Replication of the Bacillus subtilis Chromosome

International audienceEubacteria have evolved multicomponent protein machines, termed replisomes, which duplicate their chromosomes rapidly and accurately. Extensive studies in the model bacteria Escherichia coli and Bacillus subtilis have revealed that in addition to the replication core machinery, other proteins are necessary to form a functional replication fork. Specific subsets of proteins mediate: a) the assembly of the replisome at the chromosomal origin of replication [initiation]; b) the progression of the replication forks along the chromosome [elongation] and their maintenance by providing solutions for replication restart, which are adapted to overcome possible 'roadblocks' encountered on the DNA template; and c) the physiological arrest of replication when chromosome duplication is completed [termination]. Within the cell, DNA replication takes place within a factory positioned at the cell centre. This review summarises recent knowledge about chromosomal replication in Bacillus subtilis and related Gram-positive bacteria. It is focused on the events governing the assembly and the fate of the replication fork, describes protein networks connected with the replisome, and emphasises several novel aspects of DNA replication in this group of bacteria