Related Experiment Videos

Sinorhizobium meliloti plasmid pRm1132f replicates by a rolling-circle mechanism

L R Barran1, N Ritchot, E S Bromfield

  • 1Soils and Crops Research and Development Centre, Agriculture and Agri-food Canada, Sainte-Foy, Quebec G1V 2J3, Canada. barranlr@em.agr.ca

Journal of Bacteriology
|March 29, 2001
PubMed

Insights

Sinorhizobium meliloti plasmid pRm1132f is a group III rolling-circle-replicating (RCR) plasmid. Its minimal replicon includes a rep gene and replication origins, confirming RCR replication via single-stranded DNA intermediates.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Genetics

Background:

  • Sinorhizobium meliloti harbors various plasmids, including those with unique replication mechanisms.
  • Rolling-circle replication (RCR) is a common mode of plasmid replication in bacteria.

Purpose of the Study:

  • To characterize the replication mechanism of the plasmid pRm1132f from Sinorhizobium meliloti.
  • To identify the essential genetic elements involved in pRm1132f replication.

Main Methods:

  • Nucleotide sequencing of the pRm1132f plasmid.
  • Identification and analysis of open reading frames (ORFs).
  • Detection of single-stranded plasmid DNA to confirm replication intermediates.

Main Results:

  • The pRm1132f plasmid belongs to the group III RCR plasmids.
  • Seven of eight ORFs were identified as coding regions.
  • The minimal replicon comprises a rep gene and both single- and double-stranded origins of replication.
  • Single-stranded plasmid DNA was detected, supporting an RCR mechanism.

Conclusions:

  • pRm1132f utilizes a group III rolling-circle replication mechanism.
  • The identified rep gene and origins are crucial for pRm1132f replication.
  • This study elucidates the replication strategy of a Sinorhizobium meliloti plasmid.

Related Concept Videos