Functional regulatory regions of human transcription factor MEF2C
Functional regulatory regions of human transcription factor MEF2C
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DOI：
10.1016/s0169-328x(01)00187-5
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发表时间：
2001-12-16
期刊：
影响因子：
--
通讯作者：
Leifer, D
中科院分区：
文献类型：
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作者：
Janson, CG;Chen, Y;Leifer, D
肌细胞增强子结合因子 2C (MEF2C) 是一种在肌肉和大脑中高水平表达的转录因子，与神经元的终末分化和有丝分裂后存活有关。在这项研究中，MEF2C 缺失突变体和天然存在的亚型被转染到具有两种不同报告基因的 COS 和 P19 细胞中，以测试 MEF2C 构建体的相对转录活性。部分羧基末端的缺失，特别是氨基酸387-473的缺失，增强了转录激活。当氨基酸 1-86（包含 MEF2C 的 DNA 结合 (MADS/MEF) 结构域）偶联时，氨基酸 312-367 富含丝氨酸、苏氨酸、脯氨酸和酪氨酸的区域足以在低水平激活转录，但也依赖于氨基酸 87-311 才能发挥全部作用。缺少氨基酸 312-350 的构建体显示出比含有该序列的蛋白质显着更少的转录激活。通过使用 MEF2C 恒定 N 末端区域的抗体进行免疫染色，将 MEF2C 构建体均匀定位于细胞核。对转染细胞和体外转录/翻译提取物的蛋白质印迹和凝胶迁移研究表明，表达的蛋白质数量或 DNA 结合特性的变化并不能解释观察到的转录激活差异。该结构信息可能有助于阐明 MEF2C 与其他因子相互作用以调节靶基因的机制。 (C) 2001 Elsevier Science B.V. 保留所有权利。
Myocyte enhancer-binding factor 2C (MEF2C), a transcription factor expressed at high levels in muscle and brain, is implicated in the terminal differentiation and post-mitotic survival of neurons. In this study MEF2C deletion mutants and naturally-occurring isoforms were transfected into COS and P19 cells with two different reporter genes, to test the relative transcriptional activities of the MEF2C constructs. Deletion of parts of the carboxy terminus, in particular amino acids 387-473, enhanced transcription al activation. A region rich in serine, threonine, proline, and tyrosine from amino acids 312-367 was sufficient to activate transcription at low levels when coupled to amino acids 1-86, which contain the DNA-binding (MADS/MEF) domain of MEF2C, but also depended on amino acids 87-311 for full effect. A construct with amino acids 312-350 missing showed significantly less transcriptional activation than proteins containing this sequence. MEF2C constructs were uniformly localized to the cell nucleus by immunostaining with an antibody to the constant N-terminal region of MEF2C. Western blot and gel shift studies of extracts from transfected cells and from in vitro transcription/translation suggest that variation in the amount of protein expressed or in DNA-binding properties does not account for observed differences in transcriptional activation. This structural information may be useful for elucidating the mechanisms of MEF2C in interacting with other factors to regulate target genes. (C) 2001 Elsevier Science B.V. All rights reserved.