Full length RTEL1 is required for the elongation of the single-stranded telomeric overhang by telomerase

Aya Awad, Galina Glousker, Noa Lamm, Shadi Tawil, Noa Hourvitz, Riham Smoom, Patrick Revy, Yehuda Tzfati*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

Telomeres cap the ends of eukaryotic chromosomes and distinguish them from broken DNA ends to suppress DNA damage response, cell cycle arrest and genomic instability. Telomeres are elongated by telomerase to compensate for incomplete replication and nuclease degradation and to extend the proliferation potential of germ and stem cells and most cancers. However, telomeres in somatic cells gradually shorten with age, ultimately leading to cellular senescence. Hoyeraal-Hreidarsson syndrome (HHS) is characterized by accelerated telomere shortening and diverse symptoms including bone marrow failure, immunodeficiency, and neurodevelopmental defects. HHS is caused by germline mutations in telomerase subunits, factors essential for its biogenesis and recruitment to telomeres, and in the helicase RTEL1. While diverse phenotypes were associated with RTEL1 deficiency, the telomeric role of RTEL1 affected in HHS is yet unknown. Inducible ectopic expression of wild-type RTEL1 in patient fibroblasts rescued the cells, enabled telomerase-dependent telomere elongation and suppressed the abnormal cellular phenotypes, while silencing its expression resulted in gradual telomere shortening. Our observations reveal an essential role of the RTEL1 C-terminus in facilitating telomerase action at the telomeric 3' overhang. Thus, the common etiology for HHS is the compromised telomerase action, resulting in telomere shortening and reduced lifespan of telomerase positive cells.

Original languageAmerican English
Pages (from-to)7239-7251
Number of pages13
JournalNucleic Acids Research
Volume48
Issue number13
DOIs
StatePublished - 27 Jul 2020

Bibliographical note

Funding Information:
Israel Science Foundation [1729/13, 2071/18, in part]; Israel Cancer Research Fund; Worldwide Cancer Research [15-0338 to Y.T.]; Ministry of Science and Technology, Israel (Navon fellowship to A.A.); Boehringer Ingelheim Fonds (travel grants to A.A., G.G.); INSERM and Ligue Nationale contre le Cancer (Equipe Labellisée La Ligue to P.R.); P.R. is a scientist from Centre National de la Recherche Scientifique (CNRS). Funding for open access charge: Grant money.

Publisher Copyright:
© The Author(s) 2020.

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