   
               
               
                 50 
                 CUGUGGUAGUGAAAAGUCUGUAGAAAAGUAAGGGA 
                 Pri-mir-19b-1 
               
               
                   
                 AACUCAAACCCCUUU 
                 F3 
               
               
                   
               
               
                 51 
                 GGGAAACUCAAACCCCUUUCUACACAGGUUGGGAUC 
                 Pri-mir-92a-1 
               
               
                   
                 GGUUGCAAUGCUGUGUUUCUGUAUGGUAUUGCACU 
                 AIL3/8 
               
               
                   
                 UGUCCCGGCCUGUUGAGUUUUUGGUGGGGAUUGUG 
                   
               
               
                   
                 A 
                   
               
               
                   
               
               
                 52 
                 UGAGUUUUUGGUGGGGAUUGUGA 
                 Pri-mir-92a-1 
               
               
                   
                   
                 AIL3/8 F3 
               
               
                   
               
               
                 53 
                 GGGAAACUCAAACCCCUUUCUACACAGGUUGGGAUC 
                 Pri-mir-92a-1 
               
               
                   
                 GGUUGCAAUGCUGUGUUUCUGUAUGGUAUUGCACU 
                 AIL3/9 
               
               
                   
                 UGUCCCGGCCUGUUGAGUUUUUUGGUGGGGAUUGU 
                   
               
               
                   
                 GA 
                   
               
               
                   
               
               
                 54 
                 UGAGUUUUUUGGUGGGGAUUGUGA 
                 Pri-mir-92a-1 
               
               
                   
                   
                 AIL3/9 F3 
               
               
                   
               
               
                 55 
                 GGGAAACUCAAACCCCUUUCUACACAGGUUGGGAUC 
                 Pri-mir-92a-1 
               
               
                   
                 GGUUGCAAUGCUGUGUUUCUGUAUGGUAUUGCACU 
                 AIL3/3 
               
               
                   
                 UGUCCCGGCCUGUUGAGUUUGGGGAUUGUGA 
                   
               
               
                   
               
               
                 56 
                 UGAGUUUGGGGAUUGUGA 
                 Pri-mir-92a-1 
               
               
                   
                   
                 AIL3/3 F3 
               
               
                   
               
               
                 57 
                 GGGAAACUCAAACCCCUUUCUACACAGGUUGGGAUC 
                 Pri-mir-92a-1 
               
               
                   
                 GGUUGCAAUGCUGUGUUUCUGUAUGGUAUUGCACU 
                 AIL2/2 
               
               
                   
                 UGUCCCGGCCUGUUGAGUUGGGGGAUUGUGA 
                   
               
               
                   
               
               
                 58 
                 UGAGUUGGGGGAUUGUGA 
                 Pri-mir-92a-1 
               
               
                   
                   
                 AIL2/2 F3 
               
               
                   
               
               
                 59 
                 GGGAAACUCAAACCCCUUUCUACACAGGUUGGGAUC 
                 Pri-mir-92a-1 
               
               
                   
                 GGUUGCAAUGCUGUGUUUCUGUAUGGUAUUGCACU 
                 AIL1/1 
               
               
                   
                 UGUCCCGGCCUGUUGAGGGUGGGGAUUGUGA 
                   
               
               
                   
               
               
                 60 
                 UGAGGGUGGGGAUUGUGA 
                 Pri-mir-92a-1 
               
               
                   
                   
                 AIL1/1 F3 
               
               
                   
               
               
                 61 
                 GGGCUAGCAGCACUACAAUGCUUUGCUAGAGCUGGU 
                 Pri-mir-133a- 
               
               
                   
                 AAAAUGGAACCAAAUCGCCUCUUCAAUGGAUUUGGU 
                 1 AIL3/3 
               
               
                   
                 CCCCUUCAACCAGCUGUAGCUAUGCAUUGAUUACU 
                 (WT) 
               
               
                 62 
                 GGGCUAGCAGCACUACAAUGCUUUGCUAG 
                 Pri-mir-133a- 
               
               
                   
