Nopp140-mediated concentration of telomerase in Cajal bodies regulates telomere length

Jonathan Bizarro, Amit Bhardwaj, Susan Smith, U. Thomas Meiera

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

Cajal bodies (CBs) are nuclear organelles concentrating two kinds of RNA–protein complexes (RNPs), spliceosomal small nuclear (sn), and small CB-specific (sca)RNPs. Whereas the CB marker protein coilin is responsible for retaining snRNPs, the tether for scaRNPs is not known. Here we show that Nopp140, an intrinsically disordered CB phosphoprotein, is required to recruit and retain all scaRNPs in CBs. Knockdown (KD) of Nopp140 releases all scaRNPs leading to an unprecedented reduction in size of CB granules, hallmarks of CB ultrastructure. The CB-localizing protein WDR79 (aka TCAB1), which is mutated in the inherited bone marrow failure syndrome dyskeratosis congenita, is a specific component of all scaRNPs, including telomerase. Whereas mislocalization of telomerase by mutation of WDR79 leads to critically shortened telomeres, mislocalization of telomerase by Nopp140 KD leads to gradual extension of telomeres. Our studies suggest that the dynamic distribution of telomerase between CBs and nucleoplasm uniquely impacts telomere length maintenance and identify Nopp140 as a novel player in telomere biology.

Original languageEnglish (US)
Pages (from-to)3136-3150
Number of pages15
JournalMolecular biology of the cell
Volume30
Issue number26
DOIs
StatePublished - Jan 1 2019

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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