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Regulatory characteristics and promoter analysis of csiE , a stationary phase‐inducible gene under the control of σ S and the cAMP—CRP complex in Escherichia coli
Author(s) -
Marschall Christoph,
HenggeAronis Regine
Publication year - 1995
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1995.mmi_18010175.x
Subject(s) - biology , rna polymerase , gene , transcriptional regulation , promoter , transcription (linguistics) , start codon , escherichia coli , microbiology and biotechnology , gene expression , regulation of gene expression , sigma factor , genetics , messenger rna , linguistics , philosophy
Sigma‐S and the cAMP—CRP complex are global regulatory factors involved in stationary‐phase induction of large groups of genes in Escherichia coli. csiE , a gene located at 57.25 min (co‐ordinate 2674) of the physical map of the E. coli chromosome, is under the control of both of these factors. Sigma‐S plays a positive, though not absolutely essential, role in the expression of csiE . Regulation by cAMP—CRP has both positive and negative elements, with the latter being dependent on the presence of σ S , whose expression is negatively influenced by cAMP—CRP. csiE has a single transcriptional start site located 33 bp upstream of the initiation codon. By a 5′‐deletion approach, we show that 72 bp upstream of the csiE transcriptional start site are sufficient for regulation by σ S and cAMP—CRP. A deletion upstream of nucleotide −38 with respect to the start site eliminates positive cAMP—CRP control and makes the remaining expression fully dependent on σ S . Our results indicate that transcription at the csiE promoter can be initiated in vivo by σ S ‐containing RNA polymerase alone as well as by σ 70 ‐containing RNA polymerase in conjunction with cAMP—CRP or a cAMP—CRP‐dependent secondary regulator. The promoter region of poxB , the structural gene for pyruvate oxidase, which is also under the control of σ S and cAMP—CRP, is very similar to the corresponding region of csiE , suggesting a similar regulatory mechanism also for poxB .