Apoptosis induced by a postbinding step of vaccinia virus entry into Chinese hamster ovary cells.
Unlike most cell types examined, nonpermissive Chinese hamster ovary (CHO) cells readily underwent apoptosis upon infection with vaccinia virus (VV). Apoptosis was observed as early as 3 h postinfection with an electrophoretic assay of DNA fragmentation and by 8 h using an in situ (TUNEL) assay. The CHO hr gene from cowpox virus, which overcomes host range restriction of VV in CHO cells, merely delayed the onset of apoptosis by approximately 3 h. Intermediate and late viral protein synthesis were not necessary for apoptosis since these events do not proceed under nonpermissive conditions. Apoptosis also occurred in the presence of cytosine arabinoside or cycloheximide, which inhibits DNA or protein synthesis, respectively, and after infection with a mutant virus that is blocked in early transcription. We also demonstrated that viral early transcription was not required for induction of apoptosis by infecting CHO cells with psoralen/UV-inactivated virus. On the other hand, apoptosis was inhibited by a neutralizing antibody to the virion L1R protein added either before or after virus attachment to cells. These results indicate that a postbinding step associated with cell entry is sufficient and required for induction of apoptosis in CHO cells. Recent progress on apoptotic signaling pathways raises the possibility that a cellular receptor for VV may be involved in apoptosis.
Ramsey-Ewing
A
A
Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892-0445, USA.
Moss
B
B
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D016466:CHO Cells; D002460:Cell Line; D002522:Chlorocebus aethiops; D015608:Cowpox virus / Q000502:physiology; D006224:Cricetinae; D053938:DNA Fragmentation; D011564:Furocoumarins / Q000494:pharmacology; D017930:Genes, Reporter; D006367:HeLa Cells; D006801:Humans; D011994:Recombinant Proteins / Q000096:biosynthesis; D013997:Time Factors; D014158:Transcription, Genetic; D014466:Ultraviolet Rays; D014616:Vaccinia virus / Q000187:drug effects / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects; D014779:Virus Replication; D001616:beta-Galactosidase / Q000096:biosynthesis
D011564:Furocoumarins; D011994:Recombinant Proteins; D001616:beta-Galactosidase