1. Mechanisms of antigenic variation in African trypanosomes.
- Author
-
Borst P, Rudenko G, Blundell PA, van Leeuwen F, Cross MA, McCulloch R, Gerrits H, and Chaves IM
- Subjects
- Africa, Animals, Gene Expression, Genes, Switch, Life Cycle Stages, Rabbits, Transcription, Genetic, Trypanosoma brucei brucei physiology, Trypanosomiasis, African physiopathology, Antigenic Variation, Genes, Protozoan, Trypanosoma brucei brucei genetics, Trypanosoma brucei brucei immunology, Variant Surface Glycoproteins, Trypanosoma biosynthesis, Variant Surface Glycoproteins, Trypanosoma genetics
- Abstract
African trypanosomes can escape destruction by the immune system of their mammalian host by antigenic variation of the trypanosome surface coat. This coat is mainly composed of a single protein species, the Variant Surface Glycoprotein or VSG. The genes for VSGs are expressed in a polycistronic telomeric expression site together with at least eight expression site-associated genes (ESAGs). Trypanosomes may switch coat either by replacing the VSG gene in the active expression site by a different one, or by activating another expression site with concomitant silencing of the previously active one. Here we review our present knowledge of antigenic variation in Trypanosome brucei. We focus on four questions: How do trypanosomes switch from one VSG gene expression site to another one? What is the role of the novel base J in silencing expression sites? What is the functional significance of the antigenic variation of the heterodimeric transferrin receptor encoded by two ESAG genes? Why do trypanosomes have multiple expression sites at all?
- Published
- 1997