BREFELDIN A-INDUCED DISASSEMBLY OF THE GOLGI-APPARATUS IS FOLLOWED BY DISRUPTION OF THE ENDOPLASMIC-RETICULUM IN PLANT-CELLS

Brefeldin A (BFA), a fungal fatty acid derivative, is a potent agent for disrupting the Golgi apparatus in plant and animal cells. We have examined its action using marker antibodies which recognize an epitope in the plant Golgi apparatus (JIM 84), and for proteins held in the endoplasmic reticulum by the HDEL ER-retention signal (2E7), in combination with double immunolabelling. In maize root cells, disruption of the ER occurs after breakdown of the Golgi apparatus is initiated. The redistribution of the Golgi is shown to be predominantly separate from that of the ER, and as with the Golgi, the action of BFA on the ER is also reversible. The mode of action of BFA on the ER and Golgi of plant cells is compared with that described for animal cells.