Autoregulatory expression of the Escherichia coli hns gene encoding a nucleoid protein: H-NS functions as a repressor of its own transcription.
The Escherichia coli nucleoid protein, H-NS (or H1a), appears to influence the regulation of a variety of unrelated E. coli genes and operons. To gain an insight into the regulation of the hns gene itself, we constructed in this study a hns-lacZ transcriptional fusion gene and inserted a single copy at the att lambda locus on the E. coli chromosome. Expression of hns transcription appeared to be moderately regulated in a growth phase-dependent manner. It also emerged that hns transcription is under negative autoregulation, at least in the logarithmic growth phase. The results of in vitro transcription experiments confirmed that H-NS functions as a repressor for its own transcription. Thus, H-NS was shown to exhibit relatively high affinity for the DNA sequence encompassing the hns promoter region, as compared with a non-specific sequence. These results support the view that the nucleoid protein, H-NS, can function as a transcriptional regulator.
Ueguchi
C
C
Laboratory of Microbiology, School of Agriculture, Nagoya University, Japan.
Kakeda
M
M
Mizuno
T
T
D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D001426:Bacterial Proteins; D002455:Cell Division; D002474:Cell-Free System; D004269:DNA, Bacterial / Q000378:metabolism; D004274:DNA, Recombinant / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial / Q000235:genetics*; D006706:Homeostasis; D007763:Lac Operon / Q000235:genetics; D009687:Nuclear Proteins; D011401:Promoter Regions, Genetic / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics; D014158:Transcription, Genetic
D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004274:DNA, Recombinant; D004268:DNA-Binding Proteins; C031908:H-NS protein, bacteria; D009687:Nuclear Proteins; D012097:Repressor Proteins