THE PROGRAMMING OF HERPES VIRUS MULTIPLICATION IN DOUBLY-INFECTED AND IN PUROMYCIN-TREATED CELLS

Abstract

Suspensions of HEp-2 cells infected with herpes simplex virus (HSV) were treated with puromycin during the eclipse phase and at various times during the reproductive cycle. Puromycin (5 [mu]g/ml) treatment confined to the period of the eclipse prolongs the phase but does not alter the apparent rate of subsequent reproduction of the virus. Treatment between 0 and 2 hr, 2 and 4, or between 0 and 6 hr after infection causes equivalent delay in the termination of the eclipse phase. Treatment between 0 and 4 or between 2 and 4 hr after infection causes a 4-hr delay. Puromycin treatment beyond the end of the eclipse phase causes a decrease in the apparent rate of virus formation and decreases the yield. The formation of a product prerequisite to viral reproduction could be inferred from an analysis of viral multiplication on HEp-2 cells infected 3 hr apart with two marked strains of HSV. The eclipse phase of the superinfecting virus was reduced. Moreover multiplication of the superinfecting virus followed the pattern of development of the first infecting virus rather than that of the homologous virus. It is concluded that during the eclipse phase of HSV there is at least one and possibly more periods of synthesis of proteins required for the initiation of virus multiplication. It is tentatively inferred that the duplication of viral DNA does not commence until the precursors and enzymes required for its synthesis are present in the cell at a critical concentration.