title: Characterization by molecular hybridization of two viral populations derived from a radiation leukemia virus.
abstract: Two leukemogenic viral populations were derived from a radiation leukemia virus of the C57BL mouse. One (FB), in which only B-tropic virus could be detected, was obtained in vivo by serial passage of cell-free extract in newborn rats. The second (3C), a complex containing at least B-tropic and xenotropic viruses, was produced in vitro by a permanent cell line (13-3C) established from the spleen of a virus-infected C57BL mouse. In molecular hybridization experiments, the 70S RNA of Gross leukemia virus hybridized 96 and 78% of FB and 3C radioactive complementary DNA's, respectively, with a relatively high thermal stability of the duplexes formed. In contrast, the 70S RNA of Rauscher leukemia virus hybridized 23 and 20% of the FB and 3C DNA probes, respectively, with a low thermal stability. The rat-grown FB virions exhibited 50% genome homology with the viruses produced in vitro on the 13-3C cells. Finally, hybridizing the FB and 3C probes with normal or leukemic mouse spleen DNA's resulted in 89 to 100% homology. The rat-grown virions did not appear to contain detectable rat cellular DNA sequences, while about 20 complete copies of their nucleotide sequences were detected in covalent linkage with FB-infected rat spleen DNA. These findings strongly support the endogenous murine origin of the investigated virions.
mesh_terms: D000406:AKR murine leukemia virus / Q000378:metabolism; D000818:Animals; D002460:Cell Line; D004279:DNA, Viral / Q000378:metabolism; D009052:Leukemia Virus, Murine / Q000378:metabolism*; D007942:Leukemia, Experimental / Q000382:microbiology*; D007953:Leukemia, Radiation-Induced / Q000382:microbiology*; D051379:Mice; D009693:Nucleic Acid Hybridization; D012367:RNA, Viral / Q000378:metabolism*; D051381:Rats; D011925:Rauscher Virus / Q000378:metabolism; D014412:Tumor Virus Infections / Q000382:microbiology*
chemical_list: D004279:DNA, Viral; D012367:RNA, Viral