Abstract:
The invention discloses a method for detecting polymorphism in the angiotensin converting enzyme by means of a chain amplification technique, the aim being to detect whether or not the sequence of nucleotides 1451-1738 of intron 16 is present in the human angiotensin converting enzyme gene.

Description:
BACKGROUND OF THE INVENTION 
     The cloning of cDNAs corresponding to the gene coding for the human angiotensin converting enzyme (ACE) has made it possible to use it as a DNA probe for investigating DNA polymorphism in this gene in man. 
     The interest of this research in DNA polymorphisms was multiple. On the one hand, it was known that the plasma level of the ACE was stable and the effect of an allele on a major gene had been suggested following a familial study. It was thus logical to want to know whether the ACE gene itself was responsible for the effect of the major gene and to discover the importance of the interpersonal differences of the ACE level as a function of the genotype. On the other hand, it was of interest to have available a genetic marker which could be used to test the involvement of the gene in certain diseases, such as hypertension, by association or binding studies. 
     From the clinical point of view, the plasma level of the ACE was measured in 80 normal individuals and their genotypes were determined. Significant differences were observed between the ACE level of the individuals as a function of their ACE genotype (Rigat, B. et al. (1990), Journal of Clinical Investigation, 1343-1346). 
     The research into polymorphism was conducted by using the Southern blot method. The DNA of different individuals was digested by several restriction enzymes. After hybridization with the cDNA probe for ACE, it was apparent that some fragments did not have the same size in all individuals. The fact that the difference in size between the polymorphic fragments was apparently very similar with different enzymatic cleavages led to the conclusion that this polymorphism was due to the presence or absence of a DNA sequence (designated hereafter insertion) within the ACE gene. 
     SUMMARY OF THE INVENTION 
     The invention follows from the location of the insertion in intron 16 (SEQ ID NO:3) of the gene, i.e. between exon 16 (SEQ ID NO:2)and exon 17 (SEQ ID NO:4) after the nucleotide structure of this intron had itself been determined. The sequencing of the intron, and more particularly of the regions flanking the insertion and the insertion itself has enabled the inventors to determine the nature of the insertion. It is a repetitive sequence of the Alu type. 
     Hence, the subject of the invention is products, in particular nucleotide fragments deriving from this observation, more particularly primers which can be used in gene amplification procedure, for example amplification by PCR (&#34;polymerase chain reaction&#34;) type. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows to the general organization of intron 16 in alleles derived from subjects who possess the insertion (II) and from those who lack it (DD), respectively. 
     FIGS. 2 (a), 2 (b) and 2 (c) present the sequences of intron 16 and exons (exons 16 and 17 SEQ ID NO:2 and SEQ ID NO:4, respectively) which surround and flank intron 16 (SEQ ID NO:3) in the ACE gene. Only the nucleotides (nt) of intron 16 (SEQ ID:8) are numbered. FIG. 2a also includes intron 15 (SEQ ID NO:1). FIG. 2b also includes intron 17 (SEQ ID NO:5). FIG. 2c includes exon 18 (SEQ ID NO:6) and intron 18 (SEQ ID NO:7). 
     The sequence which is present or absent depending on the individual comprises the nucleotides 1451 to 1738 (SEQ ID NO:8). 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The invention relates more particularly to any DNA fragment comprising at least 8 nucleotides and characterized by a sequence contained in the DNA of intron 16 (nt 1-1856 shown in FIG. 1) (SEQ ID NO:3) and, consequently, having a maximum of 1856 nucleotides. However, it relates more particularly to any one of the following fragments. 
     DNA fragment, characterized in that it contains all or part of the sequence nt. 1451-1738 (SEQ ID NO:8) (insertion); 
     DNA fragment, characterized in that it is placed entirely within the insertion. 
     DNA fragment, characterized in that it contains at least one of the regions flanking the above-mentioned insertion. 
     DNA fragment, characterized in that its sequence lies outside the insertion sequence nt. 1451-1738 (SEQ ID NO:8). 
     Advantageously, these various DNA fragments comprise from 15 to 40 nucleotides. 
     The invention relates more particularly to pairs of distinct fragments selected from those previously mentioned, which can be used to design primers which can be used in sequence amplification procedures, in particular of the PCR type, these distinct fragments comprising non-overlapping sequences of nucleotides. 
