Biomedical subjects

R W Moyer

Publications and source records attributed to R W Moyer.

At least 55 records · Page 3Linked to original sources

PubMed1995

Mapping and investigation of the role in pathogenesis of the major unique secreted 35-kDa protein of rabbitpox virus.

Following infection, many secreted poxvirus proteins are able to modulate the host immune response through interactions with cytokines or components of the complement pathway. A comparison of the secreted protein profiles from cells infected with vaccinia Western Reserve (VV-WR), cowpox virus Brighton strain, or rabbitpox virus (RPV) showed an abundant 35-kDa protein present only in the supernatants from RPV-infected cells. The gene encoding this protein was identified and mapped by N-terminal sequencing of the protein. Examination of the predicted amino acid sequence showed it to be identical to the 35-kDa secreted protein of the Lister strain of vaccinia virus described by Patel et al. (1990, J. Gen. Virol. 71, 2013-2021). The counterpart of this gene in the commonly studied VV-WR strain is truncated and encodes a 7.5-kDa protein under control of the well-characterized p7.5 promoter. While nonessential for replication in cell culture, conservation of this gene in at least two orthopoxvirus strains suggested that this protein might play an important role in vivo. Following intranasal inoculation of Balb/c mice at several doses (10(3), 10(4), or 10(5) PFU), a mutant of RPV lacking a functional 35-kDa gene (RPV delta 35) appeared to induce an earlier onset and more severe illness at low, sublethal doses (10(3) PFU) than was observed with wild-type (wt) RPV. At higher doses (10(4) or 10(5) PFU), the behavior of wt RPV and RPV delta 35 became indistinguishable and the overall LD50 values were similar. Intradermal infection of rabbits simultaneously, at separate sites, with RPV and RPV delta 35 showed no gross or microscopic differences between either primary skin lesions or viremic extension of each virus into the lungs. Therefore, this abundant secreted protein does not appear to play a major role in the virulence of the virus.

Amino Acid Sequence↗

PubMed1995

Orthopoxvirus fusion inhibitor glycoprotein SPI-3 (open reading frame K2L) contains motifs characteristic of serine proteinase inhibitors that are not required for control of cell fusion.

The cowpox virus (CPV) SPI-3 gene (open reading frame K2L in vaccinia virus) is one of three orthopoxvirus genes whose products are members of the serpin (serine proteinase inhibitor) superfamily. The CPV SPI-3 gene, when overexpressed by using the vaccinia virus/T7 expression system, synthesized two proteins of 50 and 48 kDa. Treatment with the N glycosylation inhibitor tunicamycin converted the two SPI-3 proteins to a single 40-kDa protein, close to the size of 42 kDa predicted from the DNA sequence, suggesting that the SPI-3 protein, unlike the other two orthopoxvirus serpins, is a glycoprotein. Immunoblotting with an anti-SPI-3 antibody showed that the SPI-3 protein is synthesized early in infection prior to DNA replication. SPI-3 inhibits cell-cell fusion during infections with both CPV and vaccinia virus. A transfection assay was devised to test engineered mutants of SPI-3 for the ability to inhibit fusion. Two mutants with C-terminal deletions of 156 and 70 amino acids were completely inactive in fusion inhibition. Site-directed mutations were constructed near the C terminus of SPI-3, in or near the predicted reactive-site loop which is conserved in inhibitory serpins. Substitutions within the loop at the P1 to P1' positions and P5 to P5' positions, inclusive, did not result in any loss of activity, nor did changes at the P17 to P10 residues in the stalk of the reactive loop. Therefore, SPI-3 does not appear to control cell fusion by acting as a serine proteinase inhibitor.

Amino Acid Sequence↗

PubMed1995

A rabbitpox virus serpin gene controls host range by inhibiting apoptosis in restrictive cells.

