Tn4451 from Clostridium perfringens is a mobilizable transposon that encodes the functional Mob protein, TnpZ

Mol Microbiol. 1998 Feb;27(3):631-42. doi: 10.1046/j.1365-2958.1998.00712.x.


The 6.3 kb Clostridium perfringens transposon Tn4451 encodes a 50 kDa protein, TnpZ, which has amino acid sequence similarity to a group of plasmid mobilization and recombination proteins that comprise the Mob/Pre family. Members of this family interact with an upstream palindromic sequence called an RSA site, and an RSA-like sequence has been identified upstream of the tnpZ gene. In Escherichia coli, in the presence of a chromosomally integrated derivative of the broad-host-range IncP plasmid, RP4, TnpZ was able to promote plasmid mobilization in cis and was able to function in trans to enable the mobilization of a co-resident plasmid carrying an RSA site. It was also able to mediate the conjugative transfer of plasmids from E. coli to C. perfringens. Site-directed mutagenesis of two bases within the RSA site resulted in a significant reduction in mobilization frequency, demonstrating that the RSA site is required for efficient plasmid mobilization. TnpZ is the only Mob/Pre protein known to be associated with a transposable genetic element, and Tn4451 is the first mobilizable but non-self-transmissible transposon to be identified from a gram-positive bacterium.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins*
  • Clostridium perfringens / genetics*
  • Conjugation, Genetic*
  • DNA Transposable Elements*
  • Electrophoresis, Agar Gel
  • Escherichia coli / genetics
  • Gene Deletion
  • Genes, Bacterial
  • Mutagenesis, Site-Directed
  • Plasmids
  • Proteins / chemistry
  • Proteins / genetics*
  • Proteins / physiology
  • Restriction Mapping
  • Sequence Alignment


  • Bacterial Proteins
  • DNA Transposable Elements
  • Proteins
  • TNPZ protein, Clostridium perfringens