THE ROLE OF RNA POLYMERASE II CTD PHOSPHATASE

描述（改编自申请人的描述）： RNA聚合酶II的最大亚基的状态决定了它被 招募到一个preinitiation复合物或进行有效的RNA链 伸长率此外，C-末端七肽重复结构域（CTD），即 磷酸化的靶点对于几个额外的步骤是必需的， mRNA生物发生，包括mRNA加帽、剪接和3'末端加工。因此 很可能CTD磷酸化调节了所有这些过程， cell.了解控制CTD磷酸化的机制， 去磷酸化对于了解转录如何与 核RNA代谢的其他步骤。许多蛋白激酶能够 在不同位点上磷酸化CTD是已知的，但CTD特异性磷酸化是已知的。 直到最近才描述了磷酸酶， 克隆能够这样的酵母丝氨酸/苏氨酸磷酸酶亚基 反应，以及发现哺乳动物同源物。磷酸酶亚基 由必需的FCP 1基因编码的蛋白不足以进行CTD去磷酸化 体外活性，和一个未知的正辅因子（FcpX）已牵连。 此外，磷酸酶活性被HIV达特蛋白抑制， 已知通过RNA聚合酶的过度磷酸化形式刺激延伸 二.本研究的主要目的是：（1）分离和鉴定辅因子 （2）利用酵母遗传学方法对FCP 1进行结构-功能分析 和生物化学;以及（3）使用以下方法确定Fcp 1在细胞中的作用： 遗传抑制基因分析结合生物化学。

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.