Functional Regulation at the 9p21.3 Genetic Risk Locus in Coronary Artery Disease (CAD)

Abstract

The first genetic CAD risk locus to be identified by genome-wide association studies, single nucleotide polymorphisms (SNPs) at 9p21.3 predispose to increased risk of CAD. By bioinformatics scan analysis of the 9p21.3 locus; we interrogated the 59 linked SNPs over the 53,202bp to identify putative transcription factor-binding consensus sequences. We hypothesize that some genetic polymorphisms at the 9p21.3 locus are functional and will disrupt specific regulatory sequences within enhancers. Here, I investigated how polymorphisms affect TEAD-dependent regulation at the 9p21.3 locus, and also how polymorphisms affect GATA factor-dependent regulation at the 9p21.3 locus, using cultured HEK293 and primary human aortic smooth muscle cells (HAoSMCs) to transfect the pGL3-promoter plasmid constructs containing the reference or risk variant sequences (rs10611656, rs4977757, rs10757269, rs9632885). We showed by luciferase reporter assay that the risk allele of the SNPs disrupt activation by various TEAD transcription factors. We also performed electrophoretic mobility shift assay (EMSA) to test for allele-specific transcription factor binding that affect the family of TEAD transcription factors and the GATA factors. EMSA showed binding of TEAD3 and TEAD4, and differential binding for both GATA genotypes, and luciferase reporter assay confirmed that TEAD3 and TEAD4 activate the non-risk but not the risk allele, and for GATA factors no significant activation was shown. Our investigations lead us to conclude that rs10811656 and rs4977757 are functional and disrupt specific TEAD regulatory sequences within enhancers