FIG 9.

ORF63 deficiency is not associated with a morphogenesis defect or an egress deficit but is associated with an increased particle/PFU ratio. (A) Transmission electron microscopic (TEM) analysis for morphogenesis of the virions. BHK-21 cells were infected with WT (i and ii), ORF63 STOP (iii and iv), and ORF63 Rev (v and vi) MuHV-4 strains (1 PFU/cell, 48 h), washed with PBS, and fixed in TEM fixation buffer for TEM. The scale bars are shown below the images. nuc, nucleus; cyt, cytoplasm. No difference was observed in the assembly of nucleocapsids and their transport from the nucleus (black arrows; approximate diameter, 100 nm) among the infected cells by different viral strains. The enveloped viruses are shown with the white arrows in the cytoplasms of the infected cells. No difference in virus egress was found among the samples. (B) Distribution of different virus capsids and particle types in TEM micrographs of BHK-21 cells that were infected with the WT, ORF63 STOP, or ORF63 Rev strains for 48 h at an MOI of 0.5 PFU/cell. Average numbers of particles from 6 to 9 different micrographs spanning at least 3 different infected cells for each sample were identified based on their established characteristics (61) and enumerated before statistical analysis was performed (GraphPad software).