FIG. 6.

Different viral morphologies within Golgi subcompartments in normally infected cells. Panels A, C, and D show sections from conventionally embedded material, while panel B shows a freeze-substituted sample. All panels show TGEV-infected ST cells at 6 h p.i. In panel A immunogold labeling with the anti-TGEV polyclonal serum and a secondary antibody conjugated to 10-nm-diameter gold particles was also performed. Budding profiles (bp), large viruses (lv), and small viruses (sv) are indicated. The cis and trans sides of the Golgi complex and the TGN are indicated. (A and B) Budding profiles and large viruses are often seen at the cis side of the Golgi stack, where its first cisterna exhibits a characteristic fenestrated structure. Large viral particles are occasionally seen in the TGN (A), although the trans side of the stack usually contains small viruses (B). (C) The four Golgi cisternae are numbered from the cis to the trans side. A small virus is seen in the fourth cisterna. (D) Small viral particles are usually observed in the TGN. N, nucleus. Bars, 100 nm.