Telomere structure and function in trypanosomes: a proposal.

Telomeres are specialized DNA-protein complexes that stabilize chromosome ends, protecting them from nucleolytic degradation and illegitimate recombination. Telomeres form a heterochromatic structure that can suppress the transcription of adjacent genes. These structures might have additional roles in Trypanosoma brucei, as the major surface antigens of this parasite are expressed during its infectious stages from subtelomeric loci. We propose that the telomere protein complexes of trypanosomes and vertebrates are conserved and offer the hypothesis that growth and breakage of telomeric repeats has an important role in regulating parasite antigenic variation in trypanosomes.