Isolation of three new avian sarcoma viruses: ASV 9, ASV 17, and ASV 25.

The newly isolated avian sarcoma viruses, ASV 9, 17, and 25, cause fibrosarcomas in young chickens and induce foci of transformed cells in chick embryo fibroblast cultures. They are defective in replication and belong to envelope subgroup A. The sizes of their genomes are 6 kb (ASV 9), 5 kb (ASV 17), and 6 kb (ASV 25), respectively. All three contain long terminal repeat (LTR) and gag sequences but lack pol. env is absent from ASV 9 and ASV 25, but some env sequences are detectable in ASV 17. None of the defective viral genomes hybridized to selected onc probes representing src, fps, yes, myc, myb, and erb A. erb B appears absent from ASV 9 and ASV 17, but some hybridization between the erb B probe and the RNA of ASV 25 was detected. ASV 9 codes for a transformation-specific gag-linked protein of 130kDa. Multiple gag-linked transformation-specific proteins are seen in ASV 17 and 25; they require further study.

Characteristics of three new avian sarcoma viruses, ASV 9, ASV 17, and ASV 25.

Three new avian sarcoma viruses, ASV 9, ASV 17, and ASV 25, were isolated from spontaneous tumors. They transform chicken embryo fibroblasts but not hemopoietic cells and induce fibrosarcomas in young chicks. All three viruses belong to the envelope subgroup A and cannot replicate without a helper virus, because they lack the pol and most, if not all, of the env gene. ASV 9 and ASV 17 have a genome of 5.0 kb; the genome of ASV 25 is 6.0 kb. The following onc sequences were tested for homology to the genomes of the three new avian sarcoma viruses: src, fps, yes, myc, myb, erbA, and erbB. These tests were negative except for erbB which showed faint hybridization with the genome of ASV 25. ASV 9 codes for a prominent 130-kdalton gag-linked transformation-specific protein. ASV 17 and ASV 25 transformed cells appear to contain multiple gag-linked transformation-specific proteins that still require further study.