Control and function of the bloodstream variant surface glycoprotein expression sites in Trypanosoma brucei.
African trypanosomes escape the host immune response through a periodical change of their surface coat made of one major type of protein, the variant surface glycoprotein. From a repertoire of a thousand variant surface glycoprotein genes available, only one is expressed at a time, and this takes place in a specialised expression site itself selected from a collection of an estimated 20-30 sites. As the specialised expression sites are long polycistronic transcription units, the variant surface glycoprotein is co-transcribed with several other genes termed expression site-associated genes. How do the trypanosomes only use a single specialised expression site at a time? Why are there two dozen specialised expression sites? What are the functions of the other genes of these transcription units? We review the currently available answers to these questions.
Vanhamme
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IBMM, Free University of Brussels, 12 rue des Professeurs Jeener et Brachet, B-6041, Gosselies, Belgium. lvanham@dbm.ulb.ac.be
Lecordier
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Pays
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D000818:Animals; D000940:Antigenic Variation / Q000235:genetics* / Q000276:immunology; D005786:Gene Expression Regulation / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D014158:Transcription, Genetic / Q000235:genetics; D014346:Trypanosoma brucei brucei / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D014643:Variant Surface Glycoproteins, Trypanosoma / Q000235:genetics / Q000276:immunology / Q000502:physiology*
D014643:Variant Surface Glycoproteins, Trypanosoma