Study On The Pathogenic Mechanisms Of Polymorphisms In 3’UTR Of NOTCH1,NOTCH2 And JAG1 Genes In Conotruncal Heart Defects

Background:Congenital heart disease,with incidence up to 6‰-8‰ in liveborn infants,is one of the most common congenital malformations.Conotruncal heart defects(CTD)is a kind of congenital heart diseases caused by dysplasia of cardiac outflow tract,and accounts for 25-30% of non-syndromic congenital heart diseases.Little is known about its pathogenic genes.Notch signaling pathway plays an important role in the development of embryonic cardiac outflow tract.Mutations of the key genes NOTCH1,NOTCH2 and JAG1 can lead to ventricular outflow tract abnormalities.However,most of the current studies on NOTCH1,NOTCH2 and JAG1 genes have focused on their coding regions,and studies on their noncoding regions and CHD have not been reported.Objective: To explore the correlation and possible pathogenic mechanisms between CTD and variations in 3’untranslated regions(3’UTR)of NOTCH1,NOTCH2 and JAG1 genes.Materials and methods:Six hundred CTD patients without 22q11 deletion and three hundred healthy controls were enrolled in this case-control study.Whole genomic DNA was extracted from every subject.Mutations and single nucleotide polymorphisms(SNP)in 3’UTR of NOTCH1,NOTCH2 and JAG1 genes were detected by highthroughput sequencing.The allelic and genotypic distributions of the SNPs in two groups were compared in disease association analysis.miRNAs that could bind to SNP rs835575 or SNP rs835576 were predicted by websites such as Target Scan,DIANAmicro T and micro RNA.org.The interaction between predicted miRNAs and their corresponding SNP was verified by luciferase assays and real-time fluorescence quantitative PCR.Results: A novel mutation in 3’UTR of NOTCH1 and three novel mutations in 3’UTR of JAG1 were detected in CTD group.Three SNPs(rs835575,rs835576 and rs699779)in 3’UTR of NOTCH2 and two SNPs(rs3840074,rs8708)in 3’UTR of JAG1 may be associated with susceptibility to CTD.Hsa-miR-142-5p and hsa-miR-218-5p affected the translation of NOTCH2 by interacting with rs835575 and rs835576,respectively.Conclusion: Mutations and SNPs in 3’UTR of NOTCH1,NOTCH2 and JAG1 may be associated with the occurrence of CTD.