                   
                 1 AIL3/3 
               
               
                   
                   
                 (WT) F1; Pri- 
               
               
                   
                   
                 mir-133a-1 
               
               
                   
                   
                 AIL3/7 F1 
               
               
                   
               
               
                 63 
                 AGCUGGUAAAAUGGAACCAAAUCGCCUCUUCAAUGG 
                 Pri-mir-133a- 
               
               
                   
                 AUUUGGUCCCCUUCAACCAGCUG 
                 1 AIL3/3 
               
               
                   
                   
                 (WT) F2; Pri- 
               
               
                   
                   
                 mir-133a-1 
               
               
                   
                   
                 AIL0/0 F2; 
               
               
                   
                   
                 Pri-mir-133a- 
               
               
                   
                   
                 1 AIL7/3 F2 
               
               
                   
               
               
                 64 
                 UAGCUAUGCAUUGAUUACU 
                 Pri-mir-133a- 
               
               
                   
                   
                 1 AIL3/3 
               
               
                   
                   
                 (WT) F3; Pri- 
               
               
                   
                   
                 mir-133a-1 
               
               
                   
                   
                 AIL0/0 F3; 
               
               
                   
                   
                 Pri-mir-133a- 
               
               
                   
                   
                 1 AIL7/3 F3 
               
               
                   
               
               
                 65 
                 GGGCUAGCAGCACUACAAUGCLTUUGCUAGAGCUGGU 
                 Pri-mir-133a- 
               
               
                   
                 AAAAU 
                 1 AIL3/3 
               
               
                   
                   
                 (WT) 
               
               
                   
                   
                 unproductive 
               
               
                   
                   
                 product 1; Pri- 
               
               
                   
                   
                 mir-133a-1 
               
               
                   
                   
                 AIL3/7 
               
               
                   
                   
                 unproductive 
               
               
                   
                   
                 product 1 
               
               
                   
               
               
                 66 
                 GGAACCAAAUCGCCUCUUCAAUGGAUUUGGUCCCCU 
                 Pri-mir-133a- 
               
               
                   
                   
                 1 AIL3/3 
               
               
                   
                   
                 (WT) 
               
               
                   
                   
                 unproductive 
               
               
                   
                   
                 product 2; Pri- 
               
               
                   
                   
                 mir-133a-1 
               
               
                   
                   
                 AIL0/0 
               
               
                   
                   
                 unproductive 
               
               
                   
                   
                 product 2; Pri- 
               
               
                   
                   
                 mir-133a-1 
               
               
                   
                   
                 AIL7/3 
               
               
                   
                   
                 unproductive 
               
               
                   
                   
                 product 2; Pri- 
               
               
                   
                   
                 mir-133a-1 
               
               
                   
                   
                 AIL3/7 
               
               
                   
                   
                 unproductive 
               
               
                   
                   
                 product 2 
               
               
                   
               
               
                 67 
                 UCAACCAGCUGUAGCUAUGCAUUGAUUACU 
                 Pri-mir-133a- 
               
               
                   
                   
                 1 AIL3/3 
               
               
                   
                   
                 (WT) 
               
               
                   
                   
                 unproductive 
               
               
                   
                   
                 product 3; Pri- 
               
               
                   
                   
                 mir-133a-1 
               
               
                   
                   
                 AIL0/0 
               
               
                   
                   
                 unproductive 
               
               
                   
                   
                 product 3; Pri- 
               
               
                   
                   
                 mir-133a-1 
               
               
                   
                   
                 AIL7/3 
               
               
                   
                   
                 unproductive 
               
               
                   
                   
                 product 3 
               
               
                   
               
               
                 68 
                 GGGCUAGCAGCACUACAAUGCGUAGCUAGAGCUGGU 
                 Pri-mir-133a- 
               
               
                   
                 AAAAUGGAACCAAAUCGCCUCUUCAAUGGAUUUGGU 
                 1 AIL0/0 
               
               
                   
