... of positional information in the early Drosophila embryo . Nature 430 , 368 - 371 . 10.1038/nature02678 Jiang , J. and Levine , M. ( 1993 ). Binding affinities and cooperative interactions with bHLH activators delimit threshold responses to the dorsal gradient morphogen . Cell 72...

... ventral and posterior tissues such as mesenchyme and mesothelium. In this paper we investigate whether this threshold phenomenon involves the differential effects of the two type I activin receptors ALK-2 and ALK-4. Injection of RNA encoding constitutively active forms of the receptors (here designated...

... © 1995 by Company of Biologists 1995 Xenopus Brachyury Pintallavis goosecoid mesoderm induction thresholds Induction of the mesoderm in amphibian embryos is thought to be initiated by members of the FGF and TGF-β families of polypeptide growth factors ( Kimelman...

... by the factors. * Present address: Department of Zoology, University of California, Berkeley, CA 94720, USA Copyright © 1989 by Company of Biologists 1989 mesoderm induction mesoderm-inducing factors bFGF XTC-MIF thresholds gastrulation amphibian embryo Xenopus laevis developmental...