Figure 5.

Membrane tubules form from Golgi mini-stacks after recovery from PLA₂ inhibitor arrest of Golgi reassembly. In these experiments, cells were treated with BFA (5 μg/ml for 30 min), washed free of BFA, and incubated with the reversible PLA₂ inhibitor ONO-RS-082 (5 μM) for 60 min to allow reassembly up to the point of mini-stack formation (A). Cells were then washed free of the inhibitor and allowed to recover in normal media for 5 min (B), 10 min (C), or 50 min (D). After each experiment, cells were processed for immunofluorescence with anti-ManII antibodies. Cells incubated for 5 min in inhibitor-free media exhibit ManII-stained, thin membrane tubules emanating from many of the mini-stacks (arrows) (B). By 10 min of recovery, nearly all mini-stacks were interconnected by thin membrane tubules (arrows), and by 50 min the Golgi complex had completely reformed (D). Some of the tubules indicated by the arrows appear to be of somewhat different diameters; however, these differences are actually due to out-of-focus light from tubules in different focal planes.