title: Organization and state of methylation of endogenous type C retroviral sequences in 129 mouse differentiated and undifferentiated teratocarcinoma cell lines.
abstract: Attempts to activate type C endogenous viruses in 129 mouse fibroblasts and in teratocarcinoma-derived cell lines have never been successful, although the genome of these cells contains xenotropic virus-related sequences. We have investigated the arrangement of these sequences and their methylation state by DNA restriction endonuclease digestion, electrophoresis of digests in agarose gels, Southern blotting and hybridization with specific probes. Our results show that the majority of the sequences are organized into two complete provirus families integrated at multiple sites in the cell genome and that they are hypermethylated in embryonal carcinoma cells as compared with differentiated cells. Having previously found a higher expression of viral RNA in 129 derived embryonal carcinoma cells, our data indicate an apparent direct correlation between methylation and type C virogenes expression.
authors.forename: J
authors.initials: J
authors.lastname: Tobaly
authors.forename: M
authors.initials: M
authors.lastname: Garcette
authors.forename: R
authors.initials: R
authors.lastname: Ravicovitch-Ravier
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D004279:DNA, Viral / Q000032:analysis* / Q000378:metabolism; D009052:Leukemia Virus, Murine / Q000235:genetics; D008745:Methylation; D051379:Mice; D012190:Retroviridae / Q000235:genetics*; D013724:Teratoma / Q000382:microbiology*
chemical_list: D004279:DNA, Viral