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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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Embryo and posterior neuropore (PNP) morphology at successive stages of mouse spinal neurulation. (A, B, E, F, I, J) Whole embryos at E8.5 (A), E9.5 (E) and E10 (I) and enlarged views of the caudal region (B, F, J; white dotted boxes in A, E, I). The PNP (black dotted lines) shortens progressively as development proceeds. Arrows indicate level of sections through flat (f) and elevated (e) neural plate. (C, D, G, H, K, L) Transverse 2.5 μm thick plastic sections through the PNP showing transition from flat (C, G, K) to elevated (D, H, L) neural folds. At E8.5 (C, D; Mode 1), bending is solely at MHP (red box); at E9.5 (G, H; Mode 2), both MHP and DLHPs (black box) are present, with non-bending lateral neural plate (LAT) in between; at E10 (K, L; Mode 3), only DLHP bending occurs. Dorsolateral non-bending neural plate at Mode 1 (dotted black box, D) and midline non-bending neural plate at Mode 3 (dotted red box, L) were also analysed. Dashed lines (K, L): boundary between neural fold (nf) and neuroepithelium outside neural fold (npr); solid line (K): midline. Red arrowheads (K): surface ectoderm juxtaposed to neuroepithelium of the neural fold. Abbreviations: da, dorsal aorta; not, notochord; np, neural plate; pm, paraxial mesoderm; s, somite number. Scale bars: A,B,E,F,I,J: 0.5 mm; L (for all sections): 0.1 mm.
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f0005: Embryo and posterior neuropore (PNP) morphology at successive stages of mouse spinal neurulation. (A, B, E, F, I, J) Whole embryos at E8.5 (A), E9.5 (E) and E10 (I) and enlarged views of the caudal region (B, F, J; white dotted boxes in A, E, I). The PNP (black dotted lines) shortens progressively as development proceeds. Arrows indicate level of sections through flat (f) and elevated (e) neural plate. (C, D, G, H, K, L) Transverse 2.5 μm thick plastic sections through the PNP showing transition from flat (C, G, K) to elevated (D, H, L) neural folds. At E8.5 (C, D; Mode 1), bending is solely at MHP (red box); at E9.5 (G, H; Mode 2), both MHP and DLHPs (black box) are present, with non-bending lateral neural plate (LAT) in between; at E10 (K, L; Mode 3), only DLHP bending occurs. Dorsolateral non-bending neural plate at Mode 1 (dotted black box, D) and midline non-bending neural plate at Mode 3 (dotted red box, L) were also analysed. Dashed lines (K, L): boundary between neural fold (nf) and neuroepithelium outside neural fold (npr); solid line (K): midline. Red arrowheads (K): surface ectoderm juxtaposed to neuroepithelium of the neural fold. Abbreviations: da, dorsal aorta; not, notochord; np, neural plate; pm, paraxial mesoderm; s, somite number. Scale bars: A,B,E,F,I,J: 0.5 mm; L (for all sections): 0.1 mm.

Mentions: Embryos within specific somite number ranges were selected for analysis, in order to represent the characteristic morphology of the three Modes of neurulation: Mode 1 (MHP only), 10-12 somites; Mode 2 (MHP and DLHPs), 19-21 somites; Mode 3 (DLHPs only), 28-30 somites. Five embryos of each Mode were analysed with data gathered in each embryo from two rostro-caudal levels of the posterior neuropore (PNP): flat and elevated neural plate (Fig. 1).


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)

Embryo and posterior neuropore (PNP) morphology at successive stages of mouse spinal neurulation. (A, B, E, F, I, J) Whole embryos at E8.5 (A), E9.5 (E) and E10 (I) and enlarged views of the caudal region (B, F, J; white dotted boxes in A, E, I). The PNP (black dotted lines) shortens progressively as development proceeds. Arrows indicate level of sections through flat (f) and elevated (e) neural plate. (C, D, G, H, K, L) Transverse 2.5 μm thick plastic sections through the PNP showing transition from flat (C, G, K) to elevated (D, H, L) neural folds. At E8.5 (C, D; Mode 1), bending is solely at MHP (red box); at E9.5 (G, H; Mode 2), both MHP and DLHPs (black box) are present, with non-bending lateral neural plate (LAT) in between; at E10 (K, L; Mode 3), only DLHP bending occurs. Dorsolateral non-bending neural plate at Mode 1 (dotted black box, D) and midline non-bending neural plate at Mode 3 (dotted red box, L) were also analysed. Dashed lines (K, L): boundary between neural fold (nf) and neuroepithelium outside neural fold (npr); solid line (K): midline. Red arrowheads (K): surface ectoderm juxtaposed to neuroepithelium of the neural fold. Abbreviations: da, dorsal aorta; not, notochord; np, neural plate; pm, paraxial mesoderm; s, somite number. Scale bars: A,B,E,F,I,J: 0.5 mm; L (for all sections): 0.1 mm.
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Related In: Results  -  Collection

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f0005: Embryo and posterior neuropore (PNP) morphology at successive stages of mouse spinal neurulation. (A, B, E, F, I, J) Whole embryos at E8.5 (A), E9.5 (E) and E10 (I) and enlarged views of the caudal region (B, F, J; white dotted boxes in A, E, I). The PNP (black dotted lines) shortens progressively as development proceeds. Arrows indicate level of sections through flat (f) and elevated (e) neural plate. (C, D, G, H, K, L) Transverse 2.5 μm thick plastic sections through the PNP showing transition from flat (C, G, K) to elevated (D, H, L) neural folds. At E8.5 (C, D; Mode 1), bending is solely at MHP (red box); at E9.5 (G, H; Mode 2), both MHP and DLHPs (black box) are present, with non-bending lateral neural plate (LAT) in between; at E10 (K, L; Mode 3), only DLHP bending occurs. Dorsolateral non-bending neural plate at Mode 1 (dotted black box, D) and midline non-bending neural plate at Mode 3 (dotted red box, L) were also analysed. Dashed lines (K, L): boundary between neural fold (nf) and neuroepithelium outside neural fold (npr); solid line (K): midline. Red arrowheads (K): surface ectoderm juxtaposed to neuroepithelium of the neural fold. Abbreviations: da, dorsal aorta; not, notochord; np, neural plate; pm, paraxial mesoderm; s, somite number. Scale bars: A,B,E,F,I,J: 0.5 mm; L (for all sections): 0.1 mm.
Mentions: Embryos within specific somite number ranges were selected for analysis, in order to represent the characteristic morphology of the three Modes of neurulation: Mode 1 (MHP only), 10-12 somites; Mode 2 (MHP and DLHPs), 19-21 somites; Mode 3 (DLHPs only), 28-30 somites. Five embryos of each Mode were analysed with data gathered in each embryo from two rostro-caudal levels of the posterior neuropore (PNP): flat and elevated neural plate (Fig. 1).

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