The Genome of the Obligately Intracellular Bacterium Ehrlichia Canis Reveals Themes of Complex Membrane Structure and Immune Evasion Strategies

J Bacteriol. 2006 Jun;188(11):4015-23. doi: 10.1128/JB.01837-05.

Abstract

Ehrlichia canis, a small obligately intracellular, tick-transmitted, gram-negative, alpha-proteobacterium, is the primary etiologic agent of globally distributed canine monocytic ehrlichiosis. Complete genome sequencing revealed that the E. canis genome consists of a single circular chromosome of 1,315,030 bp predicted to encode 925 proteins, 40 stable RNA species, 17 putative pseudogenes, and a substantial proportion of noncoding sequence (27%). Interesting genome features include a large set of proteins with transmembrane helices and/or signal sequences and a unique serine-threonine bias associated with the potential for O glycosylation that was prominent in proteins associated with pathogen-host interactions. Furthermore, two paralogous protein families associated with immune evasion were identified, one of which contains poly(G-C) tracts, suggesting that they may play a role in phase variation and facilitation of persistent infections. Genes associated with pathogen-host interactions were identified, including a small group encoding proteins (n = 12) with tandem repeats and another group encoding proteins with eukaryote-like ankyrin domains (n = 7).

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Bacterial Proteins / genetics
  • Dog Diseases / microbiology
  • Dogs
  • Ehrlichia canis / classification
  • Ehrlichia canis / genetics*
  • Ehrlichia canis / immunology*
  • Ehrlichia canis / pathogenicity
  • Ehrlichiosis / veterinary
  • Gene Expression Regulation, Bacterial
  • Genome, Bacterial*
  • Glycoproteins / genetics
  • Molecular Sequence Data
  • Pseudogenes
  • RNA, Bacterial / genetics
  • Transcription, Genetic

Substances

  • Bacterial Proteins
  • Glycoproteins
  • RNA, Bacterial

Associated data

  • GENBANK/CP000107