染色质构象在热休克驱动的广泛转录变化下保持稳定。
Chromatin conformation remains stable upon extensive transcriptional changes driven by heat shock.
机构信息
Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853.
Baker Institute for Animal Health, Cornell University, Ithaca, NY 14853.
出版信息
Proc Natl Acad Sci U S A. 2019 Sep 24;116(39):19431-19439. doi: 10.1073/pnas.1901244116. Epub 2019 Sep 10.
Heat shock (HS) initiates rapid, extensive, and evolutionarily conserved changes in transcription that are accompanied by chromatin decondensation and nucleosome loss at HS loci. Here we have employed in situ Hi-C to determine how heat stress affects long-range chromatin conformation in human and cells. We found that compartments and topologically associating domains (TADs) remain unchanged by an acute HS. Knockdown of Heat Shock Factor 1 (HSF1), the master transcriptional regulator of the HS response, identified HSF1-dependent genes and revealed that up-regulation is often mediated by distal HSF1 bound enhancers. HSF1-dependent genes were usually found in the same TAD as the nearest HSF1 binding site. Although most interactions between HSF1 binding sites and target promoters were established in the nonheat shock (NHS) condition, a subset increased contact frequency following HS. Integrating information about HSF1 binding strength, RNA polymerase abundance at the HSF1 bound sites (putative enhancers), and contact frequency with a target promoter accurately predicted which up-regulated genes were direct targets of HSF1 during HS. Our results suggest that the chromatin conformation necessary for a robust HS response is preestablished in NHS cells of diverse metazoan species.
热休克 (HS) 会引发快速、广泛且在进化上保守的转录变化,伴随着 HS 基因座处的染色质去凝聚和核小体丢失。在这里,我们采用原位 Hi-C 技术来确定热应激如何影响人类和 细胞中的长程染色质构象。我们发现,急性热休克不会改变隔室和拓扑关联域 (TAD)。热休克因子 1 (HSF1) 的敲低,即 HS 反应的主要转录调节剂,确定了 HSF1 依赖性基因,并揭示了上调通常是由远端 HSF1 结合增强子介导的。HSF1 依赖性基因通常与最近的 HSF1 结合位点位于同一个 TAD 中。尽管 HSF1 结合位点与靶启动子之间的大多数相互作用是在非热休克 (NHS) 条件下建立的,但有一部分在热休克后增加了接触频率。整合 HSF1 结合强度、HSF1 结合位点(假定的增强子)处 RNA 聚合酶丰度以及与靶启动子的接触频率的信息,可以准确预测哪些上调基因是 HSF1 在 HS 期间的直接靶标。我们的结果表明,在不同后生动物物种的 NHS 细胞中,预先建立了进行稳健 HS 反应所需的染色质构象。