Activation of the Bacillus subtilis global regulator CodY by direct interaction with branched-chain amino acids

Mol Microbiol. 2004 Jul;53(2):599-611. doi: 10.1111/j.1365-2958.2004.04135.x.

Abstract

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.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adaptation, Physiological
  • Amino Acids, Branched-Chain / metabolism*
  • Amino Acids, Branched-Chain / pharmacology
  • Artificial Gene Fusion
  • Bacillus subtilis / genetics
  • Bacillus subtilis / growth & development
  • Bacillus subtilis / metabolism*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Base Sequence
  • DNA Footprinting
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Electrophoretic Mobility Shift Assay
  • Enzyme Activators / pharmacology
  • Gene Expression Regulation, Bacterial
  • Genes, Reporter
  • Guanosine Triphosphate / metabolism
  • Guanosine Triphosphate / pharmacology
  • Isoleucine / metabolism
  • Isoleucine / pharmacology
  • Lac Operon
  • Molecular Sequence Data
  • Operon
  • Promoter Regions, Genetic
  • Protein Binding
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism*
  • Valine / metabolism
  • Valine / pharmacology
  • beta-Galactosidase / genetics
  • beta-Galactosidase / metabolism

Substances

  • Amino Acids, Branched-Chain
  • Bacterial Proteins
  • DNA-Binding Proteins
  • Enzyme Activators
  • Repressor Proteins
  • Isoleucine
  • Guanosine Triphosphate
  • beta-Galactosidase
  • Valine