DDX41 is a tumor suppressor frequently mutated in human myeloid neoplasms, but whether it affects hematopoiesis is unknown. Using a knockout mouse, we demonstrate that DDX41 is required for mouse hematopoietic stem and progenitor cell (HSPC) survival and differentiation, particularly of myeloid lineage cells. Transplantation of Ddx41 knockout fetal liver and adult bone marrow (BM) cells was unable to rescue mice from lethal irradiation, and knockout stem cells were also defective in colony formation assays. RNA-seq analysis of Lin −/cKit +/Sca1 + Ddx41 knockout cells from fetal liver demonstrated that the expression of many genes associated with hematopoietic differentiation were altered. Furthermore, differential splicing of genes involved in key biological processes was observed. Our data reveal a critical role for DDX41 in HSPC differentiation and myeloid progenitor development, likely through regulating gene expression programs and splicing.
Ma and colleagues show using knockout mice that DDX41 is critical for the development of hematopoietic stem cells and particularly affects differentiation of myeloid lineage cells. This finding suggest that previous work showing that loss of DDX41 leads to hyper-proliferation in stem cells might be the result of decreased or aberrant protein expression, rather than total loss of activity