Journal
EMBO REPORTS
Volume 7, Issue 1, Pages 93-99Publisher
WILEY
DOI: 10.1038/sj.embor.7400575
Keywords
antigenic variation; silencing; trypanosome; variant surface glycoprotein
Categories
Ask authors/readers for more resources
The African trypanosome, Trypanosoma brucei, is a flagellated pathogenic protozoan that branched early from the eukaryotic lineage. Unusually, it uses RNA polymerase I (Pol I) for monotelomeric expression of variant surface glycoprotein (VSG) genes in bloodstream-form cells. Many other subtelomeric VSG genes are reversibly repressed, but no repressive DNA sequence has been identified in any trypanosomatid. Here, we show that artificially seeded de novo telomeres repress Pol I-dependent gene expression in mammalian bloodstream and insect life-cycle stages of T. brucei. In a telomeric VSG expression site, repression spreads further along the chromosome and this effect is specific to the bloodstream stage. We also show that de novo telomere extension is telomerase dependent and that the rate of extension correlates with the expression level of the adjacent gene. Our results show constitutive telomeric repression in T. brucei and indicate that an enhanced, developmental stage-specific repression mechanism controls antigenic variation.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available