Mutations in MECOM, Encoding Oncoprotein EVI1, Cause Radioulnar Synostosis with Amegakaryocytic Thrombocytopenia
Mutations in MECOM, Encoding Oncoprotein EVI1, Cause Radioulnar Synostosis with Amegakaryocytic Thrombocytopenia
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DOI：
10.1016/j.ajhg.2015.10.010
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发表时间：
2015-12-01
影响因子：
9.8
通讯作者：
Aoki, Yoko
中科院分区：
文献类型：
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作者：
Niihori, Tetsuya;Ouchi-Uchiyama, Meri;Aoki, Yoko
桡尺骨结合伴无巨核细胞性血小板减少症（RUSAT）是一种遗传性骨髓衰竭综合征，以血小板减少症和先天性桡骨和尺骨融合为特征。在两个不相关的家庭中发现了杂合HOXA 11突变是RUSAT的原因。然而，HOXA 11突变在许多患有RUSAT的个体中不存在，这表明其他遗传基因座有助于RUSAT。在目前的研究中，我们在RUSAT个体及其健康父母中进行了全外显子组测序，并在RUSAT个体中鉴定了MECOM编码EVI 1的从头错义突变。随后对另外两名RUSAT患者的MECOM分析显示了两个额外的错义突变。这三个突变聚集在EVI 1的C-末端锌指结构域的第8个锌指基序内。染色质免疫沉淀和qPCR分析的区域窝藏的ETS样基序，被称为EVI 1结合位点显示减少免疫沉淀DNA的两个EVI 1突变体相比，野生型EVI 1。此外，报告基因分析表明，MECOM突变导致AP-1和TGF-β介导的转录反应的改变。这些功能测定表明，突变EVI 1的转录失调可能与RUSAT的发展有关。我们报告错义突变MECOM导致孟德尔疾病，提供了令人信服的证据EVI 1在正常造血和人类前肢和手指的发展中的关键作用。
Radioulnar synostosis with amegakaryocytic thrombocytopenia (RUSAT) is an inherited bone marrow failure syndrome, characterized by thrombocytopenia and congenital fusion of the radius and ulna. A heterozygous HOXA11 mutation has been identified in two unrelated families as a cause of RUSAT. However, HOXA11 mutations are absent in a number of individuals with RUSAT, which suggests that other genetic loci contribute to RUSAT. In the current study, we performed whole exome sequencing in an individual with RUSAT and her healthy parents and identified a de novo missense mutation in MECOM, encoding EVI1, in the individual with RUSAT. Subsequent analysis of MECOM in two other individuals with RUSAT revealed two additional missense mutations. These three mutations were clustered within the 8th zinc finger motif of the C-terminal zinc finger domain of EVI1. Chromatin immunoprecipitation and qPCR assays of the regions harboring the ETS-like motif that is known as an EVI1 binding site showed a reduction in immunoprecipitated DNA for two EVI1 mutants compared with wild-type EVI1. Furthermore, reporter assays showed that MECOM mutations led to alterations in both AP-1-and TGF-beta-mediated transcriptional responses. These functional assays suggest that transcriptional dysregulation by mutant EVI1 could be associated with the development of RUSAT. We report missense mutations in MECOM resulting in a Mendelian disorder that provide compelling evidence for the critical role of EVI1 in normal hematopoiesis and in the development of forelimbs and fingers in humans.