DETECTION OF C-FMS PROTOONCOGENE IN EARLY MOUSE EMBRYOS BY WHOLE-MOUNT IN-SITU HYBRIDIZATION INDICATES ROLES FOR MACROPHAGES IN TISSUE REMODELING

The c-fms protooncogene which encodes the receptor for macrophage colo ny-stimulating factor (CSF-1) was localized in the developing mouse em bryo by whole in situ hybridization. c-fins was expressed first in pla cental trophoblasts. Around 9.5 dpc, isolated c-fms-positive cells bec ame detectable in the yolk sac and by 10.5 dpc large numbers were dete ctable 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 d eath.