Viral transfer, transcription, and rescue of a selectable myeloproliferative sarcoma virus in embryonal cell lines: expression of the mos oncogene.
A derivative of the myeloproliferative sarcoma virus (Neor-MPSV) carrying the mos oncogene and dominant selection marker for neomycin resistance (Neor) was introduced into embryonal carcinoma and embryo-derived cell lines by transfection and infection using pseudotypes with Friend helper virus (Friend murine leukemia virus [F-MuLV]). Cells resistant to G418 (a neomycin analog) were cloned and expanded. Transductants retained an undifferentiated phenotype as judged by morphology, tumorigenicity, and cell-surface antigen analyses. Nucleic acid analysis of infectants revealed both Neor-MPSV and F-MuLV proviruses, although no virus was released. G418-resistant transductants remained nonpermissive for the expression of other proviruses and for subsequent superinfection. Northern analysis showed expression of full-length Neor-MPSV, as well as mos-specific subgenomic RNA. mos sequences were deleted from Neor-MPSV (Neor mos-1), and pseudotypes were used to infect embryonal carcinoma cells. No morphological differences were observed in either mos+ or mos- transductants as compared with parental cell lines. However, mos+ transductants showed an enhanced anchorage-independent growth compared with that of mos- transductants in agar cloning. PCC4 transductants were induced to differentiate with retinoic acid and superinfected with F-MuLV. Infection with viral supernatant in fibroblasts and in mice confirmed the rescue of biologically active Neor-MPSV.
D000818:Animals; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D004351:Drug Resistance; D004622:Embryo, Mammalian; D005814:Genes, Viral; D051379:Mice; D008980:Moloney murine sarcoma virus / Q000235:genetics*; D009355:Neomycin / Q000494:pharmacology; D009857:Oncogenes; D009053:Sarcoma Viruses, Murine / Q000235:genetics*; D013724:Teratoma; D014158:Transcription, Genetic; D014162:Transfection
D009355:Neomycin