Three variations in the cell surface expression of the haemagglutinin-neuraminidase glycoprotein of Sendai virus.

The fate of the haemagglutinin-neuraminidase glycoprotein (HN) of Sendai virus in three types of infection was studied by measuring its sensitivity to endoglycosidase H and its rate of appearance and turnover at the cell surface. HN behaved differently in the three types of infection. When highly expressed at the surface, as in a lytic standard virus infection, HN accumulated at the surface in a stable form (half-life of disappearance from the surface much greater than 10 h). When moderately expressed, as in a non-lytic standard virus plus defective interfering virus infection, HN reached the membrane normally, but turned over rapidly (half-life about 2 h) and was re-internalized. When poorly expressed, as in long-term persistent infection, HN did not reach the cell surface and appeared to be degraded before reaching it. In contrast to HN, the other viral glycoprotein, F0, exhibited a similar turnover rate at the cell surface in the three situations. However, when compared to surface expression in standard virus-infected cells under standardized conditions, F0 surface expression in persistently infected cells was reduced. This reduction correlates with a decreased maturation rate in these cells.