Poxviruses are unique among viruses in encoding members of the serine proteinase inhibitor (serpin) superfamily. Orthopoxviruses contain three serpins, designated SPI-1, SPI-2, and SPI-3. SPI-1 encodes a 40-kDa protein that is required for the replication of rabbitpox virus (RPV) in PK-15 or A549 cells in culture (A. N. Ali, P. C. Turner, M. A. Brooks, and R. W. Moyer, Virology 202:305-314, 1994). Examination of nonpermissive human A549 cells infected with an RPV mutant disrupted in the SPI-1 gene (RPV delta SPI-1) suggests there are no gross defects in protein or DNA synthesis. The proteolytic processing of late viral structural proteins, a feature of orthopoxvirus infections associated with the maturation of virus particles, also appears relatively normal. However, very few mature virus particles of any kind are produced compared with the level found in infections with wild-type RPV. Morphological examination of RPV delta SPI-1-infected A549 cells, together with an observed fragmentation of cellular DNA, suggests that the host range defect is associated with the onset of apoptosis. Apoptosis is seen only in RPV delta SPI-1 infection of nonpermissive (A549 or PK-15) cells and is absent in all wild-type RPV infections and RPV delta SPI-2 mutant infections examined to date. Although the SPI-1 gene is expressed early, before DNA replication, the triggering apoptotic event occurs late in the infection, as RPV delta SPI-1-infected A549 cells do not undergo apoptosis when infections are carried out in the presence of cytosine arabinoside. While the SPI-2 (crmA) gene, when transfected into cells, has been shown to inhibit apoptosis, our experiments provide the first indication that a poxvirus serpin protein can inhibit apoptosis during a poxvirus infection.

Animals↗

PubMed1994

Evaluation of swinepox virus as a vaccine vector in pigs using an Aujeszky's disease (pseudorabies) virus gene insert coding for glycoproteins gp50 and gp63.

Pigs were vaccinated by scarification or intramuscular injection with a swinepox virus-Aujeszky's disease (pseudorabies) recombinant (rSPV-AD) constructed by inserting the linked Aujeszky's disease virus genes coding for glycoproteins gp50 and gp63, attached to a vaccinia virus p7.5 promoter, into the thymidine kinase gene of swinepox virus. By 21 days after vaccination, 90 and 100 per cent of the animals vaccinated by scarification or intramuscular injection, respectively, had developed serum neutralising antibodies to Aujeszky's disease virus. Upon challenge with virulent virus, significantly fewer vaccinated pigs developed clinical Aujeszky's disease, nasal shedding of challenge virus was markedly reduced, and the vaccinated groups of pigs maintained or gained weight during the week after challenge whereas the unvaccinated control group lost weight. No transmission of rSPV-AD to in-contact controls was detected during the three weeks before challenge. In a second experiment, serum neutralising antibodies to Aujeszky's disease virus persisted for 150 days after the pigs were vaccinated with rSPV-AD by scarification or intramuscular injection and all the pigs showed an anamnestic response when they were revaccinated.

Animals↗

PubMed1994

The SPI-1 gene of rabbitpox virus determines host range and is required for hemorrhagic pock formation.

Wild-type rabbitpox virus (RPV) and cowpox virus (CPV) produce red hemorrhagic lesions or pocks upon infection of the chicken chorioallantoic membrane (CAM) of 11-day-old embryonated chicken eggs. However, white, nonhemorrhagic pock variants arise spontaneously within wild-type (wt) populations of either virus at a frequency of about 1%, reflective of complex deletions/rearrangements in the termini of the viral DNA. A subpopulation of the RPV white-pock mutants fail to plaque on pig kidney (PK-15) cells and are referred to as host-range (hr) mutants. In the case of CPV, white-pock formation has been linked to mutations in the SPI-2 (crmA) gene. We show that five spontaneous RPV white-pock host-range mutants (RPV mu hr8sm, RPV mu hr23, RPV mu hr28, RPV mu hr30, and RPV mu hr31) each contain a SPI-2 (crmA) gene and express the crmA protein but lack instead a functional SPI-1 gene. Two other spontaneous RPV white-pock mutants, RPV mu 9 and RPV mu 12, which plaque on PK-15 cells (nonhost-range mutants) contain and express a SPI-1 gene but lack instead a functional SPI-2 gene. Targeted disruption of either the SPI-1 or SPI-2 genes of wtRPV, but only the SPI-2 gene of wtCPV, generates mutants which produce white pocks. The RPV delta SPI-1 mutant fails to plaque on PK-15 or human A549 cells, whereas the RPV delta SPI-2 mutant has a normal host range. No changes in host range compared to wtCPV for either the CPV delta SPI-1 or CPV delta SPI-2 mutants were noted. These differences in phenotypes observed between the two viruses may be reflective of either small sequence variations between the highly conserved SPI-1 or SPI-2 genes or the aggregate phenotypes provided by the other remaining genes.

