Genomic stability of gibbon oncornavirus

Isolation and identification of lymphocytic and myelogenous leukemia-specific sequences in genomes of gibbon oncornaviruses

Five gibbon ape leukemia virus substrains (two from gibbons with lymphocytic leukemia and three from gibbons with myelogenous leukemia) were examined for unique genomic sequences specific for each form of leukemia. By using sequential adsorption procedures, the genome from each gibbon ape leukemia virus was fractionated into four sets of distinct nucleotide sequences. Based on their hybridization specificities toward DNAs of leukemic tissues, these sequences were designated as follows: (i) "COM," (ii) "LYM" or "MYE," (iii) "UNI," and (iv) "UND." The COM fraction represented sequences common to all of the viral genomes. The LYM fraction, which was isolated only from gibbon ape leukemia viruses associated with lymphocytic leukemia, represented genomic sequences associated with lymphocytic leukemia since the RNA hybridized at a 4- to 15-fold-higher rate to infected tissue DNA from lymphocytic leukemic gibbons than to infected tissue DNA from myelogenous leukemic gibbons. The MYE fraction, which was isolated only from gibbon ape leukemia viruses associated with myelogenous leukemia, represented genomic sequences associated with myelogenous leukemia since the RNA hybridized at a 5- to 15-fold-higher rate to infected tissue DNA from myelogenous leukemic gibbons than to infected tissue DNA from lymphocytic leukemic gibbons. The UNI fraction contained sequences unique to one virus substrain. The UND fraction contained sequences which varied depending upon the substrains involved in the adsorption procedures. These findings suggest that each gibbon ape leukemia virus examined in this study contains subgenomic sequences that are specifically identifiable only with the form of leukemia from which the virus was isolated.

Oncogenicity of gibbon type-C myelogenous leukemia virus

Young gibbons that were experimentally inoculated with cell-free gibbon ape leukemia virus (GaLV) and developed peristent viremia subsequently developed chronic granulocytic leukemia (CGL) with associated multifocal bone lesions and metastases. An 8-month-old gibbon inoculated with 10(5) tissue culture infectious virus (TCIV) developed acute myeloproliferative disease with associated bone lesions after a latency of 5 months, while a 9-month-old gibbon inoculated with 10(3) TCIV developed CGL after and 11-month latency. The clinical symptoms associated with the onset of leukemia were an increased number of leukocytes which were predominantly mature granulocytes, development of anemia, and multifocal bone lesions. Terminally, the animals had elevated immature granulocytes in the blood, cellular bone marrow with a predominant number of immature granulocytes, and hepatosplenomegaly. The gibbon with CGL had metastatic growth in the spleen and lung. Two 14-month-old gibbons that were inoculated with 10(3) TCIV and developed persistent neutralizing antibody to the virus infection remained free of hematopoietic disease, as did uninoculated animals. The fact that only animals with persistent viremia developed leukemia supports the oncogenicity of GaLV in gibbons.

Structural analysis of the genomes of gibbon ape and woolly monkey leukosis viruses

Infectious retroviruses have been isolated from gibbon apes and a woolly monkey. Previous studies have shown that these isolates share some antigenic determinants and that they exhibit partial nucleic acid homology. To further define the relationships in this group of viruses, we compared the RNAs of the viruses of the woolly monkey-gibbon ape class by two-dimensional polyacrylamide gel electrophoresis of the large RNase T1-resistant oligonucleotides. The degree of sequence identity between the RNAs was determined by the similarity of the fingerprint patterns and in some cases by partial sequence analysis of individual oligonucleotides. This technique permitted us to determine the degree of sequence identity in related RNA species. These studies showed that as much as 80% of the genomes of gibbon ape leukosis virus-Halls' Island and gibbon ape leukosis virus-brain could be identical. The other viruses, simian sarcoma-associated virus, gibbon ape leukosis virus-Thailand, and gibbon ape leukosis virus-San Francisco, showed an extensive but somewhat lower degree of sequence identity (between 40 to 60% of the genomes.