FIG. 6.

DN s309 prevents viral-capsid egress from the cell nucleus and induces accumulation of aberrant capsids in the nucleus. NIH 3T3 cells were infected for 72 h at an MOI of 3 with viruses that conditionally expressed s309 in the absence (A) or in the presence (B, C, and D) of 1 μg/ml doxycycline. The cells were fixed by high-pressure freezing, freeze-substituted, embedded in plastic, and analyzed by electron microscopy. The black arrowheads point at mature C-type viral capsids, and the white arrowheads point at capsids with unusual morphology. The gray arrowheads point at intranuclear membrane accumulation. (D) Electronic zoom of panel C; the upper left capsid is indicated by a thin arrow to aid orientation. The scale bars indicate 1 μm.