Identification of transcripts and promoter regions of ovine adenovirus OAV287

The ovine adenovirus isolated OAV287 represents a new group of adenoviruses that are distinct from the Mast- and Aviadenoviruses by several criteria, including genome arrangement. The OAV major late promoter and some late transcripts were previously mapped. To better define the probable coding sequences and to identify the approximate location of early promoters a partial transcription map of the genome was elucidated using a PCR-based approach. This was possible because the complete nucleotide sequence of the genome was known. The strategy permitted the identification of transcription start sites and RNA splice junctions and allowed the approximate location of promoters in the lefthand end, IVa2, E2, P32K, and E4 regions to be deduced. The data showed that lefthand end and E4 regions are controlled by three and two temporally distinct promoters, respectively. The E2 region is controlled by a single promoter, in contrast to Mastadenoviruses, where E2 expression is controlled by the E2A and E2B promoters. The p32kDa structural protein at the lefthand end and the IVa2 protein are also expressed from their own promoters. These data contribute to the first overview of transcription from a non-Mastadenovirus genome.