Regulation of the transcriptional activators AnfA and VnfA by metals and ammonium in Azotobacter vinelandii.
Transcription of the genes encoding molybdenum (Mo)-independent nitrogenases 2 and 3 of Azotobacter vinelandii requires the activators VnfA and AnfA, respectively. The effect of NH4+, Mo, or V (vanadium) was tested on the expression of vnfA-lacZ and anfA-lacZ transcriptional fusions. Mo repressed expression of both fusions whereas NH4+ and V repressed the anfA-lacZ fusion, but not the vnfA-lacZ fusion. Thus the repressive effect on transcription of the anfHDGKOR operon by NH4+, Mo, or V is mediated through their effect on transcription of anfA and the repressive effect of Mo on the vnfHFd and vnfDGK operons is mediated through Mo repression of vnfA transcription. Mo-dependent repression of anfA transcription is influenced but not entirely mediated by the Mo-responsive regulator ModE.
U.S. Department of Agriculture, and Department of Microbiology, North Carolina State University, Raleigh 27695-7615, USA.
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R
Premakumar
R N
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Pau
L A
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Mitchenall
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M
Easo
P E
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Bishop
D000085:Acetates / Q000494:pharmacology; D016948:Azotobacter vinelandii / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D001426:Bacterial Proteins / Q000187:drug effects* / Q000235:genetics; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000187:drug effects* / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics; D008670:Metals / Q000494:pharmacology*; D008982:Molybdenum / Q000494:pharmacology; D015534:Trans-Activators / Q000187:drug effects* / Q000235:genetics; D014639:Vanadium / Q000494:pharmacology; D001616:beta-Galactosidase / Q000378:metabolism
D000085:Acetates; D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D008670:Metals; D015534:Trans-Activators; C090095:VnfA protein, Azotobacter vinelandii; D014639:Vanadium; D008982:Molybdenum; D001616:beta-Galactosidase; C018824:ammonium acetate