FIG. 6.

Electron microscopy. RK13 cells were fixed 14 h after infection with PrV-ΔUL3.5/48 (A to C), PrV-ΔUL3.5F (D), or PrV-UL3.5R (E) at a MOI of 1 and analyzed. Whereas nucleocapsids were still formed and released from the host cell nucleus in the absence of UL3.5, or UL3.5 and UL48 (A to D), secondary envelopment of cytoplasmic nucleocapsids and release of mature virus particles were detectable only in cells infected by the UL3.5 rescuant (E). Bars represent 1.5 μm (A, D, and E), 500 nm (C), or 200 nm (B). N, nucleus; C, cytoplasm.