Cell fusion by canine distemper virus-infected cells and their plasma membranes

Cells first gain detectable fusion induction ability 4-6 h after infection with canine distemper virus even though mature virions are not released until about 10 h. Plasma membranes isolated from cells as early as 6 h after infection also have the ability to induce early fusion. While protein synthesis is not required for fusion in the early fusion assay itself, it is required in infected cells for induction of fusion ability. Early cell fusion by infected cells is apparently the result of synthesis of a virus-induced protein that is found in association with the cell plasma membrane.