title: The Escherichia coli stpA gene is transiently expressed during growth in rich medium and is induced in minimal medium and by stress conditions.
abstract: 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.
authors.affiliation: Department of Microbiology, Trinity College, Dublin 2, Republic of Ireland. afree@acer.gen.tcd.ie
authors.forename: A
authors.initials: A
authors.lastname: Free
authors.forename: C J
authors.initials: CJ
authors.lastname: Dorman
mesh_terms: 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
chemical_list: 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