Nopp140-chaperoned 2'-O-methylation of small nuclear RNAs in Cajal bodies ensures splicing fidelity

Jonathan Bizarro, Svetlana Deryusheva, Ludivine Wacheul, Varun Gupta, Felix G.M. Ernst, Denis L.J. Lafontaine, Joseph G. Gall, U. Thomas Meier

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Spliceosomal small nuclear RNAs (snRNAs) are modified by small Cajal body (CB)-specific ribonucleoproteins (scaRNPs) to ensure snRNP biogenesis and pre-mRNA splicing. However, the function and subcellular site of snRNA modification are largely unknown. We show that CB localization of the protein Nopp140 is essential for concentration of scaRNPs in that nuclear condensate; and that phosphorylation by casein kinase 2 (CK2) at ∼80 serines targets Nopp140 to CBs. Transiting through CBs, snRNAs are apparently modified by scaRNPs. Indeed, Nopp140 knockdown-mediated release of scaRNPs from CBs severely compromises 2'-O-methylation of spliceosomal snRNAs, identifying CBs as the site of scaRNP catalysis. Additionally, alternative splicing patterns change indicating that these modifications in U1, U2, U5, and U12 snRNAs safeguard splicing fidelity. Given the importance of CK2 in this pathway, compromised splicing could underlie the mode of action of small molecule CK2 inhibitors currently considered for therapy in cholangiocarcinoma, hematological malignancies, and COVID-19.

Original languageEnglish (US)
Pages (from-to)1123-1141
Number of pages19
JournalGenes and Development
Volume35
Issue number15-16
DOIs
StatePublished - Aug 1 2021

Keywords

  • Cajal bodies
  • Casein kinase 2
  • Nuclear organization
  • Phosphorylation
  • Pre-mRNA splicing
  • RNA modification
  • ScaRNPs
  • SnoRNPs
  • SnRNA

ASJC Scopus subject areas

  • Genetics
  • Developmental Biology

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