Role of DNA bubble rewinding in enzymatic transcription termination
- Department of Molecular Biology and Genetics, Biotechnology Building, Cornell University, Ithaca, NY 14853
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Contributed by Jeffrey W. Roberts, February 3, 2006
Abstract
By using DNA heteroduplexes that inhibit rewinding of the upstream part of the transcription bubble, we show that transcript release in termination by the enzymes Mfd and Rho is facilitated by reannealing of DNA in the upstream region of the transcription bubble, as is also true for termination by intrinsic terminators. We also show that, like Mfd, the Rho termination factor promotes forward translocation of RNA polymerase. These results support termination models in which external forces imposed on nucleic acids induce concerted rewinding of DNA and unwinding of the DNA/RNA hybrid, possibly accompanied by forward translocation of RNA polymerase, leading to transcription complex dissociation.
Footnotes
- †To whom correspondence should be addressed. E-mail: jwr7{at}cornell.edu
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↵*Present address: Department of Molecular and Cellular Biology, Biological Laboratories, Harvard University, Cambridge, MA 02138.
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Author contributions: J.-S.P. and J.W.R. designed research; J.-S.P. performed research; J.-S.P. contributed new reagents/analytic tools; J.-S.P. and J.W.R. analyzed data; and J.-S.P. and J.W.R. wrote the paper.
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Conflict of interest statement: No conflicts declared.
- Abbreviation:
- RNAP,
- RNA polymerase.
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Freely available online through the PNAS open access option.
- © 2006 by The National Academy of Sciences of the USA
