Premium
Expression of the Bacillus subtilis gabP gene is regulated independently in response to nitrogen and amino acid availability
Author(s) -
Ferson Amy E.,
Wray, Jr Lewis V.,
Fisher Susan H.
Publication year - 1996
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 - 10.1046/j.1365-2958.1996.d01-1720.x
Subject(s) - biology , bacillus subtilis , promoter , gene , locus (genetics) , transposable element , transcription (linguistics) , gene product , gene expression , repressor , genetics , nucleic acid sequence , microbiology and biotechnology , regulation of gene expression , primer extension , nucleotide , mutant , bacteria , linguistics , philosophy
Expression from the Bacillus subtilis nrg‐21 locus increases 26‐fold during nitrogen‐limited growth. The DNA corresponding to this locus was cloned and sequenced. The nucleotide sequence revealed a gene that could encode a protein with sequence similarity to the Escherichia coli γ‐aminobutyric acid (GABA) permease. A transposon insertion in this locus eliminated the uptake of GABA and severely inhibited the utilization of GABA as a nitrogen source. Primer extension analysis revealed that the B. subtilis gabP gene was transcribed from two overlapping promoters. Transcription from the P1 promoter was repressed during growth in the presence of amino acids. The product of the codY gene proved to be required for this repression. Transcription from the P2 promoter increased during nitrogen‐limited growth and was dependent upon the product of the tnrA gene. Deletion analysis revealed that activation of the P2 promoter during nitrogen‐limited growth requires a nucleotide sequence located upstream of its −35 region. Regulation of gabP expression by the CodY and TnrA regulatory systems, which respond to different physiological signals, allows for a wide range of gabP expression during growth on various nitrogen sources.