title: Isolation of defective mutant of avian sarcoma virus.
abstract: A colony of transformed cells was isolated from chick-embryo cells infected with a stock of nondefective Schmidt-Ruppin strain of Rous sarcoma virus. The virus recovered from this colony was a stable defective mutant very similar to the Bryan strain of Rous sarcoma virus in the following characteristics: (i) noninfectiousness of virus particles released from transformed cells that lack helper factor; (ii) formation of infectious pseudotypes by coinfection with avian leukosis virus or by interaction with endogenous-helper factor in chicken cells; (iii) ability of the noninfectious form of virus to transform chick-embryo cells in the presence of ultraviolet light-inactivated Sendai virus; (iv) absence of glycoprotein in the noninfectious form; (v) failure to produce nondefective virus by recombination with avian leukosis virus; and (vi) segregation of polymerase-negative virus. The morphology of transformed cells is characteristic of those infected by the Schmidt-Ruppin strain. The demonstration of segregation of such a defective virus from nondefective sarcoma virus and failure to detect revertants of this mutant suggest that the deletion of some genes may be involved in this mutation.
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D001354:Avian Leukosis Virus; D001358:Avian Sarcoma Viruses / Q000254:growth & development* / Q000302:isolation & purification* / Q000378:metabolism; D002250:Carbon Radioisotopes; D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured; D002642:Chick Embryo; D002999:Clone Cells; D003673:Defective Viruses / Q000254:growth & development / Q000302:isolation & purification*; D004591:Electrophoresis, Polyacrylamide Gel; D005944:Glucosamine / Q000378:metabolism; D006378:Helper Viruses; D008970:Molecular Weight; D009154:Mutation; D010222:Parainfluenza Virus 1, Human; D011995:Recombination, Genetic; D014316:Tritium; D010948:Viral Plaque Assay; D014764:Viral Proteins / Q000096:biosynthesis; D014776:Virus Cultivation; D014779:Virus Replication
chemical_list: D000596:Amino Acids; D002250:Carbon Radioisotopes; D014764:Viral Proteins; D014316:Tritium; D005944:Glucosamine