Low prevalence of connexin-40 gene variants in atrial tissues and blood from atrial fibrillation subjects

BMC Medical Genetics

Jonathan D Smith³  Mina K Chung³  John Barnard²  David R Van Wagoner³  Robert C Wirka⁴  Gregory D Tchou¹ 

[1] Department of Cell Biology, 9500 Euclid Ave, Cleveland, OH, 44106, USA;Department of Quantitative Health Sciences, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH, 44106, USA;Department of Cardiovascular Med, 9500 Euclid Ave, Cleveland, OH, 44106, USA;Cleveland Clinic Lerner College of Med of Case Western Reserve University, 9500 Euclid Ave, Cleveland, OH, 44106, USA

关键词: Allelic expression imbalance;    Genetics;    Ion channels;    Connexins;    Atrial fibrillation;   

Others  :  1177779
DOI  :  10.1186/1471-2350-13-102

 received in 2011-11-07, accepted in 2012-11-01,  发布年份 2012

【 摘 要 】

Background

The atrial gap junction protein connexin-40 (Cx40) has been implicated to play an important role in atrial conduction and development of atrial fibrillation (AF). However, the frequency of Cx40 mutations in AF populations and their impact on Cx40 expression remains unclear. In this study, we sought to identify polymorphisms in the Cx40 gene GJA5, investigate the potential functional role of these polymorphisms, and determine their allelic frequencies. The prevalence of nonsynonymous Cx40 mutations in blood and atrial tissue was also compared to mutation frequencies reported in prior studies.

Methods

We conducted direct sequencing of the GJA5 coding and 3^′ UTR regions in blood samples from 91 lone AF subjects and 67 atrial tissue-derived samples from a lone cohort, a mixed AF cohort, and several transplant donors. Reporter gene transfection and tissue allelic expression imbalance assays were used to assess the effects of a common insertion/deletion polymorphism on Cx40 mRNA stability and expression.

Results

We identified one novel synonymous SNP in blood-derived DNA from a lone AF subject. In atrial tissue-derived DNA from lone and mixed AF subjects, we observed one novel nonsynonymous SNP, one rare previously reported synonymous SNP, and one novel 3^′ UTR SNP. A previously noted 25 bp insertion/deletion polymorphism in the 3^′ UTR was found to be common (minor allele frequency = 0.45) but had no effect on Cx40 mRNA stability and expression. The observed prevalence of nonsynonymous Cx40 mutations in atrial tissues derived from lone AF subjects differed significantly (p = 0.03) from a prior atrial tissue study reporting a high mutation frequency in a group of highly selected young lone AF subjects.

Conclusions

Our results suggest that Cx40 coding SNPs are uncommon in AF populations, although rare mutations in this gene may certainly lead to AF pathogenesis. Furthermore, a common insertion/deletion polymorphism in the Cx40 3^′ UTR does not appear to play a role in modulating Cx40 mRNA levels.

