[Studies on the mechanism of closure of the embryonic fissure (II). A morphological study of a transmission electron microscope].
The object of this study was to elucidate the mechanism of closure of the embryonic fissure with a transmission electron microscope in mouse embryos. Every specimen was cut at right angle to the embryonic fissure. Desmosome-like junctions and gap junctions were found between the cells of the inner wall and those of the outer wall of the optic cup. The lip facing the embryonic fissure of the optic cup was covered with the basal lamina. In the section immediately before closure, the cells composing the lip were flattened and had processes on their margins. In addition, collagen fibrils appeared in some portions on the basal lamina. The more posterior section of the same specimen showed immature cell junctions and fusing parts between the cells of both sides. It was deduced that the cells which composed the lip produced the collagen fibrils on the basal lamina when both lips drew closer together. After the adhesion of both basal laminae, immature cell junctions appeared transiently between the cells on either side. The fusion of these cells resulted from disappearance of the cell junctions.
Suzuki
T
T
Shirai
S
S
Majima
A
A
D000818:Animals; D001485:Basement Membrane / Q000648:ultrastructure; D003896:Desmosomes / Q000648:ultrastructure; D005123:Eye / Q000196:embryology* / Q000648:ultrastructure; D051379:Mice; D008813:Mice, Inbred ICR; D008854:Microscopy, Electron