Gene homology between orf virus and smallpox variola virus

Abstract

About 47% identity was observed between the deduced amino acid sequences of a protein encoded by a gene of the parapoxvirus orf virus (OV) strain NZ2 and a 6 kDa protein of unknown function reported to be produced by an open reading frame expressed early after infection by the orthopoxvirus Western Reserve vaccinia virus (VAC); the open reading frame is absent from VAC strain Copenhagen. Examination of sequences reported for variola virus (VAR) strains Bangladesh, India, Congo- 1970, Somalia- 1977 and Garcia- 1966 revealed each encoded a correlate 58 amino acid protein. The open reading frame was not reported in the original analyses of these sequences because a lower limit of 60 amino acids was used to identify potential encoded proteins. Inspection of partial reading frames reported for cowpox virus (CWV) and ectromelia virus (EMV) suggested that these viruses might also code for a correlate of the VAC WR protein. DNA sequencing of cloned fragments of CWV and EMV confirmed that both these orthopoxviruses encode closely related, full length variants of the VAC and VAR open reading frames. The OV homologue is coded in the OV strain NZ2 BamHI-E fragment E2L open reading frame, which we reported is transcribed early postinfection; moreover, analysis of an NZ2 variant showed E2L was absent, indicating that E2L, like the VAC cognate, is nonessential for virus replication in cell culture. The parapoxvirus and orthopoxvirus correlates have about 20% amino acid sequence resemblance to African swine fever virus DNA binding protein p10, suggesting an ancestral relation of genes.

African swine fever virus-cell interactions: From virus entry to cell survival

“…Moreover, this desencapsidation is a key step to ensure that the virion progresses through uncoating and egress in order to start replication. These data imply that ASFV belongs to the category of late-penetrating viruses (Brabec et al, 2006;Lozach et al, 2010;Mercer et al, 1996;Sieczkarski and Whittaker, 2003).…”

Genomes of the Parapoxviruses Orf Virus and Bovine Papular Stomatitis Virus

“…Hybridization analysis of viral DNA indicates that internal but not terminal genomic regions are conserved between PPVs (26). Data concerning PPV genomics, largely obtained by using ORFV strain NZ2, has revealed (i) colinearity between the ORFV and other poxvirus genera genomes (21,49,50), (ii) the presence of a set of genes mostly located at the termini of the viral genome with putative or known roles in virulence or immunomodulation (15,23,38,42,76), and (iii) the occurrence of genomic rearrangements of the termini upon serial virus passage in vitro (12,22). Less is known about the gene complement and genomic organization of other PPV.…”

Relatedness and heterogeneity at the near-terminal end of the genome of a parapoxvirus bovis 1 strain (B177) compared with parapoxvirus ovis (Orf virus)

“…Due to genetic heterogeneity, molecular classification of PPV remains problematic and still relies on the source of the virus isolate (Büttner & Rziha, 2002;Gilray et al, 1998;Rafii & Burger, 1985;Robinson et al, 1982Robinson et al, , 1987. So far, most information on the molecular biology and sequence data has been obtained from the New Zealand ORFV strain NZ2 (Fleming et al, 1993;Haig & Mercer, 1998;Mercer et al, 1996Mercer et al, , 1997Robinson & Lyttle, 1992;Sullivan et al, 1995a, b). Sequence data from PPV other than ORFV are very sparse.…”

“…A partial sequence of the major envelope gene has been suggested for discrimination between BPSV and ORFV (Inoshima et al, 2001). As in all poxviruses, the ORFV genome is composed of a conserved central region and variable genomic termini containing genes not required for in vitro growth (Fleming et al, 1993;Mercer et al, 1995Mercer et al, , 1996Rziha et al, 2000;Sullivan et al, 1995a). Factors determining species-and strain-specific properties and influencing virulence, pathogenesis and host range of poxviruses are encoded in the terminal parts of the viral genome (Alcamí & Koszinowski, 2000;Alcamí & Smith, 1995;Smith et al, 1997).…”