Variable telomeric repeat synthesis in Paramecium tetraurelia is consistent with misincorporation by telomerase

Monica McCormick-Graham, W. John Haynes, Daniel P. Romero

Research output: Contribution to journalArticlepeer-review

31 Scopus citations

Abstract

Telomeric DNA at the ends of chromosomes consist of short, tandem repeat sequences. The telomeres of Paramecium tetraurelia are made up of variable repeats, whereas Paramecium caudatum telomeric repeats are largely invariant. To investigate variable repeat synthesis in P.tetraurelia, mutated telomerase RNA genes were expressed in vivo. We demonstrate that the P.caudatum telomerase RNA can participate in telomere synthesis when expressed in the P.tetraurelia macronucleus, despite 24% primary sequence divergence of the RNAs between the two species. De novo telomeric repeats from transformants indicate that P.tetraurelia telomerase fidelity is dramatically affected by template substitutions and that misincorporation at a single templating position is likely to account for the majority of P.tetraurelia telomeric DNA variability. Furthermore, we show that fidelity is not solely a function of the RNA moiety, as the P.caudatum telomerase RNA does not impart high fidelity to the chimeric enzyme.

Original languageEnglish (US)
Pages (from-to)3233-3242
Number of pages10
JournalEMBO Journal
Volume16
Issue number11
DOIs
StatePublished - Jun 2 1997

Keywords

  • Mutagenesis
  • Paramecium
  • Telomerase RNA
  • Transformation

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