Nongenetic complementation of group V temperature-sensitive mutants of vesicular stomatitis virus by UV-irradiated virus.

Cells infected with temperature-sensitive (ts) mutants of complementation group V of vesicular stomatitis virus (VSV) give an enhanced yield at nonpermissive temperature when co-infected or superinfected with UV-irradiated virus. Virions produced in these mixed infections are temperature sensitive and do not complement ts V45. Rescue of group V mutants is multiplicity dependent. It can occur in the presence of cycloheximide; kinetics of rescue are similar in the absence or in the presence of the drug. Rescue is due to nongenetic complementation and is interpreted as a trigger effect on maturation of a small quantity of biologically active protein V molecules provided by UV-irradiated virus. These results are comfirmed by rescue of ts V45 by UV-irradiated, defective, interferring T particles.