C-terminal domain of hepatitis C virus core protein is essential for secretion.
OBJECTIVE
We have previously demonstrated that hepatitis C virus (HCV) core protein is efficiently released into the culture medium in insect cells. The objective of this study is to characterize the HCV core secretion in insect cells.


METHODS
We constructed recombinant baculoviruses expressing various-length of mutant core proteins, expressed these proteins in insect cells, and examined core protein secretion in insect cells.


RESULTS
Only wild type core was efficiently released into the culture medium, although the protein expression level of wild type core was lower than those of other mutant core proteins. We found that the shorter form of the core construct expressed the higher level of protein. However, if more than 18 amino acids of the core were truncated at the C-terminus, core proteins were no longer secreted into the culture medium. Membrane flotation data show that the secreted core proteins are associated with the cellular membrane protein, indicating that HCV core is secreted as a membrane complex.


CONCLUSIONS
The C-terminal 18 amino acids of HCV core were crucial for core secretion into the culture media. Since HCV replication occurs on lipid raft membrane structure, these results suggest that HCV may utilize a unique core release mechanism to escape immune surveillance, thereby potentially representing the feature of HCV morphogenesis.
Ilsong Institute of Life Science, Hallym University, 1 Ockcheon-dong, Chuncheon 200-702, South Korea.
Soo-Ho
SH
Choi
Kyu-Jin
KJ
Park
So-Yeon
SY
Kim
Dong-Hwa
DH
Choi
Jung-Min
JM
Park
Soon-B
SB
Hwang
D000818:Animals; D016367:Baculoviridae / Q000235:genetics; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D017434:Protein Structure, Tertiary / Q000502:physiology*; D011995:Recombination, Genetic; D018411:Spodoptera / Q000166:cytology; D014758:Viral Core Proteins / Q000235:genetics* / Q000378:metabolism*
D014758:Viral Core Proteins; C069130:nucleocapsid protein, Hepatitis C virus