     These primer pairs are, for example: 
     characterized in that their intrinsic sequences are such that the intermediate sequence placed in the DNA of the intron between the two sequences which, within the same intron, correspond to those of these two primers, overlaps at least one of the ends (nt.1451 or 1738) of the insertion (nt. 1451-1738) (SEQ ID NO 18) and the flanking region which is adjacent to it. 
     characterized in that the sequence of one of the two primers overlaps one of the ends (nt.1451 or 1738) of the insertion or lies outside the latter and in that the sequence of the other primer overlaps the other end (nt.1738 or 1451) of the insertion or also lies outside the latter. 
     characterized in that the sequence of one of the two primers overlaps one of the ends (nt.1451 or 1738) of the insertion or lies outside the latter and in that the sequence of the other primer is included in the insertion. 
     Hence the invention relates more particularly to the procedure for the detection of polymorphism within the gene for the angiotensin I converting enzyme (ACE gene), characterized by the search for, in particular by hybridization or sequence amplification procedures, and the detection of the presence or absence of the insertion nt.1451-1738 (SEQ ID NO:8) within intron 16 (SEQ ID NO:3) of the ACE gene. For example, a procedure of the PCR type is used by employing one of the primer pairs defined hereafter and an attempt is made to detect amplified chains likely to comprise both at least one of the terminal parts of the insertion and at least one of the two flanking regions. 
     A positive result then reveals the presence of the insertion, whereas a negative result signals the absence of such an insertion. 
     It will be obvious that the specialist skilled in the art may then have recourse to any standard procedure to have access to the genomic DNA of the cells obtained from the subject (in particular from his blood serum) whose polymorphism is to be studied. 
     The procedure according to the invention may, for example, be implemented as follows. It comprises: 
     a) the placing of the biological sample under study containing the ACE gene, in particular intron 16 (SEQ ID NO:3), made accessible beforehand to a first primer under conditions allowing the hybridization between this primer and the DNA of the gene, in the presence of nucleoside triphosphates and an agent inducing polymerization (polymerase), wherein the polymerization starts from these primers hybridized to the cDNA of the gene in order to produce--where appropriate--a duplex formed between the elongation product of the primer hybridized with the intron, 
     b) the denaturation of the duplex obtained at step a) so as to &#34;separate&#34; the elongation product of the primer from the DNA to be detected, 
     c) the placing of the elongation product obtained in contact with the second primer which has a nucleotide sequence (1) which is not complementary to a sequence of the elongation product previously formed, 
     d) where necessary, the repetition of the steps a), b) and c) in the presence of the first and second primers used in excess and reagents necessary for the production of further elongation products used in turn as matrices for additional syntheses until a sufficient quantity is obtained for the elongation products of the primers used to be detected. 
     e) the detection (where necessary) of the presence of the elongation products characteristic of the presence of at least a part of the insertion (nt.1451-1738) (SEQ ID NO:8). 
     For more details concerning the method relating to the detection procedure described above or for the development of variants of this procedure, it will be useful for the person skilled in the art to refer to the principles described in the patents U.S. Pat. No. 4,683,202 and U.S. Pat. No. 4,683,195. 
     As a result of using two primers located on either side of at least a part of the polymorphic region, it is possible to easily visualize the difference in size due to the presence or absence of the insertion, for example by migration of the amplified fragments on agarose gel and staining with ethidium bromide, wherein the possibility to determine the genotypes of the individuals under study by means of the amplification reaction of the DNA. 
     Consequently, the invention provides a procedure for the determination of polymorphism affecting normal and abnormal ACE values, in particular for the study of its impact on diseases (for example, in diabetic individuals suffering from a sarcoidosis) which, according to observations already made, were accompanied by an increase in ACE plasma levels. 
     Similarly, the results likely to be obtained by the implementation of the procedure according to the invention ought to make possible a better understanding of the degree to which ACE polymorphism is implicated in the metabolism of vasoactive peptides and in the mechanisms of hypertension. 
