Genetic and Molecular Definition of Histone Modifying Enzyme Functions

了解组蛋白修饰是如何调节组蛋白修饰的 了解正常人和正常人染色质组织和基因调控的机制 疾病状态。我们研究的总体目标是解决这个具有挑战性的问题，使用 基因和分子方法来定义哪些组蛋白修饰酶，并由此延伸， 组蛋白修饰，管理特定的基因表达程序，特别是生物 上下文。我们的工作主要集中在GCN5组蛋白乙酰转移酶(HAT)和 USP22组蛋白去泛素化酶(DUB)，它们都是一个大的多蛋白的组成部分 集合被称为传奇。Gcn5，USP22和其他SAGA组件被牵连到 人类疾病，包括癌症和神经退行性变，但分子机制 潜在的这种影响尚不清楚。在过去的20年里，我们创造了一个新的工具包 Gcn5和Usp22突变小鼠和细胞，包括零等位基因、条件性(开花)等位基因和 点突变的等位基因(在Gcn5 HAT结构域、Gcn5溴结构域或USP22 Dub中 域)，影响这些酶的活性。我们对Gcn5突变的研究揭示了关键 对这种HAT在发育过程中的转录和非转录功能的见解， 最近，他们揭示了Gcn5和Myc功能之间的重要联系 在正常的干细胞和癌症中。我们的USP22突变小鼠发现这个配对也很关键 对于胚胎存活，但通过不同的途径与那些受Gcn5丢失影响的。尽管 尽管取得了这些进展，但知识上的许多重大差距仍然存在。我们对……只有部分了解。 哪些转录程序需要哺乳动物细胞中的Gcn5。此外，现在已知Gcn5 是称为ATAC的第二组蛋白修饰复合体的一部分，但我们不知道Gcn5是如何 在这些复合体之间分配的或它们在发育或疾病中的相对作用。我们也 对USP22和SAGA配音模块在特定环境中的作用理解不全面 组织，如小脑，这是特别相关的，因为 佐贺配音模块与一种衰弱的神经退行性疾病脊髓小脑有关 共济失调7型(SCA7)。这个Mira将为我们提供稳定和灵活的资金，以继续我们的基因， 生物化学和分子研究来解决这些至关重要的问题。在更长的时间里 术语，GCN5和USP22正常功能的定义将为 为这些因子调节不当的疾病开发新的治疗方案。

Understanding how histone modifications are regulated is fundamentally important for understanding mechanisms of chromatin organization and gene regulation in both normal and disease states. The overall goal of our research is to address this challenging question, using genetic and molecular approaches to define which histone modifying enzymes, and by extension, which histone modifications, govern specific gene expression programs in particular biological contexts. Our work is focused largely on the Gcn5 histone acetyltransferase (HAT) and the USP22 histone deubiquitylase (DUB), which are both components of a large multiprotein assembly termed SAGA. Gcn5, USP22 and other SAGA components have been implicated in human maladies, including cancer and neurodegeneration, but the molecular mechanisms underlying such effects are not known. Over the past 20 years, we have created a novel toolkit of Gcn5 and USP22 mutant mice and cells, including null alleles, conditional (floxed) alleles, and point mutated alleles (in the Gcn5 HAT domain, the Gcn5 bromodomain, or the USP22 DUB domain) that affect the activity of these enzymes. Our studies of Gcn5 mutations revealed key insights to both transcriptional and non-transcriptional functions for this HAT during development, and most recently, they revealed important connections between Gcn5 and Myc functions both in normal stem cells and in cancer. Our USP22 mutant mice revealed that this DUB is also critical for embryo survival, but through different pathways than those affected by Gcn5 loss. Despite these advances, many significant gaps in knowledge still remain. We have only a partial view of which transcription programs require Gcn5 in mammalian cells. Moreover, Gcn5 is now known to be part of a second histone modifying complex called ATAC, but we do not know how Gcn5 is apportioned between these complexes or their relative roles in development or disease. We also have an incomplete understanding of the roles of USP22 and the SAGA DUB module in specific tissues such as the cerebellum, which is especially relevant since specific components of the SAGA DUB module are linked to a debilitating neurodegenerative disease, spinal cerebellar ataxia type 7 (SCA7). This MIRA will provide us stable and flexible funding to continue our genetic, biochemical, and molecular studies to address these critically important questions. In the longer term, definition of the normal functions of Gcn5 and USP22 will provide molecular foundations for development of new therapeutic options for diseases in which these factors are mis-regulated.