Interactions of Early Mouse Embryos With Oncogenic Viruses—Simian Virus 40 and Polyoma. I. Ultrastructural Studies2

Abstract

Two-celled mouse embryos, blastocysts, and egg-cylinders were exposed to simian virus 40 (SV40) and polyoma virus. Uptake of SV40 but not of polyoma was found when 2-celled embryos were exposed to virus. Blastocysts and egg-cylinders exposed to SV40 or polyoma showed adsorption and uptake of virus particles. When infected blastocysts were grown in vitro for 96 hours, replication of virus in the nuclei of endodermal cells and uptake of newly synthesized virus by neighboring cells were found. Infected egg-cylinders grew in vitro and showed signs of organogenesis after 96 hours. Replication of SV40 and polyoma was observed in endodermal cells, yolk sac cells, and cells of blood islands. Uptake of newly synthesized viruses was found in the cells of the neural tube. Although mouse somatic cells are permissive for replication of polyoma but nonpermissive for replication of SV40, this difference was not observed in early embryos which were permissive for both viruses.