Structure and Regulation of Pol II Elongation Complexes

该项目的长期目标是确定转录复合体中导致RNA聚合酶II在高等真核生物中阻滞和终止的相互作用。转录阻滞或终止有助于真核生物的基因调控，但潜在的机制尚不清楚。为了理解这些机制，需要更好地了解RNA聚合酶II转录延伸复合物的结构，包括在通常延伸有效的阻滞位点。将开发方法，以产生定义的延伸复合物，包含纯RNA聚合酶II或RNA聚合酶II，携带修饰和辅助因子，它在启动子起始时获得。这两种类型的定义延伸配合物将被分离出来，并使用各种可以揭示其内部RNA和DNA链配置的试剂探测其结构。将进行实验以测试转录阻滞的两个模型；1)转录本结构的改变产生阻滞，2)阻滞是由DNA分子弯曲或构象改变引起的。这项研究将对RNA聚合酶如何将基因（DNA）中的信息转录成表达遗传信息所需的RNA产物产生新的见解。

The long-range goal of this project is to define the interactions in the transcription complex that cause arrest and termination by RNA polymerase II in higher eukaryotes. Transcriptional arrest or termination contributes to gene regulation in eukaryotes, but the underlying mechanisms are unknown. To understand these mechanisms, a much better appreciation of the structure of RNA polymerase II transcription elongation complexes, both at arrest sites where elongation normally is efficient, will be required. Methods will be developed to produce defined elongation complexes that contain either pure RNA polymerase II or RNA polymerase II that carries the modifications and auxiliary factors it acquires during initiation at a promoter. Both types of defined elongation complexes will be isolated and their structures probed using a variety of agents that can reveal the configuration of RNA and DNA strands within them. Experiments will be performed to test two models for transcriptional arrest; 1) that altered configuration of the transcript produces arrest and 2) that arrest is caused by bent, or conformationally altered, DNA molecules. %%% This study will produce new insight into how RNA polymerase transcribes the information in genes (DNA) to an RNA product which is required to express genetic information.