Abstract
Japanese encephalitis is the most important cause of epidemic encephalitis worldwide, especially in eastern and southern Asia. In recent years, JE is spreading geographically and become a more concerned issue. The pathogen of JE, Japanese encephalitis virus (JEV) has two membrane glycoprotein prM and E, which each has one N-linked glycan. The formation of JEV prM-E complex is an important step for the biogenesis of immature virions and subviral particles. The N-linked glycans of JEV prM and E are crucial to viral replication and subviral particles formation. Co-expressing JEV prM and E proteins in insect cells infected by recombinant baculoviruses have been shown to produce recombinant subviral particles (RSPs) similar to virions. In order to analyze how the N-linked glycans affect the process of RSPs biosynthesis, wild-type and glycosylation-mutated prM and E proteins was expressed in Sf9 cells. By treating with the glycosidase PNGase F, it was confirmed that the wild-type JEV prM and E were N-linked glycosylated, while the glycosylation-mutants, prM(dg) and E(dg), were not. In the co-infection of prM(dg)/E and prM/E(dg), the secretion of RSPs was respectively reduced to 50% and 40% of the wild-type level. In the absence of N-linked glycans on both prM and E, the secretion of RSPs was more seriously decreased to 30% of the wild-type level. Furthermore, the N-linked glycans showed no significant relation to the stability, interaction of prM and E proteins, and helped the formation and the secretion of RSPs in some other uncertain mechanisms.