Ultrastructural analysis of the effects of mutation(s) in UL51 on viral nuclear egress in HaCaT cells. HaCaT cells were infected with wild-type HSV-1(F), YK631 (UL51-S184A), YK632 (UL51-S184D), YK633 (UL51-S184A/D-repair), YK634 (UL51-T190A), YK636 (UL51-S226T228S235/AAA), YK638 (ΔUL51), or YK639 (ΔUL51-repair) at an MOI of 5, fixed at 18 h postinfection, embedded, sectioned, stained, and examined by transmission electron microscopy. Nuc, nucleus; Cy, cytoplasm. Scale bars, 500 nm.