                 CCCCUUCAACCAGCUGUAGCUAUGCAUUGAUUACU 
                   
               
               
                   
               
               
                 69 
                 GGGCUAGCAGCACUACAAUGCGUAGCUAG 
                 Pri-mir-133a- 
               
               
                   
                   
                 1 AIL0/0 F1 
               
               
                   
               
               
                 70 
                 GGGCUAGCAGCACUACAAUGCGUAGCUAGAGCUGGU 
                 Pri-mir-133a- 
               
               
                   
                 AAAAU 
                 1 AIL0/0 
               
               
                   
                   
                 unproductive 
               
               
                   
                   
                 product 1 
               
               
                   
               
               
                 71 
                 GGGCUAGCAGCACUACAAUGCGCUAGAGC 
                 Pri-mir-133a-1 
               
               
                   
                 UGGUAAAAUGGAACCAAAUCGCCUCUUCAAUGGAUU 
                 AIL7/3 
               
               
                   
                 UGGUCCCCUUCAACCAGCUGUAGCUAUGCAUUGAUU 
                   
               
               
                   
                 ACU 
                   
               
               
                   
               
               
                 72 
                 GGGCUAGCAGCACUACAAUGCUUUUUUUGCUAG 
                 Pri-mir-133a- 
               
               
                   
                   
                 1 AIL7/3 F1 
               
               
                   
               
               
                 73 
                 GGGCUAGCAGCACUACAAUGCGCUAGAGC 
                 Pri-mir-133a- 
               
               
                   
                 UGGUAAAAU 
                 1 AIL7/3 
               
               
                   
                   
                 unproductive 
               
               
                   
                   
                 product 1 
               
               
                   
               
               
                 74 
                 GGGCUAGCAGCACUACAAUGCUUUGCUAGAGCUGGU 
                 Pri-mir-133a- 
               
               
                   
                 AAAAUGGAACCAAAUCGCCUCUUCAAUGGAUUUGGU 
                 1 AIL3/7 
               
               
                   
                 CCCCUUCAACCAGCUGUAGCUUUUUAUGCAUUGAUU 
                   
               
               
                   
                 ACU 
                   
               
               
                   
               
               
                 75 
                 GCUGGUAAAAUGGAACCAAAUCGCCUCUUCAAUGGA 
                 Pri-mir-133a- 
               
               
                   
                 UUUGGUCCCCUUCAACCAGCUG 
                 1 AIL3/7 F2 
               
               
                   
               
               
                 76 
                 UAGCUUUUUAUGCAUUGAUUACU 
                 Pri-mir-133a- 
               
               
                   
                   
                 1 AIL3/7 F3 
               
               
                   
               
               
                 77 
                 UCAACCAGCUGUAGCUUUUUAUGCAUUGAUUACU 
                 Pri-mir-133a- 
               
               
                   
                   
                 1 AIL3/7 
               
               
                   
                   
                 unproductive 
               
               
                   
                   
                 product 3 
               
               
                   
               
               
                 78 
                 GGGAUUACAUAGUUUUUGAUGUCGCAGAUACUGCA 
                 Pri-mir-217 
               
               
                   
                 UCAGGAACUGAUUGGAUAAGAAUCAGUCACCAUCAG 
                 AIL0/0 
               
               
                   
                 UUCCUAAUGCAUUGCCUGCGGCAUCUAAACAAGCAC 
                   
               
               
                   
                 C 
                   
               
               
                   
               
               
                 79 
                 UGCGGCAUCUAAACAAGCACC 
                 Pri-mir-217 
               
               
                   
                   
                 AIL0/0 F3 
               
               
                   
               
               
                 80 
                 CUAAUGCAUUGCCUGCGGCAUCUAAACAAGCACC 
                 Pri-mir-217 
               
               
                   
                   
                 AIL0/0 
               
               
                   
                   
                 unproductive 
               
               
                   
                   
                 product 3 
               
               
                   
               
               
                 81 
                 GGGAUUACAUAGUUUUUGAUGUCGCUUAGAUACUG 
                 Pri-mir-217 
               
               
                   
