Regulation of gene expression by chromatin remodeling enzymes

项目摘要 为了理解正常的发育和分化，有必要确定 细胞启动新的基因表达程序并促进特定细胞谱系的形成。典型地， 这涉及到转录沉默的基因的激活，这些基因可能被整合到抑制性基因中， 染色质结构有证据支持分化特异性转录调节因子和 重塑或改变染色质结构的酶合作，使基因组DNA更容易接近细胞。 转录机制哺乳动物SWI/SNF（mSWI/SNF）酶家族成员重塑 核小体结构的ATP依赖性方式，并促进转录因子的功能，在体外和 vivo.这些酶的成分是胚胎发育所必需的，有些可以作为肿瘤 抑制剂或肿瘤促进剂。此外，SWI/SNF酶参与细胞周期控制。因此 这些酶是正常细胞功能以及分化和发育所广泛需要的， 失调与肿瘤形成有关。 骨骼肌分化长期以来一直是研究组织特异性分化的基本原理的模型。 基因表达和分化。SWI/SNF染色质重塑酶在细胞凋亡中起重要作用。 这些过程。这个项目将集中在不同的激酶和磷酸酶的机制 参与信号通路调节SWI/SNF染色质重塑的磷酸化和功能 在增殖和分化成肌细胞中的酶亚基。我们将采用各种方法来操纵 特异性激酶、磷酸酶和重塑酶亚基的表达，并将操纵功能 通过使用抑制剂和诱变剂。我们将分析这些方法对基因表达的影响， 表达，染色质结合和重塑，转录因子功能，局部高阶基因结构， 和整个基因组结构。这项工作将提供新的范例，了解如何信号 分子聚集在染色质上以调节组织分化和发育。

PROJECT SUMMARY To understand normal development and differentiation, it is necessary to determine the mechanisms by which cells initiate new programs of gene expression and promote the formation of specific cell lineages. Typically, this involves activation of genes that are transcriptionally silent and that are likely incorporated into repressive chromatin structure. Evidence supports the idea that differentiation-specific transcriptional regulators and enzymes that remodel or alter chromatin structure cooperate to render genomic DNA more accessible to the transcriptional machinery. The mammalian SWI/SNF (mSWI/SNF) enzyme family members remodel nucleosome structure in an ATP dependent manner and facilitate transcription factor function in vitro and in vivo. Components of these enzymes are essential for embryonic development and some can act as tumor suppressors or tumor promoters. Additionally, SWI/SNF enzymes are implicated in cell cycle control. Thus these enzymes are broadly required for normal cell function and for differentiation and development, and their misregulation is implicated in tumor formation. Skeletal muscle differentiation has long been a model for studying fundamental principles of tissue-specific gene expression and differentiation. The SWI/SNF chromatin remodeling enzymes play essential roles in these processes. This project will focus on the mechanisms by which different kinases and phosphatases involved in signaling pathways regulate the phosphorylation and function of SWI/SNF chromatin remodeling enzyme subunits in proliferating and differentiating myoblasts. We will employ methods to manipulate the expression of specific kinases, phosphatases and remodeling enzyme subunits and will manipulate function through use of inhibitors and mutagenensis. We will analyaze the effects of such approaches on gene expression, chromatin binding and remodeling, transcription factor function, local higher-order gene structure, and overall genome organization. The work will provide new paradigms for understanding how signaling molecules converge on chromatin to regulate tissue differentiation and development.