Nucleotide Sequence, Genome Organization, and Transcription Map of Bovine Adenovirus Type 3

Abstract

The complete DNA sequence of bovine adenovirus type 3 is reported here. The size of the genome is 34,446 bp in length with a G+C content of 54%. All the genes of the early and late regions are present in the expected locations of the genome. However, the late-region genes are organized into seven families, instead of five as they are in human adenovirus type 2. The deduced amino acid sequences of open reading frames (ORFs) in the late regions and early region 2 (E2) and for IVa2 show higher degrees of homology, whereas the predicted amino acid sequences of ORFs in the E1, E3, and E4 regions and the pIX, fiber, and 33,000-molecular-weight nonstructural proteins show little or no homology with the corresponding proteins of other adenoviruses. In addition, the penton base protein lacks the integrin binding motif, RGD, but has an LDV motif instead of an MDV motif. Interestingly, as in other animal adenoviruses, the virus-associated RNA genes appear to be absent from their usual location. Sequence analysis of cDNA clones representing the early- and late-region genes identified splice acceptor and splice donor sites, polyadenylation signals and polyadenylation sites, and tripartite leader sequences.

Bovine adenovirus-3 as a vaccine delivery vehicle

“…BAdV-3 is 75 nm in diameter, non enveloped icosahedral particle containing a double stranded DNA genome. The genome of BAdV-3 is 34, 446 base pairs [12] flanked on either end by 195 bp inverted terminal repeats (ITRs) [30], which play a key role in DNA replication. Unlike other adenoviruses, the ITRs of BAdV-3 are longer and contain a high GC content [12].…”

“…The genome of BAdV-3 is 34, 446 base pairs [12] flanked on either end by 195 bp inverted terminal repeats (ITRs) [30], which play a key role in DNA replication. Unlike other adenoviruses, the ITRs of BAdV-3 are longer and contain a high GC content [12]. Like other adenoviruses, the packaging domain is located in the left end of the viral genome overlapping the transcriptional control region of E1A, but E1A region expression distinctively appears to be essential for packaging in BAdV-3 [31,32].…”

“…Based on the transcriptional analysis [12,[34][35][36][37], BAdV-3 genome appears to be organized ( Fig. 1) into early, intermediate and late regions [12].…”

“…AdVs have been proposed to be clustered in five phylogenitically distinct groups namely; Mastadenovirus, Aviadenovirus, Atadenovirus, Siadenovirus and Ichtadenovirus, with each virus group having a distinct and characteristic genome structure [7,8]. The overall genetic organization of members of the Mastadenovirus including human adenovirus (HAdV)-5 [9], canine adenovirus (CAdV)-2 [10], Simian adenovirus (SAdV) [11], bovine adenovirus (BAdV)-3 [12], porcine adenovirus (PAdV)-5 [13] and PAdV-3 [14] appears to be conserved.…”

“…Despite this genetic conservation, some regions are highly divergent (based on structure of transcripts and proteins) among different members of Mastadenoviruses. In particular, the deduced amino acid sequence of ORFs in the E1, E3 and E4 regions of BAdV-3 show little or no homology to the corresponding proteins encoded by genomes of other members of Mastadenoviruses [12]. Since these proteins are involved in virus cell interaction and viral gene expression, variations in these proteins may reflect the diverse host range and pathogenic potential of different members of Mastadenoviruses.…”