A stress-induced promoter pause release program in cardiomyocytes protecting against myocardial infarction

摘要 基因毒性应激和转录程序改变的交集影响着许多疾病和 疾病风险事件，但令人惊讶的是，在这方面机械上知之甚少，特别是关于 心肌梗死的风险等位基因。根据我们的初始数据，我们可以确认， SIRT1启动子上的CTCF位点会增加心肌梗死的风险。我们将调查这样的假设：这是 基于低氧或遗传毒性应激诱导CTCF与其结合的功能重要性 到SIRT1启动子中的同源位点，许可启动子暂停释放，导致急性 刺激SIRT1转录。这项拟议的研究旨在揭示一个以前被忽视的 基于关键染色体重分布的信号依赖性转录调控策略 建筑蛋白-CTCF-in激活具有重要生物学意义的大启动子暂停释放程序 结果，包括编码关键调控因子-SIRT1的基因。我们将调查这一假设 应激诱导的SIRT1转录增加与氧化应激反应的全球基因组计划 在心肌细胞中是通过CTCF启动子的募集和部分地通过基于 心肌细胞CTCFs和lncRNAs液-液分离的研究--MI风险等位基因缺失 承运人。我们将研究IPSC衍生的、基因组测序的应激诱导转录程序 并通过评估在小鼠中引入风险等位基因的效果来检验这一假设。使用 携带SIRT1风险等位基因致病SNP的IPSC的可用性，我们现在能够 深入研究这些事件的确切机制，并评估存在大规模 心肌细胞暂停释放程序对于心脏对急性损伤的反应很重要。这个想法 染色体结构的关键仲裁者是通过关键结构蛋白的磷酸化来调节的， 与一组含有CTCF弱位点的启动子结合和许可增加了基于 启动子暂停释放事件揭示了一种未被认识的信号依赖的控制机制 重要的生物项目。

ABSTRACT The intersection of genotoxic stress and altered transcriptional programs impacts numerous disease and disease risk events, but surprisingly little is mechanistically known in this regard, particularly with respect to risk alleles for myocardial infarction. Based on our initial data, we can confirm that a single base alteration in a CTCF site in the SIRT1 promoter can increase the risk of MI. We will investigate the hypothesis that this is based on the functional importance of induced binding of CTCF to in response to hypoxia or genotoxic stress to the cognate site in the SIRT1 promoter, licensing a promoter pause release that results in an acute stimulation of SIRT1 transcription. The proposed research is directed at revealing a previously overlooked strategy for signal-dependent transcriptional regulation based on redistribution of the critical chromosomal architectural protein - CTCF- in activation of a large promoter pause release program with important biological consequences, including the gene encoding critical regulator - SIRT1. We will investigate the hypothesis that stress-induced increased transcription of SIRT1 and a global genomic program of response to oxidative stress in cardiomyocytes is mediated by CTCF promoter recruitment and, in part, by long distance interactions based on liquid-liquid phase separation of CTCF and lncRNAs in cardiomyocytes, which is lost in MI risk allele carriers. We will investigate the stress-induced transcriptional program in iPSC-derived, genome-sequenced cardiac myocytes and the test the hypothesis by assessing effects of introducing the risk allele in mice. With the availability of iPSCs harboring the causative SNP for the SIRT1 risk allele, we are now in a position to delve into the precise mechanism of these events, and assess the possibility that there is a large cardiomyocyte pause-release program important with respect to cardiac response to acute insults. The idea that a key arbiter of chromosome architecture is regulated by phosphorylation of a key architectural protein, binding to a set of promoters harboring weak sites for CTCF and licensing increased transcription based of promoter pause release events reveals an unappreciated signal-dependent mechanism for controlling important biological program.