                 CAUCAGGAACUGAUUGGAUAAGAAUCAGUCACCAUC 
                 AILS/3 
               
               
                   
                 AGUUCCUAAUGCAUUGCCUUCAGCAUCUAAACAAGC 
                   
               
               
                   
                 ACC 
                   
               
               
                   
               
               
                 82 
                 GGGAUUACAUAGUUUUUGAUGUCGCUUAGA 
                 Pri-mir-217 
               
               
                   
                   
                 AIL5/3 F1 
               
               
                   
               
               
                 83 
                 GGGAUUACAUAGUUUUUGAUGUCGCUUAGAUACUG 
                 Pri-mir-217 
               
               
                   
                 CAUCAGGA 
                 AIL5/3 
               
               
                   
                   
                 unproductive 
               
               
                   
                   
                 product 1 
               
               
                   
               
               
                 84 
                 GGGAGGGUGGGGGUGGAGGCAAGCAGAGGACUUCC 
                 Pri-mir-204 
               
               
                   
                 UGAUCGCGUACCCAUGGCUACAGUCUUUCUUCAUGU 
                 AIL3/3 (WT) 
               
               
                   
                 GACUCGUGGACUUCCCUUUGUCAUCCUAUGCCUGAG 
                   
               
               
                   
                 AAUAUAUGAAGGAGGCUGGGAAGGCAAAGGGACGU 
                   
               
               
                   
                 UCAAUUGUCAUCACUGGCAUCUUUUUUGAUCAUUGC 
                   
               
               
                   
                 ACCAUCAUCAAAUG 
                   
               
               
                   
               
               
                 85 
                 GGGAGGGUGGGGGUGGAGGCAAGCAGAGGACUUCC 
                 Pri-mir-204 
               
               
                   
                 UGAUCGCGUACCCAUGGCUACAGUCUUUCUUCAUGU 
                 AIL3/3 (WT) 
               
               
                   
                 GACUCGUGGAC 
                 F1; Pri-mir- 
               
               
                   
                   
                 204 AIL1/1 
               
               
                   
                   
                 F1; Pri-mir- 
               
               
                   
                   
                 204 AIL3/5 
               
               
                   
                   
                 F1 
               
               
                   
               
               
                 86 
                 UUCCCUUUGUCAUCCUAUGCCUGAGAAUAUAUGAAG 
                 Pri-mir-204 
               
               
                   
                 GAGGCUGGGAAGGCAAAGGGACGU 
                 AIL3/3 (WT) 
               
               
                   
                   
                 F2; Pri-mir- 
               
               
                   
                   
                 204 ALL1/1 
               
               
                   
                   
                 F2; Pri-mir- 
               
               
                   
                   
                 204 AIL3/5 
               
               
                   
                   
                 F2 
               
               
                   
               
               
                 87 
                 UCAAUUGUCAUCACUGGCAUCUUUUUUGAUCAUUGC 
                 Pri-mir-204 
               
               
                   
                 ACCAUCAUCAAAUG 
                 AIL3/3 (WT) 
               
               
                   
                   
                 F3 
               
               
                   
               
               
                 88 
                 GGGAGGGUGGGGGUGGAGGCAAGCAGAGGACUUCC 
                 Pri-mir-204 
               
               
                   
                 UGAUCGCGUACCCAUGGCUACAGUCUUUCUUCAUGU 
                 AIL1/1 
               
               
                   
                 GACUCGUGGACUUCCCUUUGUCAUCCUAUGCCUGAG 
                   
               
               
                   
                 AAUAUAUGAAGGAGGCUGGGAAGGCAAAGGGACGU 
                   
               
               
                   
                 UCAAGAGUCAUCACUGGCAUCUUUUUUGAUCAUUGC 
                   
               
               
                   
                 ACCAUCAUCAAAUG 
                   
               
               
                   
               
               
                 89 
                 UCAAGAGUCAUCACUGGCAUCUUUUUUGAUCAUUGC 
                 Pri-mi r-204 
               
               
                   
