THE ROLES OF CP190 IN THE FAB-8 AND GYPSY CHROMATIN INSULATORS

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 黑腹果蝇的吉普赛染色质绝缘子是迄今为止最好理解的绝缘子。它是一个DNA序列，含有12个拷贝的毛翅DNA结合蛋白抑制子[Su（Hw）]的结合位点，该抑制子招募其他绝缘子蛋白来组织绝缘子复合物。中心体蛋白CP 190是吉普赛绝缘子的重要组成部分。最近发现，CP 190也存在于Fab-8绝缘子复合物中，其依赖于DNA结合蛋白CTCF而不是Su（Hw）。CTCF在基因表达的表观遗传控制中起重要作用，是人类肿瘤抑制因子。目前的证据表明，CP 190在多种类型的绝缘体中具有重要功能，并可能参与遗传印记和肿瘤抑制。该提案的主要目标是：1）确定CP 190的蛋白质亚结构域在gypsy和Fab-8绝缘子复合物中的功能; 2）鉴定CP 190的锌指的靶DNA序列; 3）通过克隆两个新的绝缘子突变来鉴定额外的染色质绝缘子组分。 拟议的研究将调查有关染色质组织和细胞核中基因表达调控的基本问题。我们将深入了解染色质绝缘子调节基因表达的分子机制，以及更普遍的染色质结构和细胞核的组织。目前，针对染色质调节剂的药物正在测试中，作为癌症和无法治疗的神经系统疾病（如亨廷顿病）的治疗方法。对染色质绝缘体的基本机制的更详细的了解可能会导致更好地设计新的治疗方法，并可能导致发现新的药物靶点。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The gypsy chromatin insulator of Drosophila melanogaster is the best understood insulator to date. It is a DNA sequence containing 12 copies of a binding site for the DNA-binding protein Suppressor of Hairy-wing [Su(Hw)] which recruits other insulator proteins to organize the insulator complex. We reported that the centrosomal protein CP190 is an essential component of the gypsy insulator. It was recently discovered that CP190 is also present in the Fab-8 insulator complex which depends on the DNA-binding protein CTCF instead of Su(Hw). CTCF has important roles on epigenetic control of gene expression and is a human tumor suppressor. Current evidence indicates that CP190 has essential functions in multiple types of insulators and may be involved in genetic imprinting and tumor suppression. The main goals of this proposal are to: 1) Determine the function of CP190's protein sub-domains in gypsy and Fab-8 insulator complexes; 2) Identify the target DNA sequences of CP190's zinc fingers; 3) Identify additional chromatin insulator components by cloning two novel insulator mutations. The proposed studies will investigate a fundamental question concerning chromatin organization and the regulation of gene expression in the cell nucleus. We will gain insights into the molecular mechanisms through which chromatin insulators regulate gene expression, and more generally, chromatin structure and organization of the cell nucleus. Currently drugs are being tested that target chromatin regulators as a therapeutic approach to cancers and to untreatable neurological conditions like Huntington disease. More detailed knowledge of the basic mechanisms of chromatin insulators could lead to better design of new treatments and may lead to discovery of new drug targets.