Figure 5.

Effects of BFA on BY-2 Cells That Have Been Treated with BFA for Longer Periods.

(A) BFA (20 min). Some cells contain regions of stacked ER cisternae, usually in a perinuclear location. These cisternae are continuous with ER that has an abnormally straight appearance and more ribosome-free areas (arrow). Some domains of the ER are greatly inflated and contain electron-dense material (open arrow). G, Golgi; M, mitochondrion; P, plastid; V, vacuole.

(B) BFA (30 min). A subset of cells does not form the large stacked ER domains shown in (A) but contains clusters of Golgi stack remnants and large aggregations of Golgi-derived vesicles, similar to the BFA compartments described in other systems (see text). The ER in these cells also has an abnormal morphology, with electron-dense material in its dilated lumen and a large bending radius of its fenestrated membranes (arrows, upper left).

(C) BFA (30 min). ER export sites depicting budding coated vesicles (arrowheads) and several detached vesicles in the adjacent cytoplasm.

(D) BFA (5 hr). Coated budding vesicle (arrowhead) associated with the outer membrane of the nuclear envelope (NE), an ER equivalent membrane system. N, nucleus.