Requirement for down-regulation of the CCAAT-binding activity of the NF-Y transcription factor during skeletal muscle differentiation
Requirement for down-regulation of the CCAAT-binding activity of the NF-Y transcription factor during skeletal muscle differentiation
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DOI：
10.1091/mbc.e02-09-0600
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发表时间：
2003-07-01
影响因子：
3.3
通讯作者：
Piaggio, G
中科院分区：
文献类型：
--
作者：
Gurtner, A;Manni, I;Piaggio, G
核因子-Y由三个亚基组成，即核因子-YA、核因子-YB和核因子-YC，它们都是DNA结合所必需的。所有亚基都在增殖中的骨骼肌细胞中表达，而在体外培养的终末分化细胞中不能单独检测到核因子-YA。通过免疫组织化学方法，我们发现在活体骨骼肌和心肌细胞的细胞核中不表达NF-YA蛋白。通过染色质免疫沉淀实验，我们证明了在分化的肌肉细胞中，核因子-Y不与靶启动子的CCAAT盒结合。与此一致的是，这些启动子的活性在分化的肌肉细胞中下调。最后，在致力于分化的细胞中强制表达NF-YA蛋白会导致Cyclin A、Cyclin B1和CDK1表达下调，并伴随着肌生成素表达的延迟。因此，我们的结果表明，抑制NF-Y功能对于抑制几个细胞周期基因和诱导有丝分裂后肌肉细胞的早期肌肉特异性程序至关重要。
NF-Y is composed of three subunits, NF-YA, NF-YB, and NF-YC, all required for DNA binding. All subunits are expressed in proliferating skeletal muscle cells, whereas NF-YA alone is undetectable in terminally differentiated cells in vitro. By immunohistochemistry, we show that the NF-YA protein is not expressed in the nuclei of skeletal and cardiac muscle cells in vivo. By chromatin immunoprecipitation experiments, we demonstrate herein that NF-Y does not bind to the CCAAT boxes of target promoters in differentiated muscle cells. Consistent with this, the activity of these promoters is down-regulated in differentiated muscle cells. Finally, forced expression of the NF-YA protein in cells committed to differentiate leads to an impairment in the down-regulation of cyclin A, cyclin B1, and cdk1 expression and is accompanied by a delay in myogenin expression. Thus, our results indicate that the suppression of NF-Y function is of crucial importance for the inhibition of several cell cycle genes and the induction of the early muscle-specific program in postmitotic muscle cells.