Myogenic regulatory factors regulate M-cadherin expression by targeting its proximal promoter elements
Myogenic regulatory factors regulate M-cadherin expression by targeting its proximal promoter elements
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DOI：
10.1042/bj20100250
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发表时间：
2010-06-01
影响因子：
4.1
通讯作者：
Chen, Shen Liang
中科院分区：
文献类型：
--
作者：
Hsiao, Sheng Pin;Chen, Shen Liang
M-和N-钙粘蛋白是钙依赖性细胞粘附分子家族的成员。M-钙粘蛋白主要在发育中的骨骼肌中表达，并参与终末肌源性分化，特别是成肌细胞融合。N-钙粘蛋白介导的细胞粘附在骨骼肌发生中也起重要作用。在本研究中，我们发现，这两个基因的差异表达C2 C12和So 18成肌细胞在成肌分化和M-钙粘蛋白的表达优先增强慢收缩肌。有趣的是，大多数MRF（肌源性调节因子）显著激活。M-钙粘蛋白启动子，而不是N-钙粘蛋白启动子。与此一致，MyoD在C3 H10 T1/2成纤维细胞中的过表达强烈诱导内源性M-钙粘蛋白表达。计算机模拟和体外启动子分析鉴定了邻接M-钙粘蛋白启动子内的转录起始位点的E盒（从2到-1-4），其被不同的MRF结合并差异活化。MRF对M-钙粘蛋白启动子的激活也受到Bhlhe 40（碱性螺旋环螺旋家族成员e40）的调节。最后，染色质免疫沉淀证明，MyoD以及肌细胞生成素结合到体内的M-钙粘蛋白启动子。总之，这些观察结果确定了MRF直接调节M-钙粘蛋白表达以确保成肌细胞终末分化的分子机制。
M- and N-cadherin are members of the Ca2+-dependent cell cell adhesion molecule family. M-cadherin is expressed predominantly in developing skeletal muscles and has been implicated in terminal myogenic differentiation, particularly in myoblast fusion. N-cadherin-mediated cell cell adhesion also plays an important role in skeletal myogenesis. In the present study, we found that both genes were differentially expressed in C2C12 and So18 myoblasts during myogenic differentiation and that the expression of M-cadherin was preferentially enhanced in slow-twitch muscle. Interestingly, most MRFs (myogenic regulatory factors) significantly activated the. promoter of M-cadherin, but not that of N-cadherin. In line with this, overexpression of MyoD in C3H10T1/2 fibroblasts strongly induced endogenous M-cadherin expression. Promoter analysis in silico and in vitro identified an E-box (from 2 to -1-4) abutting the transcription initiation site within the M-cadherin promoter that is bound and differentially activated by different MRFs. The activation of the M-cadherin promoter by MRFs was also modulated by Bhlhe40 (basic helix loop helix family member e40). Finally, chromatin immunoprecipitation proved that MyoD as well as myogenin binds to the M-cadherin promoter in vivo. Taken together, these observations identify a molecular mechanism by which MRFs regulate M-cadherin expression directly to ensure the terminal di fferentiation of myoblasts.