Synthesis of proteins and glycoproteins in dengue type 2 virus-infected vero and Aedes albopictus cells

Abstract

Fifteen proteins were detected in Vero cells infected by dengue type 2 (DEN-2) virus that were not observed in mock-infected cells, namely P98, p82, P67, GP60, gp54, GP46, p30, p28, gp22, GP20, p18, gp16, p15, p14 and gp13. With the exceptions of gp54 and gp13, polypeptides corresponding to those listed above were also observed in DEN-2 virus-infected Aedes albopictus C6/36 cells. Pulse-chase labelling experiments suggested a possible precursor-product relationship between p30 and p28, and between gp22 and GP20. Peptide mapping and immunoprecipitation experiments showed that the major glycoproteins GP60, GP46 and GP20 were unrelated. Immunoprecipitations of infected cells with antiserum prepared against the DEN-2 soluble complement-fixing (SCF) antigen demonstrated that this antigen is equivalent to the non-structural glycoprotein GP46. The envelope glycoprotein (E) from virus grown in C6/36 cells migrated faster through polyacrylamide gels containing SDS than E from virus grown in Vero cells. [3H]Mannose-labelled glycopeptides of GP60, GP46 and GP20 were separated by gel filtration and by electrophoresis in Tris-borate gels; in addition, the polypeptides synthesized in infected cells in the presence of tunicamycin were analysed. The results revealed heterogeneity among the glycan units of GP60 and GP46.