Gene regulation in response to heat stress

该项目将研究使生物体在暴露于高温后存活的机制。 使用面包酵母（酿酒酵母），实验将侧重于了解细胞如何协调热应激后基因表达的全基因组变化。 由于热应激反应在进化上是保守的，因此使用酵母作为模型的研究有望为更复杂的生物体中采用的基本机制提供见解。这项研究的其他更广泛的影响包括两名研究生的培训和夏季研究的机会，三个高中生物教师从一个学区与一个大的，代表性不足的少数民族人口。胁迫响应基因的动态调控对真核生物的生存能力至关重要。In S.热休克因子1（Heat Shock Factor 1，Hsf 1）是一种基因特异性的、进化上保守的激活因子，在刺激HSP基因的基础转录和诱导转录中起着重要作用。这些基因编码的分子伴侣对维持蛋白质稳态和对抗蛋白毒性应激至关重要。Hsf 1是否也是导致热应激后非HSP基因表达下调的原因尚不清楚。目的1采用染色质免疫沉淀结合深度测序（ChIP-seq）研究Hsf 1在非应激和应激条件下的全基因组占据，并确定激活剂在指导Mediator全基因组占据中的作用，Mediator是Pol II转录的中心共激活剂和信号整合剂。此外，比较动态转录组分析将用于测量全局转录率，并将其与全基因组Hsf 1、Mediator和Pol II占用率相关联。目的2利用染色体构象捕获技术研究热休克诱导和非诱导条件下Hsf 1调控基因的体内构象和核结构。一个关键的目标是巩固的证据表明，HSP基因环，“皱”（手风琴式）和合并成转录活性灶后，细胞暴露于热休克，并确定动力学与它们形成和消散环状DNA结构。此外，通过使用成环，起皱和聚结缺陷突变体，这些现象的生物学意义将被探讨。 研究结果有望促进对基因调控变化如何使热应激后细胞存活的理解。

This project will investigate the mechanisms that allow organisms to survive after exposure to high temperatures. Using baker's yeast (Saccharomyces cerevisiae), experiments will focus on understanding how cells coordinate genome-wide changes in gene expression following heat stress. Because the heat stress response is evolutionarily conserved, research using yeast as the model is expected to provide insights into the fundamental mechanisms employed in more complex organisms. Additional broader impacts of this research include the training of two graduate students and summer research opportunities for three high school biology teachers from a school district with a large, underrepresented minority population. The dynamic regulation of stress-responsive genes is critical for viability of all eukaryotes. In S. cerevisiae, the gene-specific and evolutionarily conserved activator, Heat Shock Factor 1 (Hsf1), plays a central role in stimulating both basal and induced transcription of HSP genes. These genes encode molecular chaperones that are critical for maintaining protein homeostasis and in combating proteotoxic stress. Whether Hsf1 is also responsible for the global down-regulation of non-HSP gene expression following exposure to thermal stress is unknown. Aim 1 employs chromatin immunoprecipitation combined with deep sequencing (ChIP-seq) to investigate genome-wide occupancy of Hsf1 under both non-stressful and stressful conditions, and determine the activator's role in directing the genome-wide occupancy of Mediator, a central coactivator and signal integrator of Pol II transcription. In addition, comparative dynamic transcriptome analysis will be used to measure global transcription rates and correlate these with genome-wide Hsf1, Mediator and Pol II occupancy. Aim 2 employs chromosome conformation capture techniques to characterize the in vivo conformation and nuclear organization of Hsf1-regulated genes under both non-inducing and heat shock-inducing conditions. A key goal is to solidify evidence that HSP genes loop, 'crumple' (accordion-style) and coalesce into transcriptionally active foci following exposure of cells to heat shock, and determine the kinetics with which they form and dissipate looped DNA structures. Additionally, through use of looping, crumpling and coalescence-deficient mutants, the biological significance of these phenomena will be explored. Results are expected to advance understanding of how gene regulatory changes enable cell survival following heat stress.