Functions of Mammalian Histone Modifiers

哺乳动物组蛋白修饰剂的功能

基本信息

批准号：
6882636
负责人：
SHARON Y. R. DENT
金额：
$ 26.43万
依托单位：
UNIVERSITY OF TX MD ANDERSON CAN CTR
依托单位国家：
美国
项目类别：
财政年份：
2003
资助国家：
美国
起止时间：
2003-05-01 至 2007-04-30
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): Enzymatic activities that post-translationally modify the histones are central to the regulation of gene expression. The best studied histone modification at present is acetylation of lysine residues. Increased histone acetylation accompanies gene activation, whereas decreased acetylation is associated with gene repression. Acetylation levels are governed by opposing histone acetyltransferase (HAT) and histone deacetylase (HDAC) activities. Although a number of transcriptional coactivators and corepressors that house these activities have been described in the last few years, the role of these enzymes in transcriptional programs of cellular differentiation is currently understudied. Few mutations in mouse genes for these enzymes have been created or identified, although mutations in specific HATs and HDACs are associated with human diseases including colon cancer and leukemias. Gcn5 was the first nuclear HAT activity to be identified, and it serves as a useful paradigm for HAT structure and function. Previously, we demonstrated that loss of Gcn5 in mouse causes embryonic lethality just after gastrulation, with a loss of particular mesodermal lineages. These lineages are specified normally but failafter 7.5 days of gestation due to increased apoptosis. These experiments demonstrate the importance of Gcn5 to normal development, but the death of Gcn5 null embryos precludes analysis of Gcn5 functions at later embryonic time points or mechanistic studies to determine the molecular basis of the increased apoptosis. Experiments here will make use of newly developed genetic tools to address these questions. Our specific aims are to 1) Determine the importance of Gcn5 at specific developmental stages using a conditional (floxed) allele 2) Determine the importance of Gcn5 HAT activity to development using alleles that carry point mutations in the catalytic center 3) Determine whether developmental defects and apoptosis are cell autonomous in mosaic animals 4) Determine the molecular effects of Gcn5 loss on cell growth, transcription, and DNA repair in Gcn5 null embryonic stem cells. These studies will provide important and novel information about the functions of this HAT during mammalian development and will provide a springboard for long term genetic studies to define the functions of this and other histone modifying activities in normal and diseased states.

描述（由申请人提供）：翻译后修改组蛋白的酶活性对于基因表达的调节至关重要。目前，研究最佳的组蛋白修饰是赖氨酸残基的乙酰化。组蛋白乙酰化增加伴随基因激活，而乙酰化降低与基因抑制有关。乙酰化水平由相反的组蛋白乙酰基转移酶（HAT）和组蛋白脱乙酰基酶（HDAC）活性控制。尽管在过去的几年中已经描述了容纳这些活动的许多转录共激活因子和核压剂，但目前正在研究这些酶在细胞分化的转录程序中的作用。尽管特定的帽子和HDAC中的突变与包括结肠癌和白血病在内的人类疾病有关，但已经创建或鉴定出了这些酶的小鼠基因突变。 GCN5是要确定的第一个核HAT活动，它是HAT结构和功能的有用范式。以前，我们证明了小鼠中GCN5的损失会导致胃酸化后胚胎致死性，而特定中胚层谱系的损失。这些谱系是正常指定的，但由于凋亡增加而导致妊娠7.5天。这些实验证明了GCN5对正常发育的重要性，但是GCN5 NULL胚胎的死亡排除了GCN5在以后的胚胎时间点或机理研究中的函数的分析来确定凋亡增加的分子基础。这里的实验将利用新开发的遗传工具来解决这些问题。 Our specific aims are to 1) Determine the importance of Gcn5 at specific developmental stages using a conditional (floxed) allele 2) Determine the importance of Gcn5 HAT activity to development using alleles that carry point mutations in the catalytic center 3) Determine whether developmental defects and apoptosis are cell autonomous in mosaic animals 4) Determine the molecular effects of Gcn5 loss on cell growth, transcription, and DNA repair in Gcn5无效的胚胎干细胞。这些研究将提供有关该帽子在哺乳动物发育过程中的功能的重要和新颖的信息，并将为长期遗传研究提供一个跳板，以定义这种和其他组蛋白在正常状态和患病状态中修改活性的功能。