Termination of DNA Replication in Prokaryotes

Abstract

Most bacteria and archaea have circular chromosomes, in which DNA replication begins at a site known as an origin of replication. Double‐stranded DNA unwound at the origin creates two replication forks that are engaged by DNA polymerase complexes (replisomes) that advance each fork and proceed in opposite directions away from the origin, copying the original strands. Termination of DNA replication occurs when the two forks meet and fuse, creating two separate double‐stranded DNA molecules. In the well‐studied bacteria Escherichia coli and Bacillus subtilis, this occurs in the terminus region, which is situated diametrically opposite the origin. Failure to terminate chromosome replication correctly can lead to problems with genome function and stability, including DNA over‐replication. In contrast, some archaea have multi‐origin chromosomes and do not appear to specifically regulate the location of termination.