1. Chromosomes and Gene Expression
Download icon

Telomerase biogenesis requires a novel Mex67 function and a cytoplasmic association with the Sm7 complex

  1. Yulia Vasianovich
  2. Emmanuel Bajon
  3. Raymund J Wellinger  Is a corresponding author
  1. Fac Medecine/Université de Sherbrooke, Canada
Research Article
  • Cited 1
  • Views 527
  • Annotations
Cite this article as: eLife 2020;9:e60000 doi: 10.7554/eLife.60000

Abstract

The templating RNA is the core of the telomerase reverse transcriptase. In Saccharomyces cerevisiae, the complex life cycle and maturation of telomerase includes a cytoplasmic stage. However, timing and reason for this cytoplasmic passage are poorly understood. Here, we use inducible RNA tagging experiments to show that immediately after transcription, newly synthesized telomerase RNAs undergo one round of nucleo-cytoplasmic shuttling. Their export depends entirely on Crm1/Xpo1, whereas re-import is mediated by Kap122 plus redundant, kinetically less efficient import pathways. Strikingly, Mex67 is essential to stabilize newly transcribed RNA before Xpo1-mediated nuclear export. The results further show that the Sm7 complex associates with and stabilizes the telomerase RNA in the cytoplasm and promotes its nuclear re-import. Remarkably, after this cytoplasmic passage, the nuclear stability of telomerase RNA no longer depends on Mex67. These results underscore the utility of inducible RNA tagging and challenge current models of telomerase maturation.

Data availability

Source data files have been uploaded. Strains and materials generated for this study will be freely available.

Article and author information

Author details

  1. Yulia Vasianovich

    Dept of Microbiology and Infectious Diseases, Fac Medecine/Université de Sherbrooke, Sherbrooke, Canada
    Competing interests
    No competing interests declared.
  2. Emmanuel Bajon

    Dept of Microbiology and Infectious Diseases, Fac Medecine/Université de Sherbrooke, Sherbrooke, Canada
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-1588-2953
  3. Raymund J Wellinger

    Dept of Microbiology and Infectious Diseases, Fac Medecine/Université de Sherbrooke, Sherbrooke, Canada
    For correspondence
    Raymund.Wellinger@Usherbrooke.ca
    Competing interests
    Raymund J Wellinger, Reviewing editor, eLife.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-6670-2759

Funding

Canada Research Chairs (CRC in telomere biology)

  • Raymund J Wellinger

Canadian Institutes of Health Research (FDN154315)

  • Raymund J Wellinger

Fonds de Recherche du Québec - Santé (Post-Doc Fellowship)

  • Yulia Vasianovich

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Reviewing Editor

  1. Andrés Aguilera, CABIMER, Universidad de Sevilla, Spain

Publication history

  1. Received: June 14, 2020
  2. Accepted: October 22, 2020
  3. Accepted Manuscript published: October 23, 2020 (version 1)
  4. Version of Record published: November 5, 2020 (version 2)

Copyright

© 2020, Vasianovich et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

Metrics

  • 527
    Page views
  • 89
    Downloads
  • 1
    Citations

Article citation count generated by polling the highest count across the following sources: Crossref, PubMed Central, Scopus.

Download links

A two-part list of links to download the article, or parts of the article, in various formats.

Downloads (link to download the article as PDF)

Download citations (links to download the citations from this article in formats compatible with various reference manager tools)

Open citations (links to open the citations from this article in various online reference manager services)

Further reading

    1. Chromosomes and Gene Expression
    2. Microbiology and Infectious Disease
    Michele Felletti et al.
    Research Article

    The ability to regulate DNA replication initiation in response to changing nutrient conditions is an important feature of most cell types. In bacteria, DNA replication is triggered by the initiator protein DnaA, which has long been suggested to respond to nutritional changes; nevertheless, the underlying mechanisms remain poorly understood. Here, we report a novel mechanism that adjusts DnaA synthesis in response to nutrient availability in Caulobacter crescentus. By performing a detailed biochemical and genetic analysis of the dnaA mRNA, we identified a sequence downstream of the dnaA start codon that inhibits DnaA translation elongation upon carbon exhaustion. Our data show that the corresponding peptide sequence, but not the mRNA secondary structure or the codon choice, is critical for this response, suggesting that specific amino acids in the growing DnaA nascent chain tune translational efficiency. Our study provides new insights into DnaA regulation and highlights the importance of translation elongation as a regulatory target. We propose that translation regulation by nascent chain sequences, like the one described, might constitute a general strategy for modulating the synthesis rate of specific proteins under changing conditions.

    1. Chromosomes and Gene Expression
    2. Developmental Biology
    Benoit Roch et al.
    Research Article

    We developed a Xrcc4M61R separation of function mouse line to overcome the embryonic lethality of Xrcc4 deficient mice. XRCC4M61R protein does not interact with Xlf, thus obliterating XRCC4-Xlf filament formation while preserving the ability to stabilize DNA Ligase IV. X4M61R mice, which are DNA repair deficient, phenocopy the Nhej1-/- (known as Xlf -/-) setting with a minor impact on the development of the adaptive immune system. The core NHEJ DNA repair factor XRCC4 is therefore not mandatory for V(D)J recombination aside from its role in stabilizing DNA ligase IV. In contrast, Xrcc4M61R mice crossed on Paxx-/-, Nhej1-/-, or Atm-/- backgrounds are severely immunocompromised, owing to aborted V(D)J recombination as in Xlf-Paxx and Xlf-Atm double KO settings. Furthermore, massive apoptosis of post-mitotic neurons causes embryonic lethality of Xrcc4M61R -Nhej1-/- double mutants. These in vivo results reveal new functional interplays between XRCC4 and PAXX, ATM and Xlf in mouse development and provide new insights in the understanding of the clinical manifestations of human XRCC4 deficient condition, in particular its absence of immune deficiency.