Both Carboxy- and Amino-Terminal Domains of the Vaccinia Virus Interferon Resistance Gene, E3L, Are Required for Pathogenesis in a Mouse Model

Brandt, Teresa; Jacobs, Bertram L.

doi:10.1128/jvi.75.2.850-856.2001

Cited by 197 publications

(210 citation statements)

References 48 publications

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“…Our findings suggest that these HCMV genes sequester PKR away from its activator, cytoplasmic dsRNA generated during the course of viral infection, and also from its target substrate, cytoplasmic ribosome-associated eIF2␣ that is participating in translation initiation. Since PKR plays a significant role in the life cycle of numerous viruses (9,12,20,29,48), further studies of how these HCMV genes modulate PKR activity are likely to contribute to our understanding of HCMV disease pathogenesis.…”

Section: Discussionmentioning

confidence: 99%

Binding and Nuclear Relocalization of Protein Kinase R by Human Cytomegalovirus TRS1

Hakki

Marshall²,

Niro³

et al. 2006

J Virol

104

100

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The human cytomegalovirus (HCMV) TRS1 and IRS1 genes block the phosphorylation of the alpha subunit of eukaryotic initiation factor 2 (eIF2␣) and the consequent shutoff of cellular protein synthesis that occur during infection with vaccinia virus (VV) deleted of the double-stranded RNA binding protein gene E3L (VV⌬E3L). To further define the underlying mechanism, we first evaluated the effect of pTRS1 on protein kinase R (PKR), the double-stranded RNA (dsRNA)-dependent eIF2␣ kinase. Immunoblot analyses revealed that pTRS1 expression in the context of a VV⌬E3L recombinant decreased levels of PKR in the cytoplasm and increased its levels in the nucleus of infected cells, an effect not seen with wild-type VV or a VV⌬E3L recombinant virus expressing E3L. This effect of pTRS1 was confirmed by visualizing the nuclear relocalization of PKR-EGFP expressed by transient transfection. PKR present in both the nuclear and cytoplasmic fractions was nonphosphorylated, indicating that it was unactivated when TRS1 was present. PKR also accumulated in the nucleus during HCMV infection as determined by indirect immunofluorescence and immunoblot analysis. Binding assays revealed that pTRS1 interacted with PKR in mammalian cells and in vitro. This interaction required the same carboxy-terminal region of pTRS1 that is necessary to rescue VV⌬E3L replication in HeLa cells. The carboxy terminus of pIRS1 was also required for rescue of VV⌬E3L and for mediating an interaction of pIRS1 with PKR. These results suggest that these HCMV genes directly interact with PKR and inhibit its activation by sequestering it in the nucleus, away from both its activator, cytoplasmic dsRNA, and its substrate, eIF2␣.Double-stranded RNA (dsRNA) activates the host cell response to viral infection in numerous ways, one of which involves the interferon-induced, dsRNA-dependent protein kinase R (PKR) (reviewed in reference 43). After binding to dsRNA, PKR dimerizes, autophosphorylates, and then phosphorylates the eukaryotic initiation factor 2 (eIF2) on its ␣ subunit. Phosphorylated eIF2␣ sequesters the guanine nucleotide exchange factor eIF2B, resulting in the inhibition of protein synthesis at the level of translation initiation. Since viruses depend on the cellular translational machinery, the shutoff of host cell protein synthesis inhibits viral replication and spread.Many viruses have mechanisms for inhibiting the PKR-mediated phosphorylation of eIF2␣ (56). The vaccinia virus (VV) E3L protein prevents the activation of PKR by binding to and sequestering dsRNA via a carboxy-terminal double-stranded RNA binding domain (dsRBD) (39). VV from which the E3L gene has been deleted (VV⌬E3L) exhibits a dsRNA-dependent restriction of host cell range, and this phenotype can be reversed by expression of the dsRBD from pE3L or dsRNAbinding proteins from other viruses (4, 47, 62). We previously found that the products of the human cytomegalovirus (HCMV) genes TRS1 and IRS1 restore the host cell range of VV⌬E3L, inhibit the phosphorylation of eIF2␣, and prevent the shutoff...

