title: Characterization of infectious oncornaviruses from MOPC-460 plasmacytomas: their relation to A-type particles.
abstract: MOPC-460 mouse plasmacytoma cells produce intracellular A-type particles and extracellular oncornavirus-like particles ("myeloma-associated virus," abbreviated MAV). The genomes of these two particles are closely related. During attempts to establish infections with MOPC-460 extracellular particles, we isolated ecotropic and xenotropic infectious forms of murine leukemia virus. We have investigated the relation of these isolates to A-type particles and to MAV by nucleic acid hybridization. Using complementary DNA probes prepared from the two isolates, we found that these infectious murine leukemia viruses differ from A-type particles and from MAV. Moreover, we found that MAV is the predominant extracellular component: the ecotropic and xenotropic forms of murine leukemia virus were present at only low levels (less than 5%) in MAV preparations. Neither the SC-1 cells infected with ectropic murine leukemia virus nor the mink cells infected with xenotropic murine leukemia virus showed any A-type particles in their cytoplasm when examined by electron microscopy. Our inability to demonstrate infection by the A-type particle-related component, MAV, suggests that these may be defective.
mesh_terms: D000818:Animals; D002460:Cell Line; D003593:Cytoplasm / Q000382:microbiology; D017988:Gammaretrovirus / Q000032:analysis* / Q000302:isolation & purification; D006023:Glycoproteins / Q000032:analysis*; D009052:Leukemia Virus, Murine / Q000032:analysis*; D051379:Mice; D009374:Neoplasms, Experimental / Q000032:analysis / Q000382:microbiology; D009693:Nucleic Acid Hybridization; D010954:Plasmacytoma / Q000032:analysis / Q000382:microbiology*; D012367:RNA, Viral / Q000032:analysis*; D014764:Viral Proteins / Q000032:analysis*
chemical_list: D006023:Glycoproteins; D012367:RNA, Viral; D014764:Viral Proteins