THE ROLE OF RNA POLYMERASE II CTD PHOSPHATASE

描述(改编自申请人的描述)：磷酸化 RNA聚合酶II最大亚基的状态决定了它的能力 被招募到预引发复合体中或进行有效的RNA链 伸长率。此外，C端七肽重复结构域(CTD)即 磷酸化的目标对于以下几个额外步骤是必不可少的 信使核糖核酸的生物发生，包括信使核糖核酸的封顶、剪接和3‘末端加工。因此， 很可能CTD的磷酸化调节了所有这些过程。 手机。了解控制CTD磷酸化和CTD的机制 去磷酸化对于了解转录是如何与 核RNA新陈代谢的其他步骤。大量的蛋白激酶能够 CTD在不同位点上的磷酸化是已知的，但CTD是特异的 直到最近，磷酸酶才被描述出来，提纯和 具有此功能的酵母丝氨酸/苏氨酸磷酸酶亚基的克隆 反应，并发现了一种哺乳动物的同源物。磷酸酶亚单位 由必需的FCP1基因编码的蛋白不足以进行CTD去磷酸化 一种未知的阳性辅因子(FcpX)可能与此有关。 此外，磷酸酶活性被HIV Tat蛋白抑制，这是 已知可通过RNA聚合酶的过度磷酸化形式刺激伸长 二、本研究的目的是：(1)分离和鉴定辅因子 FcpX；(2)利用酵母遗传学对FCP1的结构和功能进行分析 和生物化学；以及(3)确定FCP1在细胞中的作用(S) 基因抑制分析与生物化学相结合。

DESCRIPTION (adapted from the applicant's description): The phosphorylation state of the largest subunit of RNA polymerase II determines its ability to be recruited into a preinitiation complex or carry out efficient RNA chain elongation. Further, the C-terminal heptapeptide repeat domain (CTD) that is the target for phosphorylation is essential for several additional steps in mRNA biogenesis, including mRNA capping, splicing, and 3' end processing. Thus it is likely that CTD phosphorylation regulates all of these processes in the cell. Understanding the mechanisms that govern CTD phosphorylation and dephosphorylation is critical to learning how transcription is coordinated with other steps in nuclear RNA metabolism. Numerous protein kinases capable of phosphorylating the CTD on different sites are known, but CTD-specific phosphatases have not been described until recently, with the purification and cloning of a yeast serine/threonine phosphatase subunit capable of this reaction, and the discovery of a mammalian homologue. The phosphatase subunit encoded by the essential FCP1 gene is not sufficient for CTD dephosphorylation activity in vitro, and an unknown positive cofactor (FcpX) has been implicated. Further, the phosphatase activity is inhibited by the HIV Tat protein, which is known to stimulate elongation by the hyperphosphorylated form of RNA polymerase II. The aims of this research are to: (1) Isolate and characterize the cofactor FcpX; (2) Carry out a structure-function analysis of FCP1 using yeast genetics and biochemistry; and (3) determine the role(s) of Fcp1 in the cell using genetic suppressor analysis combined with biochemistry.