TnrA, a transcription factor required for global nitrogen regulation in Bacillus subtilis.
Expression of the Bacillus subtilis nrgAB operon is derepressed during nitrogen-limited growth. We have identified a gene, tnrA, that is required for the activation of nrgAB expression under these growth conditions. Analysis of the DNA sequence of the tnrA gene revealed that it encodes a protein with sequence similarity to GlnR, the repressor of the B. subtilis glutamine synthetase operon. The tnrA mutant has a pleiotropic phenotype. Compared with wild-type cells, the tnrA mutant is impaired in its ability to utilize allantoin, gamma-aminobutyrate, isoleucine, nitrate, urea, and valine as nitrogen sources. During nitrogen-limited growth, transcription of the nrgAB, nasB, gabP, and ure genes is significantly reduced in the tnrA mutant compared with the levels seen in wild-type cells. In contrast, the level of glnRA expression is 4-fold higher in the, tnrA mutant than in wild-type cells during nitrogen restriction. The phenotype of the tnrA mutant indicates that a global nitrogen regulatory system is present in B. subtilis and that this system is distinct from the Ntr regulatory system found in enteric bacteria.
Wray
L V
LV
Department of Microbiology, Boston University School of Medicine, MA 02118, USA.
Ferson
A E
AE
Rohrer
K
K
Fisher
S H
SH
D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000235:genetics*; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics; D001483:Base Sequence; D004268:DNA-Binding Proteins; D004794:Enzyme Repression; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005974:Glutamate-Ammonia Ligase / Q000096:biosynthesis; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D009584:Nitrogen / Q000378:metabolism*; D051922:PII Nitrogen Regulatory Proteins; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D015534:Trans-Activators / Q000096:biosynthesis; D014157:Transcription Factors / Q000235:genetics*
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C082451:GlnR protein, Streptomyces coelicolor; D008565:Membrane Proteins; C085245:NrgA protein, Bacillus subtilis; C085246:NrgB protein, Bacillus subtilis; D051922:PII Nitrogen Regulatory Proteins; D012097:Repressor Proteins; C101458:ScgR protein, Bacillus subtilis; D015534:Trans-Activators; D014157:Transcription Factors; C081173:glutamine synthetase I; D005974:Glutamate-Ammonia Ligase; D009584:Nitrogen