Expression from cloned cDNA of cell-surface secreted forms of the glycoprotein of vesicular stomatitis virus in eucaryotic cells.

A cDNA clone of the mRNA encoding the glycoprotein (G) of vesicular stomatitis virus was inserted into plasmid vectors under the control of either the SV40 early promoter (pSV2G) or the SV40 late promoter (pSVGL). Synthesis of G protein was observed in mouse L cells injected with pSV2G DNA or in COS1 cells transfected with pSVGL DNA. Immunofluorescent staining of G protein produced in both cell types showed a pattern of internal and cell-surface staining indistinguishable from that seen in cells infected with vesicular stomatitis virus. The G protein produced in transfected COS1 cells was the size of normal G protein and was glycosylated. Expression of a G protein lacking 79 amino acids from the COOH terminus was also examined. This G protein lacks the transmembrane domain and the hydrophilic COOH terminus, which, we postulated, anchor G protein in the lipid bilayer. This "anchorless" protein is glycosylated and is secreted, albeit slowly.