Amino Acid Sequence↗

PubMed1993

Identification of an Amsacta spheroidin-like protein within the occlusion bodies of Choristoneura entomopoxviruses.

Like baculoviruses, a characteristic feature of entomopoxviruses is the amalgamation of virions within environmentally stable occlusion bodies. It is this occluded form of the virus that is primarily responsible for dissemination to other insects. While the major protein (polyhedrin) of baculovirus occlusions is quite similar between viruses, it has been reported that the major occlusion body protein (spheroidin) of two group B entomopoxviruses, Amsacta moorei (AmEPV) and Choristoneura biennis (CbEPV) is quite different both in terms of amino acid sequence and coding capacity of the corresponding spheroidin genes (115 and 47 kDa for AmEPV and CbEPV, respectively). We report the discovery of a AmEPV spheroidin gene homolog in both CbEPV and a second Choristoneura virus, Choristoneura fumiferana (CfEPV). Antibodies directed against the AmEPV 115-kDa spheroidin reacted with the major protein of approximately 115 kDa found within the occlusion body preparation from both Choristoneura viruses. Direct protein microsequencing of small portions of the 115-kDa protein from CbEPV has resulted in peptide sequences identical to those of corresponding regions of the AmEPV spheroidin gene. We suggest that it is this Choristoneura gene which encodes spheroidin. All attempts, however, to find a homolog of the previously reported CbEPV spheroidin gene within AmEPV have been unsuccessful. We also show this newly identified Choristoneura homolog of the AmEPV spheroidin gene as well as the AmEPV spheroidin gene itself are both located at the 3' end of an NPH I gene and are highly homologous in all three viruses, indicating that this region of the genome in the three viruses is co-linear. These results and others suggest that while the insect viruses lack the traditional central core of conserved genes observed for the vertebrate poxviruses, the insect poxviruses may have also evolved an alternative central core of conserved genes, unique to the invertebrate poxviruses.

Amino Acid Sequence↗

PubMed1993

The effects of serpin gene mutations on the distinctive pathobiology of cowpox and rabbitpox virus following intranasal inoculation of Balb/c mice.

Intranasal infection of Balb/c mice with 106 plaque forming units (PFU) of wild-type cowpox virus (CPV) and rabbitpox virus (RPV) induced strikingly different pulmonary pathology despite nearly identical clinical signs of illness and LD50. Intranasal infection with CPV induced severe peribronchial, peribronchiolar, and perivascular hemorrhage with a mixed inflammatory cell infiltrate, bronchial and bronchiolar epithelial cell hyperplasia with intracytoplasmic acidophilic inclusion bodies, and alveolar hemorrhage and edema. In contrast, infection with RPV induced a mixed peribronchial and peribronchiolar inflammatory cell infiltrate, multifocal areas of bronchiolar epithelial cell coagulation necrosis, alveolar edema, and a conspicuous absence of pulmonary hemorrhage. Viremia was not detected following CPV infection and only 1 of 11 mice had brain-associated virus at death. Mice infected with RPV exhibited a viremia 2-3 days after infection and all mice had virus associated with the brain at death. Mice infected with viruses containing certain serine protease inhibitor (SPI) gene mutations (CPV delta SPI-1, CPV delta SPI-3, and RPV SPI-1-) exhibited no difference in clinical disease manifestation when compared with those infected with wild-type viruses. However, inactivation of the SPI-2 genes in either CPV or RPV resulted in disease attenuation and alteration of pulmonary pathology. Mice infected with the CPV delta SPI-2 mutant showed decreased pulmonary hemorrhage, reduced inflammation, and an absence of alveolar edema, while mice infected with the RPV delta SPI-2 mutant had a marked increase in intrapulmonary inflammatory cells and only a transient viremia.

Animals↗

PubMed1993

DNA sequence analysis of conserved and unique regions of swinepox virus: identification of genetic elements supporting phenotypic observations including a novel G protein-coupled receptor homologue.

