Investigating histone glycation as a new dynamic epigenetic mark

项目摘要 在过去的十年里，我们对组织是如何 染色质控制真核生物的基因表达。描述这些机制的大部分工作已经完成 促成了这样一种观念，即所谓的组蛋白密码，指的是组蛋白后的景观- 翻译修饰(PTM)是基因被激活或被激活的潜力的中心决定因素 对环境刺激的反应被压抑的。然而，尽管在活体内检测到，但人们对此知之甚少 关于非酶共价修饰(NECM)，如糖基化，如何影响已建立的 细胞转录程序。我们最近发现糖基化，这是糖尿病的标志， 以疾病状态依赖的方式在组蛋白上蓄积(郑等人)。自然通讯， 2019年)。利用各种生物物理、生化和遗传学方法，我们发现组蛋白糖基化 在体外和细胞内通过形成 组蛋白-组蛋白和组蛋白-DNA都是交联物。重要的是，我们发现了一种细胞调节反应 对于这种形式的脱氧核糖核酸DJ-1以及最近的精氨酸特异性脱氧核糖核酸， PAD4，进一步证实了组蛋白糖基化与其他酶促PTM之间的相互作用 (郑等人，审校)。在这项计划中，我们将采取跨学科的方法，并利用新的 我们开发的化学探针用于确定组蛋白上的糖基化位置及其在 染色质。此外，我们将执行高分辨率分析，以确定精确的机械效应 组蛋白糖基化具有高阶染色质结构和表观遗传景观。最后，我们会 通过识别这种新标记的“读取器”和“擦除器”来研究细胞对糖基化的反应。 该项目的成功完成有望产生一种详细的分子机制，将一种新的 组蛋白对转录调控的修饰，从而提供了对 基本的生物学问题，并打开了新的治疗途径的大门。

Project Summary The past decade has witnessed explosive advances in our understanding of how the organization of chromatin controls gene expression in eukaryotes. Much of the work delineating these mechanisms has contributed to the notion that a so-called ‘Histone Code,’ which refers to the landscape of histone post- translational modifications (PTMs), is a central determinant of a gene's potential to be activated or repressed in response to environmental stimuli. However, although detected in vivo, very little is known about how non-enzymatic covalent modifications (NECMs), such as glycation, affect the established cellular transcriptional program. We recently found that glycation, which is the hallmark of diabetes, accumulates on histones in a disease state-dependent manner (Zheng et al. Nature Communications, 2019). Using a variety of biophysical, biochemical and genetic methods we found that histone glycation disrupts regulatory histone PTMs as well as changes chromatin architecture in vitro and in cells by forming both histone-histone and histone-DNA crosslinks. Importantly, we identified a cellular regulatory response to this damage in the form of the deglycase DJ-1 as well as more recently, an arginine-specific deglycase, PAD4, which further demonstrates the crosstalk between histone glycation and other enzymatic PTMs (Zheng et al., in revision). In this proposal, we will take an interdisciplinary approach and leverage new chemical probes we developed to determine the sites of glycation on histones and their distribution within chromatin. In addition, we will perform a high-resolution analysis to identify the precise mechanistic effect histone glycation has on higher-order chromatin structure and the epigenetic landscape. Finally, we will investigate the cellular response to glycation by identifying “readers” and “erasers” of this new mark. Successful completion of this project is expected to yield a detailed molecular mechanism linking a new class of histone modifications to transcription regulation, thus providing essential insights into a fundamental biological problem and opening the door to new therapeutic avenues.