9405449 Abstract This project focuses on the nature of RNA polymerase II transcription termination in higher eukaryotes. In contrast to prokaryotes, the 3' ends of mature eukaryotic mRNAs are generated by processing rather than by transcription termination. The processing of the nascent RNA transcripts, combined with the inherent instability of the primary RNA products generated by termination, has thus restricted the in vivo analysis of transcription termination. It is clear, however, that RAN polymerase II transcription termination is seldom, if ever, localized to single discreet site, but rather, occurs over a region that may extend for several kilobases. both the sequence and location of the termination region with respect to the end of the mature mRNA are specific to each transcription unit. Although the sequences encompassing the termination region appear to play a significant role, the key termination signal appears to be generated by the 3' processing of the nascent RNA transcript. 3' processing is an obligatory step in the biosynthesis of a functional mRNA. Therefore the coupling of pre-mRNA 3' processing and RNA polymerase II transcription termination offers an elegant mechanism for assuring that mRNA synthesis is complete prior to transcription termination. *** The central goal of this project is to elucidate the biochemical basis for the coupling of RNA polymerase II transcription termination and mRNA 3' processing. The recent development of a well characterized and highly purified mRNA 3' processing system will form the basis of this work. The specific objectives of this proposal are to: 1) Develop an in vitro system for the investigation of the coupling of RNA polymerase II transcription termination to the 3' processing of the nascent RNA, 2) Delineate the role of a 5' to 3' processing machinery and the RNA polymerase II transcription complex. A basic knowledge of the mechansims that serve to direct the termination of RNA polymerase II t ranscription may lead to an understanding of the manner in which this process contributes to the regulation of gene expression. %%%
