The Pseudomonas aeruginosa hemA promoter is regulated by Anr, Dnr, NarL and Integration Host Factor.
Pseudomonas aeruginosa forms most of its heme under anaerobic denitrifying conditions. To study the regulation of the hemA gene, which codes for the first enzyme of heme biosynthesis in P. aeruginosa, a lacZ reporter gene fusion was constructed. Expression of lacZ under the control of the hemA promoter was found to be increased by 2.8-fold under anaerobic conditions in the presence of the alternative electron acceptor nitrate, relative to the level observed under aerobic growth conditions. Anaerobic fermentative growth or the presence of nitrite did not affect the lacZ expression. The genes encoding the oxygen sensor protein Anr, the redox regulator Dnr, the nitrate regulator NarL and the DNA-bending Integration Host Factor (IHF) are all required for the cooperative anaerobic induction of the hemA promoter hemAp (1). Potential binding sites for these regulatory proteins were identified by site-directed mutagenesis of the promoter fused to the reporter gene. The mode of regulation of P. aeruginosa hemA differs significantly from that described for the hemA gene of Escherichia coli K-12.
Krieger
R
R
Institut für Organische Chemie und Biochemie, Albert-Ludwigs-Universität Freiburg, D-79104 Freiburg i. Br., Germany.
Rompf
A
A
Schobert
M
M
Jahn
D
D
D000445:Aldehyde Oxidoreductases / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D034982:Integration Host Factors; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011550:Pseudomonas aeruginosa / Q000235:genetics; D015534:Trans-Activators; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C095475:DNR protein, Pseudomonas aeruginosa; D029968:Escherichia coli Proteins; D034982:Integration Host Factors; D015534:Trans-Activators; D014157:Transcription Factors; C440503:integration host factor, Pseudomonas; C069780:NarL protein, E coli; C072908:ANR protein, Pseudomonas aeruginosa; D000445:Aldehyde Oxidoreductases; C067282:glutamyl tRNA reductase