Rnf111 has a pivotal role in regulating development of definitive hematopoietic stem and progenitor cells through the Smad2/3-Gcsfr/NO axis in zebrafish.

The ubiquitination or SUMOylation of hematopoietic-related factors plays pivotal roles in hematopoiesis. RNF111, known as a ubiquitin ligase, is a newly discovered SUMO-targeted ubiquitin ligase involved in multiple signaling pathways mediated by transforming growth factor (TGF)-β family members. However, its role in hematopoiesis remains unclear. Herein, a heritable Rnf111 mutant zebrafish line was generated by CRISPR/Cas9-mediated genome editing. Impairment of hematopoietic stem and progenitor cells (HSPC) of definitive hematopoiesis was found in Rnf111-deficient mutants. Ablation of Rnf111 resulted in decreased phosphorylation of Smad2/3 in HSPC. Definitive endoderm 2 inducer (IDE2), which specifically activates TGF-β signaling and downstream Smad2 phosphorylation, could restore definitive hematopoiesis in Rnf111-deficient embryos. Further molecular mechanism studies revealed that Gcsfr/NO signaling was an important target pathway of Smad2/3 involved in Rnf111-mediated HSPC development. In conclusion, our study demonstrated that Rnf111 contributes to the development of HSPC by maintaining Smad2/3 phosphorylation and activation of the Gcsfr/NO signaling pathway.