FIG. 6.

P11 is absent from intracellular cores. The cryosections, all from HeLa cells infected for 30 min in the absence of actD, show intracellular cores (large arrowheads) that are devoid of p11 labeling; extracellular IMVs (I) are labeled. Note that the bulk of the labeling on the IMVs is excluded from the interior, nucleoid region. (B to D) Putative entry intermediates in which the cores are separated from the outer membranes and p11 remains extracellularly. The small arrowhead in panel B shows a possible connection between the viral membranes and the core. (B and C) Membrane fragments (small arrows) at the plasma membrane that label for p11; (B and D) such fragments adjacent to an incoming core; (D) double labeled for p11 (10-nm gold; small arrowheads) and p16 (5-nm gold; small arrows), showing a viral membrane fragment (star) labeled for both markers that is outside the cell. Bars = 100 nm.