Switching trypanosome coats: what's in the wardrobe?

Peter Medawar Building for Pathogen Research, University of Oxford, South Parks Road, Oxford OX1 3SY, UK.

The African trypanosome Trypanosoma brucei is best known for its extraordinarily sophisticated antigenic variation of a protective variant surface glycoprotein (VSG) coat. T. brucei has >1000 VSG genes and pseudogenes, of which one is transcribed at a time from one of multiple telomeric VSG expression sites. Switching the active VSG gene can involve DNA rearrangements replacing the old VSG with a new one, or alternatively transcriptional control. The astonishing revelation from the T. brucei genome sequence is that <7% of the sequenced VSGs seem to have fully functional coding regions. This preponderance of pseudogenes in the VSG gene repertoire will necessitate a rethink of how antigenic variation in African trypanosomes operates.

PMID: 16908087 [PubMed - indexed for MEDLINE]