CAREER Exploiting missense histone mutations to explore mechanisms of gene regulation

生物体内的每个细胞都包含相同的遗传信息，但对这些信息的精确调控决定了基因的表达和生物功能。调控基因表达的一部分是通过将基因组打包成染色质来完成的。核小体形成重复的染色质单位，一个DNA复合体和两个拷贝的组蛋白H3、H4、H 2A和H 2B。组蛋白变体和组蛋白翻译后修饰(PTM)是核小体可及性和染色质重塑的关键调节因子，支持基因表达的变化。这种基因调控对生物体的功能和对环境线索的反应至关重要，与人类疾病相关的组蛋白突变的流行突显了这一点。这个项目将利用酵母和人体模型系统的计算和湿实验室研究来检查自然发生的组蛋白突变失调基因表达的机制。这项工作将促进我们对组蛋白变体在核小体完整性、染色质修饰和基因表达中的作用的理解。该项目本身提供了将不同的科学实习生群体作为“组蛋白团队”的一部分的机会，该团队由高中、本科生、研究生和博士后实习生组成，以建立科学机构，并为STEM领域中代表性不足的群体提供研究和教育经验。遗传学研究表明，保守和必需的组蛋白氨基酸对维持核小体结构和功能以及适当调节基因表达具有重要意义。然而，大多数组蛋白错义突变如何影响组蛋白结构和功能目前尚不清楚。该项目确定了人类疾病中一系列反复出现的组蛋白错义突变。硅胶模型表明，这些组蛋白突变中的一些会带来局部结构变化，从而改变转录，而对酵母的研究已经定义了不同的生长和细胞表型。该项目的主要目的是使用哺乳动物和酵母模型，以及分子、细胞和计算生物学来定义这些变化改变组蛋白/核小体功能的机制(S)，并描述在模式生物和细胞中突变的组蛋白表达的生物学结果。通过利用组蛋白突变来探索组蛋白功能、核小体重塑和基因表达调控，该项目将广泛促进对组蛋白如何有助于维持适当的核小体结构和功能、为细胞和生物健康做出贡献的理解。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Each cell within an organism contains identical genetic information, but the precise regulation of this information dictates gene expression and biological function. Part of regulating gene expression is accomplished by the packaging of the genome into chromatin. The nucleosome forms the repeating chromatin unit, a complex of DNA and two copies each of histones H3, H4, H2A, and H2B. Histone variants and histone posttranslational modifications (PTMs) are key regulators of nucleosome accessibility and chromatin remodeling, supporting changes to gene expression. This gene regulation is fundamentally important to how organisms function and respond to environmental cues and is highlighted by the prevalence of histone mutations associated with human disease. This project will leverage computational and wet-lab research with yeast and human model systems to examine mechanisms by which naturally occurring histone mutations dysregulate gene expression. This work will advance our understanding of the role of histone variants in nucleosome integrity, chromatin modification, and gene expression. The project itself provides opportunities to engage a diverse group of scientific trainees as part of “Team Histone,” assembled of high school, undergraduate, graduate, and post-doctoral trainees to build scientific agency and provide research and educational experiences to underrepresented groups within STEM fields. Genetic studies demonstrate the importance of conserved and essential histone amino acids for maintaining nucleosome structure and function as well as proper regulation of gene expression. However, how most missense histone mutations impact histone structure and function is currently unknown. This project identified a series of recurrent histone missense mutations in human disease. In silico modeling suggests that some of these histone mutations impart local structural changes that alter transcription, and studies in yeast have defined diverse growth and cellular phenotypes. The major aims of this project are to use mammalian and yeast models, along with molecular, cellular, and computational biology to define the mechanism(s) by which the changes alter histone/nucleosome function and delineate the biological outcome of mutant histone expression in model organisms and cells. By exploiting histone mutations to explore histone protein function, nucleosome remodeling, and regulation of gene expression, this project will broadly advance the understanding of how histone proteins contribute to the maintenance of appropriate nucleosome structure and function, to contribute to cell and organismal fitness.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.