Analysis of General Transcription Factors in Yeast

本申请的长期目标是利用酵母S. cerevisiae和S. pombe作为模型系统。许多拟议的研究将集中在佐贺蛋白复合物，最初发现于S。啤酒。佐贺（Spt-Ada-Gcn 5 Acetyltransferase）是一类在转录调控中起关键作用的因子，称为辅激活因子。佐贺是保守的，因为已经鉴定了人SAGA样复合物。提出了一系列与转录和佐贺功能有关的问题。具体目标1阐述了佐贺和其他因子在S.啤酒。一个焦点是PAU基因，仅在厌氧条件下表达，并且以SAGA依赖的方式表达。这种表达所需的佐贺的组分是Sgf 73，其是参与脊髓小脑共济失调7的人类谷氨酰胺扩展疾病基因共济失调蛋白-7的同源物。实验将测试Sgf 73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固醇生物合成基因的抑制的分析。具体目标2提出了研究SAGA依赖性激活剂Gal 4激活的距离限制的实验。实验将研究在特定突变体中可能发生的长距离激活，并提出鉴定此类其他突变体。具体目标3开关生物，研究佐贺在远亲酵母，S。粟酒本文将从遗传学和生物化学的角度阐明佐贺在S.粟酒其他实验将解决意想不到的发现，S.粟酒裂殖酵母导致严重的生长缺陷。最后，具体目标4描述了研究S. pombe inv 1+基因，受葡萄糖水平高度调节。将分离和分析调节突变体，以了解正常控制inv 1+和其他葡萄糖抑制基因所需的因素。粟酒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.