Abstract
Herpes simplex virus type 1 (HSV-1) glycoproteins gB, gD and gHL are capable of inducing cell fusion when expressed from plasmid vectors in the absence of any other virus components. Fusion requires the expression of all four glycoproteins on the same membrane, since they are unable to cooperate in trans to induce syncytium formation. In addition, the fusion event is dependent on the expression of a gD receptor on target cell membranes and does not require the presence of cell-surface glycosaminoglycans.