Changes in the adhesive properties of dissociated and reaggregated Xenopus laevis embryo cells.
Activin A is a member of the transforming growth factor beta superfamily, and the strongest candidate mesoderm-inducer. The initial adhesive property changes in amphibians are likely to be mediated by mesoderm-inducers like activin A. The manner in which these changes actually occur, however, remains poorly understood. In the present study, the adhesive property changes mediated by activin A were directly demonstrated. Activin A functioned as a morphogen at low concentrations (less than 0.5 ng/mL), with no effect on the type A adhesive property. But at high concentrations (1 ng/mL), it induced another type of adhesive property, type N, and at very high concentrations (more than 10 ng/mL), it induced yet another type of adhesive property, type Y. Cells that have types A, N, and Y adhesive properties ultimately differentiated into atypical epidermis, notochord, and yolk-rich cells, respectively. It was also shown that these changes occurred between 5 and 10 h after induction by activin A. The implications of these results for the relationship between the adhesive property acquired during early and later stages of differentiation are also discussed.
Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Japan.
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H
Kuroda
H
H
Sakumoto
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K
Kinoshita
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M
Asashima
D028341:Activins; D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects; D004625:Embryo, Nonmammalian / Q000166:cytology*; D007265:Inhibins / Q000494:pharmacology; D014982:Xenopus laevis / Q000196:embryology
D028341:Activins; D007265:Inhibins