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Nucleic Acids Res. 2015 May 19;43(9):4687-700. doi: 10.1093/nar/gkv320. Epub 2015 Apr 13.

CWC22-dependent pre-mRNA splicing and eIF4A3 binding enables global deposition of exon junction complexes.

Author information

1
Institute for Genetics, University of Cologne, D-50674 Cologne, Germany.
2
Cologne Center for Genomics (CCG), University of Cologne, D-50931 Cologne, Germany Institute of Human Genetics, University of Cologne, D-50931 Cologne, Germany.
3
Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Straße 9b, D-50931 Cologne, Germany.
4
Institute for Genetics, University of Cologne, D-50674 Cologne, Germany ngehring@uni-koeln.de.

Abstract

In metazoan cells, spliced mRNAs are marked by the exon junction complex (EJC), a multi-protein complex that serves as a key regulator of post-transcriptional mRNA metabolism. Deposition of EJCs on mRNA is intimately linked to the splicing process. The spliceosomal protein CWC22 directly binds the core EJC-protein eIF4A3, guides it to the spliceosome and initiates EJC assembly. In addition, CWC22 is involved in the splicing process itself, but the molecular details of its dual function remain elusive. Here we analyze the mechanisms, by which CWC22 co-regulates pre-mRNA splicing and EJC assembly. We show that the core of CWC22 is sufficient to mediate both pre-mRNA splicing and EJC assembly. Nonetheless, both processes can be functionally uncoupled with an eIF4A3-binding deficient mutant of CWC22, which impedes EJC assembly. A C-terminal domain of CWC22 strongly enhances its spliceosomal interaction and likely regulates its function. High-throughput RNA-sequencing identifies global defects of pre-mRNA splicing and downregulation of diverse gene expression pathways in CWC22-depleted cells. We propose a model, in which CWC22 represents an integral component of the spliceosome and orchestrates pre-mRNA splicing and eIF4A3 binding to achieve global assembly of exon junction complexes.

PMID:
25870412
PMCID:
PMC4482076
DOI:
10.1093/nar/gkv320
[Indexed for MEDLINE]
Free PMC Article

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