CHARACTERIZATION OF ADENOVIRUS SUBGENUS-D FIBER GENES

The fiber genes of human adenovirus types 8, 9, 15, and two genome typ es of intermediate adenovirus 15/H9, all belonging to subgenus D, were sequenced and the nucleotide and predicted amino acid sequences compa red. The analyzed peptide sequences were consistent with the structura l domains described for other adenoviruses: an aminoterminal tail regi on, an intervening shaft region composed of eight repeating 15-amino-a cid segments, and a carboxyterminal knob. Furthermore, several highly conserved sequences could be confirmed. The fiber genes of AV9 and the AV15/H9 intermediate strains were 100% identical, not only in the cod ing region, but also in the presented 5'- and 3'-flanking regions. The se findings support the hypothesis that intermediate strains arise by recombination of two serologically different parent viruses. The predi cted AV8, AV9, and AV15/H9 polypeptides showed an overall homology of 92%. In the knob regions, AV8 and AV9; AV15/H9 intermediate strains re vealed nine mismatches. AV8 is the main causative agent of epidemic ke ratoconjunctivitis in man, whereas AV9 and the AV15/H9 intermediate st rains only infrequently cause acute follicular conjunctivitis. Since t he knob is the component responsible for interaction with the cell rec eptor, these differences in the receptor binding sites should be expec ted to play an important role in the differences in pathogenicity. (C) 1995 Academic Press, Inc.