Epigenetic Mechanisms of X-chromosome Inactivation

X染色体失活的表观遗传机制

基本信息

批准号：
8109229
负责人：
SUNDEEP KALANTRY
金额：
$ 23.89万
依托单位：
UNIVERSITY OF MICHIGAN AT ANN ARBOR
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-08-01 至 2012-07-31
项目状态：
已结题

项目摘要

Cells retain tlieir identity in part by inheriting gene expression profiles of their predecessors. Patterns of transcription that survive cell division are thought to be established and maintained partly through covalent modifications of histones and DNA, and do not involve changes in the DNA sequence itself. Emerging evidence increasingly implicates this epigenetic mode of inheritance in a myriad of developmental processes as well as a cause of or a significant contributor to human disease. My research strives to further our understanding of epigenetic mechanisms through the study of X-chromosome Inactivation (XCI). XCI is an instrument of dosage compensation in mammals that results in the transraiptlonal silencing of genes on one of the two X-chromosomes in eariy female embryos. Once enacted in individual cells, XCI is stably transmitted such that all descendant ceils maintain silencing of that X-chromosome. Since an entire chromosome is inactivated and tfierefore easily detected, XCI is a model system to investigate transcriptional memory mechanisms. Importantly, the memory mechanisms that operate during XCI also apply broadly to gene regulation and are being found to be important in cell fate decisions during embryogenesis and in stem cell biology as well as during disease progression. We have recently identified a novel protein enriched on the inactive X-chromosome (Xi), This protein is predicted to be a novel putative methyltransferase. The Xi is a target of two known MTases (Ezh2 and Pr- Set7), which operate on the Xi to propagate transcriptional memory by catalyzing the methylation of histones either on their own or In a complex with other proteins. We will therefore deteimine if the novel protein mediates cellular memory through histone methylation, using established biochemical assays to detect histone methylation on core histones as well as on nudeosome substrates. We also aim to Identify proteins that with which It interacts. We will also generate mice bearing a conditional-null mutation in the gene to analyze its requirement in XCI.

细胞通过遗传其前身的基因表达谱保留一部分。人们认为，幸存细胞分裂的转录模式是通过组蛋白和DNA的共价修改而部分建立和维持的，并且不涉及DNA序列本身的变化。新兴的证据越来越多地暗示了这种表观遗传学模式在无数的发育过程中，以及引起人类疾病的重要原因或重要原因。我的研究旨在通过研究X染色体失活（XCI）来进一步了解表观遗传机制。 XCI是哺乳动物中剂量补偿的一种仪器，导致在雌性雌性胚胎中的两个X染色体之一上对基因的转线沉默。一旦在单个细胞中制定，XCI就会稳定地传播，以使所有后代天花板保持沉默的X染色体。由于整个染色体被灭活并很容易检测到Tfiere，因此XCI是研究转录记忆机制的模型系统。重要的是，在XCI期间运行的记忆机制也广泛适用于基因调节，并且发现在细胞命运决策中很重要胚胎发生，干细胞生物学以及疾病进展过程中。我们最近确定了一种富含活性X染色体（XI）的新型蛋白质，该蛋白被预测为一种新型的假定甲基转移酶。 XI是两个已知MTase（EZH2和PR-SET7）的靶标，它们在XI上运行，通过自行或与其他蛋白质的复合物催化组蛋白的甲基化来传播转录记忆。因此，我们将使用已建立的生化测定法检测核心组蛋白以及裸骨体底物上的组蛋白甲基化，以检测新型蛋白通过组蛋白甲基化介导细胞记忆，并确定新型蛋白质。我们还旨在确定与之相互作用的蛋白质。我们还将在基因中产生带有条件无效突变的小鼠，以分析其在XCI中的需求。