...A. Feijen; M. J. Goumans; A. J. M. van den; Eijnden-van Raaij ABSTRACT Using in situ hybridization we have studied the localization of the messenger RNAs encoding the inhibin/activin subunits (α, βA, βB), the activin-binding protein follistatin and activin receptors (IIA, IIB) in mouse embryos...

... by the organizer. This dorsalizing signal operates throughout gastrulation, can cross a Nuclepore membrane, and is not mimicked by lithium, FGFs or activin. Anteroposterior specification also takes place during gastrulation and is probably controlled by a dominant region at the posterior end of the forming axis...