Genome Architecture and Gene Control in Response to Stress

1个项目摘要 2. 3基因组的3D拓扑在健康、疾病和疾病的转录调控中起着关键作用 4.发展。虽然Hi-C和Chia-PET等技术揭示了全球基因组的静态观点 5架构，对控制动态拓扑重排的机制知之甚少。我们 6个人在萌芽酵母中建立了一种系统-HSF1介导的热休克反应-在该系统中 7在一组特定的靶基因内部和之间发生结构重排。在热休克期间， 8HSF1驱动分散在不同染色体上的靶基因发生显著的构象变化 9并结合成离散的、转录活跃的焦点。这些HSF1靶基因编码一组专门的 10个蛋白质稳态(蛋白质稳态)因子。通过它们的调控，人类HSF1(HHSF1)的同源基因 11已被建议作为治疗恶性肿瘤和神经退行性疾病的临床靶点。因此，这一点 12建议具有双重意义：它将阐明控制染色质构象的机制 13动力学，并揭示HSF1如何协调蛋白平衡机制的表达。 14发芽酵母中HSF1介导的热休克反应是一个理想的研究模型系统 15 3D基因组重排的调节和功能有两个原因：1)大小、速度和 16基因内和基因间重排的特异性都是史无前例的，因此代表了令人兴奋的、新颖的 17生物学；2)它将使我们能够利用酵母基因学的力量来剖析机制并定义 18基因组拓扑动力学的功能相关性。 19目标1将研究在热休克过程中发生的全基因组3D重排及其作用 20 HSF1和RNA聚合酶II(包括其CTD磷酸化状态)在协调特定和 21个强大的染色体间接触。实验将主要使用CHIA-PET方法。 22目标2将深入关注HSF1结合位点及其功能域在支持其功能方面的作用 23能够动态地将其调节子的成员驱动到聚集的核内焦点。 24目标3将测试介体和其他辅助因子的作用--转录共激活因子、染色质重塑因子 25和建筑蛋白-在驱动HSP基因融合中的作用，并探讨HSP基因 26聚结表示通过液-液分离而聚集的凝析油。 27为了支持美国国立卫生研究院的任务，这项提案中确立的先例将为治疗工作提供参考 28广泛地针对3D基因组调节，并可能提出用来调节的新的分子手柄 29热休克蛋白1和蛋白质平衡机制用于治疗癌症和神经退行性疾病。

1 Project Summary 2 3 The 3D topology of the genome plays a critical role in transcriptional regulation in health, disease and 4 development. While techniques such as Hi-C and ChIA-PET have revealed static views of global genome 5 architecture, very little is known about the mechanisms that control dynamic topological rearrangements. We 6 have established a system in budding yeast – the Hsf1-mediated heat shock response – in which concerted 7 structural rearrangements within and between a set of specific target genes take place. During heat shock, 8 Hsf1 drives its target genes dispersed on different chromosomes to undergo striking changes in conformation 9 and coalesce into discrete, transcriptionally active foci. These Hsf1 target genes encode a dedicated group of 10 protein homeostasis (proteostasis) factors. Through their regulation, the human orthologue of Hsf1 (hHSF1) 11 has been suggested to be a clinical target in malignant cancers and in neurodegenerative diseases. Thus, this 12 proposal has dual significance: it will both elucidate mechanisms that control chromatin conformational 13 dynamics and reveal how Hsf1 coordinates expression of the proteostasis machinery. 14 The Hsf1-mediated heat shock response in budding yeast represents an ideal model system to investigate 15 the regulation and function of 3D genome rearrangements for two reasons: 1) The magnitude, rapidity and 16 specificity of the intra- and intergenic rearrangements are all unprecedented and thus represent exciting, novel 17 biology; and 2) It will allow us to leverage the power of yeast gene-tics to dissect the mechanisms and define 18 the functional relevance of genome topology dynamics. 19 Aim 1 will investigate the 3D rearrangements that occur genome-wide during heat shock and the role 20 played by Hsf1 and RNA polymerase II (including its CTD phosphorylation state) in orchestrating specific and 21 robust interchromosomal contacts. The experiments will use primarily ChIA-PET approaches. 22 Aim 2 will focus deeply on the role of Hsf1 binding sites and its functional domains in underpinning its 23 ability to dynamically drive members of its regulon into coalesced intranuclear foci. 24 Aim 3 will test the role of Mediator and other cofactors - transcriptional co-activators, chromatin remodelers 25 and architectural proteins - in driving HSP gene coalescence and investigate the possibility that HSP gene 26 coalescence represents a condensate that assembles through liquid-liquid phase separation. 27 In support of the NIH mission, the precedents established in this proposal will inform therapeutic efforts 28 aimed broadly at 3D genome regulation and may suggest novel molecular handles with which to modulate 29 Hsf1 and the proteostasis machinery to treat cancer and neurodegenerative diseases.