Mutations that affect vertebrate limb development provide insight into pattern formation, evolutionary biology and human birth defects. Patterning of the limb axes depends on several interacting signaling centers; one of these, the zone of polarizing activity (ZPA), comprises a group of mesenchymal cells along the posterior aspect of the limb bud that express sonic hedgehog (Shh) and plays a ke...

Fibroblast growth factor homologous factors (FHFs) have been implicated in limb and nervous system development. In this paper we describe the expression of the cFHF-4 gene during early chicken development. cFHF-4 is expressed in the paraxial mesoderm, lateral ridge, and, most prominently, in the posterior-dorsal side of the base of each limb bud. The expression pattern of cFHF-4 at the base of ...

Two closely related homeobox transcription factors, Pitx1 and Pitx2, have been implicated in patterning of lateral plate mesoderm derivatives: Pitx1 for specification of hindlimb identity and Pitx2 for determination of laterality. We show that, together, Pitx1 and Pitx2 are required for formation of hindlimb buds and, when present in limited doses, for development of proximal (femur) and anteri...

Early in embryogenesis, precursors of the limb musculature are generated in the somite, migrate to the limb buds and undergo terminal differentiation. Although myogenic differentiation in culture is affected by several growth factors including fibroblast growth factor (FGF), it remains uncertain whether migration and differentiation of myogenic cells in vivo are directly regulated by such growt...

Outgrowth and patterning of the vertebrate limb requires a functional apical ectodermal ridge (AER). The AER is a thickening of ectodermal tissue located at the distal end of the limb bud. Loss of this structure, either through genetic or physical manipulations results in truncation of the limb. A number of genes, including Bmps, are expressed in the AER. Previously, it was shown that removal o...

We have isolated the cDNA of avian Mox2 and analyzed its expression pattern during somitogenesis and limb bud formation. Mox2 plays an important role in limb muscle differentiation in the mouse. Mox2 is expressed in the somites of developing chick embryos and in presumptive migrating myoblasts from the dermomyotome to the limb buds. It is also expressed in the ventral and dorsal part of limb bu...

This study is a continuing investigation of the effect of the brachypod mouse mutation on cell interactions and chondrogenesis during early limb development. In this report, cell adhesiveness was assessed in fused fragments of brachypod and normal limb-bud mesenchyme. Examination of the interface of fused distal postaxial limb fragments show brachypod limb mesenchyme to be more adhesive than no...

During limb development, the mesenchymal cells in restricted areas of limb bud, anterior necrotic zone, posterior necrotic zone, opaque zone and interdigital necrotic zones, are eliminated by programmed cell death. The transcripts of bone morphogenetic protein (Bmp)-2 and -4 were first detected in the areas where cell death was observed, then showed overlapping expression with the programmed ce...