title: T-Ag inhibits implantation by EC cell derived embryoid bodies.
abstract: When introduced into EC cells of a blastocyst, polyomavirus (Py) T-Ag results in mice mosaic for T-Ag but otherwise essentially normal. It had been reported that SV40 T-Ag does not inhibit differentiation of F9 EC cells, but did inhibit endogenous retrovirus (ERV) production. We therefore sought to determine if Py T-Ag had any affect on EC derived embryoid body implantation onto mouse placenta. F9 EC cells were selected for T-Ag maintenance. Like the SV40 transformed cells, we show that these Py T-Ag selected EC cells no longer express IAP transcripts following differentiation into embryoid bodies. Normal and Py T-Ag selected F9 cells were differentiated into embryoid bodies then implanted into pseudopregnant mice. We observe, that normal F9 derived embryoid bodies underwent the initial stages of implantation whereas the Py T-Ag selected embryoid bodied did not implant. The implications of this observation with respect to trophectoderm and ERV function are discussed. We examine the idea that ERVs may be a required element for normal embryo implantation.
authors.affiliation: Department of Molecular Biology and Biochemistry, University of California, Irvine, USA.
authors.forename: A
authors.initials: A
authors.lastname: Espinosa
authors.forename: L P
authors.initials: LP
authors.lastname: Villarreal
mesh_terms: D000818:Animals; D000952:Antigens, Polyomavirus Transforming / Q000378:metabolism*; D001755:Blastocyst / Q000166:cytology / Q000378:metabolism; D002454:Cell Differentiation; D004475:Ectoderm / Q000166:cytology; D010064:Embryo Implantation / Q000235:genetics / Q000502:physiology*; D054278:Embryonal Carcinoma Stem Cells; D020077:Endogenous Retroviruses / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D005260:Female; D015686:Gene Products, env / Q000378:metabolism; D007426:Genes, Intracisternal A-Particle; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D014411:Neoplastic Stem Cells / Q000166:cytology* / Q000378:metabolism; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D000952:Antigens, Polyomavirus Transforming; D015686:Gene Products, env; D012333:RNA, Messenger