RESUMEN

Somatic mutations in spliceosome genes are found in ∼50% of patients with myelodysplastic syndromes (MDS), a myeloid malignancy associated with low blood counts. Expression of the mutant splicing factor U2AF1(S34F) alters hematopoiesis and mRNA splicing in mice. Our understanding of the functionally relevant alternatively spliced target genes that cause hematopoietic phenotypes in vivo remains incomplete. Here, we demonstrate that reduced expression of H2afy1.1, an alternatively spliced isoform of the histone H2A variant gene H2afy, is responsible for reduced B cells in U2AF1(S34F) mice. Deletion of H2afy or expression of U2AF1(S34F) reduces expression of Ebf1 (early B cell factor 1), a key transcription factor for B cell development, and mechanistically, H2AFY is enriched at the EBF1 promoter. Induced expression of H2AFY1.1 in U2AF1(S34F) cells rescues reduced EBF1 expression and B cells numbers in vivo. Collectively, our data implicate alternative splicing of H2AFY as a contributor to lymphopenia induced by U2AF1(S34F) in mice and MDS.

Asunto(s)

Empalme Alternativo , Linfocitos B/metabolismo , Histonas/metabolismo , Linfopoyesis , Síndromes Mielodisplásicos/metabolismo , Factor de Empalme U2AF/metabolismo , Animales , Linfocitos B/inmunología , Sitios de Unión , Estudios de Casos y Controles , Células HEK293 , Histonas/genética , Humanos , Células K562 , Ratones de la Cepa 129 , Ratones Endogámicos C57BL , Ratones Noqueados , Mutación , Síndromes Mielodisplásicos/genética , Síndromes Mielodisplásicos/inmunología , Regiones Promotoras Genéticas , Transducción de Señal , Factor de Empalme U2AF/genética , Transactivadores/genética , Transactivadores/metabolismo