The Escherichia coli stpA gene is transiently expressed during growth in rich medium and is induced in minimal medium and by stress conditions.
The transcriptional regulation of the stpA gene, encoding the Escherichia coli H-NS-like protein StpA, has been studied as a function of a variety of environmental conditions, and its response to trans-acting factors has been characterized. Chromosomally located stpA is expressed primarily from a promoter immediately upstream of the gene which is severely repressed by the homologous nucleoid-associated protein H-NS. However, we show here that even in a strain containing functional H-NS, stpA is transiently induced during growth of a batch culture in rich medium. It can also be induced strongly by osmotic shock and, to a lesser extent, by an increase in growth temperature. Moreover, when cells are grown in minimal medium, we observe a more sustained induction of stpA which is dependent on the leucine-responsive regulatory protein (Lrp). This enhanced level of stpA transcription is virtually abolished in an H-NS-independent manner when the culture undergoes carbon starvation. A sensitivity of the stpA promoter to DNA topology may contribute to some of these responses. Results reported here show that cloned fragments of the stpA promoter region can confer H-NS and Lrp responsiveness upon a lacZ reporter gene and suggest that several hundred base pairs of DNA upstream of the transcriptional start may be required for regulation by these two proteins.
Free
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Department of Microbiology, Trinity College, Dublin 2, Republic of Ireland. afree@acer.gen.tcd.ie
Dorman
C J
CJ
D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000096:biosynthesis*; D002244:Carbon / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D002876:Chromosomes, Bacterial; D003470:Culture Media; D004269:DNA, Bacterial / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D006358:Hot Temperature; D034982:Integration Host Factors; D026503:Low Density Lipoprotein Receptor-Related Protein-1; D018832:Molecular Chaperones; D009154:Mutation; D009690:Nucleic Acid Conformation; D009997:Osmotic Pressure; D011401:Promoter Regions, Genetic; D011971:Receptors, Immunologic / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D013217:Starvation; D013489:Suppression, Genetic; D013997:Time Factors
D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; D003470:Culture Media; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C031908:H-NS protein, bacteria; D034982:Integration Host Factors; D026503:Low Density Lipoprotein Receptor-Related Protein-1; D018832:Molecular Chaperones; D011971:Receptors, Immunologic; D011993:Recombinant Fusion Proteins; C090104:StpA protein, E coli; C440502:integration host factor, E coli; D002244:Carbon