Analysis of General Transcription Factors in Yeast

描述（由申请人提供）：本申请的长期目标是更多地了解真核生物的转录控制，使用酵母S. cerevisiae和S. pombe作为模型系统。许多拟议的研究将集中在最初在酿酒酵母中发现的SAGA蛋白复合物上。SAGA （Spt-Ada-Gcn5乙酰转移酶）是一类被称为共激活因子的因子中的一员，在转录控制中起着关键作用。SAGA是保守的，因为已鉴定出人类SAGA样复合物。一套广泛的问题提出了有关转录和SAGA功能。特异性目标1解决了SAGA和其他因素在酿酒酵母氧介导转录中的作用。一个焦点是PAU基因，仅以厌氧方式表达，并以saga依赖的方式表达。这种表达所需的SAGA成分是Sgf73，它是人类谷氨酰胺扩增病基因ataxin-7的同源物，参与脊髓小脑性共济失调7。实验将测试Sgf73在PAU诱导中的作用。该目的的另一部分提出了在厌氧条件下麦角甾醇生物合成基因抑制的分析。Specific Aim 2提出了研究saga依赖性激活剂Gal4激活的距离约束的实验。实验将研究可能发生在特定突变体中的长距离激活，并提出识别该类的其他突变体。特异性Aim 3开关生物体，研究远亲酵母的SAGA， S. pombe。遗传学和生物化学的方法将阐明SAGA在pombe中的作用。其他实验将解决这一意想不到的发现，即S. pombe的Spt3缺失会导致严重的生长缺陷。最后，Specific Aim 4描述了研究S. pombe inv1+基因调控的实验，该基因受葡萄糖水平的高度调控。将分离和分析调节突变体，以了解正常控制S. pombe的inv1+和其他葡萄糖抑制基因所需的因素。这些研究应该揭示转录控制的重要方面。

DESCRIPTION (provided by applicant): The long-term objectives of this application are to learn more about transcriptional control in eukaryotes, using the yeasts S. cerevisiae and S. pombe as model systems. Many of the proposed studies will focus on the SAGA protein complex, initially discovered in S. cerevisiae. SAGA (Spt-Ada-Gcn5 Acetyltransferase) is a member of a class of factors, called coactivators, that play critical roles in transcriptional control. SAGA is conserved, as human SAGA-like complexes have been identified. A broad set of issues are proposed relating to transcription and to SAGA function. Specific Aim 1 addresses the role of SAGA and other factors in oxygen-mediated transcription in S. cerevisiae. One focus is on PAU genes, expressed only anaerobically, and in a SAGA-dependent fashion. The component of SAGA required for this expression is Sgf73, the homologue of a human glutamine-expansion disease gene, ataxin-7, involved in spinocerebellar ataxia 7. Experiments will test the roles of Sgf73 in PAU induction. The other section of this aim proposes analysis of repression of ergosterol biosynthetic genes under anaerobic conditions. Specific Aim 2 proposes experiments to study the distance constraints for activation by the SAGA-dependent activator Gal4. Experiments will study the long distance activation that can occur in particular mutants and proposes to identify additional mutants of this class. Specific Aim 3 switches organisms, to study SAGA in the distantly related yeast, S. pombe. Genetic and biochemical approaches will be taken to elucidate the roles of SAGA in S. pombe. Other experiments will address the unexpected finding that loss of Spt3 of S. pombe causes a severe growth defect. Finally, Specific Aim 4 describes experiments to study regulation of the S. pombe inv1+ gene, highly regulated by glucose levels. Regulatory mutants will be isolated and analyzed to understand factors required for normal control of inv1+ and other glucose-repressed genes of S. pombe. These studies should reveal important aspects of transcriptional control.