Control of Transcriptional Attenuation of Stress-induced Genes in Yeast

酵母中应激诱导基因转录减弱的控制

• 批准号: 8514017
• 负责人: DAVID E. LEVIN
• 金额: $ 30.01万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-23 至 2016-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8514017
• 关键词: Antifungal Agents; Attenuated; Cell Survival; Cell Wall; Cells; Code; Complex; DNA-Directed RNA Polymerase; Development; Drug Targeting; Elongation Factor; Environment; Failure; Gene Expression; Gene Silencing; Gene Targeting; Genes; Genetic Transcription; Goals; Hand; Human; Link; MAP Kinase Gene; MAPK7 gene; Mediating; Mitogen-Activated Protein Kinases; Modeling; Mutate; Orthologous Gene; Pharmaceutical Preparations; Phosphotransferases; Physiological; Polymerase; Process; Protein Kinase; RNA Polymerase II; Recruitment Activity; Role; Saccharomyces cerevisiae; Series; Signal Pathway; Signal Transduction; Stress; System; Testing; Therapeutic; Transcription Initiation; Transcription Process; Transcriptional Activation; Transcriptional Regulation; Yeasts; attenuation; base; extracellular; gene function; genetic selection; histone modification; novel; novel strategies; premature; promoter; response; small molecule; termination factor; transcription factor; transcription termination

DESCRIPTION (provided by applicant): Cell survival depends on the ability to respond to stress signals from the extracellular environment. Diverse stress signals induce the expression of specific genes that function in the physiologic response to the stress. In the absence of stress, expression of many of these genes is maintained at a minimal level. We have found in the yeast S. cerevisiae, a model eukaryotic system, that the basal expression of many stress-induced genes is minimized by a novel mechanism - premature transcriptional termination, or transcriptional attenuation. Genes induced by cell wall stress require the MAP kinase Mpk1 to carry out two separate steps in the transcription process, neither of which requires its protein kinase activity. The first is to recruit a transcription factor to promoters of target genes. The second involves blocking attenuation, which occurs within the promoter-proximal region of target genes under non-inducing conditions. Attenuation is mediated by the Sen1 termination complex and is blocked by the translocation of Mpk1 to the elongating RNA polymerase (Pol II). Under inducing conditions, gene expression depends upon the relief of attenuation. For Mpk1-induced genes, this happens through the association of Mpk1 with the elongation factor Paf1, which blocks the recruitment of the Sen1 complex to Pol II. This interaction is conserved in the human ortholog of Mpk1, ERK5, suggesting that regulated transcriptional attenuation operates in humans. Based on our preliminary findings, we propose that a wide variety of stress-induced genes are silenced by transcriptional attenuation under non-inducing conditions and that a constellation of transcription factors are likely to relieve attenuation under inducing conditions through interactions with the Paf1C (a complex containing Paf1). The long-term objective of this project is to provide a novel approach to blocking the expression of specific genes, or groups of genes, by inhibiting relief of transcriptional attenuation. We propose to elucidate the mechanisms that regulate transcriptional attenuation and the degree to which various stresses use similar or different attenuation-relief factors to regulate a variety of target genes. One immediate goal will be to determine if other MAP kinases that respond to different signals also function as attenuation-relief factors. Another project will identify non-MAP kinase attenuation- relief factors that allow the induction of a variety of stress-induced genes we have found to be under attenuation control. A third goal will be to understand the role of the Paf1C in the recruitment of the Sen1 termination complex to Pol II. Overall, these studies will yield a mechanistic understanding of regulated transcriptional attenuation and reveal the ubiquity of the process in yeast, which will inform subsequent studies on human cells.

描述（由申请人提供）：细胞存活取决于对来自细胞外环境的应激信号的反应能力。不同的应激信号会诱导特定基因的表达，这些基因在应激的生理反应中发挥作用。在没有压力的情况下，许多这些基因的表达维持在最低水平。我们在酿酒酵母（一种模型真核系统）中发现，许多应激诱导基因的基础表达通过一种新机制（过早转录终止或转录减弱）最小化。细胞壁应激诱导的基因需要 MAP 激酶 Mpk1 在转录过程中执行两个单独的步骤，这两个步骤都不需要其蛋白激酶活性。第一个是将转录因子募集到目标基因的启动子上。第二个涉及阻断衰减，其在非诱导条件下发生在靶基因的启动子近端区域内。衰减由 Sen1 终止复合物介导，并通过 Mpk1 易位至延伸 RNA 聚合酶 (Pol II) 来阻断。在诱导条件下，基因表达取决于减毒的缓解。对于 Mpk1 诱导的基因，这是通过 Mpk1 与延伸因子 Paf1 的结合而发生的，Paf1 阻止 Sen1 复合物招募到 Pol II。这种相互作用在 Mpk1 的人类直系同源物 ERK5 中是保守的，表明受调控的转录衰减在人类中起作用。根据我们的初步发现，我们提出，在非诱导条件下，多种应激诱导基因会因转录衰减而沉默，并且一系列转录因子可能通过与 Paf1C（一种复合体）相互作用，在诱导条件下减轻转录衰减。含有 Paf1)。该项目的长期目标是提供一种新方法，通过抑制转录衰减的缓解来阻断特定基因或基因组的表达。我们建议阐明调节转录衰减的机制以及各种应激使用相似或不同的衰减缓解因子来调节各种靶基因的程度。一个近期目标是确定对不同信号做出反应的其他 MAP 激酶是否也能起到衰减缓解因子的作用。另一个项目将鉴定非 MAP 激酶衰减缓解因子，这些因子可以诱导我们发现处于衰减控制之下的各种应激诱导基因。第三个目标是了解 Paf1C 在将 Sen1 终止复合物招募到 Pol II 中的作用。总体而言，这些研究将对调控转录衰减产生机制上的理解，并揭示该过程在酵母中的普遍性，这将为后续对人类细胞的研究提供信息。