The central roles of telomeres and subtelomeres in antigenic variation in African trypanosomes.

Telomeres and subtelomeres are important to the virulence of a number of pathogens, as they harbour large diverse gene families associated with the maintenance of infection. Evasion of immunity by African trypanosomes involves the differential expression of variant surface glycoproteins (VSGs), which are encoded by a family of >1500 genes and pseudogenes. This silent archive is located subtelomerically and is activated by gene conversion into specialized transcription units, which themselves are subject to silencing by allelic exclusion. Current research addresses the role of telomeres in the conversion and silencing mechanisms and in the diversification of the VSG archive.