Regulation of the replication cycle: conserved and diverse regulatory systems for DnaA and oriC

DNA replication is an essential process that requires very careful regulation. Tsutomu Katayama and colleagues describe the many ways in which the initiation of chromosomal DNA replication is controlled, with a particular focus on the regulation of DnaA. Chromosomal replication must be limited to once and only once per cell cycle. This is accomplished by multiple regulatory pathways that govern initiator proteins and replication origins. A principal feature of DNA replication is the coupling of the replication reaction to negative-feedback regulation. Some of the factors that are important in this process have been discovered, including the clamp (DNA polymerase III subunit-β (DnaN)), the datA locus, SeqA, DnaA homologue protein (Hda) and YabA, as well as factors that are involved at other stages of the regulatory mechanism, such as DnaA initiator-associating protein (DiaA), the DnaA-reactivating sequence (DARS) loci and Soj. Here, we describe the regulation of DnaA, one of the central proteins involved in bacterial DNA replication, by these factors in Escherichia coli , Bacillus subtilis and Caulobacter crescentus .