                 ACCAUCAUCAAAUG 
                 AIL1/1 F3 
               
               
                   
               
               
                 90 
                 GGGAGGGUGGGGGUGGAGGCAAGCAGAGGACUUCC 
                 Pri-mir-204 
               
               
                   
                 UGAUCGCGUACCCAUGGCUACAGUCUUUCUUCAUGU 
                 AIL3/5 
               
               
                   
                 GACUCGUGGACUUCCCUUUGUCAUCCUAUGCCUGAG 
                   
               
               
                   
                 AAUAUAUGAAGGAGGCUGGGAAGGCAAAGGGACGU 
                   
               
               
                   
                 UCAAAUUUGUCAUCACUGGCAUCUUUUUUGAUCAUU 
                   
               
               
                   
                 GCACCAUCAUCAAAUG 
                   
               
               
                   
               
               
                 91 
                 UCAAAUUUGUCAUCACUGGCAUCUUUUUUGAUCAUU 
                 Pri-mir-204 
               
               
                   
                 GCACCAUCAUCAAAUG 
                 AIL3/5 F3 
               
               
                   
               
               
                 92 
                 GGGUUUCUGUCUCCCAUCCCCUUCAGAUACUUACAG 
                 Pri-mir-181a- 
               
               
                   
                 AUACUGUAAAGUGAGUAGAAUUCUGAGUUUUGAGG 
                 1 AIL0/0 
               
               
                   
                 UUGCUUCAGUGAACAUUCAACGCUGUCGGUGAGUUU 
                   
               
               
                   
                 GGAAUUAAAAUCAAAACCAUCGACCGUUGAUUGUAC 
                   
               
               
                   
                 CCUGAGGCUAACCAUCAUCUACUCCAUGGUGCUCAG 
                   
               
               
                   
                 AAUUCGCUGAAGACA 
                   
               
               
                   
               
               
                 93 
                 CUGAGGCUAACCAUCAUCUACUCCAUGGUGCUCAGA 
                 Pri-mi r-181a- 
               
               
                   
                 AUUCGCUGAAGACA 
                 1 AIL0/0 F3 
               
               
                   
               
               
                 94 
                 GGGUUUCUGUCUCCCAUCCCCUUCAGAUACLTUACAG 
                 Pri-mir-181a- 
               
               
                   
                 AUACUGUAAAGUGAGUAGAAUUCUGAGUUUUGAGG 
                 1 AIL2/5 
               
               
                   
                 UUGCUUCAGUGAACAUUCAACGCUGUCGGUGAGUUU 
                   
               
               
                   
                 GGAAUUAAAAUCAAAACCAUCGACCGUUGAUUGUAC 
                   
               
               
                   
                 CCUAAAAUGGCUAACCAUCAUCUACUCCAUGGUGCU 
                   
               
               
                   
                 CAGAAUUCGCUGAAGACA 
                   
               
               
                   
               
               
                 95 
                 CUAAAAUGGCUAACCAUCAUCUACUCCAUGGUGCUC 
                 Pri-mir-181a- 
               
               
                   
                 AGAAUUCGCUGAAGACA 
                 1 AIL2/5 F3 
               
               
                   
               
               
                 96 
                 GGGUAACAGGAUGGCUGUGAGUUGGCUUAAUCUCA 
                 Pri-mir-216a 
               
               
                   
                 GCUGGCAACUGUGAGAUGUUCAUACAAUCCCUCACA 
                 AIL0/0 
               
               
                   
                 GUGGUCUCUGGGAUUAUGCUAACUCAGAGCAAUUUC 
                   
               
               
                   
                 CUA 
                   
               
               
                   
               
               
                 97 
                 GGGUAACACGGAUGGCUGUGAGUUGGCU 
                 Pri-mir-216a 
               
               
                   
                   
                 AIL0/0 F1 
               
               
                   
               
               
                 98 
                 GCUAACUCAGAGCAAUUUCCUA 
                 Pri-mir-216a 
               
               
                   
