Question: Double-stranded RNA contains how many strands?
About the article "RNA", section "Double-stranded RNA".

Candidate passages:
Double-stranded RNA (dsRNA) is RNA with two complementary strands, similar to the DNA found in all cells.
dsRNA forms the genetic material of some viruses (double-stranded RNA viruses).
Double-stranded RNA such as viral RNA or siRNA can trigger RNA interference in eukaryotes, as well as interferon response in vertebrates.
In transcription, a template DNA strand is transcribed in the 3'→5' direction, beginning at the promoter region, by an RNA polymerase, which separates the strands of double-stranded DNA.
RNA polymerase attaches nucleotides and builds the primary RNA transcript in the 5'→3' direction, antiparallel to the template DNA strand. 
Nuclease protection assay is a laboratory technique used in biochemistry and genetics to identify individual RNA molecules in a heterogeneous RNA sample extracted from cells.
The technique can identify one or more RNA molecules of known sequence even at low total concentration.
The extracted RNA is first mixed with antisense RNA or DNA probes that are complementary to the sequence or sequences of interest and the complementary strands are hybridized to form double-stranded RNA (or a DNA-RNA hybrid).
The mixture is then exposed to ribonucleases that specifically cleave only "single"-stranded RNA but have no activity against double-stranded RNA.
When the reaction runs to completion, susceptible RNA regions are degraded to very short oligomers or to individual nucleotides; the surviving RNA fragments are those that were complementary to the added antisense strand and thus contained the sequence of interest. 
Transcription involves the production of mRNA by using DNA as a template through three steps: initiation, elongation, and termination .
During initiation, transcriptional factors, or molecules that initiate transcription, along with RNA Polymerase II bind to a region of the DNA called the promoter, forming the pre initiation complex.
The double stranded DNA is separated and unwound, providing access to the template strand from which the RNA will be made .
Promoter escape occurs as RNA Polymerase II exits the complex while nucleotides are continually added to the growing transcript and elongation begins.
Many events are occurring during this phase: the upstream DNA strands must be unwound, nucleotides must be added to the growing chain of RNA, and proof reading.
In Eukaryotes, termination, or the end of transcription, occurs as the mRNA's 3' end gets polyadenylated Link to other topics such transcription, RNA Polymerases, RNA Polymerase IIDefine transcription and describe the role of polymerases in the process. 
RNA recognition motif, RNP-1 is a putative RNA-binding domain of about 90 amino acids that are known to bind single-stranded RNAs.
It was found in many eukaryotic proteins.
The largest group of single strand RNA-binding protein is the eukaryotic RNA recognition motif (RRM) family that contains an eight amino acid RNP-1 consensus sequence.
RRM proteins have a variety of RNA binding preferences and functions, and include heterogeneous nuclear ribonucleoproteins (hnRNPs), proteins implicated in regulation of alternative splicing (SR, U2AF2, Sxl), protein components of small nuclear ribonucleoproteins (U1 and U2 snRNPs), and proteins that regulate RNA stability and translation (PABP, La, Hu).
The RRM in heterodimeric splicing factor U2 snRNP auxiliary factor appears to have two RRM-like domains with specialised features for protein recognition.
The motif also appears in a few single stranded DNA binding proteins.
The typical RRM consists of four anti-parallel beta-strands and two alpha-helices arranged in a beta-alpha-beta-beta-alpha-beta fold with side chains that stack with RNA bases.
A third helix is present during RNA binding in some cases.
The RRM is reviewed in a number of publications.