Structural, Biochemical and Functional Studies of RNAPII CTD Interacting Proteins

描述(申请人提供)：RNA聚合酶II(RNAPII)的C末端结构域(CTD)在协调RNA加工和其他共转录事件以实现适当的基因表达方面发挥着关键作用。它由多个七肽重复序列(Y1S2P3T4S5P6S7)组成，这些重复序列在酵母和人类之间高度保守。CTD修饰的主要形式是七肽重复序列中Ser2和/或Ser5的磷酸化。CTD的磷酸化水平和模式受转录周期中CTD激酶和磷酸酶协同作用的调节。大量的CTD磷酸化状态，也被称为“CTD密码”，形成了将特定的大分子复合体招募到转录聚合酶的基础。最近发现的新的磷酸化CTD相关蛋白已经将CTD的已知功能从介导RNA加工扩展到协调其他共转录事件，如染色质重塑。与CTD生物学的快速发展相比，CTD相关蛋白和CTD修饰酶识别CTD的结构知识非常有限。我们的长期目标是了解CTD修饰酶的结构和机制以及CTD介导的共转录复合体的组装。在这个方案中，我们描述了结构、生化和功能研究，以研究(1)Set2组蛋白甲基转移酶SRI结构域的结构及其与磷酸CTD的相互作用；(2)CA150的串联FF域与磷酸CTD之间的相互作用；(3)一种新的Ser5特异性CTD磷酸酶Ssu72的结构和机制。公共卫生相关性(公共卫生相关性声明)CTD磷酸化状态及其相关过程的异常变化与多种人类疾病有关。许多病毒，包括HIV-1，已经开发出有效的手段来调节CTD磷酸化模式或招募CTD相关的核因子，以增强病毒基因的表达。我们对(磷酸化)CTD相关蛋白的结构理解、它们与(磷酸化)CTD的相互作用以及CTD修饰酶的研究进展可能会对与人类疾病相关的问题产生重大影响，并最终有助于改善人类健康。

DESCRIPTION (provided by applicant): The C-terminal domain (CTD) of RNA polymerase II (RNAPII) plays a pivotal role in orchestrating RNA processing and other co-transcriptional events to achieve proper gene expression. It consists of multiple heptad repeats (Y1S2P3T4S5P6S7) that are highly conserved from yeast to human. The predominant form of CTD modification is the phosphorylation of Ser2 and/or Ser5 within the heptad repeats. The level and pattern of CTD phosphorylation are regulated by the concerted action of CTD kinases and phosphatases during the transcription cycle. The vast number of CTD phosphorylation states, also known as the "CTD code," form the basis for recruitment of specific macromolecular complexes to the transcribing polymerase. Recent identification of novel phosphoCTD-associating proteins has expanded the known functions of the CTD from mediating RNA processing to coordinating other co-transcriptional events, such as chromatin remodeling. Compared to the rapid progress in CTD biology, the structural knowledge of CTD recognition by CTD- associating proteins and CTD-modifying enzymes is very limited. Our long term goal is to understand the structures and mechanisms of CTD-modifying enzymes and CTD-mediated assembly of co-transcriptional complexes. In this proposal, we describe structural, biochemical and functional studies to investigate (1) the structure of the SRI domain of the Set2 histone methyltransferase and its interaction with the phosphoCTD; (2) the interactions between tandem FF domains of CA150 and the phosphoCTD; (3) the structure and mechanism of a novel Ser5-specific CTD phosphatase, Ssu72. PUBLIC HEALTH RELEVANCE (Public Health Relevance Statement) Abnormal changes of CTD phosphorylation states and their associated processes have been connected to a variety of human diseases. A number of viruses, including HIV-1, have developed effective means to modulate the CTD phosphorylation pattern or recruit CTD-associating nuclear factors in order to enhance viral gene expression. Advances in our structural understanding of (phospho)CTD-associating proteins, their interactions with the (phospho)CTD, and CTD-modifying enzymes are likely to generate a significant impact on issues related to human disease and ultimately contribute to improving human health.