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.
Kuroda
H
H
Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Japan.
Sakumoto
H
H
Kinoshita
K
K
Asashima
M
M
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