Nucleotide and amino acid sequence analysis of the porcine adenovirus 23K protein

Nucleotide sequence and transcription map of porcine adenovirus type 3

The complete nucleotide sequence of porcine adenovirus type 3 was determined and a transcriptional map for the genome was constructed. The size of the genome is 34094 bp in length with an unusually high G + C content (63.7%), the highest thus far reported for any adenovirus. Overall organization of the genome is similar to that for previously sequenced adenoviral DNAs, but there also were distinct differences. The late regions genes are organized into six families, instead of five as they are in human adenovirus type 2. In contrast to bovine adenovirus type 3 and ovine adenovirus, which lack virion-associated RNA genes, the nucleotide sequence analysis of the viral genome indicates that it encodes one short VA RNA species. With the exception of the fiber and a 33-kDa nonstructural protein, the predicted amino acid sequences of the open reading frames in the late regions and the E2 region and IVa2 exhibited a high level of homology, whereas the deduced amino acid sequences of ORFs in E1, E3, and E4 regions, and the pIX showed a lesser homology with the corresponding proteins of other adenoviruses. The proteins V, VII, and IX are unusually long, and the protein VII lacks the consensus protease cleavage site. Genomic and cDNA sequence analysis has identified promoters, cap sites, intron-exon boundaries, polyadenylation signals, and polyadenylation sites in the viral genome.

Sequence and transcription map analysis of early region-1 of porcine adenovirus type-3

The nucleotide sequence of a region of the genome of porcine adenovirus-3 (PAV-3) between map units 1 and 12.2 was determined. The sequenced region included four major open reading frames, and several transcription control elements. Homology studies, using the deduced amino acid sequences of the open reading frames, revealed genes coding for the E1A, E1B 202R, E1B 474R and pIX proteins. The region was characterized by Northern blot analysis and sequencing of cDNA clones. In PAV-3, the E1A region is located between 1.5 and 3.8 map units. Alternate splice donor sites are used to produce four different types of transcripts from the primary transcript of the E1A region. The E1A proteins of PAV-3 contain a consensus zinc finger motif, which was shown to be the principal transactivation region of human adenovirus-5 (HAV-5) E1A proteins. The PAV-3 E1A proteins also contain a retinoblastoma susceptibility protein (pRb) binding motif, which in HAVs interacts with cellular Rb protein to overcome the pRb mediated transcription repression. The E1B region in PAV-3 maps between 4.0 and 12.2 map units, and shares a polyadenylation signal and polyadenylation sites with the gene coding for pIX. A single major and a number of minor mRNA species are produced from the E1B region. The open reading frame (ORF) analysis of cDNA representing major mRNA produced from the E1B region showed two overlapping ORFs corresponding to 19K and 55K ORFs of HAV-2. In PAV-3, the gene coding for pIX is located between 9.9 and 12.2 map units and codes for a protein of 199 amino acids.

Nucleotide and amino acid sequence analysis of the 100K protein of a serotype 3 porcine adenovirus

The genomic region between map units 69 and 78 of a type 3 porcine adenovirus (PAV3) was sequenced and analysed. An open reading frame (ORF) of 2514 nucleotides encoding a polypeptide of 838 amino acids and approximately 94.1 kDa was found. The size and location of the ORF suggested it was the PAV3 homologue of the 100K gene and this was confirmed by nucleotide sequence comparison with the 100K of human adenovirus type 2. Amino acid sequence alignment of the predicted polypeptide with the sequences of the 100K proteins of four human adenoviruses and type 10 fowl adenovirus revealed sequence identities of between 31% and 52%. Although amino acid conservation was present throughout the entire sequences compared, lower identity was noted in both the amino- and carboxy-termini.

Gene expression by atypical recombinant ovine adenovirus vectors during abortive infection of human and animal cells in vitro

An bovine adenovirus, which is phylogenetically distinct from the Mastadeno- and Aviadenoviruses, was used to construct recombinants in which reporter genes were expressed from the OAV major late, or human cytomegalovirus promoters. It was demonstrated by transgene expression that OAV could infect bovine nasal turbinate and rabbit kidney cells as well as a range of human cell types, including lung and foreskin fibroblasts as well as liver, prostate, breast, colon, and retinal lines. Some human lines, e.g., 293 and LNCaP were not detectably infected. Infection occurred even though OAV has a fiber protein with a unique cell binding domain and a penton protein that lacks the integrin-binding Arg-Gly-Asp motif which facilitates entry by human adenoviruses. Most cell lines showed little or no ill effect for several days after infection but a prominent cytopathic effect appeared in fibroblasts after 3-4 days. However, no viral DNA synthesis was detected and replication was abortive. Viral promoter activity during infection of nonpermissive cell types was assayed by RT-PCR. Early promoter activity was detectable in some, but not all cell types. In a liver and a colon carcinoma cell line, none of the promoters examined was significantly active, even when a higher multiplicity of infection was used. Major late promoter activity was not detectable in any cell type. The lack of DNA replication and MLP function suggests that a critical transition from early to late gene expression does not occur during abortive infection by OAV.