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Section: Discussionmentioning

confidence: 99%

Binding and Nuclear Relocalization of Protein Kinase R by Human Cytomegalovirus TRS1

Hakki

Marshall²,

Niro³

et al. 2006

J Virol

104

100

View full text Add to dashboard Cite

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“…These animals were intranasally infected with 10 6 p.f.u. VACV-WR or GP2V in 10 ml PBS (Brandt & Jacobs, 2001). Mice from the negative control group were inoculated intranasally with 10 ml PBS.…”

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confidence: 99%

Vaccinia virus: shedding and horizontal transmission in a murine model

Ferreira

Abrahão

Drumond

et al. 2008

Journal of General Virology

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Vaccinia virus (VACV) has been associated with several bovine vaccinia outbreaks in Brazil, affecting cattle and humans. There are no available data about VACV environmental circulation or the role of wildlife in the emergence of an outbreak. Since VACV was isolated from rodents in Brazil, we investigated shedding and transmission of VACV strains in mice. The VACV excretion profile was assessed by PCR and chicken chorioallantoic membrane infection, revealing viral DNA and infectious virus in the faeces and urine of intranasally infected mice. Horizontal transmission was assessed by exposure of sentinel mice to wood shavings contaminated with excrement, to mimic a natural infection. Sentinel mice showed orthopoxvirus antibodies, and VACV DNA and infectious virus were detected in their faeces and intestines, even after six rounds of natural transmission. Together, these data suggest that murine excrement could play a relevant role in VACV spread and transmission, perhaps helping to explain how these viruses circulate between their natural hosts.

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“…The IFN resistance gene (ORF 020) is an orthologue of VACV E3L, which is essential for the broad host-range of VACV in vitro and affects virulence in vivo (Brandt & Jacobs, 2001;Vijaysri et al, 2003Vijaysri et al, , 2008. As a result of the variation seen between the N-terminal domains of the ORFV and BPSV proteins, Delhon et al (2004) suggested that this domain might have a role to play in host range and pathogenesis.…”

Section: Hautaniemi and Othersmentioning

confidence: 99%

The genome of pseudocowpoxvirus: comparison of a reindeer isolate and a reference strain

Hautaniemi

Ueda

Tuimala

et al. 2010

Journal of General Virology

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Parapoxviruses (PPV), of the family Poxviridae, cause a pustular cutaneous disease in sheep and goats (orf virus, ORFV) and cattle (pseudocowpoxvirus, PCPV and bovine papular stomatitis virus, BPSV). Here, we present the first genomic sequence of a reference strain of PCPV (VR634) along with the genomic sequence of a PPV (F00.120R) isolated in Finland from reindeer (Rangifer tarandus tarandus). The F00.120R and VR634 genomes are 135 and 145 kb in length and contain 131 and 134 putative genes, respectively, with their genome organization being similar to that of other PPVs. The predicted proteins of F00.120R and VR634 have an average amino acid sequence identity of over 95 %, whereas they share only 88 and 73 % amino acid identity with the ORFV and BPSV proteomes, respectively. The most notable differences were found near the genome termini. F00.120R lacks six and VR634 lacks three genes seen near the right terminus of other PPVs. Four genes at the left end of F00.120R and one in the middle of both genomes appear to be fragmented paralogues of other genes within the genome. VR634 has larger than expected inverted terminal repeats possibly as a result of genomic rearrangements. The high G+C content (64 %) of these two viruses along with amino acid sequence comparisons and whole genome phylogenetic analyses confirm the classification of PCPV as a separate species within the genus Parapoxvirus and verify that the virus responsible for an outbreak of contagious stomatitis in reindeer over the winter of 1999-2000 can be classified as PCPV.

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Both Carboxy- and Amino-Terminal Domains of the Vaccinia Virus Interferon Resistance Gene, E3L, Are Required for Pathogenesis in a Mouse Model

Cited by 197 publications

References 48 publications

Binding and Nuclear Relocalization of Protein Kinase R by Human Cytomegalovirus TRS1

Binding and Nuclear Relocalization of Protein Kinase R by Human Cytomegalovirus TRS1

Vaccinia virus: shedding and horizontal transmission in a murine model

The genome of pseudocowpoxvirus: comparison of a reindeer isolate and a reference strain

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