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DNA replication and transcription in a temperature-sensitive mutant of E. coli with a defective DNA gyrase B subunit

โœ Scribed by Mirkin, S. M. ;Shmerling, Zh. G.

Publisher
Springer
Year
1982
Tongue
English
Weight
532 KB
Volume
188
Category
Article
ISSN
0026-8925

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โœฆ Synopsis

A temperature-sensitive mutant of E. coli with a defective DNA gyrase B subunit has been obtained. The mutation is expressed in the thermolability of DNA gyrase in vitro and in DNA relaxation in vivo. DNA replication in the mutant does not stop under non-permissive conditions; its rate gradually falls by a factor of 2 to 3. The transcription rate also drops by a factor of 2 to 3, but before replication. Small concentrations of rifampicin, an inhibitor of bacterial RNA polymerase, make for a partial survival of the mutant cells under non-permissive conditions. The results suggest the conclusion that DNA supercoiling is mainly required to ensure the optimum transcription level in the cell.

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