Cellular basis of neuroepithelial bending during mouse spinal neural tube closure.
Bottom Line: As the neural folds elevate, cell numbers increase to a greater extent in the dorsolateral neural plate that contacts the surface ectoderm, compared with the more ventromedial neural plate where cells contact paraxial mesoderm and notochord.We hypothesised that neuroepithelial cells may translocate in a ventral-to-dorsal direction as DLHP formation occurs, and this was confirmed by vital cell labelling in cultured embryos.These findings suggest a model in which DLHP formation may proceed through 'buckling' of the neuroepithelium at a dorso-ventral boundary marked by a change in cell-packing density.
Affiliation: Newlife Birth Defects Research Centre, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK.Show MeSH
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Mentions: A dorso-ventral difference in 3H-thymidine incorporation was evident in the PNP of a Mode 2 embryo following 2 h labelling in vitro (Fig. 5A). Moreover, Cdk4 expression was detected in the dorsal neural plate and adjacent surface ectoderm (Fig. 5B). Cyclin D1, which interacts with Cdk4 during G1 to S transition of the cell cycle (Sherr and Roberts, 2004), was widely expressed in the neuroepithelium, with an apparent dorsal-to-ventral gradient of expression intensity (Fig. 5C). The notochord also showed intense Cyclin D1 expression (Fig. 5C) but this was co-expressed with the cell cycle inhibitor p27 (Fig. 5E), perhaps accounting for the notochord’s diminished cell proliferative activity (Smith and Schoenwolf, 1987; Copp et al., 1988).
Affiliation: Newlife Birth Defects Research Centre, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK.