The aim of this work was to investigate the role played by the axial organs, neural tube and notochord, on the differentiation of muscle cells from the somites in the avian embryo. Two of us have previously shown that neuralectomy and notochordectomy is followed by necrosis of the somites and consecutive absence of vertebrae and of most muscle cells derived from the myotomes while the limbs dev...

BACKGROUND The differentiation of floor plate cells and motor neurons in the vertebrate neural tube appears to be induced by signals from the notochord. The secreted protein encoded by the Sonic hedgehog (Shh) gene is expressed by axial midline cells and can induce floor plate cells in vivo and in vitro. Motor neurons can also be induced in vitro by cells that synthesize Sonic hedgehog protein ...

The signalling molecule Sonic hedgehog (Shh) controls a wide range of differentiation processes during vertebrate development. Numerous studies have suggested that the absolute levels as well as correct spatial and temporal expression of shh are critical for its function. To investigate the regulation of shh expression, we have studied the mechanism controlling its spatial expression in the zeb...

It is well known that glycoconjugate components of the cell surface and extracellular matrix, play an essential role(s) in many developmental phenomena such as cell differentiation, migration, and cellular interactions. The purpose of this study was to investigate distribution of this macromolecules during differentiation of the notochord and paraxial mesoderm. Formalin fixed paraffin sections ...

The development of the notochord, perichordal sheath and vertebrae was studied in C57BL/6 and Danforth's short-tail (Sd) mutant mice on days 9-14 of gestation, using histochemical stains to detect possible extracellular matrix (ECM) components or precursors. Stains used were periodic-acid Schiff (PAS) after diastase treatment (glycoproteins, neutral polysaccharides) and alcian blue (glycosamino...