title: trans-acting factors affecting carbon catabolite repression of the hut operon in Bacillus subtilis.
abstract: In Bacillus subtilis, CcpA-dependent carbon catabolite repression (CCR) mediated at several cis-acting carbon repression elements (cre) requires the seryl-phosphorylated form of both the HPr (ptsH) and Crh (crh) proteins. During growth in minimal medium, the ptsH1 mutation, which prevents seryl phosphorylation of HPr, partially relieves CCR of several genes regulated by CCR. Examination of the CCR of the histidine utilization (hut) enzymes in cells grown in minimal medium showed that neither the ptsH1 nor the crh mutation individually had any affect on hut CCR but that hut CCR was abolished in a ptsH1 crh double mutant. In contrast, the ptsH1 mutation completely relieved hut CCR in cells grown in Luria-Bertani medium. The ptsH1 crh double mutant exhibited several growth defects in glucose minimal medium, including reduced rates of growth and growth inhibition by high levels of glycerol or histidine. CCR is partially relieved in B. subtilis mutants which synthesize low levels of active glutamine synthetase (glnA). In addition, these glnA mutants grow more slowly than wild-type cells in glucose minimal medium. The defects in growth and CCR seen in these mutants are suppressed by mutational inactivation of TnrA, a global nitrogen regulatory protein. The inappropriate expression of TnrA-regulated genes in this class of glnA mutants may deplete intracellular pools of carbon metabolites and thereby result in the reduction of the growth rate and partial relief of CCR.
authors.affiliation: Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts 02118, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Zalieckas
authors.forename: L V
authors.initials: LV
authors.lastname: Wray
authors.forename: S H
authors.initials: SH
authors.lastname: Fisher
mesh_terms: D001412:Bacillus subtilis / Q000201:enzymology / Q000235:genetics*; D001426:Bacterial Proteins; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004794:Enzyme Repression; D015964:Gene Expression Regulation, Bacterial; D005941:Glucokinase / Q000378:metabolism; D005974:Glutamate-Ammonia Ligase / Q000235:genetics; D006639:Histidine / Q000378:metabolism*; D009876:Operon; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000235:genetics / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism*; D013489:Suppression, Genetic; D015534:Trans-Activators / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; C118042:Crh protein, Bacillus subtilis; D004268:DNA-Binding Proteins; D010750:Phosphoproteins; D012097:Repressor Proteins; C101458:ScgR protein, Bacillus subtilis; D015534:Trans-Activators; D014157:Transcription Factors; C069286:catabolite control proteins, bacteria; D006639:Histidine; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; C030182:phosphocarrier protein HPr; D005941:Glucokinase; C081173:glutamine synthetase I; D005974:Glutamate-Ammonia Ligase