Repression of polymerase I-mediated gene expression at Trypanosoma brucei telomeres

Lucy Glover, David Horn (Lead / Corresponding author)

Research output: Contribution to journalArticlepeer-review

39 Citations (Scopus)


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 mono-telomeric 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.

Original languageEnglish
Pages (from-to)93-99
Number of pages7
JournalEMBO Reports
Issue number1
Publication statusPublished - Jan 2006


  • Antigenic variation
  • Silencing
  • Trypanosome
  • Variant surface glycoprotein

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Genetics


Dive into the research topics of 'Repression of polymerase I-mediated gene expression at Trypanosoma brucei telomeres'. Together they form a unique fingerprint.

Cite this