Gfi1ab-Cebpβ axis promotes eosinophilopoiesis in zebrafish

Eosinophils play essential roles in parasite defense, allergic responses, and tissue homeostasis, yet the regulatory mechanisms governing their development remain incompletely understood. GFI1 is an important regulator of multiple hematopoietic lineages, but its role in eosinophil development is unclear. Using zebrafish as a model, we demonstrate that Gfi1ab promotes eosinophil development, as gfi1ab mutation significantly reduces eosinophil numbers, whereas its overexpression enhances eosinophilopoiesis. This effect is probably eosinophil-specific, as gfi1ab mutation does not significantly affect erythrocyte, neutrophil, or macrophage development. Integrative RNA-Seq and Chromatin immunoprecipitation sequencing (ChIP-Seq) analyses identify cebpb as a potential downstream target of Gfi1ab. Mechanistically, gfi1ab deficiency reduces cebpb expression, and cebpb overexpression partially rescues the eosinophil defects in gfi1ab -deficient larvae. These findings identify a Gfi1ab–Cebpβ regulatory axis that promotes eosinophil development and provide new insight into the transcriptional control of eosinophilopoiesis.