Fig. 4. VSVG is first found in COPII-positive vesicle chains/clusters upon release from the ER at 15°C. Transmission electron micrographs of three 70 nm serial sections (A, B and C) of VSV-infected NRK cells subjected to the rapid ethane freezing procedure for 3 hours upon transfer from 40°C to 15°C. The sections were double-labeled for VSVG (9 nm gold particles, small arrowheads) and Sec13 (14 nm gold particles, large arrowheads). Bar, 0.1 µm.