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Mechanism of DmS-II-mediated pause suppression by Drosophila RNA polymerase II
Journal article   Open access   Peer reviewed

Mechanism of DmS-II-mediated pause suppression by Drosophila RNA polymerase II

Hongliang Guo and David H Price
The Journal of biological chemistry, Vol.268(25), pp.18762-18770
1993
DOI: 10.1016/S0021-9258(17)46695-6
PMID: 7689559
url
https://doi.org/10.1016/S0021-9258(17)46695-6View
Published (Version of record) Open Access

Abstract

Transcription elongation factor S-II mediates nascent transcript cleavage by RNA polymerase II (Reines, D. (1992) J. Biol. Chem. 267, 3795-3800). We have examined the mechanism of action of the Drosophila S-II analog, DmS-II, in a defined transcription system. Our results show that DmS-II is necessary and sufficient to activate nascent transcript cleavage by RNA polymerase II during transcription of a dC-tailed template. The pattern of transcripts resulting from prolonged action by DmS-II indicates that there are kinetic barriers to transcript shortening. During the cleavage reaction, the polymerase remains in register with the template strand and generates mainly nucleotide dimers. The ability of DmS-II to mediate transcript shortening resides in the carboxyl-terminal half of the protein. Our results support a model for pause suppression in which DmS-II binds to the paused polymerase, causes one cleavage event and is then released from the complex. Elongation by the polymerase then allows a second encounter with the pause site and a second chance of passing the site. Complete pause suppression may require multiple transcript shortening events for some polymerase molecules.
 Molecular Genetics Fundamental and applied biological sciences. Psychology Biological and medical sciences Transcription. Transcription factor. Splicing. Rna processing Molecular and cellular biology

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