RBP2 regulation through differential recruitment to genomic loci

描述（由申请人提供）：越来越清楚的是，表观遗传变化在癌症中的作用与正常发育中的作用一样多。我们最近发现了一种与pRB肿瘤抑制因子相互作用的蛋白RBP2，它似乎介导了pRB在分化中的功能。RBP2和密切相关的蛋白PLU1是两种新发现的与恶性肿瘤相关的组蛋白去甲基化酶。它们的转录调控与组蛋白H3 （H3K4me3）的三甲基化赖氨酸4的去甲基化有关。我们最近在全基因组范围内发现了分化特异性RBP2靶点。我们提出，RBP2以依赖于pRB的方式建立了一个转录程序，该程序调节进展到更分化的状态，并且可能是白血病和淋巴瘤发展的必要组成部分。在本应用中，我们将研究RBP2如何被招募到其基因组靶点，以及哪些因素改变了RBP2结合的亲和力或特异性。我们建议使用分子、细胞生物学和遗传学方法来实现以下具体目标：(1)确定组蛋白H3K4甲基化、序列特异性DNA结合、三个PHD手指盒和E2F结合对RBP2募集到基因组位点的要求；(2)剖析RBP2募集导致基因表达变化的机制；(3)比较RBP2功能缺失癌细胞与正常细胞中RBP2靶基因的表达。这项研究将有助于开发涉及这类新型表观遗传调控因子的治疗方法。公共卫生相关性：了解RBP2的功能可以在几个方面对公共卫生产生巨大影响：1)提高适应个体风险因素的癌症筛查计划的成本效益；2)确定将从特定预防策略中获益最多的个人；3)导致合理的药物设计去甲基化酶抑制剂，如双底物类似物，以针对广泛的癌症。

DESCRIPTION (provided by applicant): It is becoming clear that epigenetic changes are involved in cancer as much as in normal development. We recently identified RBP2, a protein interacting with the pRB tumor suppressor, which seems to mediate the pRB function in differentiation. RBP2 and the closely related protein PLU1 are two newly identified histone demethylases associated with malignancy. Their transcriptional regulation has been connected to the demethylation of trimethylated lysine 4 of histone H3 (H3K4me3). We recently identified differentiation- specific RBP2 targets genome-wide. We propose that RBP2 establishes, in a pRB dependent manner, a transcriptional program that regulates progression to a more differentiated state and may be a requisite component of leukemia and lymphoma development. In this application we will study how RBP2 is recruited to its genomic targets and which factors change the affinity or specificity of RBP2 binding. We suggest to use molecular, cell biological and genetic approaches to fulfill the following specific aims: (1) To determine the requirements of histone H3K4 methylation, sequence-specific DNA binding, the three PHD finger cassettes and E2F binding for RBP2 recruitment to genomic loci; (2) To dissect the RBP2 recruitment mechanisms that result in gene expression changes; (3) To determine RBP2 target gene expression in cancer cells deficient in RBP2 function compared with normal cells. This study will contribute to the development of therapeutic approaches involving this novel class of epigenetic regulators. PUBLIC HEALTH RELEVANCE: Understanding RBP2 function could lead to tremendous impact on public health in several ways: 1) improve cost-efficiency of cancer screening programs adapted to individual's risk factors; 2) identify individuals who will most benefit from a particular prevention strategy; 3) lead to rational drug design of demethylase inhibitors, for example, bisubstrate analogues, to target wide range of cancers.