title: Infection with Langat Flavivirus or expression of the envelope protein induces apoptotic cell death.
abstract: Langat (LGT) flavivirus, derived from infectious full-length cDNA clone 636, was investigated for its apoptotic activities in mouse neuroblastoma (Neuro-2a) and simian kidney (Vero and LLC-MK(2)) cells. The hallmark of apoptosis, cleavage of cellular DNA, was observed 48 h after infection of Vero, LLC-MK(2), and Neuro-2a cells by electrophoresis analysis. Apoptosis in infected cells was also confirmed by TUNEL assay. LGT-infected Neuro-2a cells showed an increase in caspase-3-like protease (DEVDase) activity. Expression of the major envelope glycoprotein (E) alone reduced cell viability in both Vero and Neuro-2a cells, and the baculovirus P35 protein, which inhibits multiple caspases, completely blocked this effect. Cleavage of cellular DNA was observed in E gene-transfected Vero cells by TUNEL assay. Expression of E protein or caspase-9 resulted in activation of caspase-3-like proteases in Neuro-2a cells. The caspase-3-like protease specific inhibitor, Ac-DEVD-CHO peptide, partially inhibited E protein- or caspase-9-induced apoptosis in Neuro-2a cells. These observations indicate that infection of cells with LGT virus or expression of LGT virus E protein induces apoptosis through a caspase-3-like protease pathway.
authors.affiliation: Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA. PrikhodkoG@usa.redcross.org
authors.forename: G G
authors.initials: GG
authors.lastname: Prikhod'ko
authors.forename: E A
authors.initials: EA
authors.lastname: Prikhod'ko
authors.forename: J I
authors.initials: JI
authors.lastname: Cohen
authors.forename: A G
authors.initials: AG
authors.lastname: Pletnev
mesh_terms: D000818:Animals; D017209:Apoptosis; D002460:Cell Line; D002522:Chlorocebus aethiops; D053938:DNA Fragmentation; D004669:Encephalitis Viruses, Tick-Borne / Q000378:metabolism / Q000472:pathogenicity*; D004789:Enzyme Activation; D020287:In Situ Nick-End Labeling; D051379:Mice; D009474:Neurons / Q000821:virology*; D010447:Peptide Hydrolases / Q000378:metabolism; D014407:Tumor Cells, Cultured; D014709:Vero Cells; D014759:Viral Envelope Proteins / Q000235:genetics / Q000378:metabolism*; D014774:Virulence
chemical_list: D014759:Viral Envelope Proteins; C065696:glycoprotein E, Flavivirus; D010447:Peptide Hydrolases; C108711:DEVDase