aldB, an RpoS-dependent gene in Escherichia coli encoding an aldehyde dehydrogenase that is repressed by Fis and activated by Crp.
Escherichia coli aldB was identified as a gene that is negatively regulated by Fis but positively regulated by RpoS. The complete DNA sequence determined in this study indicates that aldB encodes a 56.3-kDa protein which shares a high degree of homology with an acetaldehyde dehydrogenase encoded by acoD of Alcaligenes eutrophus and an aldehyde dehydrogenase encoded by aldA of Vibrio cholerae and significant homology with a group of other aldehyde dehydrogenases from prokaryotes and eukaryotes. Expression of aldB is maximally induced during the transition from exponential phase to stationary phase. Its message levels are elevated three- to fourfold by a fis mutation and abolished by an rpoS mutation. In addition, the expression of an aldB-lacZ fusion was decreased about 20-fold in the absence of crp. DNase I footprinting analysis showed that five Fis binding sites and one Crp binding site are located within the aldB promoter region, suggesting that Fis and Crp are acting directly to control aldB transcription. AldB expression is induced by ethanol, but in contrast to that of most of the RpoS-dependent genes, the expression of aldB is not altered by an increase in medium osmolarity.
Xu
J
J
Department of Biological Chemistry, UCLA School of Medicine 90095, USA.
Johnson
R C
RC
D000444:Aldehyde Dehydrogenase / Q000235:genetics*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000502:physiology; D001483:Base Sequence; D001665:Binding Sites; D002352:Carrier Proteins / Q000502:physiology; D002373:Cyclic AMP Receptor Protein / Q000502:physiology; D017931:DNA Primers / Q000737:chemistry; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D000431:Ethanol / Q000494:pharmacology; D035021:Factor For Inversion Stimulation Protein; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D034982:Integration Host Factors; D008969:Molecular Sequence Data; D009994:Osmolar Concentration; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012808:Sigma Factor / Q000502:physiology
D001426:Bacterial Proteins; D002352:Carrier Proteins; D002373:Cyclic AMP Receptor Protein; D017931:DNA Primers; D029968:Escherichia coli Proteins; D035021:Factor For Inversion Stimulation Protein; D034982:Integration Host Factors; D012333:RNA, Messenger; D012808:Sigma Factor; C440502:integration host factor, E coli; C069567:sigma factor KatF protein, Bacteria; D000431:Ethanol; D000444:Aldehyde Dehydrogenase