REGULATION OF MYOD POST TRANSCRIPTIONAL MODIFICATIONS

MYOD 转录后修饰的调控

• 批准号: 6413426
• 负责人: Vittorio Sartorelli
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF ARTHRITIS AND MUSCULOSKELETAL AND SKIN DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6413426
• 关键词: genetic transcription; muscle satellite cell; myogenesis; neoplastic transformation; posttranscriptional RNA processing; regeneration; rhabdomyosarcoma; striated muscles

The present study is aimed at the understanding of the molecular and cellular mechanisms that regulate the transcriptional activity of the myogenic bHLH proteins. More specifically, we are interested in studying the switches that allow MyoD to become transcriptionally active once undifferentiated myoblasts transition into differentiated myotubes. MyoD activity is required for proliferation of satellite cells and is deregulated in rhabdomyosarcoma, a pediatric solid tumor. The molecular mechanisms of regeneration and neoplastic transformation of skeltal muscle cells remian unclear. Acetylation is a dynamic process involving the actions of both acetyltransferases and deacetylases. MyoD is a direct target of acetylation by both p300 and PCAF. Nonetheless, acetylation mediated by PCAF, but not by p300, is required to assist MyoD-dependent transcription and muscle differentiation. PCAF-mediated acetylation of MyoD results in an increased DNA binding capability and modify the conformation of MyoD bound to DNA. We have previously analyzed the contribution of the p300 and PCAF acetyltransferases to muscle differentiation. We propose to continue this line of investigation. The specific aims are:1. To investigate whether the HDACs physically associate with MyoD and impede muscle differentiation. 2. To analyze the functional interplay of MyoD, pRb and HDAC1 in regulating muscle specific transcription.3. To investigate the role of acetylation in both regeneration and neoplastic transformation of skeletal muscle cells. In the past year, we have begun characterizing the composition of a cellular complex containing MyoD and HDAC1 and have initiated experiments of HDAC1 overexpression in muscle cells. Our preliminary results indicate that forced expression of HDAC1 antagonizes MyoD-dependent transcription and prohibits muscle differentiation.

本研究旨在了解调节肌源性bHLH蛋白转录活性的分子和细胞机制。更具体地说，我们感兴趣的是研究当未分化的成肌细胞转变为分化的肌管时，允许MyoD具有转录活性的开关。MyoD活性是卫星细胞增殖所必需的，在横纹肌肉瘤（一种小儿实体肿瘤）中不受调节。骨骼肌细胞再生和肿瘤转化的分子机制尚不清楚。乙酰化是一个涉及乙酰转移酶和去乙酰化酶共同作用的动态过程。MyoD是p300和PCAF乙酰化的直接靶点。然而，辅助myod依赖性转录和肌肉分化需要PCAF介导的乙酰化，而不是p300介导的乙酰化。pcaf介导的MyoD乙酰化导致DNA结合能力增强，并改变MyoD与DNA结合的构象。我们之前分析了p300和PCAF乙酰转移酶对肌肉分化的贡献。我们建议继续这方面的调查。具体目标是：1。研究hdac是否与MyoD有物理关联并阻碍肌肉分化。2. 2 .分析MyoD、pRb和HDAC1在调节肌肉特异性转录中的功能相互作用。目的探讨乙酰化在骨骼肌细胞再生和肿瘤转化中的作用。在过去的一年里，我们已经开始表征含有MyoD和HDAC1的细胞复合体的组成，并开始了HDAC1在肌肉细胞中过表达的实验。我们的初步结果表明，强迫表达HDAC1可拮抗myod依赖性转录并阻止肌肉分化。