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Increase in negative supercoiling of plasmid DNA in Escherichia coli exposed to cold shock
Author(s) -
Mizushima Tohru,
Kataoka Kazuhiro,
Ogata Yasuyuki,
Inoue Ryuichi,
Sekimizu Kazuhisa
Publication year - 1997
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.1997.2181582.x
Subject(s) - dna supercoil , dna gyrase , biology , plasmid , microbiology and biotechnology , dna , escherichia coli , cold shock domain , heat shock , plasmid preparation , mutant , nalidixic acid , heat shock protein , dna replication , biochemistry , gene , rna , pbr322
Negative supercoiling of plasmid DNA in Escherichia coli cells can decrease transiently when exposed to heat shock. The effect of cold shock on DNA supercoiling was examined, and analysis by agarose gel electrophoresis in the presence of chloroquine revealed that negative supercoiling of plasmid DNA in cells increased when cells were exposed to cold shock. This increase was transient and was nil when the cells were pretreated with nalidixic acid, an inhibitor of DNA gyrase. In a mutant deficient in expression of HU protein, the increase in negative supercoiling of DNA by cold shock is less apparent than in wild‐type cells. It is proposed that DNA gyrase and HU protein have a role in the DNA supercoiling reaction seen with cold shock.