title: Chromosome breakage and xenotropic C-type virus in embryonic cultures from New Zealand black mice.
abstract: A considerable increase in chromatid and chromosome breaks, as well as excessive fragmentation and "pulverization" of whole metaphase plates was observed in embryonic fibroblast cultures from New Zealand black mice. A C-type RNA virus with a xenotropic host range was isolated from the supernatant fluid of co-cultures of NZB cells and heterologous permissive cells (SIRC cell line). One of the NZB cultures produced this virus without amplification by co-cultivation after spontaneous transformation of the cells. NZB cells are supposed to lack normal restriction of complete xenotropic virus expression and to release this endogenous virus spontaneously at a high level. It is hypothesized that the excessive chromosome damage observed in these cell cultures is related to the permanent production of virus, thus indicating a chromosome breaking effect of endogenous viruses.
mesh_terms: D000367:Age Factors; D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D002869:Chromosome Aberrations; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D005347:Fibroblasts / Q000648:ultrastructure; D008677:Metaphase; D051379:Mice; D008814:Mice, Inbred NZB / Q000196:embryology*; D012328:RNA Viruses / Q000201:enzymology / Q000302:isolation & purification; D012190:Retroviridae / Q000201:enzymology / Q000302:isolation & purification; D014779:Virus Replication
chemical_list: D012321:DNA-Directed RNA Polymerases