Physiologic Expression of Sf3b1 K700E Causes Impaired Erythropoiesis, Aberrant Splicing, and Sensitivity to Therapeutic Spliceosome Modulation

RNA Splicing Mice, Transgenic Hematopoietic Stem Cells Phosphoproteins 3. Good health Dioxygenases DNA-Binding Proteins Mice Myelodysplastic Syndromes Proto-Oncogene Proteins Spliceosomes Animals Humans Point Mutation Erythropoiesis RNA Splicing Factors
DOI: 10.1016/j.ccell.2016.08.006 Publication Date: 2016-09-12T16:00:56Z
ABSTRACT
More than 80% of patients with the refractory anemia with ring sideroblasts subtype of myelodysplastic syndrome (MDS) have mutations in Splicing Factor 3B, Subunit 1 (SF3B1). We generated a conditional knockin mouse model of the most common SF3B1 mutation, Sf3b1(K700E). Sf3b1(K700E) mice develop macrocytic anemia due to a terminal erythroid maturation defect, erythroid dysplasia, and long-term hematopoietic stem cell (LT-HSC) expansion. Sf3b1(K700E) myeloid progenitors and SF3B1-mutant MDS patient samples demonstrate aberrant 3' splice-site selection associated with increased nonsense-mediated decay. Tet2 loss cooperates with Sf3b1(K700E) to cause a more severe erythroid and LT-HSC phenotype. Furthermore, the spliceosome modulator, E7017, selectively kills SF3B1(K700E)-expressing cells. Thus, SF3B1(K700E) expression reflects the phenotype of the mutation in MDS and may be a therapeutic target in MDS.
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