FIG. 1.
trans complementation of an F13L deletion mutant virus. (A) Panel of F13L PCR products. *, the approximate location of the YxxL motif within F13L. (B) Six-well plates containing BSC40 cells seeded at a density of 2 × 105 cells/well were infected with an F13L deletion mutant virus for 1 h and then transfected with a PCR product containing one of several F13L YxxL mutations. Twenty-four hours postinfection, the transfection inoculum was replaced with medium containing 1% methylcellulose and incubated for an additional 48 h. The cells were fixed, and plaques were visualized by staining with 0.1% crystal violet.