Swinepox virus (SPV) contains a double-stranded cross-linked linear DNA genome of approximately 175 kilobase pairs with terminal inverted repetitions (TIRs) of 4.3 kb. The nucleotide sequence was determined for fragments from several regions of the genome including a 2.85-kb fragment from the central potentially conserved portion and two fragments within the presumed variable near-terminal regions which tend to be unique to a given poxvirus. The core sequence contains one partial and two complete open reading frames that are highly conserved and colinear with three contiguous ORFs within the HindIII D fragment of vaccinia virus (VV). The two near-terminal fragments, encompassing 14.2 and 3.6 kb, are respectively located 2.1 kb internal to the left and right cross-linked termini of the DNA and span the TIR junctions. The sequences encode 25 open reading frames including numerous proteins predicted to be membrane-bound or secreted in infected cells. Several ORFs unique to SPV were identified that may be involved in cell attachment, immune modulation, and pathogenesis including a novel poxvirus G protein-coupled receptor. In addition, several polypeptides encoded within the near-terminal regions of vaccinia virus DNA that function as host range or virulence factors are lacking within this region of swinepox virus including the VV growth factor, complement-binding protein, and ORFs C7L and K1L, associated with host range. The lack of these functional homologues could explain the characteristic attenuated phenotype and limited host range of SPV.

Amino Acid Sequence↗

PubMed1993

A revised HindIII map and sequence analysis of a large 'left-hand' non-essential region of the rabbit poxvirus genome.

Sequence analysis of a 21.5 kb region of the left-hand non-essential region of rabbit poxvirus (RPV) was performed to analyze the structure and gene organization of this region. Initial mapping and cloning studies revealed that the early published HindIII maps are incorrect in that the location of the terminal HindIII B and C fragments, as previously published, are reversed. The sequence of this region was compared to similar regions of several strains of vaccinia virus. The results indicate that this region of RPV has a high degree of homology with a similar region of vaccinia. Analysis of the translated open reading frames (ORFs) has facilitated the detection of several previously unreported ORFs related to human complement proteins. In addition, two defective copies of a homologue of the 77 kDa cowpox virus (CPV) host range gene which allows CPV to grow on Chinese hamster ovary cells have been detected, suggesting a gene duplication has occurred. However, one copy of this gene is segmented into three separate ORFs. Analysis has also identified a large number of indirect repeat elements. A possible role of these repeats in the generation of deletions and gene duplications is suggested.

Amino Acid Sequence↗

PubMed1993

The ps/hr gene (B5R open reading frame homolog) of rabbitpox virus controls pock color, is a component of extracellular enveloped virus, and is secreted into the medium.

Wild-type rabbitpox virus (RPV) produces red hemorrhagic pocks on the chorioallantoic membranes (CAMs) of embryonated chicken eggs. Like the crmA (SPI-2) gene of cowpox virus, disruption of the RPV ps/hr gene results in a mutant which produces white pocks on the CAMs. An examination of the properties of the RPV(ps/hr) mutant in cell culture also reveals a significantly reduced host range, defined as the inability to form plaques, compared with wild-type virus. One of several cell types on which RPV(ps/hr) mutants fail to produce plaques is chicken embryo fibroblasts, cells which have been traditionally used to propagate spontaneously arising white pock mutants isolated from CAMs. The inability of the RPV(ps/hr) mutant to form plaques in chicken embryo fibroblasts correlates with a failure of a low multiplicity of infection to spread to neighboring cells and to form extracellular enveloped virus (EEV), although the formation and yields of infectious intracellular naked virus appear relatively normal. The gene product of the ps/hr gene, initially synthesized as a 45-kDa glycoprotein, is found as a component of EEV, but not intracellular naked virus, and as a smaller, secreted soluble protein of 35 kDa. Production of the secreted 35-kDa protein was found to be independent of any viral morphogenesis, suggesting two distinct pathways for release of the ps/hr gene product from the cell, i.e., as a component of the EEV particle and as a separately secreted glycoprotein.

Allantois↗

PubMed1992

Mapping and molecular characterization of a functional thymidine kinase from Amsacta moorei entomopoxvirus.

A thymidine kinase (TK) gene from the entomopoxvirus of Amsacta moorei (AmEPV) has been identified, mapped, cloned, and sequenced. The AmEPV TK was shown to be biologically functional as cloning of the gene into a TK-derivative of the orthopoxvirus vaccinia creates a TK+ virus. The gene has been localized to a 1.5-kb EcoRI-Q DNA fragment which maps to the far left end of the viral genome. Sequence analysis reveals an open reading frame (ORF) of 182 amino acids potentially encoding a polypeptide of 21.2 kDa. Amino acid homology comparisons indicate that the gene is most closely related to the TKs of a variety of poxviruses (approximately 45%) and less so to the TKs of vertebrates (approximately 40%). The TK from African swine fever virus (ASF) showed the least homology (31.4%) to the AmEPV TK gene, suggesting that these two viruses are not closely related although ASF shares some biological features of poxviruses, and both ASF and AmEPV can replicate within arthropod hosts.