                   
                 AIL0/0 F3 
               
               
                   
               
               
                 99 
                 GGGUAACAGGAUGGCUGUGAGUUGGCUUAAUCUCA 
                 Pri-mir-216a 
               
               
                   
                 GCUGGCAACUGUGAGAUGUUCAUACAAUCCCUCACA 
                 AIL2/2 
               
               
                   
                 GUGGUCUCUGGGAUUAUGCUAAAACAGAGCAAUUUC 
                   
               
               
                   
                 CUA 
                   
               
               
                   
               
               
                 100 
                 GCUAAAACAGAGCAAUUUCCUA 
                 Pri-mir-216a 
               
               
                   
                   
                 AIL2/2 F3; 
               
               
                   
                   
                 Pri-mir-216a 
               
               
                   
                   
                 AIL6/2 F3; 
               
               
                   
                   
                 Pri-mir-216a 
               
               
                   
                   
                 AIL8/2 F3 
               
               
                   
               
               
                 101 
                 GGGUAACAGGAUGGCUGUGAAAAAGUUGGCUUAAU 
                 Pri-mir-216a 
               
               
                   
                 CUCAGCUGGCAACUGUGAGAUGUUCAUACAAUCCCU 
                 AIL6/2 
               
               
                   
                 CACAGUGGUCUCUGGGAUUAUGCUAAAACAGAGCAA 
                   
               
               
                   
                 UUUCCUA 
                   
               
               
                   
               
               
                 102 
                 GGGUAACAGGAUGGCUGUGAAAAAGUUGGCU 
                 Pri-mir-216a 
               
               
                   
                   
                 AIL6/2 F1 
               
               
                   
               
               
                 103 
                 GGGUAACAGGAUGGCUGUGAAAAAGUUGGCUUAAU 
                 Pri-mir-216a 
               
               
                   
                 CUCAGCUG 
                 AIL6/2 
               
               
                   
                   
                 unproductive 
               
               
                   
                   
                 product 1 
               
               
                   
               
               
                 104 
                 GCAACUGUGAGAUGLTUCAUACAAUCCCUCACAGUGG 
                 Pri-mir-216a 
               
               
                   
                 UCU 
                 AIL6/2 
               
               
                   
                   
                 unproductive 
               
               
                   
                   
                 product 2; Pri- 
               
               
                   
                   
                 mir-216a 
               
               
                   
                   
                 AIL8/2 
               
               
                   
                   
                 unproductive 
               
               
                   
                   
                 product 2 
               
               
                   
               
               
                 105 
                 CUGGGAUUAUGCUAAAACAGAGCAAUUUCCUA 
                 Pri-mir-216a 
               
               
                   
                   
                 AIL6/2 
               
               
                   
                   
                 Vunproductive 
               
               
                   
                   
                 product 3; Pri- 
               
               
                   
                   
                 mir-216a 
               
               
                   
                   
                 AIL8/2 
               
               
                   
                   
                 unproductive 
               
               
                   
                   
                 product 3 
               
               
                 106 
                 GGGUAACAGGAUGGCUGUGAAAAAAAGUUGGCUUA 
                 Pri-mir-216a 
               
               
                   
                 AUCUCAGCUGGCAACUGUGAGAUGUUCAUACAAUCC 
                 AIL8/2 
               
               
                   
                 CUCACAGUGGUCUCUGGGAUUAUGCUAAAACAGAGC 
                   
               
               
                   
                 AAUUUCCUA 
                   
               
               
                   
               
               
                 107 
                 GGGUAACAGGAUGGCUGUGAAAAAAAGUUGGCU 
                 Pri-mir-216a 
               
               
                   
                   
                 AIL8/2 F1 
               
               
                   
               
               
                 108 
                 GGGUAACAGGAUGGCUGUGAAAAAAAGUUGGCUUA 
                 Pri-mir-216a 
               
               
                   
                 AUCUCAGCUG 
                 AIL8/2 
               
               
                   
                   
                 unproductive 
               
               
                   
                   
                 product 1