Gene organization of the transforming region of adenovirus type 7 DNA.
The sequence of the leftmost 11% of the weakly oncogenic human adenovirus type 7 (Ad7) DNA has been determined. This part of the Ad7 viral genome encompasses early region E1 which has been shown to be involved in the process of cell transformation in vitro (Dijkema et al., 1979). From the nucleotide sequence and determined coordinates of the E1 mRNAs, we are able to predict the primary structure of the polypeptides encoded by the transforming region of Ad7. The organization of the E1 region of Ad7 and of other adenovirus serotypes (Bos et al. 1981) leads to the proposal of a novel mechanism for gene regulation at the translational level in which protein synthesis can initiate at either the first or the second AUG triplet available in mRNA. The differences between the large E1b-specific tumor antigens of adenovirus types 12, 7 and 5 may explain the differences in oncogenicity of these viruses.