Amino Acid Sequence↗

PubMed1992

Nucleotide sequence analysis of a unique near-terminal region of the tumorigenic poxvirus, Shope fibroma virus.

Shope fibroma virus (SFV), a tumorigenic poxvirus, has a DNA genome of approximately 160 kb. Previous DNA sequence analysis of SFV has been mainly limited to the terminal inverted repetitions (about 12 kb at each end of the genome) and immediately adjacent regions. We have sequenced a 4 kb fragment located approximately 20 kb from the right-terminal hairpin. Within this region three complete and two partial open reading frames (ORFs) have been identified. Each of the putative polypeptides has sequence similarity to one or more previously identified poxvirus or cellular proteins, with homology to protein kinases, erythrocyte ankyrin and a vaccinia virus virulence-related protein (ORF N1L). The potential significance of these gene products with regard to the phenotype of SFV is discussed.

Amino Acid Sequence↗

PubMed1992

An orthopoxvirus serpinlike gene controls the ability of infected cells to fuse.

Most orthopoxviruses encode a functional hemagglutinin (HA), which is nonessential for virus growth in cell culture. However, inactivation of the HA gene leads to the formation of polykaryocytes (syncytia) by fusion of infected cells at neutral pH. Fusion is not observed when a functional HA gene is present. Deletion of open reading frames (ORFs) K2, K3, and K4 within the HindIII K fragment of the HA-positive (HA+) vaccinia virus strain WR also led to fusion of cells upon infection at neutral pH. A novel ORF inactivation procedure utilizing the polymerase chain reaction was used to specifically implicate the K2 ORF in this phenomenon. The K2 ORF (the viral SPI-3 gene) encodes a protein resembling serine protease inhibitors (serpins). Inactivation of the SPI-3 gene in any of the HA+ orthopoxviruses tested caused infected cells to fuse in a manner which appeared identical to that seen for HA- mutants, although fusion was most pronounced with cowpox virus. SPI-3-negative strains fused despite the fact that the HA was expressed and processed normally, i.e., cells infected with SPI-3 mutants remained functionally hemadsorption positive, and analysis of the HA protein by Western immunoblot suggested that posttranslational modifications of the HA protein appeared normal. Fusion triggered by SPI-3 mutants, like that for HA- mutants, was inhibited by the monoclonal antibody C3 directed against the vaccinia virus 14-kDa envelope protein. Therefore SPI-3- and HA-mediated fusion share a requirement for the 14-kDa protein, suggesting linkage of the seemingly disparate SPI-3 and HA genes through a common pathway which normally acts to prevent fusion of cells infected with wild-type virus.

Antibodies, Monoclonal↗

PubMed1992

A PCR-based method for manipulation of the vaccinia virus genome that eliminates the need for cloning.

A general method is described for altering specific genes of vaccinia virus (VV). We demonstrate and evaluate the procedure by gene inactivation, using a dominant selectable marker in conjunction with recombinant polymerase chain reaction (PCR). Primers based on the sequence of the target gene enable amplification of flanking arms and their subsequent attachment to the gpt cassette that confers resistance to mycophenolic acid. Linear PCR constructs are transfected into cells infected with wild-type vaccinia virus. Mutant viruses with gpt inserted into the target gene by homologous recombination are then selected by growth in the presence of MPA. This technique was applied to the vaccinia virus thymidine kinase gene and compared to the traditional method of constructing gpt-containing plasmids by cloning. The PCR scheme was found to be highly efficient and could theoretically be used to insert any foreign DNA element into any nonessential target gene for which partial or complete sequence information is available. The procedure can potentially be used for a wide variety of genetic modifications, including the insertion of foreign genes, with poxviruses and other DNA viruses. Genomes of microorganisms, such as bacteria and yeast that can be transformed with linear DNA, are also candidates for manipulation by this methodology.

Base Sequence↗

PubMed1991

The nature of naturally occurring mutations in the hemagglutinin gene of vaccinia virus and the sequence of immediately adjacent genes.

