Detection of c-fms protooncogene in early mouse embryos by whole mount in situ hybridization indicates roles for macrophages in tissue remodelling.

The c-fms protoncogene which encodes the receptor for macrophage colony-stimulating factor (CSF-1) was localized in the developing mouse embryo by whole in situ hybridization. c-fms was expressed first in placental trophoblasts. Around 9.5 dpc, isolated c-fms-positive cells became detectable in the yolk sac and by 10.5 dpc large numbers were detectable throughout the embryo. The localization of c-fms expression was consistent with its restriction to macrophages, and with the location of those macrophages in sites of tissue turnover and extensive cell death.