Regulation of DNA Damage Induced Genes by Yeast TAFIIs

描述（由申请人提供）：基因调控在所有细胞功能中起核心作用，并且该过程中的改变与人类的许多发育缺陷和疾病状态相关。基因表达的起始需要改变基因的染色质环境，并在启动子处形成起始前复合物（pre-initiation complex， PIC）。PIC是由多个通用转录因子（GTFs）的有序募集形成的。过去五年的进展表明，染色质不仅仅是转录的惰性屏障，而且可能在基因组内特定转录因子的招募中发挥重要作用。此外，由于发现某些gtf具有内在的染色质修饰活性，或者可以将它们招募到启动子中，gtf与染色质重塑机制之间的功能区别已经变得模糊。本提案的总体目标是了解染色质重塑复合物和主要研究者C组分如何被招募到抑制启动子中，以及染色质重塑和转录步骤如何协调发生。我们正在使用出芽酵母的DNA损伤反应核糖核苷酸还原酶3基因（RNR3）来探索TFIID复合物的功能，该复合物由tata结合蛋白和14个称为taf的相关因子组成。我们在上一个资助期的研究表明，TFIID对于SWI/SNF核小体重塑复合体的募集和RNR3启动子核小体的重塑是必需的。本提案的目的是确定RNR3的特征，使其依赖于TAFIIS和核小体重塑的一般转录机制。本研究的目的是研究转录和核心启动子的作用，确定SWI/SNF募集所需的起始前复合物（pre-initiation complex， PIC）的组分，并分析PIC组分、SWI/SNF和染色质在体外系统中的相互作用。此外，我们将利用遗传策略改变核心组蛋白修饰状态和突变组蛋白尾部，探索“组蛋白编码”对RNR3重塑和转录因子募集的贡献。这些研究将确定转录因子募集、染色质重塑和TFIID复合物功能的机制，并将适用于其他真核模型系统。

DESCRIPTION (provided by applicant): Gene regulation plays a central role in all cellular functions, and alterations in this process have been associated with a number of developmental defects and disease states in humans. Initiation of gene expression requires changes to the chromatin environment of genes and the formation of the pre-initiation complex (PIC) at the promoter. The PIC is formed by the ordered recruitment of multiple general transcription factors (GTFs). Advances over the last five years indicate that chromatin is not simply an inert barrier to transcription, but may also play an important function in the recruitment of specific transcription factors to sites within the genome. Further, the distinction between the functions of GTFs and the chromatin remodeling machinery has been blurred by the discovery that certain GTFs have intrinsic chromatin modifying activities, or can recruit them to promoters. The overall goal of this proposal is to understand how chromatin remodeling complexes and Principal Investigator C components are recruited to repressed promoters, and how coordination of the chromatin remodeling and transcription steps occurs. We are using the DNA damage-responsive ribonucleotide reductase 3 gene (RNR3) of budding yeast to explore the functions of the TFIID complex, which is composed of the TATA-binding protein and 14 associated factors called TAFs. Our efforts over the last funding period revealed that TFIID is required for the recruitment of the SWI/SNF nucleosome remodeling complex and the remodeling of nucleosomes at the promoter of RNR3. The objectives of this proposal are to identify the features of RNR3 that confer its dependence upon TAFIIS and the general transcription machinery for nucleosome remodeling. The aims of this proposal will address the role of transcription and the core promoter, identify the components of the pre-initiation complex (PIC) required for SWI/SNF recruitment, and analyze the interactions between PIC components, SWI/SNF and chromatin in an in vitro system. Further, we will explore the contributions of the "histone code" in the remodeling and recruitment of transcription factors to RNR3 using genetic strategies to alter core histone modification states and mutating histone tails. These studies will define mechanisms of transcription factor recruitment, chromatin remodeling and the functions of the TFIID complex that will be applicable to other eukaryotic model systems.