The expression of the vaccinia IHD-J hemagglutinin (HA) gene is regulated by two promoters, an early/late and a second distinct late promoter. The first promoter results in transcripts that begin early and are synthesized throughout the infection. All transcripts from this promoter initiate at the same 5' site. A second promoter is only active late in infection and initiates transcription some distance upstream of the first promoter. We have previously shown that the transcriptional start site controlled by this second, "late only" promoter lies within the coding sequence of an upstream reading frame (p16-ORF), whereas the termination of early transcription of the HA gene utilizes a transcription termination signal (TTTTTNT) located just beyond the coding region of an immediately downstream reading frame (p17-ORF). In order to assist our understanding of HA gene expression, we report here the sequence of these two ORFs adjacent to the HA gene. The HA-ORF itself consists of 945 bp, whereas the upstream p16-ORF consists of 429 bp and the downstream p17-ORF of 453 bp, sufficient to encode polypeptides of 16 and 17 kD, respectively. While many strains of vaccinia are HA+, rabbitpox virus and the variant of vaccinia IHD-J, designated IHD-W, are HA-. We report and compare here the HA gene sequences of wild-type rabbit poxvirus, two spontaneous HA+ revertants of rabbit poxvirus, and the HA- vaccinia strain IHD-W to that of the previously sequenced (1) prototype HA+ IHD-J strain of vaccinia. All differences were found to occur within the HA open reading frame.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗

PubMed1991

The molecular biology of swinepox virus. I. A characterization of the viral DNA.

Swinepox virus (SPV), the prototype member of the Suipoxvirus genus, is uncharacterized at the molecular level. We have analyzed the DNA of SPV and demonstrate that the genome is 175 kb in size and like the more commonly studied Orthopoxvirus, Avipoxvirus, and Leporipoxvirus genera, is terminally cross-linked and contains inverted terminal repetitions (ITRs). In addition, the ITRs are unstable, probably due to the presence of a variable number of direct repeats of approximately 70 bp in length. Restriction enzyme cleavage maps for the enzymes HindIII, AvaI, HaeII, KpnI, BglI, SalI, and XhoI are also presented.

Animals↗

PubMed1991

The molecular biology of swinepox virus. II. The infectious cycle.

Studies based on low-stringency hybridizations of radiolabeled swinepox virus (SPV) DNA to Southern blots containing DNA of representative members of the Orthopoxvirus, Leporipoxvirus, and Avipoxvirus genera and the Entomopoxvirus subfamily have revealed no DNA homology at this level of resolution. Antigenic relatedness between SPV and vaccinia was also analyzed using immunoprecipitations and revealed little if any cross-reactivity. The growth characteristics of SPV in tissue culture were examined by light microscopy and revealed both a delayed and a different cytopathology than that of vaccinia virus. SPV causes foci in pig kidney cells that are not evident until at least 4 days postinfection, whereas vaccinia rapidly generates plaques on these cells. The kinetics of DNA accumulation, protein expression, and RNA transcription of SPV have been examined and indicate that each of these facets of the SPV growth cycle is also considerably delayed when compared to vaccinia virus. Our data indicate that swinepox virus is unique from other poxviruses characterized to date and supports the classification of swinepox virus into a separate genus, Suipoxvirus, within the poxvirus family.

Animals↗

PubMed1991

Isolation and molecular characterization of the swinepox virus thymidine kinase gene.

Swinepox virus (SPV), the only member of the Suipoxvirus genus, shows little antigenic relatedness or DNA homology to members of the other poxvirus genera. A SPV thymidine kinase (TK) gene was detected and mapped to the left end of the HindIII G fragment using degenerate oligonucleotide probes. Cloning and sequencing of a 1.8-kb HindIII-BamHI fragment containing the SPV TK gene revealed an open reading frame (ORF) of 181 amino acids yielding a predicted polypeptide of Mr 20.6 kDa with significant homology to both poxvirus and vertebrate thymidine kinases. Comparison with other TK protein sequences showed that the SPV thymidine kinase was closely related to the TK genes of avipoxviruses (52.0%) and vertebrates (57.1-59.7%). The TK gene from African swine fever virus (ASF) showed little homology (30.5%) to the SPV TK gene suggesting that these two viruses are not closely related though they share many biochemical features and infect a single, common mammalian host (swine). The SPV TK gene, like that of other poxviruses, is transcribed early, and when cloned into a TK- strain of vaccinia converted the virus to a TK+ phenotype. BUdRR mutants of SPV contained frameshift, deletion, and missense mutations in the TK ORF.

Amino Acid Sequence↗