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Conjugative Mating Assays for Sequence-specific Analysis of Transfer Proteins Involved in Bacterial Conjugation
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Functional analysis of replication and stability regions of broad-host-range conjugative plasmid CTX-M3 from the

Jolanta Mierzejewska1, Anna Kulińska, Grazyna Jagura-Burdzy

  • 1Institute of Biochemistry and Biophysics, PAS, 02-106 Warsaw, Pawinskiego 5A, Poland.

Plasmid
|November 8, 2006
PubMed

Insights

This study characterizes the mosaic plasmid CTX-M3, detailing its replication, conjugation, and stability functions. The par operon was found crucial for plasmid stability, unlike the pemIK system.

Area of Science:

  • Molecular Biology
  • Microbiology
  • Genetics

Background:

  • Plasmid CTX-M3, isolated from Citrobacter freundii, exhibits a mosaic structure.
  • It possesses replication functions identical to IncL/M group plasmids and conjugative operons homologous to IncI plasmids.

Purpose of the Study:

  • To characterize the broad-host-range plasmid pCTX-M3.
  • To define its minireplicon in Escherichia coli.
  • To analyze the role of stability cassettes, specifically the par operon and pemIK system.

Main Methods:

  • Plasmid isolation and characterization.
  • Sequence analysis and homology searches.
  • Minireplicon definition in Escherichia coli.
  • Deletion analysis of stability operons (par and pemIK).

Main Results:

  • pCTX-M3 demonstrated broad-host-range capabilities.
  • The par operon, comprising parA, parB, and nuc, was identified as essential for pCTX-M3 stability.
  • Deletion of the par operon significantly destabilized the plasmid.
  • The pemIK toxin-antidote system did not influence plasmid stability.

Conclusions:

  • The par operon plays a critical role in maintaining the stability of the mosaic plasmid pCTX-M3.
  • The pemIK system, despite its presence, does not contribute to the stability of this specific plasmid.
  • Understanding these elements is crucial for studying plasmid dynamics in bacteria.

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