RNA binding RNA polymerase II CTD associated proteins

描述(申请人提供)：拟议研究的目的是了解一组RNA结合蛋白如何调节真核转录、延伸和终止。我们最近的研究表明，特定的RNA序列元件可以指导RNA聚合酶II的终止，而不会导致新生转录物的聚腺苷酸化。在酿酒酵母中，这一机制被用来在非多聚腺苷化的小核仁和小核仁RNA(SnRNAs和snoRNAs)上产生三端。此外，我们已经证明了几个mRNAs受类似的机制调控。这个调控途径需要两个RNA结合蛋白Nrd1和NaB3的功能，并通过识别新生转录本中的特定顺式元件来发挥作用。该途径还需要Seni RNA解旋酶以及PolII CTD和CTD激酶。这些研究的近期目标是准确地了解Nrd1和NaB3如何导致转录终止，而长期目标是了解CTD和SCAFs在RNA聚合酶II调控转录中的作用。在这个建议中，我们的具体目标是：(1)定义通过Nrd1-Nab3途径调节转录延伸的顺式元件；(2)进一步剖析Nrd1途径各组成部分之间的遗传相互作用；(3)建立一种依赖于Nrd1p-NaB3p的体外终止实验；以及(4)鉴定哺乳动物的Nrd1-Ike蛋白(SCAFs)，并确定它们是否在转录终止中发挥类似的作用。新生的PolII转录本中的序列是否能够触发非多腺化转录本的终止是一种新的调节机制。这一途径类似于调节HIV LTR转录本延伸的机制。与HIV的调控类似，Nrd1-Nab3机制需要PolII CTD和CTD激酶。进一步了解这一途径对于理解真核基因是如何被调控的以及这些途径是如何出于治疗目的而被调节的将是很重要的。

DESCRIPTION (provided by applicant): The objective of the proposed studies is to understand how a set of RNA-binding proteins regulate eucaryotic transcription elongation and termination. Our recent studies indicate that specific RNA sequence elements can direct RNA polymerase II termination in a manner that does not lead to polyadenylation of the nascent transcript. In Saccharomyces cerevisiae this mechanism is used to produce 3-ends on non-polyadenylated small nuclear and small nucleolar RNAs (snRNAs and snoRNAs). In addition, we have shown that several mRNAs are regulated by a similar mechanism. This regulatory pathway requires the function of two RNA-binding proteins, Nrd1 and Nab3, and operates through recognition of specific cis-elements in the nascent transcript. This pathway also requires the Seni RNA helicase and both the pol II CTD and a CTD kinase. The immediate objective of the proposed studies is to understand precisely how Nrd1 and Nab3 function to cause transcription termination while the longer term objective is to understand the role of the CTD and SCAFs in regulating transcription by RNA polymerase II.In this proposal our specific aims are to: (1) Define cis-elements that regulate transcription elongation through the Nrd1 -Nab3 pathway; (2) Further dissect the genetic interactions among components of the Nrd1 pathway; (3) Develop a Nrd1p-Nab3p-dependent in vitro termination assay; and (4) Characterize mammalian Nrd1-Iike proteins (SCAFs) and determine whether they play a similar role in regulating transcription termination.The ability of sequences in the nascent pol II transcript to trigger termination of non-polyadenylated transcripts is a novel regulatory mechanism. This pathway is similar to the mechanism that regulates elongation of transcripts from the HIV LTR. Similar to HIV regulation, the Nrd1-Nab3 mechanism requires the pol II CTD and a CTD kinase. Further understanding of this pathway will be important in understanding how eucaryotic genes are regulated and how these pathways may be modulated for therapeutic reasons