Ultrastructural modifications of vesicular and Golgi elements in the Saccharomyces cerevisiae sec21 mutant at permissive and non‐permissive temperatures

Abstract

It is thus postulated that, in the above mentioned conditions, the small vesicles of the sec21 mutant did not act as intermediate carriers between the endoplasmic reticulum and a pre-existing Golgi apparatus, but rather fused together to produce newly formed Golgi networks.

Requirement for Neo1p in Retrograde Transport from the Golgi Complex to the Endoplasmic Reticulum

“…This same vesicle accumulation phenotype is observed when sec21 is incubated at a semipermissive temperature (Rambourg et al, 1994). These vesicles are likely in transit between the ER and Golgi, but whether they are COPI or COPII vesicles is not known.…”

Characterization of the ORF YBR264c in Saccharomyces cerevisiae, which encodes a new yeast Ypt that is degraded by a proteasome-dependent mechanism

“…We observed other vesicles in the form of networks of nodular tubules and large anastomizing nodular tubules. In light of the morphological studies of Rambourg et al (1994), it may be that YPT10 overexpression leads to accumulation of a large excess of Golgi-like cisternae with budding vesicles. This phenotype in part recalls that described for strains aected in the genes encoding the GTPases Ypt31p and Ypt32p; stacked Golgi-like cisternae and other membrane-enclosed structures resembling the socalled``Berkeley bodies'' were ®rst noted in Ypt31p/ Ypt32p-depleted cells (Benli et al 1996).…”

“…We also observed an increase in the size of a network of nodular tubules and large anastomizing nodular tubules. The vesicles could correspond to secretory granules; the other structures could represent Golgi elements, appearing as tubular networks and as elaborate networks of interconnected tubules (Rambourg et al 1994). Based on the morphological descriptions given by these authors, YPT10 overexpression could give rise to a massive accumulation of Golgi-like cisternae with budding vesicles in yeast cells; these structures seem to derive from the Golgi apparatus itself.…”

Modifications of the golgi apparatus inSaccharomyces cerevisiae lacking microtubules

“…These vesicles, which are seldom seen in the cytoplasm of control wildtype strains (Rambourg et al, 1993, have been shown to accumulate in mutations, which affect the transport of proteins between the endoplasmic reticulum and the Golgi apparatus (Novick et al, 1980;Kaiser and Schekman, 1990;Rambourg et al, 1994). Furthermore, when examined by radioautography, disruption of microtubules by colchicine in rat lacrymal glands decreased the transfer of labeled proteins from the rough endoplasmic reticulum to the Golgi area (Busson-Mabillot et al, 1982).…”