Chromosome I controls chromosome II replication in Vibrio cholerae

PLoS Genet. 2014 Feb 27;10(2):e1004184. doi: 10.1371/journal.pgen.1004184. eCollection 2014 Feb.

Abstract

Control of chromosome replication involves a common set of regulators in eukaryotes, whereas bacteria with divided genomes use chromosome-specific regulators. How bacterial chromosomes might communicate for replication is not known. In Vibrio cholerae, which has two chromosomes (chrI and chrII), replication initiation is controlled by DnaA in chrI and by RctB in chrII. DnaA has binding sites at the chrI origin of replication as well as outside the origin. RctB likewise binds at the chrII origin and, as shown here, to external sites. The binding to the external sites in chrII inhibits chrII replication. A new kind of site was found in chrI that enhances chrII replication. Consistent with its enhancing activity, the chrI site increased RctB binding to those chrII origin sites that stimulate replication and decreased binding to other sites that inhibit replication. The differential effect on binding suggests that the new site remodels RctB. The chaperone-like activity of the site is supported by the finding that it could relieve the dependence of chrII replication on chaperone proteins DnaJ and DnaK. The presence of a site in chrI that specifically controls chrII replication suggests a mechanism for communication between the two chromosomes for replication.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Adenosine Triphosphatases / genetics
  • Adenosine Triphosphatases / metabolism
  • Bacterial Proteins / genetics*
  • Bacterial Proteins / metabolism
  • Binding Sites
  • Chromosomes, Bacterial / genetics*
  • DNA Replication / genetics*
  • DNA-Binding Proteins / genetics*
  • DNA-Binding Proteins / metabolism
  • Gene Expression Regulation, Bacterial
  • Humans
  • Molecular Chaperones / genetics
  • Molecular Chaperones / metabolism
  • Protein Binding / genetics
  • Replication Origin
  • Vibrio cholerae / genetics*
  • Vibrio cholerae / growth & development

Substances

  • Bacterial Proteins
  • DNA-Binding Proteins
  • DnaA protein, Bacteria
  • Molecular Chaperones
  • Adenosine Triphosphatases
  • DnaK protein, Brevibacillus choshinensis