SRSF2 mutations impair hematopoiesis and alter exon recognition

Mutations within genes encoding spliceosomal proteins are the most common class of mutations in patients with myelodysplastic syndromes, yet it is currently not well understood how these mutations impact hematopoiesis or RNA splicing. Here we report that mutations affecting the splicing factor SRSF2 alter its normal RNA recognition activity, resulting in impaired hematopoietic differentiation and myelodysplasia. Commonly occurring SRSF2 mutations impaired wildtype SRSF2’s normal RNA-binding avidity and preference for specific exonic splicing enhancer RNA motifs. Integration of murine and human transcriptome data identified recurrent mis-splicing of key transcriptional regulators in the presence of mutant SRSF2, including promotion of a highly conserved “poison” exon of EZH2 that results in nonsense-mediated decay and contributes to impaired hematopoiesis. These data provide a mechanistic basis for the enrichment of specific mutations in spliceosomal proteins in myelodysplasia, and suggest that altered RNA recognition activity is a novel mechanism of leukemogenesis. Overall design: mRNA profiles of murine model and K562 cells expressing SRSF2 WT, mutants and knockdown of SRSF2 in TF-1 cells generated by deep sequencing.