Elongation by RNA polymerase II on chromatin templates requires topoisomerase activity
Transcription on chromatin by RNA polymerase II (pol II) is repressed as compared with transcription on histone‐free DNA. In this study, we show that human topoisomerase I (topo I) and yeast topoisomerase II (topo II), each of which relax both positive and negative superhelical tension, reverse the...
Saved in:
Published in | Nucleic acids research Vol. 31; no. 17; pp. 5016 - 5024 |
---|---|
Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
England
Oxford University Press
01.09.2003
Oxford Publishing Limited (England) |
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | Transcription on chromatin by RNA polymerase II (pol II) is repressed as compared with transcription on histone‐free DNA. In this study, we show that human topoisomerase I (topo I) and yeast topoisomerase II (topo II), each of which relax both positive and negative superhelical tension, reverse the transcriptional repression by chromatin. In the presence of bacterial topo I, which can relax only negative superhelical tension, the transcription is repressed on chromatin templates. The data together show that the relaxation of positive superhelical tension by these enzymes was the key property required for RNA synthesis from chromatin templates. In the absence of topoisomerase, transcriptional repression on chromatin depended on RNA length. The synthesis of transcripts of 100 nt or shorter was unaffected by chromatin, but repression was apparent when the RNA transcript was 200 nt or longer. These findings suggest that transcription on chromatin templates results in the accumulation of positive superhelical tension by the elongating polymerase, which in turn inhibits further elongation in the absence of topoisomerase activity. |
---|---|
Bibliography: | istex:0A5E2CDA63D921C4D59632E153D5B596B9A43947 Received May 22, 2003; Revised June 23, 2003; Accepted July 8, 2003 To whom correspondence should be addressed. Tel: +1 617 278 0818; Fax: +1 617 732 7449; Email: jparvin@rics.bwh.harvard.edu ark:/67375/HXZ-B8LRLKT4-T local:gkg705 ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 ObjectType-Article-1 ObjectType-Feature-2 |
ISSN: | 0305-1048 1362-4962 1362-4962 |
DOI: | 10.1093/nar/gkg705 |