Noc protein binds to specific DNA sequences to coordinate cell division with chromosome segregation.
Coordination of chromosome segregation and cytokinesis is crucial for efficient cell proliferation. In Bacillus subtilis, the nucleoid occlusion protein Noc protects the chromosomes by associating with the chromosome and preventing cell division in its vicinity. Using protein localization, ChAP-on-Chip and bioinformatics, we have identified a consensus Noc-binding DNA sequence (NBS), and have shown that Noc is targeted to about 70 discrete regions scattered around the chromosome, though absent from a large region around the replication terminus. Purified Noc bound specifically to an NBS in vitro. NBSs inserted near the replication terminus bound Noc-YFP and caused a delay in cell division. An autonomous plasmid carrying an NBS array recruited Noc-YFP and conferred a severe Noc-dependent inhibition of cell division. This shows that Noc is a potent inhibitor of division, but that its activity is strictly localized by the interaction with NBS sites in vivo. We propose that Noc serves not only as a spatial regulator of cell division to protect the nucleoid, but also as a timing device with an important role in the coordination of chromosome segregation and cell division.
Wu
Ling Juan
LJ
Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne, UK. l.j.wu@ncl.ac.uk
Ishikawa
Shu
S
Kawai
Yoshikazu
Y
Oshima
Taku
T
Ogasawara
Naotake
N
Errington
Jeff
J
D001412:Bacillus subtilis / Q000502:physiology*; D001426:Bacterial Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D002455:Cell Division; D020090:Chromosome Segregation; D002876:Chromosomes, Bacterial / Q000235:genetics / Q000378:metabolism*; D004247:DNA / Q000032:analysis* / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D023281:Genomics; D010957:Plasmids / Q000378:metabolism
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D004247:DNA