Glycosylation of the hepatitis C virus envelope protein E1 occurs posttranslationally in a mannosylphosphoryldolichol-deficient CHO mutant cell line.
The addition of N-linked glycans to a protein is catalyzed by oligosaccharyltransferase, an enzyme closely associated with the translocon. N-glycans are believed to be transferred as the protein is being synthesized and cotranslationally translocated in the lumen of the endoplasmic reticulum. We used a mannosylphosphoryldolichol-deficient Chinese hamster ovary mutant cell line (B3F7 cells) to study the temporal regulation of N-linked core glycosylation of hepatitis C virus envelope protein E1. In this cell line, truncated Glc(3)Man(5)GlcNAc(2) oligosaccharides are transferred onto nascent proteins. Pulse-chase analyses of E1 expressed in B3F7 cells show that the N-glycosylation sites of E1 are slowly occupied until up to 1 h after protein translation is completed. This posttranslational glycosylation of E1 indicates that the oligosaccharyltransferase has access to this protein in the lumen of the endoplasmic reticulum for at least 1 h after translation is completed. Comparisons with the N-glycosylation of other proteins expressed in B3F7 cells indicate that the posttranslational glycosylation of E1 is likely due to specific folding features of this acceptor protein.
Duvet
Sandrine
S
CNRS-UMR 8576/USTL, 59655 Villeneuve d'Ascq Cedex, France.
Op De Beeck
Anne
A
Cocquerel
Laurence
L
Wychowski
Czeslaw
C
Cacan
René
R
Dubuisson
Jean
J
D000818:Animals; D016466:CHO Cells / Q000378:metabolism; D006224:Cricetinae; D004287:Dolichol Monophosphate Mannose / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D006031:Glycosylation; D018936:Hepatitis C Antigens / Q000378:metabolism*; D007700:Kinetics; D011233:Precipitin Tests; D011485:Protein Binding; D017510:Protein Folding; D011499:Protein Processing, Post-Translational; D012845:Sindbis Virus / Q000378:metabolism; D014759:Viral Envelope Proteins / Q000378:metabolism*
C087035:E1 protein, Hepatitis C virus; D018936:Hepatitis C Antigens; D014759:Viral Envelope Proteins; D004287:Dolichol Monophosphate Mannose