Open AccessIncreased thermosensitivity associated with topoisomerase I deletion and promoter mutations in Escherichia coli
Author(s) -
Qi Haiyan,
Menzel Rolf,
TseDinh YukChing
Publication year - 1999
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1999.tb13770.x
Subject(s) - topoisomerase , mutant , escherichia coli , promoter , gene , transcription (linguistics) , biology , microbiology and biotechnology , wild type , genetics , mutation , dna , gene expression , linguistics , philosophy
An Escherichia coli mutant with three of the promoters for the topoisomerase I gene ( topA ) deleted, such that only the σ 32 ‐dependent promoter (P1) remained, had a decreased level of topoisomerase I at 30°C and showed increased thermosensitivity at 52°C. However, it could still develop thermotolerance and had a wild‐type level of resistance to 52°C treatment if exposed first to 42°C. This indicated that newly synthesized topoisomerase I from transcription initiated at P1 was important for development of thermotolerance. Two other E. coli mutants lacking topA were >100 times more sensitive to high temperature than their wild‐type isogenic strains.