BMP-7 influences pattern and growth of the developing hindbrain of mouse embryos

Development ◽  
1997 ◽  
Vol 124 (1) ◽  
pp. 1-12 ◽  
Author(s):  
R. Arkell ◽  
R.S. Beddington
Keyword(s):  
Sonic Hedgehog ◽  
Neural Tube ◽  
Mouse Embryos ◽  
Chick Embryos ◽  
Dorsoventral Patterning ◽  
Surface Ectoderm ◽  
Bone Morphogenetic Protein 7 ◽  
Cos Cells ◽  
Morphogenetic Protein ◽  
Timing Mechanisms

The expression pattern of bone morphogenetic protein-7 (BMP-7) in the hindbrain region of the headfold and early somite stage developing mouse embryo suggests a role for BMP-7 in the patterning of this part of the cranial CNS. In chick embryos it is thought that BMP-7 is one of the secreted molecules which mediates the dorsalizing influence of surface ectoderm on the neural tube, and mouse surface ectoderm has been shown to have a similar dorsalizing effect. While we confirm that BMP-7 is expressed in the surface ectoderm of mouse embryos at the appropriate time to dorsalize the neural tube, we also show that at early stages of hindbrain development BMP-7 transcripts are present in paraxial and ventral tissues, within and surrounding the hindbrain neurectoderm, and only later does expression become restricted to a dorsal domain. To determine more directly the effect that BMP-7 may have on the developing hindbrain we have grafted COS cells expressing BMP-7 into the ventrolateral mesoderm abutting the neurectoderm in order to prolong BMP-7 expression in the vicinity of ventral hindbrain. Three distinct actvities of BMP-7 are apparent. Firstly, as expected from previous work in chick, BMP-7 can promote dorsal characteristics in the neural tube. Secondly, we show that it can also attenuate the expression of sonic hedgehog (Shh) in the floorplate without affecting Shh expression in the notochord. Finally, we find that ectopic BMP-7 appears to promote growth of the neurectoderm. These findings are discussed with respect to possible timing mechanisms necessary for the coordination of hindbrain dorsoventral patterning.

scholarly journals Cadherin-7 enhances Sonic Hedgehog signalling by preventing Gli3 repressor formation during neural tube patterning

Open Biology ◽  
2017 ◽  
Vol 7 (12) ◽  
pp. 170225 ◽  
Author(s):  
Rie Kawano ◽  
Kunimasa Ohta ◽  
Giuseppe Lupo
Keyword(s):  
Spinal Cord ◽  
Sonic Hedgehog ◽  
Neural Tube ◽  
Target Genes ◽  
Dorsoventral Patterning ◽  
Dorsal Spinal Cord ◽  
Suppressor Of Fused ◽  
Intracellular Movement ◽  
Sonic Hedgehog Signalling ◽  
Dorsal Spinal

Sonic Hedgehog (Shh) is a ventrally enriched morphogen controlling dorsoventral patterning of the neural tube. In the dorsal spinal cord, Gli3 protein bound to suppressor-of-fused (Sufu) is converted into Gli3 repressor (Gli3R), which inhibits Shh-target genes. Activation of Shh signalling prevents Gli3R formation, promoting neural tube ventralization. We show that cadherin-7 (Cdh7) expression in the intermediate spinal cord region is required to delimit the boundary between the ventral and the dorsal spinal cord. We demonstrate that Cdh7 functions as a receptor for Shh and enhances Shh signalling. Binding of Shh to Cdh7 promotes its aggregation on the cell membrane and association of Cdh7 with Gli3 and Sufu. These interactions prevent Gli3R formation and cause Gli3 protein degradation. We propose that Shh can act through Cdh7 to limit intracellular movement of Gli3 protein and production of Gli3R, thus eliciting more efficient activation of Gli-dependent signalling.

scholarly journals Vital dye labelling demonstrates a sacral neural crest contribution to the enteric nervous system of chick and mouse embryos

Development ◽  
1991 ◽  
Vol 111 (4) ◽  
pp. 857-866 ◽  
Author(s):  
G.N. Serbedzija ◽  
S. Burgan ◽  
S.E. Fraser ◽  
M. Bronner-Fraser
Keyword(s):  
Nervous System ◽  
Neural Crest ◽  
Enteric Nervous System ◽  
Neural Tube ◽  
Neural Crest Cells ◽  
Mouse Embryos ◽  
Chick Embryos ◽  
Vital Dye ◽  
Dorsal Portion ◽  
Sacral Neural Crest

