Distinct patterns of IFN sensitivity observed in cells infected with vaccinia K3L- and E3L- mutant viruses.
Recent results have implicated a role for both the VV K3L- and E3L-encoded gene products in conferring VV with an IFN-resistant phenotype (Beattie et al., Virology 183, 419-422, 1991; Beattie et al., J. Virol. 69, 499-505, 1995). As a means of further establishing the mechanisms by which these functions mediate this process in VV-infected cells, we have further assessed the IFN phenotype in K3L- (vP872) and E3L- (vP1080) virus-infected cells. Biochemical and molecular biological analyses were performed comparing the effects of IFN on wild-type as well as K3L- and E3L- virus-infected cells. Expression analyses of the K3L and E3L gene products revealed that both are evidenced in virus-infected cells as early as 0.5 hr postinfection. E3L expression, however, appears more prolonged, in that it was detectable between 3 to 4 hr postinfection while K3L was undetectable after 3 hr postinfection. Despite having similar expression profiles at early times postinfection, a pronounced sensitivity of protein synthesis to IFN was observed by 30 min postinfection in VV K3L- virus-infected cells, whereas IFN sensitivity was not observed in VV E3L(-)-infected cells until 2 hr postinfection. Subsequent analyses of the IFN-induced antiviral pathways in VV-infected cells demonstrated that the K3L gene product does not contribute to the previously identified specific kinase inhibitory factor (SKIF) activity but does reduce the level of phosphorylated eIF-2 alpha in VV-infected cells. Interestingly, the IFN-induced 2',5'-oligoadenylate synthetase-mediated antiviral pathway was active in VV K3L(-)-infected cells and not in wild-type virus-infected cells. Collectively these results suggest that the K3L(-)- and E3L(-)-encoded products abrogate the antiviral effect of IFN at distinct levels.
Beattie
E
E
Department of Biomedical Sciences, School of Public Health, University at Albany, New York 12222, USA.
Paoletti
E
E
Tartaglia
J
J
D015088:2',5'-Oligoadenylate Synthetase / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D002522:Chlorocebus aethiops; D015536:Down-Regulation; D004352:Drug Resistance, Microbial / Q000235:genetics; D015967:Gene Expression Regulation, Viral / Q000187:drug effects / Q000502:physiology; D007372:Interferons / Q000494:pharmacology*; D007739:L Cells; D051379:Mice; D008969:Molecular Sequence Data; D020652:Peptide Elongation Factor 2; D010445:Peptide Elongation Factors / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D012335:RNA, Ribosomal / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D017384:Sequence Deletion / Q000502:physiology*; D014616:Vaccinia virus / Q000187:drug effects* / Q000235:genetics; D014709:Vero Cells; D014764:Viral Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D019892:eIF-2 Kinase
C081374:E3L protein, Vaccinia virus; D020652:Peptide Elongation Factor 2; D010445:Peptide Elongation Factors; D012335:RNA, Ribosomal; D016601:RNA-Binding Proteins; D014764:Viral Proteins; C081646:pK3 protein, Vaccinia virus; D007372:Interferons; D017346:Protein Serine-Threonine Kinases; D019892:eIF-2 Kinase; D015088:2',5'-Oligoadenylate Synthetase