Identification of a heat shock promoter in the topA gene of Escherichia coli.
The transcriptional activity of the topA gene which codes for topoisomerase I was examined. An in vitro assay determined that the P1 promoter was dependent on the sigma 32 subunit of RNA polymerase. The transcriptional activity of the four topA promoters was examined by nuclease S1 mapping of the transcripts during a heat shock. This sigma 32-dependent promoter was shown to function as a heat shock promoter, although topoisomerase I is not a heat shock protein. A possible method of compensation of transcription activity by the other promoters to maintain the level of topoisomerase I during heat shock is proposed.
Lesley
S A
SA
McArdle Laboratory for Cancer Research, University of Wisconsin-Madison 53706.
Jovanovich
S B
SB
Tse-Dinh
Y C
YC
Burgess
R R
RR
D001483:Base Sequence; D004264:DNA Topoisomerases, Type I / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D006360:Heat-Shock Proteins / Q000235:genetics*; D006358:Hot Temperature; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics; D012808:Sigma Factor / Q000235:genetics*; D014158:Transcription, Genetic
D004269:DNA, Bacterial; D006360:Heat-Shock Proteins; D012333:RNA, Messenger; D012808:Sigma Factor; D004264:DNA Topoisomerases, Type I