Interaction of reconstituted Sendai viral envelopes with sperm cells: reconstituted Sendai virus envelope-induced fusion-mediated introduction of foreign material into bull sperm cells.

Reconstituted Sendai virus envelopes (RSVE), i.e. membrane vesicles bearing the viral envelope glycoproteins and phospholipids, are able to fuse with bull sperm cells. This was inferred from the increase in the degree of fluorescence dequenching (DQ) obtained following incubation of fluorescently labeled (R18 labeled) RSVE with bull sperm cells and from electron microscopy studies of RSVE-sperm interaction. Only a low degree of DQ was observed, under the same conditions, with non-fusogenic fluorescently labeled RSVE. This, and electron microscopy results, show that binding and membrane fusion events occur between RSVE and sperm cells. In addition, DQ was observed following incubation of RSVE that had been pre-loaded with the self-quenched fluorochrome Calcein, with bull sperm cells, indicating fusion-mediated injection of the dye from the RSVE space into the sperm cells.