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

Small-molecule antagonists of Myc/Max dimerization inhibit Myc-induced transformation of chicken embryo fibroblasts

“…One day after seeding, the cells were infected with 10-fold serial dilutions of oncogenic retroviruses. These viruses were (i) the RCAS viral vector expressing chicken cellular Myc (27), (ii) the Prague strain of Rous sarcoma virus coding for the Src oncoprotein (28), and (iii) the avian sarcoma viruses 17 and 31 expressing the oncoproteins Jun (29,30) and Qin (31), respectively. The cultures were then overlaid with nutrient agarose consisting of 57.5% (vol͞vol) of media (75% F10 2ϫ, 5% FBS, 2% chicken serum, 15% tryptose-phosphate broth, 1.5% of L-glutamine͞penicillin͞ streptomycin solution, screening compounds in DMSO, final concentration of DMSO:1%) and 42.5% (vol͞vol) of 1.5% Sea Plaque Agarose.…”

Jun, the oncoprotein

“…The avian retrovirus ASV17, expressing v-Jun fused to viral Gag sequences induces characteristic foci of transformed cells in cultures of primary CEF (Cavalieri et al, 1985;Maki et al, 1987). These foci consist of needle like cells growing in multiple layers and parallel arrays.…”

“…AP-1 had been described as a 12-O-tetradecanoyl-phorbol-13-acetate (TPA) inducible transcription factor activity that addresses speci®c sequences in the enhancer of the metallothionein gene and in the 72-base pair repeat of the simian virus 40 enhancer region (Angel et al, 1987;Lee et al, 1987a,b). Jun was found as a novel oncoprotein encoded by a cellular insert in the genome of avian sarcoma virus 17 (ASV17), an acutely oncogenic retrovirus isolated from a spontaneous tumor in a chicken (Cavalieri et al, 1985;Maki et al, 1987). The two ®ndings became linked by the discovery of homology between Jun and the yeast transcriptional regulator GCN4 .…”

Microarray analysis identifies Autotaxin, a tumour cell motility and angiogenic factor with lysophospholipase D activity, as a specific target of cell transformation by v-Jun

“…Many of the remaining downregulated genes can be assigned to one of three general functional categories: cytoskeletal components, chaperones, and DNA replication factors. Decreased expression of cytoskeletal components such as actin gamma (0.26), myosin light chain (0.29), and alpha and beta tubulin (0.24 and 0.3, respectively), could contribute to the unusual morphological alterations induced by v-Jun (Cavalieri et al, 1985), while downregulation of the chaperones Hsc70 (0.15-0.33), Hsc71 (0.22-0.33), and HSP90 (0.22-0.33) suggests that cell transformation may be associated with alterations in protein folding or degradation. Decreases were also observed in the expression of ribonucleotide reductase (0.2-0.24-fold), MCM4 and 6 (0.25),).…”