Structural and functional features of cis-acting sequences in the basic replicon of plasmid ColIb-P9

Nucleic Acids Res. 1992 Jun 11;20(11):2705-10. doi: 10.1093/nar/20.11.2705.

Abstract

We have structurally and functionally analyzed the cis-elements essential for ColIb-P9 plasmid DNA replication. The putative oriV region encompassed a region of 172 base pairs (bp) located 152 bp downstream of the repZ gene. A typical dnaA box found in this region proved nonessential for the DNA replication of ColIb-P9. The ssi signal of ColIb-P9 is a homologue of the G-sites of R1 and R100 plasmids. Deletion of the G-site led to 1.5-fold reduction of the copy number, suggesting that although this G-site is not essential, it is important for efficient ColIb-P9 DNA replication. In addition, the ColIb-P9 replicon is highly and extensively homologous with the P307 (RepFIC) replicon, and highly homologous with the R100 (RepFIIA) replicon around the G-site region. These facts imply a common ancestry from which the plasmids have evolved.

Publication types

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

MeSH terms

  • Base Sequence
  • DNA Replication*
  • DNA, Bacterial / genetics*
  • Molecular Sequence Data
  • Plasmids*
  • Regulatory Sequences, Nucleic Acid*
  • Replicon*
  • Restriction Mapping
  • Sequence Homology, Nucleic Acid
  • Shigella sonnei / genetics
  • Structure-Activity Relationship

Substances

  • DNA, Bacterial

Associated data

  • GENBANK/M34837