Leukemia Virus, MurineMice, Inbred AKRMoloney murine leukemia virusAvian Sarcoma VirusesFriend murine leukemia virusSarcoma Viruses, MurineLeukemia, ExperimentalAbelson murine leukemia virusSarcomaLeukemia Virus, FelineRauscher VirusRetroviridae InfectionsLeukemia Virus, BovineRetroviridaeGenes, ViralVirus ReplicationGammaretrovirusCell LineCell Transformation, ViralDNA, ViralSarcoma Viruses, FelineKirsten murine sarcoma virusReceptors, VirusLeukemiaRNA-Directed DNA PolymeraseMoloney murine sarcoma virusRNA, ViralDefective VirusesGene Products, gagViral ProteinsRous sarcoma virusMolecular Sequence DataBase SequenceMink Cell Focus-Inducing VirusesTumor Virus InfectionsRNA VirusesHelper VirusesProvirusesVirus IntegrationSarcoma, ExperimentalVirus AssemblyVirus CultivationHarvey murine sarcoma virusMice, Inbred StrainsSarcoma, AvianAlpharetrovirusOncogenic VirusesMinkLeukemia, Myeloid, AcuteVirionRepetitive Sequences, Nucleic AcidGenetic VectorsLeukemia Virus, Gibbon ApeAmino Acid Sequence3T3 Cells