Fig. 2.

Appearance of the crescent by conventional embedding, CEMOVIS and by 3D rendering.

A–D. The images are from HeLa cells infected for 8 h with VACV. In (A) the cells were chemically fixed and embedded at room temperature in epoxy resin. In (B) to (D) the cells were preserved by high pressure freezing (HPF) and in (B) embedded in lowicryl after freeze substitution (FS) whereas in (C) and (D) the cells were imaged by CEMOVIS. The latter reveals two separate layers with different appearances that are not seen the same way after dehydration and resin embedding.

E. A typical crescent analysed by ET and the tomogram was subjected to volume segmentation. It shows how the growing crescent membrane (yellow), coated on the outside by the scaffold protein (red), is connected to a collection of open membrane structures that contribute to its formation. The connected membranes typically curve in the opposite direction compared with the forming crescent and are not coated with scaffold. The growing crescent forms around the viral core proteins (green).

The images are from Chlanda et al. (2009) reproduced with permission.