FIG. 1.

Single-cycle growth analysis of PV1 and Δ3′ NCR PV1. HeLa cell monolayers were infected with either wild-type PV1 (•) or Δ3′ NCR PV1 (4-1 M) (▴) at an MOI of 15 and incubated at 37°C, and cells were harvested at 1.5, 3, 4.5, 6, and 7.5 h postinfection. The virus titer was determined by plaque assays.