Cryo-EM structure of human telomerase dimer reveals H/ACA RNP-mediated dimerization

  • Sebastian Balch
  • , Zala Sekne
  • , Elsa Franco-Echevarría
  • , Patryk Ludzia
  • , Rachael C. Kretsch
  • , Wenqing Sun
  • , Haopeng Yu
  • , George E. Ghanim
  • , Sigurdur Thorkelsson
  • , Yiliang Ding
  • , Rhiju Das
  • , Thi Hoang Duong Nguyen

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Telomerase ribonucleoprotein (RNP) synthesizes telomeric repeats at chromosome ends using a telomerase reverse transcriptase (TERT) and a telomerase RNA (hTR in humans). Previous structural work showed that human telomerase is typically monomeric, containing a single copy of TERT and hTR. Evidence for dimeric complexes exists, although the composition, high-resolution structure, and function remain elusive. Here, we report the cryo–electron microscopy (cryo-EM) structure of a human telomerase dimer bound to telomeric DNA. The structure reveals a 26-subunit assembly and a dimerization interface mediated by the Hinge and ACA box (H/ACA) RNP of telomerase. Premature aging disease mutations map to this interface. Disrupting dimer formation affects RNP assembly, bulk telomerase activity, and telomere maintenance in cells. Our findings address a long-standing enigma surrounding the telomerase dimer and suggest a role for the dimer in telomerase assembly.

Original languageEnglish (US)
Article numbereadr5817
JournalScience
Volume389
Issue number6756
DOIs
StatePublished - Jul 10 2025
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General

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