Plasmid-mediated transformation tropism of chlamydial biovars

Pathog Dis. 2014 Mar;70(2):189-93. doi: 10.1111/2049-632X.12104. Epub 2013 Nov 11.


Chlamydia trachomatis and C. muridarum are human and mouse pathogens, respectively, which show high conservation of gene order and content. Both species contain a common 7.5-kb plasmid that is an important virulence factor. Recently described transformation systems have been used to characterize C. trachomatis L2 plasmid gene functions; however, similar studies have not been reported for C. trachomatis ocular tropic serovar A or the mouse strain, C. muridarum. Here, we have conducted genetic experiments with C. trachomatis serovar A and C. muridarum and report the following: (1) successful transformation of C. muridarum and C. trachomatis serovar A is restricted to a shuttle vector with a C. muridarum or C. trachomatis serovar A plasmid backbone, respectively; (2) transformation of plasmid-deficient C. muridarum with the C. muridarum-based shuttle vector complement glycogen accumulation and inclusion morphology; and (3) C. muridarum plasmid-encoded Pgp4 is a regulator of chromosomal (glgA) and plasmid (pgp3) virulence genes. In summary, our findings show a previously unrecognized and unexpected role for the chlamydial plasmid in its transformation tropism and confirm the plasmids regulatory role of virulence genes in C. muridarum.

Keywords: Chlamydiae; plasmid; transformation; tropism.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Animals
  • Chlamydia muridarum / genetics*
  • Chlamydia trachomatis / genetics*
  • Gene Expression Regulation, Bacterial
  • Gene Transfer, Horizontal*
  • Genetic Vectors
  • Host Specificity*
  • Humans
  • Mice
  • Plasmids*
  • Transformation, Bacterial*
  • Virulence Factors / biosynthesis


  • Virulence Factors