Four new inverted terminal repeat sequences from bovine adenoviruses reveal striking differences in the length and content of the ITRs

The inverted terminal repeat (ITR) of the genome of four bovine adenovirus (BAdV) types have been sequenced, analysed and compared to the ITRs of othe r adenoviruses. The length of ITRs of the examined BAdVs ranged between 59 and 368 base pairs, thus the presently known longest adenovirus ITR sequenc e is from BAdV-10. The conserved motifs and characteristic sequence element s of the ITRs providing different binding sites for replicative proteins of viral and cellular origin seemed to be distributed according to the propos ed genus classification of BAdVs. The ITRs of BAdV-10 share similarity with the members of the genus Mastadenovirus, while the ITRs of the other three sequenced serotypes (BAdV-4, 5 and strain Rus) which are candidate members of the genus Atadenovirus are very short and contain NFI and Sp1 binding s ites only. The analysis of the new ITRs implied that the nucleotide sequenc e of the so-called core origin is highly preserved within the mastadenoviru s genus only.