Studies on the expression of intracellular and surface polarity in animal pole cells of Xenopus embryos cultured on various substrata

The expression of intracellular and surface polarity in animal pole cells of Xenopus embryos (stage 10) cultured on various substrata was studied by electron microscopy. When animal pole cells of Xenopus embryos were cultured on type I collagen- or gelatin-coated dishes until control embryos reached stage 23, the cells in confluent layers expressed an apical-basal polarity so that the apical surface membrane domain faced the culture medium. However, the cells in confluent layers cultured on naked plastic dishes were suppressed to express intracellular and surface polarity. In addition, single attached cells which were formed by being sparsely plated neither spread on any substrata nor displayed the apical-basal polarity perpendicular to the dishes. These results indicate that the expression of intracellular and surface polarity in cultured animal pole cells of Xenopus embryos requires not only cell-cell contact but also an adhesive substrata such as type I collagen or gelatin.