The ATPase SpoIIIE transports DNA across fused septal membranes during sporulation in Bacillus subtilis

Cell. 2007 Dec 28;131(7):1301-12. doi: 10.1016/j.cell.2007.11.009.


The FtsK/SpoIIIE family of ATP-dependent DNA transporters mediates proper chromosome segregation in dividing bacteria. In sporulating Bacillus subtilis cells, SpoIIIE translocates much of the circular chromosome from the mother cell into the forespore, but the molecular mechanism remains unclear. Using a new assay to monitor DNA transport, we demonstrate that the two arms of the chromosome are simultaneously pumped into the forespore. Up to 70 molecules of SpoIIIE are recruited to the site of DNA translocation and assemble into complexes that could contain 12 subunits. The fusion of the septal membranes during cytokinesis precedes DNA translocation and does not require SpoIIIE, as suggested by analysis of lipid dynamics, serial thin-section electron microscopy, and cell separation by protoplasting. These data support a model for DNA transport in which the transmembrane segments of FtsK/SpoIIIE form linked DNA-conducting channels across the two lipid bilayers of the septum.

Publication types

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

MeSH terms

  • Bacillus subtilis / enzymology
  • Bacillus subtilis / metabolism
  • Bacillus subtilis / physiology*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Bacterial Proteins / ultrastructure
  • Cell Membrane / metabolism*
  • Cell Membrane / ultrastructure
  • Chromosome Segregation
  • Chromosomes, Bacterial / metabolism*
  • Conjugation, Genetic
  • Cytokinesis*
  • DNA, Bacterial / metabolism*
  • Fluorescence Recovery After Photobleaching
  • Membrane Fusion*
  • Microscopy, Electron
  • Microscopy, Fluorescence
  • Models, Genetic
  • Mutation
  • Recombinant Fusion Proteins / metabolism
  • Spores, Bacterial
  • Time Factors


  • Bacterial Proteins
  • DNA, Bacterial
  • Recombinant Fusion Proteins
  • spore-specific proteins, Bacillus