Analysis of General Transcription Factors in Yeast

描述(由申请人提供)：本申请的长期目标是学习更多关于真核生物转录调控的知识，使用酿酒酵母和庞贝酵母作为模型系统。许多拟议的研究将集中在最初在酿酒酵母中发现的SAGA蛋白质复合体。SAGA(SPT-Ada-Gcn5乙酰转移酶)是一类在转录调控中起关键作用的辅助激活因子。佐贺是保守的，因为人类佐贺样复合体已经被发现。提出了一系列与转录和佐贺功能有关的问题。具体目标1阐述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，只在厌氧状态下表达，并以传奇依赖的方式表达。这种表达所需的SAGA组分是Sgf73，它是人类谷氨酰胺扩张性疾病基因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。这一目标的另一部分提出了在厌氧条件下对麦角固醇生物合成基因进行抑制的分析。特定目的2提出实验来研究SAGA依赖的激活剂Gal4激活的距离限制。实验将研究在特定突变体中可能发生的长距离激活，并建议识别这一类的更多突变体。具体目的3切换生物体，研究远缘酵母S.pombe中的SAGA。将采用遗传和生化方法来阐明SAGA在S.pombe中的作用。其他实验将解决这一意外发现，即失去S.pombe的Spt3会导致严重的生长缺陷。最后，特定目标4描述了研究受葡萄糖水平高度调控的S.pombe inv1+基因调控的实验。将分离和分析调节突变体，以了解正常控制庞氏葡萄球菌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调控的重要方面。

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.