PRMT5 Modulates Splicing in Hematopoietic Stem Cells

This study aimed to clarify the role of PRMT5 in the hematopoietic stem cell (HSC) compartment, and elucidate the functional relevance of PRMT5-mediated splicing in HSCs. We confirm the cell intrinsic requirement for PRMT5 in HSC maintenance, and present evidence suggesting that PRMT5 deficiency perturbs HSC proteostasis. Notably, we also uncover a critical role for PRMT5 in maintaining HSC genomic integrity by modulating splicing of genes involved in DNA repair; loss of which leads to unresolved DNA damage, p53 activation and rapid HSC exhaustion. Overall, these findings establish PRMT5-mediated splicing as a major determinant of HSC fate, and highlight the need to maintain an adequate level of PRMT5 activity in HSCs. Overall design: Hematopoietic stem cells (HSCs; Lineage-Sca-1+CD48-CD150+), isolated from Prmt5fl/fl or Prmt5?/? littermate- and gender-matched mice 7 days post-induction, were subjected to RNA-seq. HSCs for each independent sample were obtained from bone marrow cells pooled from two mice. Three independent samples were obtained for each group.