Early and late transformations occurring at organelles of the Golgi area under the influence of brefeldin A: an ultrastructural and lectin cytochemical studyM Pavelka and A Ellinger Institute of Histology and Embryology, University of Innsbruck, Austria. We investigated the early and late changes of the Golgi region under the influence of the fungal metabolite brefeldin A (BFA) by electron microscopy and lectin cytochemistry using the beta-galactose-specific lectin from the beetle Allomyrina dichotoma (Allo A). In control cells, Allo-A reactions were confined to trans-Golgi elements, the trans-Golgi network, and to endosomes and lysosomes; the nuclear envelope and endoplasmic reticulum were consistently free of Allo A reactions. Our findings with cells from three different lines (i.e., HepG2 hepatoma cells, WI38 fibroblasts, and L132 embryonic lung cells) showed tubular- reticular transformations of the Golgi stacks as early as 30 sec after application of BFA. The transformations started at the cis side and proceeded rapidly; after only a few minutes the Golgi apparatus was no longer apparent as an individual entity. Simultaneously, giant tubules grew out of the Golgi region and traversed the cytoplasm over micrometer-long distances. In part, they were reactive for Allo A. Reactions for beta-galactose occurred in cisternae of the endoplasmic reticulum after 4-5 min of BFA treatment; after 30 min the entire endoplasmic reticulum was intensely reactive for Allo A. At 5 min and later, the tubular-reticular transformations appeared more compact, forming glomerulus-like structures (glomerulini). These were closely associated with cisternae of the endoplasmic reticulum. Initially, glomerulini were mostly Allo A negative or showed peripheral Allo A- positive segments. The number of Allo A-positive glomerulini increased with the duration of treatment. Our findings identify the glomerulini as bipolar structures forming a link between the endoplasmic reticulum and the dissociating Golgi stacks.
Volume 41,
Issue 7,
pp. 1031-1042,
07/01/1993
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A. Mironov, A. Colanzi, M. G. Silletta, G. Fiucci, S. Flati, A. Fusella, R. Polishchuk, A. Mironov Jr., G. D. Tullio, R. Weigert, et al. Role of NAD+ and ADP-Ribosylation in the Maintenance of the Golgi Structure J. Cell Biol., December 1, 1997; 139(5): 1109 - 1118. [Abstract] [Full Text] [PDF] |
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R. Weigert, A. Colanzi, A. Mironov, R. Buccione, C. Cericola, M. G. Sciulli, G. Santini, S. Flati, A. Fusella, J. G. Donaldson, et al. Characterization of Chemical Inhibitors of Brefeldin A-activated Mono-ADP-ribosylation J. Biol. Chem., May 30, 1997; 272(22): 14200 - 14207. [Abstract] [Full Text] [PDF] |
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