Regulation of gene expression by chromatin remodeling enzymes

项目总结 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，促进特定细胞系的形成。通常， 这涉及到转录沉默的基因的激活，这些基因很可能被整合到抑制基因中。 染色质结构。有证据支持这种观点，即分化特异性转录调控因子和 重塑或改变染色质结构的酶相互作用，使基因组DNA更容易被 转录机器。哺乳动物SWI/SNF(mSWI/SNF)酶家族成员的重构 ATP依赖的核小体结构和促进转录因子的体外和体内功能 活着。这些酶的成分对胚胎发育是必不可少的，其中一些可以起到肿瘤的作用 抑制者或肿瘤促进者。此外，SWI/SNF酶与细胞周期调控有关。因此， 这些酶广泛地需要正常的细胞功能以及分化和发育，而它们的 调节失调与肿瘤的形成有关。 长期以来，骨骼肌分化一直是研究组织特异性的基本原理的模型。 基因表达和分化。SWI/SNF染色质重塑酶在 这些过程。该项目将重点研究不同的激酶和磷酸酶 参与信号通路调节SWI/SNF染色质重构的磷酸化和功能 成肌细胞增殖和分化中的酶亚基。我们将使用方法来操纵 特异的激酶、磷酸酶和重塑酶亚基的表达及其调控功能 通过使用抑制剂和诱变剂。我们将分析这些方法对基因的影响。 表达，染色质结合和重塑，转录因子功能，局部高级基因结构， 以及整个基因组结构。这项工作将提供新的范式来理解信号如何 分子聚集在染色质上，调节组织的分化和发育。

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.