Defining a centromere-like element in Bacillus subtilis by Identifying the binding sites for the chromosome-anchoring protein RacA

Mol Cell. 2005 Mar 18;17(6):773-82. doi: 10.1016/j.molcel.2005.02.023.


Chromosome segregation during sporulation in Bacillus subtilis involves the anchoring of sister chromosomes to opposite ends of the cell. Anchoring is mediated by RacA, which acts as a bridge between a centromere-like element in the vicinity of the origin of replication and the cell pole. To define this element we mapped RacA binding sites by performing chromatin immunoprecipitation in conjunction with gene microarray analysis. RacA preferentially bound to 25 regions spread over 612 kb across the origin portion of the chromosome. Computational and biochemical analysis identified a GC-rich, inverted 14 bp repeat as the recognition sequence. Experiments with single molecules of DNA demonstrated that RacA can condense nonspecific DNA dramatically against appreciable forces to form a highly stable protein-DNA complex. We propose that interactions between DNA bound RacA molecules cause the centromere-like element to fold up into a higher order complex that fastens the chromosome to the cell pole.

Publication types

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

MeSH terms

  • Bacillus subtilis / genetics
  • Bacillus subtilis / metabolism*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Binding Sites
  • Cell Division / physiology
  • Cell Polarity
  • Centromere / genetics*
  • Chromatin Immunoprecipitation
  • Chromosomes, Bacterial / metabolism*
  • DNA, Bacterial / metabolism*
  • GC Rich Sequence
  • Gene Expression Regulation, Bacterial
  • Microarray Analysis
  • Protein Binding
  • Replication Origin
  • Spores, Bacterial


  • Bacterial Proteins
  • DNA, Bacterial