Decreased activity of RCAN1-4 promoter is a potentially risk factor for congenital heart defects in Han Chinese population

【摘要】：Objective The regulator of calcineurin 1(RCAN1) gene is located at human chromosome 21 q22.12,which region is thought to be associated with congenital heart defects(CHD) observed in Do wn syndrome(DS). Human chromosome 21 q22.12 habors more than 50 genes, but none has be en proved to be responsible for the pathogenesis of CHD in DS. Calcineurin/NFAT signal transdu ction pathway that plays important roles for heart development and RCAN1 encodes a regulatory protein of calcineurin/NFAT signaling. Therefore, we hypothesized that RCAN1 also play a role in prevention of CHD. RCAN1-4 regulatory region are also related to CHDs. Method To test our hypothesis, we sequenced the 5 kb of upstream regulatory region of the RCA N1 in 868 CHD patients and 1320 controls in a Han Chinese population. Then we used q-PCR, lu ciferase assay,EMSA and Bioinformatics analysis method to complete the study. Result The five single nucleotide polymorphisms(SNPs) were identified and three of which are in strong linkage disequilibrium and the minor alleles are associated with higher CHD risk(for rs2243890 chosen as tag SNP, p = 6.51 e-06, OR(95% CI) = 1.62(1.29-2.03)). To further analyze if the se SNP are functional allele we performed functional analysis. Our ouciferase reporter assay sho wed that the minor G allele of rs2243890 has lower transcriptional activity than major A allele of rs2243890 in both human heart tissues and three human and mouse heart cell lines. The electroph oretic mobility shift assay also suggests that the minor allele exhibit higher binding affinity with cer tain transcription repressors.Conclusion Our results indicate that a moderately lower RCAN1 activity potentially increases CH D risk in the Han Chinese population, providing new insight in the study of CHD etiology.