The Spemann organizer in amphibian embryos is a tissue with potent head-inducing activity,
the molecular nature of which is unresolved. Here we describe dickkopf-1 (dkk-1), which …

The Spemann organizer of the amphibian embryo can be subdivided into two discrete
activities, namely trunk organizer and head organizer. Several factors secreted from the …

A SECRETED signalling molecule encoded by the Wnt-1 gene is required for development
of the central nervous system. In mouse embryos homozygous for a Wnt-1-null allele, the …

Formation of the head during vertebrate embryogenesis has been one of the most-studied
topics in development, probably because we are such cephalized beings ourselves. Early …

Embryological and genetic evidence indicates that the vertebrate head is induced by a
different set of signals from those that organize trunk–tail development,,,,,. The gene …

Growth factor antagonists play important roles in mediating the inductive effects of the
Spemann organizer in amphibian embryos and its equivalents in other vertebrates. Dual …

Members of the Wnt and TGF-β superfamilies regulate both cell fate and proliferation during
development and tissue maintenance,,. In the early amphibian embryo, the Wnt and TGF-β …

The Wnt family of secreted glycoproteins mediate cell–cell interactions during cell growth
and differentiation in both embryos and adults,. Canonical Wnt signalling by way of the β …

The vertebrate body plan is established during gastrulation, when cells move inwards to
form the mesodermal and endodermal germ layers. Signals from a region of dorsal …

Segmentation in Drosophila is based on a cascade of hierarchical gene interactions initiated
by maternally deposited morphogens that define the spatially restricted domains of gap …