Functional characterization of a novel mutation in NKX2-5 associated with congenital heart disease and adult-onset cardiomyopathy.
Functional characterization of a novel mutation in NKX2-5 associated with congenital heart disease and adult-onset cardiomyopathy.
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DOI：
10.1161/circgenetics.113.000057
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发表时间：
2013-06
期刊：
影响因子：
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通讯作者：
Harvey RP
中科院分区：
文献类型：
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作者：
Costa MW;Guo G;Wolstein O;Vale M;Castro ML;Wang L;Otway R;Riek P;Cochrane N;Furtado M;Semsarian C;Weintraub RG;Yeoh T;Hayward C;Keogh A;Macdonald P;Feneley M;Graham RM;Seidman JG;Seidman CE;Rosenthal N;Fatkin D;Harvey RP
转录因子NKX 2 -5对心脏发育至关重要，该基因的突变与小鼠模型和人类的各种先天性心脏病（CHD）和传导缺陷（CD）有关。NKX 2 -5突变是否在成人发作性心脏病中起作用尚不清楚。对220例成人型扩张型心肌病（DCM）先证者进行突变筛查。鉴定了6种NKX 2 -5编码序列变体，包括3种非同义变体。一个新的杂合突变，I184 M，位于NKX 2 -5同源结构域（HD），在一个家庭中被确定。一部分家庭成员患有CHD，但DCM的患病率出乎意料地高。I184 M在体外的功能分析表明，当转染到COS-7细胞或HL-1心肌细胞中时，蛋白表达显著增加，这是由于泛素-蛋白酶体系统（UPS）的降解减少。在功能测定中，I184 M的DNA结合活性降低，导致靶基因的活化受损，尽管突变蛋白的表达水平增加。某些NKX 2 -5 HD突变显示通过UPS的异常蛋白质降解和部分受损的转录活性。我们认为这类突变会损害心脏发育和成熟的心脏功能，并导致严重程度分级的NKX 2 -5相关心肌病。
The transcription factor NKX2-5 is crucial for heart development and mutations in this gene have been implicated in diverse congenital heart diseases (CHD) and conduction defects (CD) in mouse models and humans. Whether NKX2-5 mutations have a role in adult-onset heart disease is unknown. Mutation screening was performed in 220 probands with adult-onset dilated cardiomypathy (DCM). Six NKX2-5 coding sequence variants were identified, including 3 non-synonymous variants. A novel heterozygous mutation, I184M, located within the NKX2-5 homeodomain (HD), was identified in one family. A subset of family members had CHD, but there was an unexpectedly high prevalence of DCM. Functional analysis of I184M in vitro demonstrated a striking increase in protein expression when transfected into COS-7 cells or HL-1 cardiomyocytes, due to reduced degradation by the ubiquitin-proteasome system (UPS). In functional assays, DNA binding activity of I184M was reduced, resulting in impaired activation of target genes, despite increased expression levels of mutant protein. Certain NKX2-5 HD mutations show abnormal protein degradation via the UPS and partially impaired transcriptional activity. We propose that this class of mutation can impair heart development and mature heart function, and contribute to NKX2-5-related cardiomyopathies with graded severity.