Noninfectious vesicular stomatitis virus particles deficient in the viral nucleocapsid.

Several temperature-sensitive mutants of vesicular stomatitis virus in complementation group III produce, at nonpermissive temperature, noninfectious particles which contain the viral M (matrix) and G (glycoprotein) proteins but less than 10% of the normal proportion of N protein or RNA. Since group III mutants are thought to be defective in the structural gene for the virus M protein, these findings demonstrate that an interaction between M and the nucleocapsid is of importance in virus budding. Taken together with earlier results, they suggest that M is the key protein in bud formation.