Respiratory syncytial virus polypeptides. V. The kinetics of glycoprotein synthesis

The cell-associated glycoproteins of respiratory syncytial virus included GP1 (90K), VP70 (70K), VGP48 (48K) and GP26 (26K). The time course of virus protein synthesis in HeLa cells revealed that the nucleocapsid protein (VPN41) was the first to appear at 11 h post-infection followed by the appearance of the other viral proteins at 16 h post-infection. Pulse-chase experiments with [3H]leucine or [35S]methionine demonstrated that the precursor for VGP48 and GP26 was an uncleaved protein of 70K (VP70) which required at least 30 min to chase into its final products, while the precursor for GP1 was a glycoprotein of 46K, and also required at least 30 min to chase into GP1. Trypsin treatment of monensin-treated infected cells suggested that VP70 can be cleaved intracellularly into its products VGP48 and GP26.