SUBCELLULAR-LOCALIZATION OF THE NONSTRUCTURAL PROTEIN NS3 OF AFRICAN HORSESICKNESS VIRUS

The subcellular localization of the minor nonstructural protein NS3 of Af rican horsesickness virus (AHSV) has been investigated by means of immunogold electron-microscopical analysis. NS3 was observed in pertu rbed regions of the plasma membrane of AHSV-infected VERO cells, and i ts presence appears to be associated with events of viral release. The se events are budding, whereby released viruses acquire fragments from the host-cell membrane, as well as by the extrusion of nonenveloped p articles through the cell membrane. The membrane association of NS3 wa s confirmed by its detection in the disrupted plasma membranes of cell s infected with an NS3 baculovirus recombinant. The absence of NS3 on intact cell membranes suggests that the protein is not exposed extrace llularly.