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J Biol Chem. 2017 Aug 11;292(32):13381-13390. doi: 10.1074/jbc.M117.784371. Epub 2017 Jun 27.

RBM25 is a global splicing factor promoting inclusion of alternatively spliced exons and is itself regulated by lysine mono-methylation.

Author information

1
From the Department of Biology, Stanford University, Stanford, California 94305.
2
the Departments of Molecular, Cell, and Developmental Biology and.
3
the Department of Chemical and Systems Biology, School of Medicine, Stanford University, Stanford, California 94305, and.
4
Biomolecular Engineering, University of California, Santa Cruz, California 95060 anbrooks@ucsc.edu.
5
From the Department of Biology, Stanford University, Stanford, California 94305, ogozani@stanford.edu.

Abstract

In eukaryotes, precursor mRNA (pre-mRNA) splicing removes non-coding intron sequences to produce mature mRNA. This removal is controlled in part by RNA-binding proteins that regulate alternative splicing decisions through interactions with the splicing machinery. RNA binding motif protein 25 (RBM25) is a putative splicing factor strongly conserved across eukaryotic lineages. However, the role of RBM25 in global splicing regulation and its cellular functions are unknown. Here we show that RBM25 is required for the viability of multiple human cell lines, suggesting that it could play a key role in pre-mRNA splicing. Indeed, transcriptome-wide analysis of splicing events demonstrated that RBM25 regulates a large fraction of alternatively spliced exons throughout the human genome. Moreover, proteomic analysis indicated that RBM25 interacts with components of the early spliceosome and regulators of alternative splicing. Previously, we identified an RBM25 species that is mono-methylated at lysine 77 (RBM25K77me1), and here we used quantitative mass spectrometry to show that RBM25K77me1 is abundant in multiple human cell lines. We also identified a region of RBM25 spanning Lys-77 that binds with high affinity to serine- and arginine-rich splicing factor 2 (SRSF2), a crucial protein in exon definition, but only when Lys-77 is unmethylated. Together, our findings uncover a pivotal role for RBM25 as an essential regulator of alternative splicing and reveal a new potential mechanism for regulation of pre-mRNA splicing by lysine methylation of a splicing factor.

KEYWORDS:

RNA splicing; alternative splicing; protein methylation; protein-protein interaction; proteomics

PMID:
28655759
PMCID:
PMC5555197
DOI:
10.1074/jbc.M117.784371
[Indexed for MEDLINE]
Free PMC Article

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