title: T-antigen-independent replication of polyomavirus DNA in murine embryonal carcinoma cells.
abstract: Expression of wild-type polyomavirus (Py) is restricted in murine embryonal carcinoma (EC) cells. The block appears to be located at the level of early transcription. Since no T antigen is produced, we investigated the fate of viral DNA upon infection of these cells; we showed that wild-type Py DNA replicates efficiently in all EC cells, probably via a T-antigen-independent mechanism. Furthermore, we studied, at permissive and restrictive temperatures, the replication of tsa (thermosensitive for T antigen) viral DNA of an in vitro-constructed deletion mutant lacking part of the early region coding sequences and of a double mutant carrying both the tsa mutation and the PyEC F9 mutation (allowing expression of early and late viral functions in EC cells). Our results imply that replication of wild-type A2 strain Py DNA can occur in EC cells in the absence of a functional T antigen. However, this protein clearly enhances viral DNA replication and is absolutely required in differentiated cells.
mesh_terms: D000818:Animals; D000957:Antigens, Viral, Tumor / Q000235:genetics*; D002460:Cell Line; D004261:DNA Replication; D004279:DNA, Viral / Q000096:biosynthesis*; D054278:Embryonal Carcinoma Stem Cells; D051379:Mice; D009154:Mutation; D014411:Neoplastic Stem Cells; D011120:Polyomavirus / Q000235:genetics*; D013724:Teratoma; D014212:Tretinoin / Q000494:pharmacology; D014779:Virus Replication
chemical_list: D000957:Antigens, Viral, Tumor; D004279:DNA, Viral; D014212:Tretinoin