Paradigms of Plasmid Organization

Mol Microbiol. 2000 Aug;37(3):485-91. doi: 10.1046/j.1365-2958.2000.02006.x.


Plasmids are extrachromosomal elements built from a selection of generally quite well understood survival and propagation functions, including replication, partitioning, multimer resolution, post-segregational killing and conjugative transfer. Evolution has favoured clustering of these modules to form plasmid cores or backbones. Co-regulation of these core genes can also provide advantages that favour retention of the backbone organization. Tumour-inducing and symbiosis-determining plasmids appear to co-regulate replication and transfer in response to cell density, both being stimulated at high density. Broad-host-range plasmids of the IncP-1 group, on the other hand, have autogenous control circuits, which allow a burst of expression during establishment in a new host, but a minimum of expression during maintenance. The lessons that plasmids have for clustering and co-regulation may explain the logic and organization of many small bacterial genomes currently being investigated.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • DNA Replication
  • DNA, Bacterial*
  • Plasmids*


  • DNA, Bacterial