TABLE 1.
Summary of fusion potentiation activity of GS upon coexpression with heterologous viral fusion proteinsa
| Glycoprotein | Fusion enhancement by GS |
|---|---|
| GIND | +/++ |
| GNJ | ++/+++ |
| SV5 F | ++++ |
| Moloney murine leukemia virus | + |
| HIVW3IGS | ++++ |
| Measles virus F | − |
| Measles virus F + H | +/− |
BHK-21 cells were transfected with plasmids encoding GSHA and the respective viral glycoprotein (1 μg each). After 24 h, the cells were removed from the dish, divided into three aliquots, and replated. After an additional 24 h, the cells were examined by phase-contrast microscopy to determine the number and size of the syncytia that were formed. Symbols: +, 2- to 10-fold increase in cell-cell fusion observed when GSHA was coexpressed compared to when the glycoprotein was expressed alone; ++, 10- to 20-fold increase; +++, 20- to 30-fold increase; ++++, 30- to 40-fold increase; −, no fusion potentiation was observed. CV-1 cells were used for the measles virus F and H fusion assays because the measles virus receptor is not present on BHK-21 cells.