Dual repression by Fe(2+)-Fur and Mn(2+)-MntR of the mntH gene, encoding an NRAMP-like Mn(2+) transporter in Escherichia coli

J Bacteriol. 2001 Aug;183(16):4806-13. doi: 10.1128/JB.183.16.4806-4813.2001.


The uptake of Mn(2+), a cofactor for several enzymes in Escherichia coli, is mediated by MntH, a proton-dependent metal transporter, which also recognizes Fe(2+) with lower affinity. MntH belongs to the NRAMP family of eukaryotic Fe(2+) and Mn(2+) transporters. In E. coli strains with chromosomal mntH-lacZ fusions, mntH was partially repressed by both Mn(2+) and Fe(2+). Inactivation of fur resulted in the loss of Fe(2+)-dependent repression of mntH transcription, demonstrating that Fe(2+) repression depends on the global iron regulator Fur. However, these fur mutants still showed Mn(2+)-dependent repression of mntH. The Mn(2+)-responsive transcriptional regulator of mntH was identified as the gene product of o155 (renamed MntR). mntR mutants were impaired in Mn(2+) but not Fe(2+) repression of mntH transcription. Binding of purified MntR to the mntH operator was manganese dependent. The binding region was localized by DNase I footprinting analysis and covers a nearly perfect palindrome. The Fur binding site, localized within 22 nucleotides of the mntH operator by in vivo operator titration assays, resembles the Fur-box consensus sequence.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Substitution
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Base Sequence
  • Binding Sites
  • Carrier Proteins / genetics*
  • Carrier Proteins / metabolism
  • Cation Transport Proteins*
  • Chromosome Mapping
  • DNA, Bacterial / chemistry
  • DNA, Bacterial / genetics
  • Escherichia coli / genetics*
  • Escherichia coli / metabolism
  • Escherichia coli Proteins*
  • Gene Expression Regulation, Bacterial*
  • Iron / metabolism*
  • Manganese / metabolism*
  • Metalloproteins / metabolism
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Recombinant Fusion Proteins / metabolism
  • Recombinant Proteins / metabolism
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism*
  • Sequence Alignment
  • Sequence Homology, Nucleic Acid


  • Bacterial Proteins
  • Carrier Proteins
  • Cation Transport Proteins
  • DNA, Bacterial
  • Escherichia coli Proteins
  • Metalloproteins
  • MntH protein, E coli
  • MntH protein, bacteria
  • MntR protein, E coli
  • MntR protein, bacteria
  • Recombinant Fusion Proteins
  • Recombinant Proteins
  • Repressor Proteins
  • ferric uptake regulating proteins, bacterial
  • Manganese
  • Iron