Three‐dimensional architecture of the Golgi apparatus in Sertoli cells of the rat

Abstract

Glutaraldehyde-fixed testes were stained "en bloc" with the Ur-Pb-Cu technique of Thiéry and Rambourg ('76) or post-fixed and stained with the osmium tetroxide-potassium ferrocyanide method of Karnovsky ('71). Thin or thick (up to 3 micron) sections were examined with the Philips (301 or 400) EM or the high voltage EM. Stereopairs were prepared with photographs of tilted specimens (+/- 7 degrees). At low magnification, in thick sections (0.5-3 micron) stained with Ur-Pb-Cu, the whole Golgi apparatus formed a single network of interconnected wavy ribbon or platelike structures extending from the juxtanuclear region toward the apex of the cell. At higher magnifications, with the two staining techniques, this Golgi network showed two distinct types of regions: the "saccular region" corresponding to the conventional stack of saccules and the "intersaccular connecting region" made up of anastomotic tubules which bridge adjacent stacks. In the saccurlar regions, there was, on the cis-face of the stack, a tight polygonal meshwork of anastomotic tubules (osmiophilic element). Underlying it there were three to seven closely apposed saccules perforated with pores of various diameters, and finally, on the trans-face, a network of tubules was usually connected to the last saccule of the stack, which seemed to peel off" from the pile. The intersaccular connecting regions showed proximal and distal zones with regard to the associated stacks. The proximal zone was made up of superimposed and parallel polygonal networks of membranous tubules which were continuous with corresponding saccules of the stack. In the distal zone they interdigitated, intertwined, anastomosed and bridged adjacent saccular regions; others turned at right angles and established connections with tubular extensions arising at various levels of the same stack. While cisternae of endoplasmic reticulum were contiguous with tubules or saccules located on the transface of the Golgi apparatus, a close association between the ER cisternae and the cis-face of the stacks was not usually observed.

Structure of the Golgi and Distribution of Reporter Molecules at 20°C Reveals the Complexity of the Exit Compartments

“…It has been described as being continuous with either multiple transcisternae (Rambourg et al, 1979) or with only the trans-most cisterna in the stack (Griffiths and Simons, 1986). In our studies of both chemically fixed (Ladinsky et al, 1994) and rapidly frozen cells (Ladinsky et al, 1999;Marsh et al, 2001a), 3-D reconstructions have revealed tubules extending from multiple trans-cisternae but did not show this "traditional" TGN.…”

“…These studies showed that all cisternae, including the trans-most, appear to be labeled (see for example, Geuze et al, 1984;Orci et al, 1987). However, individual thin sections rarely reveal the full extent of the cisternae in a given Golgi stack, because of convolution of the membranes and the presence of openings in the cisternae, such as fenestrae and "holes" (Rambourg et al, 1979;Rambourg and Clermont, 1990;Ladinsky et al, 1999).…”

<b>Changes in the three-dimensional ultrastructure of membranous organelles in male rat pituitary gonadotropes after castration</b>

“…Observation of the osmium-macerated specimens with high-resolution SEM also revealed the 3D ultrastructure of the tubuloreticular network in the pre-Golgi compartment in gonadotropes. The occurrence of the osmiophilic tubular network/elements in the proximity of the cis-face of the Golgi apparatus was identified by the stereoscopic observation of paired tilted images by high voltage TEM (9,(36)(37)(38). Based on the specific localization of a 53-58 kD protein, designated ERGIC-53 (42) or p58 (41) in the structure, this tubular network in the vicinity of the cis-Golgi is regarded as a discrete compartment, the ERGIC (3, 4, 18) or VTC (4).…”

Glucose‐6‐phosphatase activity of endoplasmic reticulum and Golgi apparatus in spermatocytes and spermatids of the rat: an electron microscopic cytochemical study

“…Clusters of small vesicles observed next to such ER protrusions are considered as carriers of partly glycosylated proteins from the ER to the Golgi saccules [5,6,10,29]. The relationship of ER cisternae with the trans-aspect of the Golgi stacks, although described in some cells [8, 11-13, 30,31], has been given less attention. Novikoff et al [27,28] have emphasized the close association of ER cisternae with secretory vesicles and lysosomes on the trans-aspect of the Golgi apparatus (GERL concept).…”