title: Concentration-dependent inducing activity of activin A.
abstract: Human recombinant activin A, which is identical with erythroid differentiation factor (EDF), was tested for its mesoderm-inducing activity in concentrations from 0.3-50 ng/ml, using ectoderm of Xenopus late blastula (Stage 9) as the responding tissue. At a low concentration of activin A, blood-like cells, mesenchyme, and coelomic epithelium were induced; at a moderate concentration muscle and neural tissue, and at a high concentration notochord. Activin A thus induced all mesodermal tissues in a dose-dependent manner, such that a low dose induced ventral structures and a high dose induced dorsal structures. Activin may act as an intrinsic inducing molecule responsible for establishing the dorso-ventral axis in early Xenopus development.
authors.affiliation: Department of Biology, Yokohama City University, 22-2 Seto, 236, Kanazawa-ku, Yokohama, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Ariizumi
authors.affiliation: Department of Biology, Yokohama City University, 22-2 Seto, 236, Kanazawa-ku, Yokohama, Japan.
authors.forename: Naomi
authors.initials: N
authors.lastname: Moriya
authors.affiliation: Department of Biology, Yokohama City University, 22-2 Seto, 236, Kanazawa-ku, Yokohama, Japan.
authors.forename: Hideho
authors.initials: H
authors.lastname: Uchiyama
authors.affiliation: Department of Biology, Yokohama City University, 22-2 Seto, 236, Kanazawa-ku, Yokohama, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Asashima
keywords: Activin A; Amphibians; Erythroid differentiation factor; Gradient; Mesoderm induction