FIG. 6.

Q548R mutant IE86 protein is unable to inhibit cellular DNA synthesis in infected HFF cells. (A) Serum-starved, contact-inhibited HFF cells were synchronized in G₀ for 48 h. Cells were infected for 6 h in low-serum medium with Towne, Q548A, or Q548R RV at an MOI of approximately 0.9. Cells were then split onto glass coverslips for release from contact inhibition and grown in high-serum medium, to promote cell cycle progression, plus BrdU, to detect DNA synthesis, for 42 h. Cells were fixed and permeabilized in methanol and acetone (1:1), stained with anti-IE86 and anti-BrdU antibodies, counterstained with DAPI, and imaged by fluorescent microscopy. (B) Ten fields, with at least 30 cells per field, from the above experiment were counted to determine the percentage of uninfected and infected BrdU-positive cells for each sample.