Host induced alteration of avian sarcoma virus B-77 genome.

Abstract

The genome of an avian oncornavirus was altered after infection of a heterologous host. This was studied with avian sarcoma virus B-77 in duck embryonic fibroblasts (DEF) and chicken embryonic fibroblasts (CEF). To detect alteration of the viral genome, we hybridized 35S B-77 RNA with normal duck DNA by either one of two techniques: when viral RNA was in excess and when DNA was in excess. The RNA of B-77 passaged only in gs-chf-CEF does not have homology with duck DNA. However, after several passages of B-77 through DEF the viral genome acquired duck specific RNA sequences. After 4 and 10 passages, B-77 RNA acquired 2.2 and 6.6%, respectively, complementarity to normal duck DNA. The duck specific RNA sequences were found to be covalently linked to the B-77 RNA genome. Also, the host specific sequences acquired by the virus appear to be from a region of the duck DNA which is repeated four to six times per cell. After 5 back passages in CEF some of the duck specific RNA sequences in the viral genome were lost.Avian oncornaviruses have the ability to be modified by the host through which they are passaged. Even Rous sarcoma virus (RSV) may have had to be adapted to induce tumors and replicate in chickens (1). After the isolation of chicken tumor no. 1 by Rous in 1911, the tumor cells could cause sarcomas only in chickens of the same strain as that in which the tumor originated and only by inoculation of large numbers of tumor cells. Subsequently, tumors could be induced in other strains of chickens but only after several more passages could sarcomas be induced by a cell-free filtrate. After more than 60 years of laboratory manipulations, RSV can now rapidly induce tumors in a wide host range including primates (2, 3). DuranReynals reported that after several passages in ducks, a duck adapted variant of RSV appeared (4). In addition to the ability to cause tumors in ducks, the duck-adapted virus had acquired new tissue affinities causing tumors in bone, skin, and digestive tract, whereas the original RSV did not. Furthermore, the duck-adapted virus had altered surface antigenic properties. A similar phenomenon has also been noted with RSV that has been rescued from transformed rat cells (5-12). These findings led Altaner and Temin (6) to suggest that the alteration of physical and biological properties in the virus may reflect recombination between viral and host genetic material. Host-induced alterations of murine sarcoma viruses have also been reported after passage in rat cells (13). Kirsten and Harvey sarcoma viruses appear to contain murine and rat oncornavirus specific RNA sequences but these sequences have Abbreviations: DEF, duck embryo fibroblasts; CEF, chicken embryo fibroblasts; RSV, Rous sarcoma virus; AMV, avian myeloblastosis virus; Cot, nucleotide concentration (mol/l) X time (sec); TCA, trichloroacetic acid.1031 not been shown to be covalently linked. Also, in those studies the DNA probe synthesized in vitro with reverse transcriptase may have contained cellular as well as viral sequences sin...

Host Antigens on Avian Oncoviruses: Presence on Viruses Produced by Quail, Duck and Rat Cells of Antigens Related to Membrane Antigens of Chick Embryo Fibroblasts and Chicken Erythrocytes

“…Subsequent transfer of this chromosome from an RBI cell to a hamster cell would also account for the linked expression of the three antigens in RBH cells. The second and third mechanisms are suggested, respectively, by observations of Stehelin et al (1980) showing that B77 virus may contain an important amount of host RNA sequences, and a report of Shoyab et al (1977) who observed the incorporation of host nucleotide sequences into the genome of B77 passaged in duck cells. However, it is most unlikely that the genetic information of three chicken genes may have been transferred to the same rat cell by these mechanisms.…”

Transfer of duck cell DNA sequences to the nucleus of 3T3 cells by Rous sarcoma virus.

“…Shoyab et al (12) reported one of the most direct approaches to this question. These authors infected Peking duck cells, whose genome is void of RSV sequences (12,(14)(15)(16)(17), with B-77 RSV and demonstrated that RNA complementary to Peking duck DNA was covalently linked to the high molecular weight (high Mr) RNA of virus produced by the Peking duck cells after 4-10 passages.…”

“…These authors infected Peking duck cells, whose genome is void of RSV sequences (12,(14)(15)(16)(17), with B-77 RSV and demonstrated that RNA complementary to Peking duck DNA was covalently linked to the high molecular weight (high Mr) RNA of virus produced by the Peking duck cells after 4-10 passages. For some time we have suspected that not only could host genetic information be incorporated into the viral genomes but, even more significantly, that the virus could pass this information on to a second, unrelated host, as in bacterial transduction.…”

“…Consequently it was demonstrated that type C retroviruses are capable of associating host genetic material with the viral genome (7,(10)(11)(12)(13).…”

“…Altaner and Temin (7) postulated that these alterations were a result of recombination between viral and host genetic material. Consequently it was demonstrated that type C retroviruses are capable of associating host genetic material with the viral genome (7,(10)(11)(12)(13) (21,22). The medium was clarified by centrifugation at 3000 X g at 20 for 10 min.…”