U2AF1 is involved in the recognition of the 3′ splice site during pre-mRNA splicing. Mutations in U2AF1 are frequently observed in myelodysplastic syndromes. However, the role of wild-type U2AF1 in normal hematopoiesis has remained elusive. Using a novel conditional U2af1 knockout allele, we have found that deletion of U2af1 results in profound defects in hematopoiesis characterized by pancytopenia, ablation of hematopoietic stem/progenitor cells (HSPC) leading to bone marrow failure and early lethality in mice. U2af1 deletion impairs HSPC function and repopulation capacity. U2af1 deletion also causes increased DNA damage and reduced survival in hematopoietic progenitors. RNA sequencing analysis reveals significant alterations in the expression of genes related to HSC maintenance, cell proliferation, and DNA damage response-related pathways in U2af1-deficient HSPC. U2af1 deficiency also induces splicing alterations in genes important for HSPC function. This includes altered splicing and perturbed expression of Nfya and Pbx1 transcription factors in U2af1-deficient HSPC. Collectively, these results suggest an important role for U2af1 in the maintenance and function of HSPC in normal hematopoiesis. A better understanding of the normal function of U2AF1 in hematopoiesis is important for development of appropriate therapeutic approaches for U2AF1 mutant induced hematologic malignancies.
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The RNA-Sequencing datasets generated in this study are deposited to NCBI GEO database (GSE162888).
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We thank Dr Roberto Mantovani (University of Milan) and Dr Licia Selleri (University of California San Francisco) for NF-Ya and Pbx1 expression constructs, and Ms Julia Dreksler for assistance with generating U2AF1 knockdown cell lines. We also thank the flow cytometry and microscopy core facilities at the University of Virginia for assistance with FACS sorting and confocal microscopy. Flow cytometry and microscopy cores are supported by the UVA Cancer Center through NCI P30CA044578 grant. This work was supported in part by US National Institute of Health (NIH) grants R01 HL095685 (GM), R35 GM133712 (CZ) and a start-up fund from the Department of Biochemistry and Molecular Genetics of the University of Virginia (GM).
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Dutta, A., Yang, Y., Le, B.T. et al. U2af1 is required for survival and function of hematopoietic stem/progenitor cells. Leukemia (2021). https://doi.org/10.1038/s41375-020-01116-x