A second essential function of the Est1-binding arm of yeast telomerase RNA

Kevin J. Lebo, Rachel O. Niederer, David C. Zappulla

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


The enzymatic ribonucleoprotein telomerase maintains telomeres in many eukaryotes, including humans, and plays a central role in aging and cancer. Saccharomyces cerevisiae telomerase RNA, TLC1, is a flexible scaffold that tethers telomerase holoenzyme protein subunits to the complex. Here we test the hypothesis that a lengthy conserved region of the Est1-binding TLC1 arm contributes more than simply Est1-binding function. We separated Est1 binding from potential other functions by tethering TLC1 to Est1 via a heterologous RNA-protein binding module. We find that Est1-tethering rescues in vivo function of telomerase RNA alleles missing nucleotides specifically required for Est1 binding, but not those missing the entire conserved region. Notably, however, telomerase function is restored for this condition by expressing the arm of TLC1 in trans. Mutational analysis shows that the Second Essential Est1-arm Domain (SEED) maps to an internal loop of the arm, which SHAPE chemical mapping and 3D modeling suggest could be regulated by conformational change. Finally, we find that the SEED has an essential, Est1-independent role in telomerase function after telomerase recruitment to the telomere. The SEED may be required for establishing telomere extendibility or promoting telomerase RNP holoenzyme activity.

Original languageEnglish (US)
Pages (from-to)862-876
Number of pages15
Issue number5
StatePublished - May 1 2015


  • Est1
  • RNA
  • RNP
  • S. cerevisiae
  • SEED
  • TLC1
  • Telomerase
  • Yeast
  • lncRNA
  • ncRNA

ASJC Scopus subject areas

  • Molecular Biology


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