Secretory Expression of
Different C-terminal Truncated HCV E1 Proteins in Mammalian Cells and
Characterization of the Expressed Products
ZHU Jun, KONG Yu-Ying, LIU Jing, ZHANG Zu-Chuan, WANG Yuan*,
LI Guang-Di*
( Institute of Biochemistry and Cell Biology, Shanghai Institute for
BiologicalSciences, the Chinese Academy of Sciences, Shanghai 200031,
China )
Abstract Three
fragments of the HCV envelope 1 (E1) with different C-terminal truncation at
aa310, aa325, aa340 were cloned into the mammalian expression vector pSecTagB.
An epitope in the hepatitis B surface antigen, preS1(21–47), were genetically
engineered onto the N-terminus of the recombinant protein and used as an
affinity tag for detection and purification. The resulting pSec-preS1-E1t310,
pSec-preS1-E1t325 and pSec-preS1-E1t340 were transiently expressed in the HeLa
cells and the antigenicity, secretory efficiency and glycosylation type of the
recombinant E1 proteins were compared. All of the three recombinant proteins
could be detected by both preS1 monoclonal antibody and E1 polyclonal
antiserum. The expression products were secreted and highly mannose-type glycosylated,
with S1E1t325 being secreted, indicating the influence of the hydrophobic
regions on the secretion of the E1 protein. Three CHO cell lines expressing the
proteins, S1E1t310, S1E1t325 and S1E1t340, were established and the
CHO/pSecS1E1t325 was chosen for further study. The secreted S1E1t325 could be
enriched from cell culture medium by the preS1 antibody-coupled Sepharose.The
glycosylation analysis indicated the lack of complex glycogen even after the E1
was secreted via Golgi complexes. The established stable cell lines and
anti-preS1 affinity method could be utilized to enrich and purify the HCV E1
expressed in mammalian cells, and may be used for further characterization of
this protein.
Key words HCV E1； HBV preS1； double antigenicity； secretary expression； glycosylation
*Corresponding author： Tel, 86-21-64374430-5319； Fax, 86-21-64338357； e-mail, [email protected]