Planar-cell-polarity (PCP) signalling is necessary for initiation of neural tube closure in higher vertebrates. In mice with PCP gene mutations, a broad embryonic midline prevents the onset of neurulation through wide spacing of the neural folds. In order to evaluate the role of convergent extension in this defect, we vitally labelled the midline of loop-tail (Lp) embryos mutant for the PCP gen...

The morphogenetic movements of the ectoderm during neurulation include: (1) the movements taking place within the neural plate, which becomes longer and more concentrated in a medio-lateral direction (Jacobson, 1962); and (2) those found in the lateral epidermis layer which, in an epibolic way, moves in a dorsal direction, thus exerting a pushing effect on the lateral edges of the neural plate ...

Previous studies have shown that diabetic embryopathy results from impaired expression of genes that are required for formation of embryonic structures. We have focused on Pax3, a gene that is expressed in embryonic neuroepithelium and is required for neural tube closure. Pax3 expression is inhibited in embryos of diabetic mice due to hyperglycemia-induced oxidative stress. DNA methylation sile...

The importance of Transforming Growth Factor β (TGFβ) signalling during early development has been well established. In particular, Nodal ligands have been shown to play essential roles for the specification and the patterning of the mesendoderm, axes formation and organogenesis. Activin ligands, like Nodal, signal by inducing the phosphorylation of the intracellular signal transducers Smad2 an...

Neural crest cells (NCCs) arising from trunk neural tube (NT) during primary and secondary neurulation give rise to melanocytes, glia and neurons, except for those in the caudal-most region during secondary neurulation (somites 47 to 53 in the chick embryo), from which no neurons are formed, either in vivo or in vitro. To elucidate this discrepancy, we have specifically analyzed caudal-most NCC...

Previous studies of the avian blastoderm have revealed that extensive displacements occur within the epiblast during gastrulation and neurulation. The present study had two main purposes: (1) to map the origin and movement of prospective surface epithelial cells, and (2) to ask whether neurepithelial and surface epithelial cell fates are determined prior to cell movement, or whether they arise ...