High Mobility Group Protein HMG I(Y) in Transcription

描述(申请人提供)：真核生物利用多种 控制其表达的重要但知之甚少的机制 基因。充分了解这些机制是一个重要的问题，因为 基因表达调控在肿瘤的发生和发展中起着重要的作用。 在精确的空间中区分功能不同的细胞类型 举止。最终控制基因表达的基因组调控网络 决定了每个物种的形态和功能。此外，监管 转录反应细胞对细胞外信号的反应能力 以及环境压力。监管机构的可操作性 由顺式调控DNA序列之间的相互作用指定的编程， 同源转录因子和转录共激活因子有 被确定为人类干扰素-β基因，其转录被激活 以应对病毒感染。干扰素-β基因的激活是暂时的 需要三组不同转录因子的现象，这与 HMG I(Y)蛋白协同结合增强子DNA组装 增强体。增强体通过指示一个 有秩序地招募染色质修饰活动，如组蛋白乙酰 转移酶(CBP和GCN5)和ATP依赖的重塑机制(SWI/SNF)， 其改变局部染色质结构的方式使得后续的 基本转录复合体的组装和转录的启动。 同时，GCN5和CBP在不同的赖氨酸残基上乙酰化HMG I 对增强小体稳定性产生相反的影响。的总体目标 这一建议是为了阐明增强体的机制 组蛋白的体内组装/拆解及其分子基础 乙酰化作用形成一种“组蛋白密码”，由其他蛋白质读取，从而实现 染色质重塑和转录激活。我们的方法将使用 缺乏HMG I(Y)基因的细胞。我们将转换几个HMG I(Y)导数 缺乏蛋白质的不同功能，我们将调查 染色质免疫沉淀实验增强体内小体组装。 此外，我们将通过识别组蛋白乙酰化密码来解码 病毒作用下体内乙酰化的组蛋白和特异性残基 感染及其在基因激活中的作用。最后，我们将在体内进行 和体外实验，以了解染色质重塑的本质 干扰素-β启动子和一般转录机制是如何 在增强体的指导下，组装在重塑的干扰素-β启动子上。

DESCRIPTION (provided by applicant): Eukaryotic organisms employ a variety of important but poorly understood mechanisms to control the expression of their genes. A full understanding of these mechanisms is an important issue since regulation of gene expression plays an important role in the development and differentiation of functionally distinct cell types in a precise spatial manner. The genomic regulatory network that controls gene expression ultimately determines form and function in each species. In addition, regulation of transcription reflects the ability of cells to respond to extracellular signals and environmental stresses. The operational nature of the regulatory programming specified by the interplay between cis-regulatory DNA sequences, the cognate transcription factors and the coactivators of transcription has been determined for the human IFN-beta gene, whose transcription is activated in response to virus infection. Activation of the IFN-beta gene is a transient phenomenon requiring three distinct sets of transcription factors, which with the help of the HMG I(Y) protein bind to enhancer DNA cooperatively to assemble the enhanceosome. The enhanceosome activates transcription by instructing an ordered recruitment of chromatin modifying activities such as Histone Acetyl Transferases (CBP and GCN5) and ATP-dependent remodeling machines (SWI/SNF), which alter the local chromatin structure in a way that allows subsequent assembly of the basal transcriptional complex and initiation of transcription. In parallel, GCN5 and CBP acetylate HMG I at distinct lysine residues conferring opposite effects on enhanceosome stability. The overall goals of this proposal are to elucidate the mechanisms of enhanceosome assembly/disassembly in vivo and the molecular basis by which histone acetylation acts to form a "histone code" read by other proteins to bring about chromatin remodeling and transcriptional activation. Our approach will use cells lacking the HMG I(Y) gene. We will transduce several HMG I(Y) derivatives deficient in distinct functions of the protein and we will investigate enhanceosome assembly in vivo by chromatin immunoprecipitation experiments. Furthermore, we will decode the "histone acetylation code" by identifying the histones and the specific residues acetylated in vivo in response to virus infection and their role in gene activation. Finally, we will carry out in vivo and in vitro experiments to understand the nature of chromatin remodeling at the IFN-beta promoter and how the general transcriptional machinery is instructed by the enhanceosome to assemble on the remodeled IFN-beta promoter.