     The procedure according to the invention can be used with particular advantage to the in vitro diagnosis of atherosclerosis, granulomatous diseases and complications in diabetes mellitus, 
     
         __________________________________________________________________________SEQUENCE LISTING(1) GENERAL INFORMATION:(iii) NUMBER OF SEQUENCES: 8(2) INFORMATION FOR SEQ ID NO:1:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 82 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: DNA (genomic)(vii) IMMEDIATE SOURCE:(B) CLONE: Intron 15(xi) SEQUENCE DESCRIPTION: SEQ ID NO:1:AATGGGGCCTGGGGGCAGTGCAGGCCCCAGAGAGACCAAGTGCAAAAGGAGTACAGCTCA60TTGCCTCTCCTTCCTCCTGCAG82(2) INFORMATION FOR SEQ ID NO:2:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 88 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: DNA (genomic)(vii) IMMEDIATE SOURCE:(B) CLONE: Exon 16(xi) SEQUENCE DESCRIPTION: SEQ ID NO:2:TACAACAAGATCCTGTTGGATATGGAAACCACCTACAGCGTGGCCACTGTGTGCCACCCG60AATGGCAGCTGCCTGCAGCTCGAGCCAG88(2) INFORMATION FOR SEQ ID NO:3:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 1856 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: DNA (genomic)(vii) IMMEDIATE SOURCE:(B) CLONE: Intron 16 of human angiotension convertingenzyme (ACE) gene(xi) SEQUENCE DESCRIPTION: SEQ ID NO:3:GTGAGAGCTCATGTGCAGGCTGAGTGAGAGGCGAGGGCTGGGACTGGCATGGGGCCCGGG60GGTGCTGGGTGAGAGCACAGAGTTGGGCTCCCCTCGCTCTTGGGGTCAGCGTGCCCAGGA120AATGCCCTTTCTTGTTTTCCACGAGGGGGGCTTCTCTGCCCACTGAGAGCCGGCACCTAC180TTCATACCATGCCCCGATCAGCTGCCCCTCCCTCAGAACCGCCCTCTGCTTAAGGGTGTC240CACTCTCTCCTGTCCTCTCTGCATGCCGCCCCTCAGAGCAGCGGGATCTCAAAGTTATAT300TTCATGGGCTTGGACTCCAAATGGGGGGAACTCGGGGACACTAGCTCCCCCCGGCCTCCT360TTCGTGACCCTGCCCTTGACTTCCTCACCTTCTCTGTCTTTCCTGAGCCCCTCTCCCAGC420ATGTGACTGATAAGGAAATTGAGTCACACAGCCCCTGAAAGCGCCAGACTAGAACCTGAG480CCTCTGATTCCTCTCACTTCCCTCCCCTACCCTGCCACTTCCTACTGGATAGAAGTAGAC540AGCTCTTGACTGTCCTCTTTTCTCCCCACTGGCTGGTCCTTCTTAGCCCCAGCCCGTTTG600AAAGAGCTCACCCCCGACACAAGGACCCGCACACAGATACCTCCCAGCTCCCTCTCAACC660CACCCTTTCCAGGGTTGGAGAACTTGAGGCATAAACATTCTTCCATGAGGAATCTCCACC720CAGAAATGGGTCTTTCTGGCCCCCAGCCCAGCTCCCACATTAGAACAATGACAAATAGAA780GGGGAAATGGAAAATAAACAGGAGAAACGGTTTTCCCAGGACAGGGTTTGGCCTACAAGT840TGTGGATGTGGGTACCCATGCCAAGTGTGAGGGGAGGCTGGCCGGGTGTGGTGGCTCATG900CTCTAATCCCAGCACTTTGGGAGGCCAAGGTGAGTAGATCACTTGAGGCCGGGAGTTTGA960GACCAGCCTGGCCAACATGGTGAAACCCCATCTGTACTAAAAATACAAAAGTTAGCTGGG1020CGTGGTGGTAGATGCCTGTAGTCCCAGCTACTTGGGAGGCTGAGGCATGAGAATCGCTTG1080AGCCCAGCCAGGGCAATACAGCAAGACCCCGTCTCTACAAATAAAATACAAAAAATTAGT1140TGGATGTGGTGGTGCATGCCTGTAGTCCTAGCTGCTAGGGAGGCTGAGATGGAAGGATTG1200CTTGAGCCTGGGAGGTCAAGGCTGCAGTGAGCCGAGATGGCGCCACTGCACTCCAGCCTG1260GGCAACAGAGTGAGACCCTGTCTCAGAAAGAAAAAAAAAAAAAAAGGAGAGGAGAGAGAC1320TCAAGCACGCCCCTCACAGGACTGCTGAGGCCCTGCAGGTGTCTGCAGCATGTGCCCAGG1380CCGGGGACTCTGTAAGCCACTGCTGGAGACCACTCCCATCCTTTCTCCCATTTCTCTAGA1440CCTGCTGCCTATACAGTCACTTTTTTTTTTTTTTTGAGACGGAGTCTCGCTCTGTCGCCC1500AGGCTGGAGTGCAGTGGCGGGATCTCGGCTCACTGCAACGTCCGCCTCCCGGGTTCACGC1560CATTCTCCTGCCTCAGCCTCCCAAGTAGCTGGGACCACAGCGCCCGCCACTACGCCCGGC1620TAATTTTTTGTATTTTTAGTAGAGACGGGGTTTCACCGTTTTAGCCGGGATGGTCTCGAT1680CTCCTGACCTCGTGATCCGCCCGCCTCGGCCTCCCAAAGTGCTGGGATTACAGGCGTGAT1740ACAGTCACTTTTATGTGGTTTCGCCAATTTTATTCCAGCTCTGAAATTCTCTGAGCTCCC1800CTTACAAGCAGAGGTGAGCTAAGGGCTGGAGCTCAAGCCATTCAACCCCCTACCAG1856(2) INFORMATION FOR SEQ ID NO:4:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 144 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: DNA (genomic)(vii) IMMEDIATE SOURCE:(B) CLONE: Exon 17(xi) SEQUENCE DESCRIPTION: SEQ ID NO:4:ATCTGACGAATGTGATGGCCACATCCCGGAAATATGAAGACCTGTTATGGGCATGGGAGG60GCTGGCGAGACAAGGCGGGGAGAGCCATCCTCCAGTTTTACCCGAAATACGTGGAACTCA120TCAACCAGGCTGCCCGGCTCAATG144(2) INFORMATION FOR SEQ ID NO:5:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 149 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: DNA (genomic)(vii) IMMEDIATE SOURCE:(B) CLONE: Intron 17(xi) SEQUENCE DESCRIPTION: SEQ ID NO:5:GTGAGTCCCTGCTGCCAACATCACTGGCACTTGGGTCCCTTCATTTTCCTCAAAGAGGTG60CTGTGAAACCCCAAGCCTAGGAAAAGGTAGATCCCTGGAGGAGGCAGGTAATGTGGTGTT120CGGAGAGCCTGGCTGTGTCCCCTCTGTAG149(2) INFORMATION FOR SEQ ID NO:6:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 192 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: DNA (genomic)(vii) IMMEDIATE SOURCE:(B) CLONE: Exon 18(xi) SEQUENCE DESCRIPTION: SEQ ID NO:6:GCTATGTAGATGCAGGGGACTCGTGGAGGTCTATGTACGAGACACCATCCCTGGAGCAAG60ACCTGGAGCGGCTCTTCCAGGAGCTGCAGCCACTCTACCTCAACCTGCATGCCTACGTGC120GCCGGGCCCTGCACCGTCACTACGGGGCCCAGCACATCAACCTGGAGGGGCCCATTCCTG180CTCACCTGCTGG192(2) INFORMATION FOR SEQ ID NO:7:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 138 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: DNA (genomic)(vii) IMMEDIATE SOURCE:(B) CLONE: Intron 18(xi) SEQUENCE DESCRIPTION: SEQ ID NO:7:GTAAGGGCACATGTCGGGCCTTGAGGAGGGTAAAGACGGACCACAGTGTGAGTGAGGGTT60GGGACAGGGCTGACTAGAGGGTAGGGAGCAGGCTGGGGACTGAGAGACTCCAGCCCTGTG120GGGATGGTTGCCCAGGCT138(2) INFORMATION FOR SEQ ID NO:8:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 288 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: DNA (genomic)(xi) SEQUENCE DESCRIPTION: SEQ ID NO:8:ATACAGTCACTTTTTTTTTTTTTTTGAGACGGAGTCTCGCTCTGTCGCCCAGGCTGGAGT60GCAGTGGCGGGATCTCGGCTCACTGCAACGTCCGCCTCCCGGGTTCACGCCATTCTCCTG120CCTCAGCCTCCCAAGTAGCTGGGACCACAGCGCCCGCCACTACGCCCGGCTAATTTTTTG180TATTTTTAGTAGAGACGGGGTTTCACCGTTTTAGCCGGGATGGTCTCGATCTCCTGACCT240CGTGATCCGCCCGCCTCGGCCTCCCAAAGTGCTGGGATTACAGGCGTG288__________________________________________________________________________