FIG. 7.

vindA14 is a conditionally lethal mutant, and plaque formation and the production of infectious viral progeny are dependent upon TET. (A) vtetR and vindA14 were titrated on monolayers of BSC40 cells in the presence (+) or absence (−) of TET. (B) Cells were infected with vtetR or vindA14 for 24 h in either the presence (+) or the absence (○) of TET; cell lysates were prepared and virus was titrated on BSC40 cells in the presence of TET.