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Functions of an E1A-Associated Cellular Protein

E1A 相关细胞蛋白的功能

基本信息

批准号：
8066180
负责人：
BAYAR THIMMAPAYA
金额：
$ 2.5万
依托单位：
NORTHWESTERN UNIVERSITY AT CHICAGO
依托单位国家：
美国
项目类别：
财政年份：
1998
资助国家：
美国
起止时间：
1998-04-01 至 2010-11-30
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): The N-terminal region of the adenovirus transforming protein E1A binds to several host proteins whose functions are critical for the cell cycle control. These include p400, p300 and the highly related CBP, Retinoblastoma protein (Rb), and two Rb related proteins p107 and p130. E1A interactions with these host proteins result in profound alterations in cellular growth control, p300/CBP is a coactivator and a histone acetyl transferase that links chromatin remodeling with transcription. The focus of this application is to investigate the roles played by p300 in cell cycle control and to investigate how E1A binding to p300 deregulates the cell cycle related p300 functions. Recently, this laboratory has shown that depletion of p300 in quiescent cells leads to premature G1 exit and upregulation of c-Myc. Conversely, overexpression of p300 in quiescent cells leads to downregulation of c-Myc followed by inhibition of S phase entry. Thus, p300 provides an important function in G1 control of the cell cycle by negatively regulating Myc, and preventing a premature G1 exit. These results provide a molecular basis for the previously documented need for viral oncoproteins such as E1A and SV40 large-T to inactivate the p300 functions during cell transformation. Here, studies are proposed to investigate the mechanism by which p300 negatively regulates c-Myc at the chromatin level. The specific aims include the identification of the domains and activities of p300 that are critical for the negative regulation of Myc, the Myc promoter specific transcription factors and chromatin remodeling proteins that interact with p300 during this negative regulation, and the mechanism of their interactions that results in the repression of the Myc promoter. Finally, studies are proposed to investigate the mechanism by which EIA inactivates p300 functions that leads to Myc upregulation, and how E1A binding to p300 contributes to the G1 exit. p300/CBP is a key regulator of cell proliferation with tumor suppression properties. Therefore, understanding the functions of this protein in cell cycle control, and the mechanism by which viral oncogene products interfere with its functions will be valuable in understanding the p300 mediated growth regulatory pathways.

描述（由申请人提供）：腺病毒转化蛋白E1 A的N-末端区域与几种宿主蛋白结合，这些蛋白的功能对细胞周期控制至关重要。这些包括p400，p300和高度相关的CBP，视网膜母细胞瘤蛋白（Rb），以及两种Rb相关蛋白p107和p130。E1 A与这些宿主蛋白的相互作用导致细胞生长控制的深刻改变，p300/CBP是一种共激活剂和组蛋白乙酰转移酶，将染色质重塑与转录联系起来。本申请的重点是研究p300在细胞周期控制中所起的作用，并研究E1 A与p300的结合如何解除与细胞周期相关的p300功能。最近，该实验室已经表明，在静止细胞中p300的耗竭导致过早的G1期退出和c-Myc的上调。相反，p300在静止期细胞中的过表达导致c-Myc下调，随后抑制S期进入。因此，p300通过负调节Myc并防止过早的G1期退出，在细胞周期的G1期控制中提供重要功能。这些结果提供了一个分子基础，以前记录的需要病毒癌蛋白，如E1 A和SV 40大T，以阻止p300的功能在细胞转化。在这里，研究提出了调查的机制，p300负调控c-Myc在染色质水平。具体目标包括鉴定对Myc的负调控至关重要的p300的结构域和活性，Myc启动子特异性转录因子和染色质重塑蛋白，它们在这种负调控期间与p300相互作用，以及它们相互作用导致Myc启动子抑制的机制。最后，研究提出了调查的机制，EIA失活p300功能，导致Myc上调，以及如何E1 A结合p300有助于G1出口。p300/CBP是细胞增殖的关键调节因子，具有肿瘤抑制特性。因此，了解该蛋白在细胞周期控制中的功能，以及病毒癌基因产物干扰其功能的机制，将有助于了解p300介导的生长调节途径。