Abstract
Supercoiled plasmid DNAs with negative superhelicity several times higher than normal have been isolated from Escherichia coli topA mutants. The formation of these hypernegatively supercoiled plasmid DNAs is apparently induced by transcription. We show that hypernegatively supercoiled plasmid DNAs isolated from topA mutants contain R-loop(s). To study the mechanism of formation of hypernegatively supercoiled plasmid DNA, we have been able to reproduce hypernegatively supercoiled DNA in vitro using purified DNA polymerase and DNA gyrase. The formation of hypernegatively supercoiled plasmid DNA template in vitro is shown to require transcription elongation and is tightly linked to R-loop formation. We propose that one of the roles of topoisomerase I is to suppress R-loop formation during transcription elongation.
| Original language | English |
|---|---|
| Pages (from-to) | 2068-2074 |
| Number of pages | 7 |
| Journal | Journal of Biological Chemistry |
| Volume | 269 |
| Issue number | 3 |
| Publication status | Published - Jan 21 1994 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Biochemistry
Cite this
Hypernegative supercoiling of the DNA template during transcription elongation in vitro. / Drolet, Marc; Bi, Xin; Liu, Leroy-Fong.
In: Journal of Biological Chemistry, Vol. 269, No. 3, 21.01.1994, p. 2068-2074.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Hypernegative supercoiling of the DNA template during transcription elongation in vitro
AU - Drolet, Marc
AU - Bi, Xin
AU - Liu, Leroy-Fong
PY - 1994/1/21
Y1 - 1994/1/21
N2 - Supercoiled plasmid DNAs with negative superhelicity several times higher than normal have been isolated from Escherichia coli topA mutants. The formation of these hypernegatively supercoiled plasmid DNAs is apparently induced by transcription. We show that hypernegatively supercoiled plasmid DNAs isolated from topA mutants contain R-loop(s). To study the mechanism of formation of hypernegatively supercoiled plasmid DNA, we have been able to reproduce hypernegatively supercoiled DNA in vitro using purified DNA polymerase and DNA gyrase. The formation of hypernegatively supercoiled plasmid DNA template in vitro is shown to require transcription elongation and is tightly linked to R-loop formation. We propose that one of the roles of topoisomerase I is to suppress R-loop formation during transcription elongation.
AB - Supercoiled plasmid DNAs with negative superhelicity several times higher than normal have been isolated from Escherichia coli topA mutants. The formation of these hypernegatively supercoiled plasmid DNAs is apparently induced by transcription. We show that hypernegatively supercoiled plasmid DNAs isolated from topA mutants contain R-loop(s). To study the mechanism of formation of hypernegatively supercoiled plasmid DNA, we have been able to reproduce hypernegatively supercoiled DNA in vitro using purified DNA polymerase and DNA gyrase. The formation of hypernegatively supercoiled plasmid DNA template in vitro is shown to require transcription elongation and is tightly linked to R-loop formation. We propose that one of the roles of topoisomerase I is to suppress R-loop formation during transcription elongation.
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UR - http://www.scopus.com/inward/citedby.url?scp=0028006543&partnerID=8YFLogxK
M3 - Article
VL - 269
SP - 2068
EP - 2074
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 3
ER -