The oncogenicity of Jun

A mutational analysis of the delta regions of the Jun protein shows an inverse correlation between transforming and tansactivation potential of the mutant proteins if both properties are measured in chicken embryo fibroblasts. The possibility that Jun acquires oncogenicity not by gain but by loss of function is also suggested by the down regulation of the differentiation control element MyoD by Jun and by the low transactivating potential of highly transforming chimeric proteins of Jun and JunD and Jun and herpes simplex VP16