Full-length core sequence dependent complex-type glycosylation of hepatitis C virus E2 glycoprotein.
OBJECTIVE
To study HCV polyprotein processing is important for the understanding of the natural history of HCV and the design of vaccines against HCV. The purpose of this study is to investigate the affection of context sequences on hepatitis C virus (HCV) E2 processing.


METHODS
HCV genes of different lengths were expressed and compared in vaccinia virus/T7 system with homologous patient serum S94 and mouse anti-serum M( E2116) raised against E.coli -derived E2 peptide, respectively. Deglycosylation analysis and GNA ( Galanthus nivalus ) lectin binding assay were performed to study the post-translational processing of the expressed products.


RESULTS
E2 glycoproteins with different molecular weights (-75 kDa and -60 kDa) were detected using S94 and M( E2116), respectively. Deglycosylation analysis showed that this difference was mainly due to different glycosylation. Endo H resistance and its failure to bind to GNA lectin demonstrated that the higher molecular weight form (75 kDa) of E2 was complex-type glycosylated, which was readily recognized by homologous patient serum S94. Expression of complex-type glycosylated E2 could not be detected in all of the core-truncated constructs tested, but readily detected in constructs encoding full-length core sequences.


CONCLUSIONS
The upstream conserved full-length core coding sequence was required for the production of E2 glycoproteins carrying complex-type N-glycans which reacted strongly with homologous patient serum and therefore possibly represented more mature forms of E2. As complex-type N-glycans indicated modification by Golgi enzymes, the results suggest that the presence of full-length core might be critical for E1/E2 complex to leave ER. Our data may contribute to a better understanding of the processing of HCV structural proteins as well as HCV morphogenesis.
Zhu
Li-Xin
LX
Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China.
Liu
Jing
J
Li
Ying-Chun
YC
Kong
Yu-Ying
YY
Staib
Caroline
C
Sutter
Gerd
G
Wang
Yuan
Y
Li
Guang-Di
GD
D000818:Animals; D002460:Cell Line; D006031:Glycosylation; D006367:HeLa Cells; D016174:Hepacivirus / Q000235:genetics* / Q000276:immunology / Q000378:metabolism*; D018937:Hepatitis C Antibodies; D006801:Humans; D008970:Molecular Weight; D011499:Protein Processing, Post-Translational; D014759:Viral Envelope Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism
D018937:Hepatitis C Antibodies; D014759:Viral Envelope Proteins; C091015:glycoprotein E2, Hepatitis C virus