REGULATION OF DNA DAMAGE INDUCED GENES BY YEAST TAFIIS

癌症、出生缺陷和衰老都被认为是由 遗传损伤的积累。 细胞对DNA的挑战做出反应 通过激活蛋白激酶级联导致细胞周期 阻止和诱导修复基因。其中任何一个的改变 反应导致人类疾病。这些通路中的激酶已经被 然而，它们的转录因子靶点仍然存在， 难以捉摸。 我们已经确定了潜在的目标。 通过我们的基因 TATA盒结合蛋白相关因子（yTAFIIS）的研究 芽殖酵母酿酒酵母，我们发现， yTAFIIS是细胞对DNA损伤和损伤的反应所必需的- 诱导转录 这是一个重大的发现，因为 TAFIIS的体内功能在很大程度上是未知的。生物化学研究表明， 暗示它们对控制转录非常重要， 所有的促进剂，他们被认为是这样做，作为共活化剂 和启动子选择性因子。 然而，TAFII突变体的分析 在酵母和哺乳动物系统中的体内试验已经挑战了这种模型。 多个酵母TAFIIS的突变，以及最大哺乳动物的突变 TAFII不会导致转录的整体缺陷，但会导致细胞凋亡。 循环缺陷和转录中的改变， 基因. 以前的工作确定了两类基因， TAF 145用于转录。 最令人惊讶的是，TAF 145决定簇 不是激活剂结合位点，而是核心启动子元件， 什么信号通过TAFIIS起作用的问题是一个悬而未决的问题。我们 已经发现DNA损伤反应基因的转录需要 多个TAFII亚基，这使得它们的调节不同于 以前发现的基因类型。 这项提案将扩大这些 通过描述TAFIIS在 DNA损伤应答基因的调控，并探讨其信号转导途径 调节其活动的途径。 这些研究将确定 TAFII依赖基因的决定因素，细胞信号控制 TAFIS功能，并试图建立TAFIS作为转录 DNA损伤蛋白激酶级联的因子靶点。 这项工作将 影响转录、DNA损伤和细胞周期控制领域。

Cancer, birth defects and aging are all thought to result from of an accumulation of genetic damage. Cells respond to the challenge of DNA damage by activating a protein kinase cascade that causes cell cycle arrest and the induction of repair genes. Alterations in either of these responses lead to human disease. Kinases in these pathways have been identified, however, their transcription factor targets have remained elusive. We have identified potential targets. Through our genetic study of the TATA-box binding protein associated factors (yTAFIIS) from the budding yeast Saccharomyces cerevisiae, we have discovered that yTAFIIS are required for the cellular response to DNA damage and damage- induced transcription. This is a significant discovery, because the in vivo functions of TAFIIS are largely unknown. Biochemical studies have implicated them as being important for the control of transcription from all promoters, and they are thought to do so by acting as coactivators and promoter selectivity factors. However, analysis of TAFII mutants in vivo in both yeast and mammalian systems have challenged this model. Mutation of multiple yeast TAFIIS, and mutation of the largest mammalian TAFII, do not lead to global defects in transcription, but lead to cell cycle defects and alterations in transcription of a select number of genes. Previous work identified two classes of genes that are dependent upon TAF145 for transcription. Most surprisingly, TAF145 determinants are not activator binding sites, but core promoter elements, leaving the issue of what signals are acting through TAFIIS an open question. We have found that the transcription of DNA damage response genes requires multiple TAFII subunits, which makes their regulation distinct from the previously identified gene classes. This proposal will extend these preliminary observations by characterizing the role of TAFIIS in the regulation of DNA damage responsive genes and explore the signaling pathways that mediate their activities. These studies will identify the determinants of TAFII-dependent genes, the cellular signals controlling TAFII function, and attempt to establish TAFIIS as the transcription factor targets of the DNA damage protein kinase cascade. This work will impact the fields of transcription, DNA damage and cell cycle control.