Regulation of RNA polymerase II pausing and directionality by ATP-dependent chromatin remodelers

总结 目的是研究SWI/SNF ATP依赖性染色质重塑复合物在细胞凋亡中的作用。 RNA聚合酶II的启动子近端暂停和转录方向性的确定，关键 在发育和疾病中重要的转录调控步骤。在过去的几年里，研究人员 他们发现，在哺乳动物中，大多数基因的RNA聚合酶（RNAP）II在25-60 nt处暂停， 转录起始位点，且一旦提供适当信号，转录可以恢复。调控 启动子近端停顿已经被发现是基因表达调控中至关重要的一步，甚至可能更重要。 表达比起始前复合体的形成更重要。目前对连接知之甚少 RNAPII暂停和ATP依赖性染色质重塑如SWI/SNF之间的关系，即使 已知启动子区的染色质结构是RNAPII暂停的重要决定因素。 聚合酶的暂停也与趋异转录的发生有关，这是最近的另一项发现， 转录。大多数非编码RNA来自趋异或双向转录， 在编码区的上游以反义方向发生。与RNAP II类似， 转录是发育控制的过程。初步数据显示，SWI/SNF参与了 这两个过程的调控和本提案的目标是描绘分子手段， SWI/SNF调节这些相对较新的转录方面。 SWI/SNF是癌症中最常见的突变表观遗传因子之一，约占所有突变表观遗传因子的20%。 癌症和SWI/SNF突变是两种神经系统疾病的分子驱动因素， 和Coffin-Siris综合征SWI/SNF复合物对于多能性和分化也至关重要。作为 作为染色质的主要看门人，它被认为主要参与使DNA可用于 转录起始复合物的形成。这项建议的前提是，社会工作局/国家家庭基金会在 RNAPII暂停和方向性的调节对于其在发育和人类疾病中的作用至关重要， 促进转录起始复合物的形成。此外，我们还将探讨一个重要问题， SWI/SNF如何调节eRNA的合成，eRNA是在增强子区域转录的短RNA， 增强子和启动子都被转录的显著相似性，通常是双向的， 相同的转录和延伸因子。eRNA促进启动子之间的长程相互作用， 增强子，并且在合成其相应的编码RNA之前合成。该提案审查了 SWI/SNF如何影响RNAPII在增强子区域的暂停和方向性，这可能很重要 for enhancer增强剂activity活性.

Summary The objective is to study the function of the SWI/SNF ATP-dependent chromatin remodeling complex in promoter proximal pausing of RNA polymerase II and determination of transcriptional directionality, key regulatory steps in transcription important in development and diseases. In the last several years, researchers have found that in mammals most genes have RNA polymerase (RNAP) II paused 25-60 nts from the transcription start site and that transcription can resume once the appropriate signal is provided. Regulation of promoter proximal pausing has been uncovered to be as crucial, or perhaps more, of a regulatory step in gene expression than formation of the preinitiation complex. There is currently very little known about connections between RNAPII pausing and ATP-dependent chromatin remodelers such as SWI/SNF, even though the chromatin structure at the promoter region is known to be an important determining factor in RNAPII pausing. Polymerase pausing is also connected to the occurrence of divergent transcription, another recent finding in transcription. Most non-coding RNA comes from divergent or bidirectional transcription in which transcription occurs upstream of the coding region in the anti-sense direction. Similar to RNAP II pausing the directionality of transcription is a developmentally controlled process. Preliminary data shows SWI/SNF’s involvement in the regulation of both of these processes and the goals of this proposal are to delineate the molecular means of SWI/SNF regulation of these relatively new aspects of transcription. SWI/SNF is one of the most frequently mutated epigenetic factors in cancer, occurring in ~20% of all cancers, and mutations in SWI/SNF are the molecular drivers for two neurological disorders, Nicolaides-Baraister and Coffin-Siris syndromes. The SWI/SNF complex is also crucial for both pluripotency and differentiation. As a master gatekeeper of chromatin, it has been assumed to be primarily involved in making DNA accessible for formation of the transcription initiation complex. The premise of this proposal is that the functions of SWI/SNF in regulation of RNAPII pausing and directionality is as vital for its role in development and human disease as promoting formation of the transcription initiation complex. In addition, we will examine the important question of how SWI/SNF regulates the synthesis of eRNAs, short RNAs transcribed at enhancer regions, given the remarkable similarity with which both enhancers and promoters are transcribed, often bi-directionally, and using the same transcription and elongation factors. eRNAs facilitate long-range interactions between promoters and enhancers, and are synthesized prior to the synthesis of its corresponding coding RNAs. This proposal examines how SWI/SNF influences RNAPII pausing and directionality at enhancer regions, which is likely to be important for enhancer activity.