On the Regulation of the Initiation of DNA Replication in Bacteria

It has been postulated that in bacteria, the initiation of new episodes of replication of DNA, termed rounds of replication, has a regulatory role in DNA synthesis (Maaløe, 1961; Jacob et al., 1963). Recently, Goulian and Kornberg (1967) reported initiation of biologically active DNA synthesis in vitro when circular, single-stranded DNA was used as a template. One of us has demonstrated a covalent linkage between the origin and terminus of Bacillus subtilis chromosomes at the beginning of new rounds of replication (Yoshikawa, 1967). However, in vivo and in vitro, the mechanism and regulation of initiation remain unknown.