Genetic analysis of the promoter region of the GATA4 gene in patients with ventricular septal defects.
ABSTRACT Ventricular septal defects (VSDs) are the most common type of congenital heart diseases (CHDs). To date, the genetic causes for sporadic VSDs remain largely unknown. GATA transcription factor 4 (GATA4) is a zinc-finger transcription factor that is expressed in developing heart and adult cardiomyocytes. Mutations in the coding region of the GATA4 gene have been identified in CHD patients, including VSD. As the GATA4 factor is a dosage-sensitive regulator, we hypothesized that the promoter region variants of the GATA4 gene may be genetic causes of VSD. In this study, we analyzed the promoter region of the GATA4 gene by bidirectional sequencing in 172 VSD patients and 171 healthy controls. The results showed that 5 heterozygous sequence variants (NG_008177:g.4071T>C, NG_008177:g.4148C>A, NG_008177:g.4566C>T, NG_008177:g.4653G>T, and NG_008177:g.4690G>deletion) within the promoter region of the GATA gene were identified in 5 VSD patients, but in none of controls. One heterozygous sequence variant (g.4762C>A) was found only in one control, which may have no functional significance. A functional analysis revealed that the transcriptional activity of variant NG_008177:g.4566C>T was reduced significantly, whereas the transcriptional activities of the variants (NG_008177:g.4071T>C, NG_008177:g.4148C>A, NG_008177:g.4653G>T, and NG_008177:g.4690G>deletion) were increased significantly compared with the wild-type GATA4 gene promoter. As GATA4 is a dosage-sensitive regulator during development, our data suggest that these sequence variants within the promoter region of the GATA4 gene may contribute to the VSD etiology by altering its gene expression. Additional studies in experimental animals will deepen our understanding of the genetic basis of VSD and shed light on designing novel molecular therapies for adult VSD patients carrying these variants.
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ABSTRACT: NKX2-5 is a transcriptional factor, which plays an important role in heart formation and development. Two genetic variants in the coding region of NKX2-5, 63A>G (rs2277923) and 606G>C (rs3729753), have been investigated in the risk of congenital heart disease (CHD), although with inconsistent results. Thus, a meta-analysis was performed to clarify the associations between the two variants and CHD risk in the Chinese population. Relevant studies were identified by searching PubMed, ISI Web of Science and CNKI databases and by reviewing the reference lists of retrieved articles. Then, the data from eligible studies were combined in an allelic model. A total of 7 and 4 studies were ultimately included for 63A>G and 606G>C, respectively. The results of overall meta-analyses showed that significant association was detected for 63A>G (OR = 1.26, 95% CI = 1.02-1.56, P heterogeneity = 0.009, I (2) = 65.1%), but not for 606G>C (OR = 1.22, 95% CI = 0.75-1.96, P heterogeneity = 0.412, I (2) = 0.0%). Regarding 63A>G variant, positive results were also obtained in the subgroups of atrial septal defect and large-sample-size study. Besides, the sensitivity analysis indicated that significant association was still detected after deletion of the individual studies with positive result and striking heterogeneity. Our results revealed that the 63A>G variant in NKX2-5, but not the 606G>C, may contribute to CHD risk for Chinese.PLoS ONE 01/2013; 8(8):e70979. · 3.73 Impact Factor
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ABSTRACT: Mutations in cardiac transcription factor genes, such as GATA-4, NKX2-5 and TBX5 genes, have been associated to the patients with familial and isolated congenital heart disease (CHD). Little work has been done on the epigenetic causes for CHD. Sirtuis are highly conserved NAD-dependent class III deacetylases. In mammals, there are seven members of surtuin family, SIRT1–SIRT7. SIRT1, the closest to yeast Sir2, has deacetylase activity and ADP-ribosyltransferase activity. SIRT1 has been involved in many cellular processes and implicated in human diseases, such as obesity, type 2 diabetes, cancer and neurodegenerative diseases. We hypothesized that altered levels of SIRT1 gene expression, rather than mutations in SIRT1 gene, may contribute to the human diseases. In this study, we genetically analyze the SIRT1 gene promoter in patients with ventricular septal defects (VSD) (n = 333) and ethic-matched healthy controls (n = 348). In all, six single-nucleotide polymorphisms (SNPs) and twelve heterozygous sequence variants were identified. Four novel heterozygous variants, g.69643693A > G, g.69643963A > T, g.69643971G > A and g.69644366Ins, were found in six VSD patients, but in none of controls. Six SNPs and variants, g.69643707A > C (rs35706870), g.69643874C > A, g.69644209C > G, g.69644213G > A, g.69644268T > A and g.69644441G > A, were only identified in controls. The other SNPs and variants were found in both groups with similar frequencies. Therefore, the variants within the SIRT1 gene promoter identified in VSD patients may alter the transcriptional activities of SIRT1 gene promoter. Changed SIRT1 protein levels may contribute to the VSD etiology by affecting the activities of its substrates.Biochemical and Biophysical Research Communications 09/2012; 425(4):741–745. · 2.41 Impact Factor
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ABSTRACT: Mortality in patients with congenital heart disease (CHD) is significantly increased even with successful surgeries. The main causes are late cardiac complications, such as heart failure and arrhythmia, probably due to genetic defects. To date, genetic causes for CHD remain largely unknown. NKX2-5 gene encodes a highly conserved homeobox transcription factor, which is essential to the heart development in embryos and cardiac function in adults. Mutations in NKX2-5 gene have been implicated in diverse types of CHD, including ventricular septal defect (VSD). As NKX2-5 is a dosage-sensitive regulator, we have speculated that changed NKX2-5 levels may mediate CHD development by influencing cardiac gene regulatory network. In previous studies, we have analyzed the NKX2-5 gene promoter and a proximal enhancer in VSD patients. In the present study, we further genetically and functionally analyzed an upstream enhancer of the NKX2-5 gene in large cohorts of VSD patients (n=340) and controls (n=347). Two novel heterozygous DNA sequence variants (DSVs), g.17483576C>G and g.17483564C>T, were identified in three VSD patients, but in none of controls. Functionally, these two DSVs significantly decreased the activity of the enhancer (P<0.01). Another novel heterozygous DSV, g.17483557Ins, was found in both VSD patients and controls with similar frequencies (P>0.05). Taken together, our data suggested that the DSVs within the upstream enhancer of the NKX2-5 gene may contribute to a small number of VSD. Therefore, genetic studies of CHD may provide insight into designing novel therapies for adult CHD patients.Gene 05/2013; · 2.20 Impact Factor