Rolling Circle Replicating Plasmids
The replication of plasmids by the rolling circle replication mechanism represents one of the simplest strategies, relying as it does on nicking one strand to generate the primer for leading strand initiation and on a single priming site for lagging strand synthesis. The generation of single-stranded intermediates, which are potentially unstable and can also induce SOS response, means that there is selection against such plasmids growing very large. Their genomes therefore consist of a number of basic elements: leading strand initiation and control, lagging strand origin, phenotypic determinants, and mobilization generally in that order of frequency. Although phenotypic determinants may be part of transposable elements, it also appears that recombination mediated by short repeated sequences can drive construction and reassortment of plasmid cassettes. This can create enigmatic variations where core functions may exhibit high conservation while being interspersed with totally...
- Boer DR, Ruíz-Masó JA, López-Blanco JR, Blanco AG, Vives-Llàcer M, Chacón P, Usón I, Gomis-Rüth FX, Espinosa M, Llorca O, del Solar G, Coll M (2009) Plasmid replication initiator RepB forms a hexamer reminiscent of ring helicases and has mobile nuclease domains. EMBO J 28:1666–1678PubMedPubMedCentralCrossRefGoogle Scholar