The mouse adenovirus type 1 contains an unusual E3 region.

Since the E3 region of human adenoviruses codes for a series of proteins that are probably involved in viral pathogenesis, the nucleotide sequence for a 3.6-kilobase DNA fragment in the corresponding region (map units 77 through 89) of the mouse adenovirus type 1 genome has been determined. Analysis of the sequence revealed that the genes for the fiber and for the precursor to the hexon-associated protein, pVIII, that usually flank the E3 region, are well conserved. However, many of the open reading frames contained in the E3 region of human adenoviruses between the pVIII and the fiber genes were absent from the mouse adenovirus type 1 genome.