Activation of the Bacillus subtilis global regulator CodY by direct interaction with branched-chain amino acids.
CodY, a GTP-activated global transcriptional regulator of early stationary phase genes, is conserved in many Gram-positive bacterial species. Recently, a number of novel targets regulated by CodY have been identified, including three Bacillus subtilis operons involved in branched-chain amino acid (BCAA) biosynthesis (Molle, V., et al., 2003, J Bacteriol 185: 1911-1922). The mechanism of involvement of CodY in regulating the ilvB operon was investigated here using in vivo transcriptional fusions, in vitro gel mobility shift assays and DNase I footprinting assays. CodY was found to mediate regulation of the ilvB operon by GTP and BCAAs and to bind to the ilvB promoter region. BCAAs increased the affinity of CodY for the ilvB promoter and for all other CodY targets tested. This effect of BCAAs in vitro was additive with the effect of GTP on CodY DNA-binding activity.
Shivers
Robert P
RP
Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 136 Harrison Ave., Boston, MA 02111, USA.
Sonenshein
Abraham L
AL
D000222:Adaptation, Physiological; D000597:Amino Acids, Branched-Chain / Q000378:metabolism* / Q000494:pharmacology; D019677:Artificial Gene Fusion; D001412:Bacillus subtilis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D018983:DNA Footprinting; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D020536:Enzyme Activators / Q000494:pharmacology; D015964:Gene Expression Regulation, Bacterial; D017930:Genes, Reporter; D006160:Guanosine Triphosphate / Q000378:metabolism / Q000494:pharmacology; D007532:Isoleucine / Q000378:metabolism / Q000494:pharmacology; D007763:Lac Operon; D008969:Molecular Sequence Data; D009876:Operon; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D014633:Valine / Q000378:metabolism / Q000494:pharmacology; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
D000597:Amino Acids, Branched-Chain; D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D020536:Enzyme Activators; D012097:Repressor Proteins; D007532:Isoleucine; D006160:Guanosine Triphosphate; D001616:beta-Galactosidase; D014633:Valine