FIG 6.

Growth of C-terminal pUL71 mutants. (A) Focus expansion assay of the indicated viruses in HFFs under methylcellulose overlay. HCMV-infected cells were detected by indirect immunofluorescence staining for IE1/2 antigen at 9 days postinfection (dpi). Each data point represents the relative number of IE1/2-positive nuclei per focus. Shown is the mean focus size for each virus (black line) normalized to the mean focus size of TB40-BAC4. At least 80 foci from three independent experiments were determined for each virus. Significance testing was performed by a Kruskal-Wallis test followed by a Dunn’s multiple-comparison test (P < 0.05). Significance is given compared to TB40-BAC4 and TB71stop. ***, P < 0.0001; n.s., not significant. (B) Multistep growth kinetics experiments of the indicated viruses were performed by infecting HFFs with an infection rate of 0.3%. Virus yields in the supernatants of infected cells were determined at the indicated times by titration on HFFs. Growth curves show the mean virus yields and standard deviations from three independent virus supernatants. Virus yields at time zero represent the starting infection rates determined at 24 h postinfection. (C) Single-step growth kinetics experiments of the indicated viruses were performed on HFFs with an MOI of 3. Virus yields in the supernatants of infected cells were determined at the indicated times by titration on HFFs. Growth curves show the mean virus yields and standard deviations from three independent virus supernatants. Virus yields at time zero represent the virus yields of the inocula.