Comparison of the nucleotide sequences of early region E1b DNA of human adenovirus types 12, 7 and 5 (subgroups A, B and C).

The nucleotide sequences of human adenovirus serotypes 12 (Ad12, oncogenic subgroups A), 7 (Ad7, weakly oncogenic subgroup B) and 5 (Ad5, non-oncogenic subgroup C) DNAs have been compared. The region studied stretches from the termination codon of region E1a (m.p. 4.2) and comprises the entire region of the three viral DNAs, ending at the polyadenylation signal of the gene for viral polypeptide IVa2 (m.p. 11.2). The homology in the sequences encoding the E1b proteins of Mr 20 000 and Mr 55 000 is 55-60%, when two serotypes are compared, and about 45% in a three-strain comparison. However, a short internal segment encoding the C terminus of the Mr 20 000 protein, and at the same time amino acids 23-120 of the Mr 55 000 protein show a much higher degree of divergence in the three strains, as do the noncoding areas. The present study does not reveal how the three serotypes are phylogenetically related.