Open AccessRegulation of the transcriptional activators AnfA and VnfA by metals and ammonium in Azotobacter vinelandii
Author(s) -
Premakumar R,
Pau Richard N,
Mitchenall Lesley A,
Easo Mary,
Bishop Paul E
Publication year - 1998
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1998.tb13068.x
Subject(s) - azotobacter vinelandii , operon , transcription (linguistics) , lac operon , psychological repression , microbiology and biotechnology , transcriptional regulation , chemistry , promoter , transcription factor , biology , gene , biochemistry , gene expression , nitrogenase , escherichia coli , genetics , bacteria , nitrogen fixation , linguistics , philosophy
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 NH + 4 , Mo, or V (vanadium) was tested on the expression of vnfA‐lacZ and anfA‐lacZ transcriptional fusions. Mo repressed expression of both fusions whereas NH + 4 and V repressed the anfA‐lacZ fusion, but not the vnfA‐lacZ fusion. Thus the repressive effect on transcription of the anfHDGKOR operon by NH + 4 , 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.