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Cellular basis of neuroepithelial bending during mouse spinal neural tube closure.

McShane SG, Molè MA, Savery D, Greene ND, Tam PP, Copp AJ - Dev. Biol. (2015)

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.

View Article: PubMed Central - PubMed

Affiliation: Newlife Birth Defects Research Centre, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK.

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Markers of cell cycle variation during neural plate bending. (A) 3H-thymidine incorporation in the PNP at Mode 2, following 2 h exposure in vitro. Incorporation intensity (black autoradiographic grains on Toluidine Blue stained background) appears highest dorsolaterally (arrow) and lowest at the MHP. (B-E) Immunohistochemistry for Cdk4 (B), Cyclin D1 (C, D) and p27 (E). The dorsolateral neural plate exhibits the most intense signal for both Cdk4 and Cyclin D1 (arrows in B-D), consistent with enhanced 3H-thymidine incorporation dorsally. When the surface ectoderm (DSE and LSE: see Fig. 5A) is removed surgically from the PNP region (dashed line in D), Cyclin D1 expression is lost within 30 min. The cell cycle inhibitor p27 (E) is expressed solely in the notochord (no) consistent with its prolonged cell cycle time. Serial sections from a minimum of three embryos were analysed with each antibody. Scale bars: 25 μm in A; 50  μm in B (also C-E).
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f0025: Markers of cell cycle variation during neural plate bending. (A) 3H-thymidine incorporation in the PNP at Mode 2, following 2 h exposure in vitro. Incorporation intensity (black autoradiographic grains on Toluidine Blue stained background) appears highest dorsolaterally (arrow) and lowest at the MHP. (B-E) Immunohistochemistry for Cdk4 (B), Cyclin D1 (C, D) and p27 (E). The dorsolateral neural plate exhibits the most intense signal for both Cdk4 and Cyclin D1 (arrows in B-D), consistent with enhanced 3H-thymidine incorporation dorsally. When the surface ectoderm (DSE and LSE: see Fig. 5A) is removed surgically from the PNP region (dashed line in D), Cyclin D1 expression is lost within 30 min. The cell cycle inhibitor p27 (E) is expressed solely in the notochord (no) consistent with its prolonged cell cycle time. Serial sections from a minimum of three embryos were analysed with each antibody. Scale bars: 25 μm in A; 50  μm in B (also C-E).

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).


Cellular basis of neuroepithelial bending during mouse spinal neural tube closure.

McShane SG, Molè MA, Savery D, Greene ND, Tam PP, Copp AJ - Dev. Biol. (2015)

Markers of cell cycle variation during neural plate bending. (A) 3H-thymidine incorporation in the PNP at Mode 2, following 2 h exposure in vitro. Incorporation intensity (black autoradiographic grains on Toluidine Blue stained background) appears highest dorsolaterally (arrow) and lowest at the MHP. (B-E) Immunohistochemistry for Cdk4 (B), Cyclin D1 (C, D) and p27 (E). The dorsolateral neural plate exhibits the most intense signal for both Cdk4 and Cyclin D1 (arrows in B-D), consistent with enhanced 3H-thymidine incorporation dorsally. When the surface ectoderm (DSE and LSE: see Fig. 5A) is removed surgically from the PNP region (dashed line in D), Cyclin D1 expression is lost within 30 min. The cell cycle inhibitor p27 (E) is expressed solely in the notochord (no) consistent with its prolonged cell cycle time. Serial sections from a minimum of three embryos were analysed with each antibody. Scale bars: 25 μm in A; 50  μm in B (also C-E).
© Copyright Policy - CC BY
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4528075&req=5

f0025: Markers of cell cycle variation during neural plate bending. (A) 3H-thymidine incorporation in the PNP at Mode 2, following 2 h exposure in vitro. Incorporation intensity (black autoradiographic grains on Toluidine Blue stained background) appears highest dorsolaterally (arrow) and lowest at the MHP. (B-E) Immunohistochemistry for Cdk4 (B), Cyclin D1 (C, D) and p27 (E). The dorsolateral neural plate exhibits the most intense signal for both Cdk4 and Cyclin D1 (arrows in B-D), consistent with enhanced 3H-thymidine incorporation dorsally. When the surface ectoderm (DSE and LSE: see Fig. 5A) is removed surgically from the PNP region (dashed line in D), Cyclin D1 expression is lost within 30 min. The cell cycle inhibitor p27 (E) is expressed solely in the notochord (no) consistent with its prolonged cell cycle time. Serial sections from a minimum of three embryos were analysed with each antibody. Scale bars: 25 μm in A; 50  μm in B (also C-E).
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).

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.

View Article: PubMed Central - PubMed

Affiliation: Newlife Birth Defects Research Centre, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK.

Show MeSH
Related in: MedlinePlus