Dynamic control of the DNA replication initiation protein DnaA by Soj/ParA.
Regulation of DNA replication and segregation is essential for all cells. Orthologs of the plasmid partitioning genes parA, parB, and parS are present in bacterial genomes throughout the prokaryotic evolutionary tree and are required for accurate chromosome segregation. However, the mechanism(s) by which parABS genes ensure proper DNA segregation have remained unclear. Here we report that the ParA ortholog in B. subtilis (Soj) controls the activity of the DNA replication initiator protein DnaA. Subcellular localization of several Soj mutants indicates that Soj acts as a spatially regulated molecular switch, capable of either inhibiting or activating DnaA. We show that the classical effect of Soj inhibiting sporulation is an indirect consequence of its action on DnaA through activation of the Sda DNA replication checkpoint. These results suggest that the pleiotropy manifested by chromosomal parABS mutations could be the indirect effects of a primary activity regulating DNA replication initiation.
Murray
Heath
H
Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Framlington Place, Newcastle Upon Tyne, NE2 4HH, UK. heath.murray@ncl.ac.uk
Errington
Jeff
J
D001412:Bacillus subtilis / Q000378:metabolism*; D001426:Bacterial Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D002876:Chromosomes, Bacterial / Q000378:metabolism; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000032:analysis; D017354:Point Mutation
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C066312:DnaA protein, Bacteria; C052883:chromosome partition proteins, bacterial; D049452:Green Fluorescent Proteins