Oncogenicity of gibbon retrovirus determined by leukemia-specific genomic sequences

Abstract The genome of a type C virus, GaLV-5, isolated from several clinically healthy gibbons, was examined for the presence of nucleotide sequences related to the myelogenous leukemia-specific “MYE” RNA and the lymphocytic leukemia-specific “LYM” RNA which have been isolated from several strains of oncogenic GaLV (L. Sun and T. G. Kawakami, J. Virol. , 35 , 400–408 (1980)). The genomes of these oncogenic GaLVs were each separated into sequences homologous and nonhomologous to GaLV-5. Based on hybridization analysis, the nonhomologous RNA fractions were found to contain either the MYE RNA or the LYM RNA. This indicates that the leukemia-specific RNAs are lacking in the genome of GaLV-5. This lack was further confirmed by analysis of hybridization kinetics. The presence of leukemia-specific RNA sequences in GaLV genomes that were isolated from animals with leukemia and the absence of these sequences in virus strains isolated from animals free of clinical symptoms of leukemia indicate that the leukemia-specific RNA sequences are closely associated with the oncogenesis of leukemia in gibbons.