It was shown by Brandt (1944) that phocomelias and atrophied limbs can be produced experimentally after deep implantation of embryonic ectoderm into the primordium of the limb bud in the tail-bud stage (Harrison's stage no. 35) of the amblystoma embryo. The following microscopical analysis of the operated specimens shows some new results which concern the histological changes of the implanted e...

We have identified chick frizzled (Fz)-10, encoding a Wnt receptor, and examined the expression pattern during embryogenesis. Fz-10 is expressed in the region posterior to the Hensen's node at stage 6. Fz-10 expression is detected in the dorsal domain of the neural tube and the central nervous system of the developing embryo. In the developing limb, Fz-10 expression starts at stage 18 in the po...

IIntroduction I-1. Developmental genes in Drosophila I-2. Skeletal development in human IIDevelopment of the axial skeleton II-1. Signaling molecules involved in the determination of sclerotome to cartilage II2. Role of Hox genes in the regulation of vertebral segments IIIDevelopment of the limbs (appendicular skeleton) III-1. Limb bud differentiation with respect to three axes III-2. Role of F...

We are currently investigating the mechanism by which the apical ectodermal ridge (AER) of the embryonic chick limb bud exerts its negative effect on the cytodifferentiation of limb mesenchymal cells directly subjacent to it, and the mechanism by which cytodifferentiation is triggered when the cells leave the influence of the AER. Since there is a gradation of differentiation along the proximod...

Several well-characterized extracellular matrix (ECM) components have been localized to the amphibian limb regenerate, but the identification and characterization of novel ECM molecules have received little attention. Here we describe, using mAb MT1 and immunocytochemistry, an ECM molecule expressed during limb regeneration and limb development. In limb stumps, mAb MT1 reactivity was restricted...

A crucial issue in limb development is how a correct set of precisely shaped digits forms in the digital plate. This process relies on patterning across the anterior-posterior axis of the limb bud, which is under the control of Sonic hedgehog emanating from the zone of polarizing activity. Recently, Sonic hedgehog function in the limb bud has been shown to have a dual character controlling both...

The development of vertebrate limbs is an excellent model to study patterning and growth regulation in embryogenesis (Capdevila and Izpisua Belmonte, 2001; Johnson and Tabin, 1997). The limb buds that result in morphologically distinct forelimbs and hindlimbs arise from the lateral plate mesoderm (LPM) at precise locations along the anteroposterior (AP) axis of the embryo. The induction of limb...

Several factors have been proposed as contributors to interfamilial and intrafamilial phenotypic variability in autosomal dominant disorders, including allelic variation, modifier genes, environmental factors and complex genetic and environmental interactions. However, regardless of the similarity of genetic background and environmental factors, asymmetric limb or trunk anomalies in a single in...