FIG. 5.

Immunoelectron micrograph. RK13 cells were infected with wild-type PrV-Ka (A, C, and D), PrV-ΔUS3 (B), or PrV-ΔUL37 (E) at an MOI of 1 and analyzed 16 h after infection by immunolabeling with the anti-UL36 serum and gold-tagged secondary anti-rabbit antibodies. Label was not detected in primary enveloped virions in the perinuclear space (A) which accumulate in the US3 deletion mutant (B). In contrast, intracytoplasmic (C) and extracellular wild-type virions (D) were labeled with the anti-UL36 serum, as were capsid aggregates in the cytoplasm which form in the absence of the UL37 protein (E) (21). Bars, 200 nm.