YEAST GENES INVOLVED IN GENERAL TRANSCRIPTIONAL CONTROL

本研究的目的是阐明真核基因调控的机制。 选择研究的系统是多蛋白质CCR 4-NOT复合物，它对基因表达产生积极和消极的影响。 它由两个复合物组成，大小为1.9和1.0 mD，与其他转录重要的蛋白质组不同，如SNF/SWI和佐贺复合物，TFIID和RNA聚合酶II全酶。 较小的CCR 4-NOT复合物包含CCR 4，CAF 1，五种NOT蛋白和几种未鉴定的蛋白。CCR 4-NOT蛋白的抑制作用似乎是通过使TBP与非典型TATAA序列的结合不稳定而发生的，可能是通过它们与TFIIA、TAF或其他TBP相关因子的直接相互作用。 SRB 9 -11全酶亚复合物也显示与CCR 4-NOT复合物的物理和功能相互作用。 这项拨款提案的中心焦点是三方面的：1）两个CCR 4-NOT复合物的组成和生理作用是什么？ 2)CCR 4-NOT蛋白如何影响TBP及其相关因素的功能？和3）CCR 4-NOT复合物是如何被激活转录所需的？将分离1.9 mD CCR 4-NOT复合物，在质谱分析后克隆其组分，并表征其功能。 CCR 4-NOT复合物影响TBP及其相关因子的作用的机制将通过几项生化研究来阐述。 将进行遗传筛选，以确定新的因素或CCR 4-NOT复合物和转录重要蛋白质之间的新相互作用。 CCR 4激活剂功能将通过表征其独特的C-和N-末端与SRB 9 -11，SPT 5，TAF 60和其他蛋白质的相互作用来探索。 将鉴定响应于CCR 4-NOT复合物的ADH 2启动子的关键特征，以确定CCR 4-NOT复合物如何以阳性方式控制ADH 2基因。

The goal of this research is to elucidate the mechanisms of eucaryotic gene regulation. The system chosen to study is the multi-protein CCR4-NOT complex, which affects gene expression both positively and negatively. It consists of two complexes, 1.9 and 1.0 mD in size, that are distinct from other transcriptionally important groups of proteins, such as the SNF/SWI and SAGA complexes, TFIID, and the RNA polymerase II holoenzyme. The smaller of the CCR4-NOT complexes contains CCR4, CAF1, the five NOT proteins and several unidentified proteins. The repressive effects of the CCR4-NOT proteins appear to occur through destabilizing TBP association with non-canonical TATAA sequences, probably through their direct interaction with TFIIA, TAFs or other TBP-associated factors. The SRB9-11 holoenzyme subcomplex also displays physical and functional interactions with the CCR4-NOT complex. The central focus of this grant proposal is three-fold: 1) What are the components and physiological roles of the two CCR4-NOT complexes? 2) How do the CCR4-NOT proteins affect the function of TBP and its associated factors? and 3) How is the CCR4-NOT complex required for activated transcription? The 1.9 mD CCR4-NOT complex will be isolated, its components cloned following mass spectrometric analysis, and their functions characterized. The mechanism by which the CCR4-NOT complex affects the action of TBP and its associated factors will be elaborated by several biochemical studies. Genetic screens will be undertaken to identify new factors or novel interactions between the CCR4-NOT complex and transcriptionally important proteins. CCR4 activator function will be explored through characterizing its unique C- and N-terminal interactions with SRB9-11, SPT5, TAF60, and other proteins. The key features of the ADH2 promoter which are responsive to the CCR4-NOT complex will be identified to determine how the CCR4-NOT complex controls the ADH2 gene in a positive manner.