【 授权许可】

   
2012 Tchou et al.; licensee BioMed Central Ltd.

【 图 表 】

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【 参考文献 】

• [1]Go AS, Hylek EM, Phillips KA, Chang Y, Henault LE, Selby JV, Singer DE: Prevalence of diagnosed atrial fibrillation in adults: national implications for rhythm management and stroke prevention: the AnTicoagulation and Risk Factors in Atrial Fibrillation (ATRIA) Study. JAMA 2001, 285(18):2370-2375.
• [2]Miyasaka Y, Barnes ME, Gersh BJ, Cha SS, Bailey KR, Abhayaratna WP, Seward JB, Tsang TS: Secular trends in incidence of atrial fibrillation in Olmsted County, Minnesota, 1980 to 2000, and implications on the projections for future prevalence. Circulation 2006, 114(2):119-125.
• [3]Naccarelli GV, Varker H, Lin J, Schulman KL: Increasing prevalence of atrial fibrillation and flutter in the United States. Am J Cardiol 2009, 104(11):1534-1539.
• [4]Wolf PA, Abbott RD, Kannel WB: Atrial fibrillation as an independent risk factor for stroke: the Framingham Study. Stroke 1991, 22(8):983-988.
• [5]Benjamin EJ, Wolf PA, D’Agostino RB, Silbershatz H, Kannel WB, Levy D: Impact of atrial fibrillation on the risk of death: the Framingham Heart Study. Circulation 1998, 98(10):946-952.
• [6]Stewart S, Hart CL, Hole DJ, McMurray JJ: A population-based study of the long-term risks associated with atrial fibrillation: 20-year follow-up of the Renfrew/Paisley study. Am J Med 2002, 113(5):359-364.
• [7]Bagwe S, Berenfeld O, Vaidya D, Morley GE, Jalife J: Altered right atrial excitation and propagation in connexin40 knockout mice. Circulation 2005, 112(15):2245-2253.
• [8]Kirchhoff S, Nelles E, Hagendorff A, Kruger O, Traub O, Willecke K: Reduced cardiac conduction velocity and predisposition to arrhythmias in connexin40-deficient mice. Curr Biol 1998, 8(5):299-302.
• [9]Gollob MH, Jones DL, Krahn AD, Danis L, Gong XQ, Shao Q, Liu X, Veinot JP, Tang AS, Stewart AF, et al.: Somatic mutations in the connexin 40 gene (GJA5) in atrial fibrillation. N Engl J Med 2006, 354(25):2677-2688.
• [10]Dupays L, Mazurais D, Rucker-Martin C, Calmels T, Bernot D, Cronier L, Malassine A, Gros D, Theveniau-Ruissy M: Genomic organization and alternative transcripts of the human Connexin40 gene. Gene 2003, 305(1):79-90.
• [11]Wirka RC, Gore S, Van Wagoner DR, Arking DE, Lubitz SA, Lunetta KL, Benjamin EJ, Alonso A, Ellinor PT, Barnard J, et al.: A Common Connexin-40 Gene Promoter Variant Affects Connexin-40 Expression in Human Atria and Is Associated With Atrial Fibrillation. Circ Arrhythm Electrophysiol 2011, 4(1):87-93.
• [12]Claycomb WC, Lanson NA Jr, Stallworth BS, Egeland DB, Delcarpio JB, Bahinski A, Izzo NJ Jr: HL-1 cells: a cardiac muscle cell line that contracts and retains phenotypic characteristics of the adult cardiomyocyte. Proc Natl Acad Sci U S A 1998, 95(6):2979-2984.
• [13]Gray LC, Hughes TR, van den Berg CW: Binding of human antigen R (HuR) to an AU-rich element (ARE) in the 3′untranslated region (3′UTR) reduces the expression of decay accelerating factor (DAF). Mol Immunol 2010, 47(16):2545-2551.
• [14]Clifford RJ, Edmonson MN, Nguyen C, Scherpbier T, Hu Y, Buetow KH: Bioinformatics tools for single nucleotide polymorphism discovery and analysis. Ann N Y Acad Sci 2004, 1020:101-109.
• [15]Ge B, Gurd S, Gaudin T, Dore C, Lepage P, Harmsen E, Hudson TJ, Pastinen T: Survey of allelic expression using EST mining. Genome Res 2005, 15(11):1584-1591.
• [16]Johnson AD, Zhang Y, Papp AC, Pinsonneault JK, Lim JE, Saffen D, Dai Z, Wang D, Sadee W: Polymorphisms affecting gene transcription and mRNA processing in pharmacogenetic candidate genes: detection through allelic expression imbalance in human target tissues. Pharmacogenet Genomics 2008, 18(9):781-791.
• [17]Bray NJ, Buckland PR, Owen MJ, O’Donovan MC: Cis-acting variation in the expression of a high proportion of genes in human brain. Hum Genet 2003, 113(2):149-153.
• [18]Sherry ST, Ward MH, Kholodov M, Baker J, Phan L, Smigielski EM: Sirotkin K: dbSNP: the NCBI database of genetic variation. Nucleic Acids Res 2001, 29(1):308-311.
• [19]A map of human genome variation from population-scale sequencing Nature 2010, 467(7319):1061-1073.
• [20]Adzhubei IA, Schmidt S, Peshkin L, Ramensky VE, Gerasimova A, Bork P, Kondrashov AS, Sunyaev SR: A method and server for predicting damaging missense mutations. Nat Methods 2010, 7(4):248-249.
• [21]Levy S, Sutton G, Ng PC, Feuk L, Halpern AL, Walenz BP, Axelrod N, Huang J, Kirkness EF, Denisov G, et al.: The diploid genome sequence of an individual human. PLoS Biol 2007, 5(10):e254.
• [22]Firouzi M, Ramanna H, Kok B, Jongsma HJ, Koeleman BP, Doevendans PA, Groenewegen WA, Hauer RN: Association of human connexin40 gene polymorphisms with atrial vulnerability as a risk factor for idiopathic atrial fibrillation. Circ Res 2004, 95(4):e29-e33.
• [23]Juang JM, Chern YR, Tsai CT, Chiang FT, Lin JL, Hwang JJ, Hsu KL, Tseng CD, Tseng YZ, Lai LP: The association of human connexin 40 genetic polymorphisms with atrial fibrillation. Int J Cardiol 2007, 116(1):107-112.
• [24]Sampath P, Mazumder B, Seshadri V, Fox PL: Transcript-selective translational silencing by gamma interferon is directed by a novel structural element in the ceruloplasmin mRNA 3′ untranslated region. Mol Cell Biol 2003, 23(5):1509-1519.
• [25]Serre D, Gurd S, Ge B, Sladek R, Sinnett D, Harmsen E, Bibikova M, Chudin E, Barker DL, Dickinson T, et al.: Differential allelic expression in the human genome: a robust approach to identify genetic and epigenetic cis-acting mechanisms regulating gene expression. PLoS Genet 2008, 4(2):e1000006.
• [26]Yang YQ, Liu X, Zhang XL, Wang XH, Tan HW, Shi HF, Jiang WF, Fang WY: Novel connexin40 missense mutations in patients with familial atrial fibrillation. Europace 2010, 12(10):1421-1427.
• [27]Ellinor PT, Lunetta KL, Albert CM, Glazer NL, Ritchie MD, Smith AV, Arking DE, Muller-Nurasyid M, Krijthe BP, Lubitz SA, et al.: Meta-analysis identifies six new susceptibility loci for atrial fibrillation. Nat Genet 2012, 44(6):670-675.