The eukaryotic translation initiation factor 4E is not modified during the course of vaccinia virus replication.
The ability of vaccinia virus to inhibit processes of cap-dependent translational initiation by inactivating the eukaryotic translation initiation factor 4E (eIF-4E) has been examined. Analyses of the quantities of eIF-4E present in either uninfected mouse L929 cells or vaccinia virus-infected cells showed that during the first 12 hr of virus replication, when there is a marked decrease in host gene expression in infected cells, there is no change in the total amount of eIF-4E present. Analyses of eIF-4E that was metabolically labeled with [32P] and then purified by affinity chromatography using m7GTP-Sepharose 4B, indicated that neither the incorporation of radiolabel into eIF-4E nor the amounts of eIF-4E capable of binding to cap structures changed significantly during virus replication. Immunodetection of phosphorylated and unphosphorylated eIF-4E in cell lysates fractionated by two-dimensional gel electrophoresis showed that the steady-state levels of phosphorylated and unphosphorylated forms of eIF-4E were similar in uninfected and virus-infected cells. These results suggest that vaccinia virus does not gain preferential translation of viral mRNAs over other mRNAs in the cell by reducing either eIF-4E phosphorylation or its ability to bind to the cap structure.
Gierman
T M
TM
Department of Microbiology and Immunology, Duke University Medical Center, Durham, North Carolina 27710.
Frederickson
R M
RM
Sonenberg
N
N
Pickup
D J
DJ
D000818:Animals; D015180:Electrophoresis, Gel, Two-Dimensional; D039561:Eukaryotic Initiation Factor-4E; D015967:Gene Expression Regulation, Viral; D066298:In Vitro Techniques; D007739:L Cells; D051379:Mice; D010448:Peptide Initiation Factors / Q000378:metabolism*; D010766:Phosphorylation; D012315:RNA Caps / Q000378:metabolism; D014616:Vaccinia virus / Q000235:genetics*; D014779:Virus Replication
D039561:Eukaryotic Initiation Factor-4E; D010448:Peptide Initiation Factors; D012315:RNA Caps