Figure 6.

AAA substitutions at residues 657–59, 680–82, 704–06, and 739–41 of pUL37 result in significant reduction of mature enveloped virus particles. Vero cells were infected with viruses specifying AAA substitutions or WT and TEM analysis of infected cells was carried out 18 hours post-infection. In the mutant-infected cells, there was an accumulation of capsids in the nucleus (n) (black arrowheads) and electron-dense DNA-filled capsids in the cytoplasm (white arrowheads). Perinuclear enveloped capsids were observed in some infected cells (pe). Occasionally, a mature particle was observed leaving the cell infected with AAA mutant viruses (arrow). Cytoplasmic capsids surrounded by an envelope were not observed in these cells, whereas they are clearly evident in WT pUL37-infected cells. Scale bar = 1 µm.