|
|
|
|
|
|
|
|
|||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | |||||
|
Fig. 3. Transmission electron microscopy reveals TJs in wild-type and mutant cystic EBs. Micrographs show junctional complexes between epithelial cells of wild-type (B), heterozygous (+/–) (A,C) and homozygous (–/–) (D) EBs. Images were obtained from cystic EBs sectioned through their centers in a near-equatorial position. The outer surface of the cyst is at the top of each frame. (A) Low-magnification micrograph showing an example of a cystic EB (+/–), comprising an outer layer of epithelial cells (corresponding to visceral endoderm, indicated by bracket) and an inner layer. The outer layer cells were polarized, with apical microvilli (mv) projecting towards the outer surface and phagocytic vesicles (ph) in the cytoplasm. The two layers were usually separated by an intercellular space and the inner layer was not consistently detected. The inner layer of cells is referred to in the literature as ectoderm (Doetschman et al., 1985; Ikeda et al., 1999; Saitou et al., 1998) or undifferentiated cells (Soudais et al., 1995). The same ultrastructure was observed in all wild-type and mutant EBs. (B-D) Higher-magnification micrographs showing the apico-lateral membranes of adjoining outer epithelial cells. Inserts show, at higher magnifications, the areas of junctional complexes. The typical morphology of TJs, with intimate membrane interconnections, is seen irrespective of the cells genotype (B-D, arrows). TJs are occasionally associated with desmosomes (De in D). Scale bars, 2 µm (A), 100 nm (B-D).
|
