Congenital heart disease-causing Gata4 mutation displays functional deficits in vivo.
Congenital heart disease-causing Gata4 mutation displays functional deficits in vivo.
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DOI：
10.1371/journal.pgen.1002690
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发表时间：
2012
期刊：
影响因子：
4.5
通讯作者：
Garg V
中科院分区：
文献类型：
--
作者：
Misra C;Sachan N;McNally CR;Koenig SN;Nichols HA;Guggilam A;Lucchesi PA;Pu WT;Srivastava D;Garg V
房间隔缺损和室间隔缺损是先天性心脏病最常见的形式，几乎占所有病例的50%。我们之前报道了GATA4的杂合G296S错义突变导致人类心房和室间隔缺损和肺动脉瓣狭窄。GATA4编码一种心脏转录因子，当在小鼠中缺失时，会导致胚胎日(E)9.5时的心脏裂和致死。在体外，突变体GATA4蛋白具有降低的DNA结合亲和力和转录活性，并消除了与TBX5的物理相互作用，TBX5是正常心脏形成的关键转录因子。为了在体内表征该突变，我们制造了具有相同突变Gata4 G295S的小鼠。纯合子Gata4 G295S突变等位基因的小鼠具有正常的腹侧体图案和心脏环，但具有薄的心室心肌，单心室，E11.5致死。虽然杂合子Gata4 G295S突变小鼠可以存活，但其中一部分小鼠存在半月瓣狭窄和房间隔小缺损。纯合子突变小鼠的基因表达研究表明，G295S蛋白可以充分激活内胚层中Gata4的下游靶点，但不能激活发育中的心脏。细胞周期蛋白家族成员、Gata4的直接靶点CCND2在Gata4 G295S等位基因纯合子和杂合子的胚胎中均发现心肌细胞增殖缺陷和心脏表达降低。为了进一步确定Gata4 G295S突变在体内的功能，我们产生了复合突变小鼠，其中特定细胞系同时含有Gata4 G295S突变和Gata4空等位基因。对这些小鼠的检查表明，Gata4 G295S蛋白在早期心肌发育中存在功能缺陷。综上所述，Gata4 G295S突变在体内作为一种低变形，在胚胎发生过程中导致心肌细胞增殖缺陷，这可能与人类先天性心脏缺陷的发生有关。心脏畸形是由心脏发育异常引起的，是人类最常见的先天缺陷。房间隔缺损和室间隔缺损是最常见的先天性心脏缺损类型，是房间隔和室间隔不完全闭合的结果，这是形成四室心脏所必需的过程。心房和室间隔缺损的分子机制尚不清楚。我们之前发表了GATA4的高渗透性常染色体显性突变（G296S），该突变与大量亲属的心房和室间隔缺陷有关。致病突变具有影响DNA结合和蛋白质-蛋白质相互作用的生化缺陷谱。在这里，我们报道了携带Gata4 （G295S）同源突变的小鼠的产生和表型特征。纯合突变小鼠表现出胚胎致命性和心脏缺陷，但表型比gata4缺失小鼠轻。Gata4 G295S杂合子小鼠的一个子集显示出持续的房间通讯（卵圆孔未闭）和半月瓣狭窄。突变小鼠的分子特征表明，Gata4 G295S突变蛋白导致Gata4靶基因在心脏中的表达减少，心肌细胞增殖功能缺陷。因此，心肌细胞增殖缺陷可能有助于在GATA4突变的人类中发现的心隔缺陷。
Defects of atrial and ventricular septation are the most frequent form of congenital heart disease, accounting for almost 50% of all cases. We previously reported that a heterozygous G296S missense mutation of GATA4 caused atrial and ventricular septal defects and pulmonary valve stenosis in humans. GATA4 encodes a cardiac transcription factor, and when deleted in mice it results in cardiac bifida and lethality by embryonic day (E)9.5. In vitro, the mutant GATA4 protein has a reduced DNA binding affinity and transcriptional activity and abolishes a physical interaction with TBX5, a transcription factor critical for normal heart formation. To characterize the mutation in vivo, we generated mice harboring the same mutation, Gata4 G295S. Mice homozygous for the Gata4 G295S mutant allele have normal ventral body patterning and heart looping, but have a thin ventricular myocardium, single ventricular chamber, and lethality by E11.5. While heterozygous Gata4 G295S mutant mice are viable, a subset of these mice have semilunar valve stenosis and small defects of the atrial septum. Gene expression studies of homozygous mutant mice suggest the G295S protein can sufficiently activate downstream targets of Gata4 in the endoderm but not in the developing heart. Cardiomyocyte proliferation deficits and decreased cardiac expression of CCND2, a member of the cyclin family and a direct target of Gata4, were found in embryos both homozygous and heterozygous for the Gata4 G295S allele. To further define functions of the Gata4 G295S mutation in vivo, compound mutant mice were generated in which specific cell lineages harbored both the Gata4 G295S mutant and Gata4 null alleles. Examination of these mice demonstrated that the Gata4 G295S protein has functional deficits in early myocardial development. In summary, the Gata4 G295S mutation functions as a hypomorph in vivo and leads to defects in cardiomyocyte proliferation during embryogenesis, which may contribute to the development of congenital heart defects in humans. Cardiac malformations occur due to abnormal heart development and are the most prevalent human birth defect. Defects of atrial and ventricular septation are the most common type of congenital heart defect and are the result of incomplete closure of the atrial and ventricular septa, a process required for formation of a four-chambered heart. The molecular mechanisms that underlie atrial and ventricular septal defects are unknown. We previously published a highly penetrant autosomal dominant mutation (G296S) in GATA4, which was associated with atrial and ventricular septal defects in a large kindred. The disease-causing mutation has a spectrum of biochemical deficits affecting both DNA binding and protein–protein interactions. Here, we report the generation and phenotypic characterization of mice harboring the orthologous mutation in Gata4 (G295S). While homozygous mutant mice display embryonic lethality and cardiac defects, the phenotype is less severe than Gata4-null mice. A subset of Gata4 G295S heterozygote mice display a persistent interatrial communication (patent foramen ovale) and stenosis of the semilunar valves. Molecular characterization of the mutant mice suggests that the Gata4 G295S mutant protein results in diminished expression of Gata4 target genes in the heart and functional deficits in cardiomyocyte proliferation. Thus, cardiomyocyte proliferation defects may contribute to defects of cardiac septation found in humans with GATA4 mutations.
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影响因子：
8
作者：
Botto, LD;Correa, A;Erickson, JD
通讯作者：
Erickson, JD
影响因子：
2.7
作者：
Laforest, Brigitte;Nemer, Mona
通讯作者：
Nemer, Mona
DOI：
10.1073/pnas.042390499
发表时间：
2002-03-05
影响因子：
11.1
作者：
Gaussin, V;Van de Putte, T;Schneider, MD
通讯作者：
Schneider, MD
影响因子：
2.7
作者：
Artus J;Piliszek A;Hadjantonakis AK
通讯作者：
Hadjantonakis AK
影响因子：
2.7
作者：
Kisanuki, YY;Hammer, RE;Yanagisawa, M
通讯作者：
Yanagisawa, M