RBP2 regulation through differential recruitment to genomic loci

描述(由申请人提供)：表观遗传变化与癌症的发生和正常发育过程一样，变得越来越明显。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在分化中的作用。RBP2和PLU1是两个新发现的与恶性肿瘤相关的组蛋白去甲基酶。它们的转录调控与组蛋白H3(H3K4me3)的三甲基化赖氨酸4去甲基化有关。我们最近在全基因组范围内确定了分化特异的RBP2靶标。我们认为，RBP2以一种依赖于pRB的方式建立了一个转录程序，该程序调节向更高分化状态的进展，可能是白血病和淋巴瘤发展的必要组成部分。在这个应用中，我们将研究RBP2是如何被招募到其基因组靶标上的，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特定目标：(1)确定组蛋白H3K4甲基化、序列特异性DNA结合、三个PHD指盒和E2F结合对RBP2募集到基因组位点的要求；(2)剖析导致基因表达变化的RBP2募集机制；(3)确定RBP2靶基因在RBP2功能缺陷的癌细胞中的表达。这项研究将有助于开发涉及这类新的表观遗传调节因子的治疗方法。

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.