Freeze-Etching Observation on the Development of Intercellular Junctions of the Duodenal Epithelial Cells in the Chick Embryo

Okamoto, Hisao; Ishimura, Kazunori

doi:10.1679/aohc1950.41.325

Cited by 13 publications

(3 citation statements)

References 24 publications

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“…Perhaps, this kind of tight junction formation process is a general phenomenon in mammalian epithelial cell development. As has been noted previously by other authors [Simionescu and Simionescu, 1977;Okamoto and Ishimura. 1978;Yan cey cr al., 1979;Minutli et al.…”

Section: Discussionsupporting

confidence: 82%

Formation of Tight and Gap Junctions in the Inner Enamel Epithelium and Preameloblasts in Human Fetal Tooth Germs

Sasaki¹,

Segawa

Takiguchi

et al. 1985

Cells Tissues Organs

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Human fetal primary tooth germs in the cap stage were fixed with a glutaraldehyde-formaldehyde mixture, and formative processes of tight and gap junctions of the inner enamel epithelium and preameloblasts were examined by means of freeze-fracture replication. Chains of small clusters of particles on the plasma membrane P-face of the inner enamel epithelium and preameloblasts were the initial sign of tight junction formation. After arranging themselves in discontinuous, linear arrays in association with preexisting or forming gap junctions, these particles later began revealing smooth, continuous tight junctional strands on the plasma membrane P-face and corresponding shallow grooves of a similar pattern on the E-face. Although they exhibited evident meshwork structures of various extents at both the proximal and distal ends of cell bodies, they formed no zonulae occludentes. Small assemblies of particles resembling gap junctions were noted at points of cross linkage of tight junctional strands; but large, mature gap junctions no longer continued into the tight junction meshwork structure. Gap junctions first appeared as very small particle clusters on the plasma membrane P-face of the inner enamel epithelium. Later two types of gap junctions were recognized: one consisted of quite densely aggregated particles with occasional particle-free areas, and the other consisted of relatively loosely aggregated particles with particle-free areas and aisles. Gap junction maturation seemed to consist in an increase of particle numbers. Fusion of gap junctions in the forming stage too was recognized. The results of this investigation suggest that, from an early stage in their development, human fetal ameloblasts possess highly differentiated cell-to-cell interrelations.

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Section: Discussionsupporting

confidence: 82%

Formation of Tight and Gap Junctions in the Inner Enamel Epithelium and Preameloblasts in Human Fetal Tooth Germs

Sasaki¹,

Segawa

Takiguchi

et al. 1985

Cells Tissues Organs

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show abstract

“…Using a freeze-etching procedure, Okamoto and Ishimura (1978) studied the development of intercellular junctions in the duodenal epithelium of chick embryos, and reported that incomplete tight junctions were already present after 6-7 days of incubation in the apical portion of the lateral plasma membrane, suggesting that tight junctions begin to form in the gastrointestinal tract at an early developmental stage. Thereafter, tight junctions develop rapidly and form complicated networks (Okamoto and Ishimura 1978). This developmental process has also been reported in the rat small intestine and thyroid follicles (Yamamoto et al 1992).…”

Section: Discussionmentioning

confidence: 99%

“…This indicates that the developmental expression of occludin in the gastrointestinal tract is closely correlated with the morphological as well as functional development of the tight junction. Okamoto and Ishimura (1978) reported that formation of the tight junction in chick duodenum might be complete by day 18 of incubation. Recently, the distribution of 7H6 and occludin has been studied during develop-ment of the chick intestine (Kimura et al 1996).…”

Section: Discussionmentioning

confidence: 99%

Developmental expression of the tight junction protein, occludin, in the gastrointestinal tract of the chick embryo

Kawasaki

Hayashi

Nishida

et al. 1997

Histochemistry and Cell Biology

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The developmental expression of occludin was studied biochemically in whole chick embryos to determine when intercellular tight junctions develop. Occludin mRNA was first detected after 3 days of incubation by the reverse transcriptase-polymerase chain reaction. On northern blot analysis, although occludin mRNA was not discernible in 3-day-old embryos, weak but clear expression was noted on day 4 of incubation and increased dramatically in 5-day-old embryos. Occludin was not detectable on days 3 or 4 of incubation by western blot analysis, and was first detected in 5-day-old embryos. In addition, the expression of occludin was examined immunohistochemically in the gastrointestinal tract of 3- to 21-day-old embryos. Immunoreactivity for occludin was not expressed on day 3 of incubation. On day 4 of incubation, weak immunoreactivity was demonstrated in the gastrointestinal tract, and gradually became stronger with development. By day 11 of incubation, a positive immunoreaction was obtained only on the apical surfaces of the epithelial cells, i.e., at the junctional complexes, while weak immunoreactivity was diffusely distributed throughout the epithelial cells. The possible roles of occludin in the developing gastrointestinal tract are discussed.

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The structure of tight junctions in the tracheal epithelium may not correlate with permeability

et al. 1984

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To test the hypothesis that cigarette smoke produces changes in the morphology of tight junctions guinea pigs were exposed to cigarette smoke or air in a previously standardized fashion (Simani et al. 1974). Permeability is greatest one half hour following exposure to cigarette smoke (Hulbert et al. 1981). The animals were sacrificed at that time. The tracheal epithelium was studied using both thin-section and freeze-fracture techniques. A quantitative analysis of the organization and integrity of junctional complexes was performed for each animal. Organization was assessed by measuring and comparing areas delimited by PF fibers and EF furrows. PF fiber integrity was assessed by measuring uninterrupted lengths of fibers and furrows from freeze-fracture replicas. This assessment did not demonstrate a change in tight-junction morphology following exposure to cigarette smoke.

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Freeze-Etching Observation on the Development of Intercellular Junctions of the Duodenal Epithelial Cells in the Chick Embryo

Cited by 13 publications

References 24 publications

Formation of Tight and Gap Junctions in the Inner Enamel Epithelium and Preameloblasts in Human Fetal Tooth Germs

Formation of Tight and Gap Junctions in the Inner Enamel Epithelium and Preameloblasts in Human Fetal Tooth Germs

Developmental expression of the tight junction protein, occludin, in the gastrointestinal tract of the chick embryo

The structure of tight junctions in the tracheal epithelium may not correlate with permeability

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