Structural diversity and function of the granulocyte colony-stimulating factor in medaka fish.

Diversity in the granulocyte repertoire, including neutrophils, basophils, and eosinophils, has been reported in vertebrate species. Medaka fish (Oryzias latipes) have only neutrophils; however, the storage pool of granulopoiesis tissues and the molecular mechanism of granulopoiesis in medaka fish have not been explored. Granulocyte colony-stimulating factor (G-CSF) is a cytokine responsible for neutrophil differentiation, survival, and proliferation.