We have used the vital dye, DiI, to analyze the contribution of sacral neural crest cells to the enteric nervous system in chick and mouse embryos. In order to label premigratory sacral neural crest cells selectively, DiI was injected into the lumen of the neural tube at the level of the hindlimb. In chick embryos, DiI injections made prior to stage 19 resulted in labelled cells in the gut, which had emerged from the neural tube adjacent to somites 29–37. In mouse embryos, neural crest cells emigrated from the sacral neural tube between E9 and E9.5. In both chick and mouse embryos, DiI-labelled cells were observed in the rostral half of the somitic sclerotome, around the dorsal aorta, in the mesentery surrounding the gut, as well as within the epithelium of the gut. Mouse embryos, however, contained consistently fewer labelled cells than chick embryos. DiI-labelled cells first were observed in the rostral and dorsal portion of the gut. Paralleling the maturation of the embryo, there was a rostral-to-caudal sequence in which neural crest cells populated the gut at the sacral level. In addition, neural crest cells appeared within the gut in a dorsal-to-ventral sequence, suggesting that the cells entered the gut dorsally and moved progressively ventrally. The present results resolve a long-standing discrepancy in the literature by demonstrating that sacral neural crest cells in both the chick and mouse contribute to the enteric nervous system in the postumbilical gut.

Alteration of the retinotectal projection map by the graft of mesencephalic floor plate or sonic hedgehog

Development ◽  
2000 ◽  
Vol 127 (9) ◽  
pp. 1899-1910
Author(s):  
T. Nomura ◽  
H. Fujisawa
Keyword(s):  
Sonic Hedgehog ◽  
Neural Tube ◽  
Crucial Role ◽  
Floor Plate ◽  
Chick Embryos ◽  
Dorsal Part ◽  
Retinotectal Projection ◽  
Original Target ◽  
Retinal Fibers

The floor plate plays crucial roles in the specification and differentiation of neurons along the dorsal-ventral (DV) axis of the neural tube. The transplantation of the mesecephalic floor plate (mfp) into the dorsal mesencephalon in chick embryos alters the fate of the mesencephalon adjacent to the transplant from the tectum to the tegmentum, a ventral tissue of the mesencephalon. In this study, to test whether the mfp is involved in the specification of the DV polarity of the tectum and affects the projection patterns of retinal fibers to the tectum along the DV axis, we transplanted quail mfp into the dorsal mesencephalon of chick embryos, and analyzed projection patterns of dorsal and ventral retinal fibers to the tectum. In the embryos with the mfp graft, dorsal retinal fibers grew into the dorsal part of the tectum which is the original target for ventral but not dorsal retinal fibers and formed tight focuses there. In contrast, ventral retinal fibers did not terminate at any part of the tectum. Transplantation of Sonic hedgehog (Shh)-secreting quail fibroblasts into the dorsal mesencephalon also induced the ectopic tegmentum and altered the retinotectal projection along the DV axis, as the mfp graft did. These results suggest that some factors from the mesencephalic floor plate or the tegmentum, or Shh itself, play a crucial role in the establishment of the DV polarity of the tectum and the retinotectal projection map along the DV axis.

Relationship between Wnt-1 and En-2 expression domains during early development of normal and ectopic met-mesencephalon

Development ◽  
1992 ◽  
Vol 115 (4) ◽  
pp. 999-1009 ◽  
Author(s):  
L. Bally-Cuif ◽  
R.M. Alvarado-Mallart ◽  
D.K. Darnell ◽  
M. Wassef
Keyword(s):  
In Situ Hybridization ◽  
Neural Tube ◽  
Expression Patterns ◽  
Mouse Embryos ◽  
Chick Embryos ◽  
Expression Domain ◽  
General Role ◽  
Maximal Expression

Grafting a met-mesencephalic portion of neural tube from a 9.5-day mouse embryo into the prosencephalon of a 2-day chick embryo results in the induction of chick En-2 (ChickEn) expression in cells in contact with the graft (Martinez et al., 1991). In this paper we investigate the possibility of Wnt-1 being one of the factors involved in En-2 induction. Since Wnt-1 and En-2 expression patterns have been described as diverging during development of the met-mesencephalic region, we first compared Wnt-1 and En-2 expression in this domain by in situ hybridization in mouse embryos after embryonic day 8.5. A ring of Wnt-1-expressing cells is detected encircling the neural tube in the met-mesencephalic region at least until day 12.5. This ring consistently overlapped with the En-2 expression domain, and corresponds to the position of this latter gene's maximal expression. We subsequently studied ChickEn ectopic induction in chick embryos grafted with various portions of met-mesencephalon. When the graft originated from the level of the Wnt-1-positive ring, ChickEn induction was observed in 71% of embryos, and in these cases correlated with Wnt-1 expression in the grafted tissue. In contrast, this percentage dropped significantly when the graft was taken from more rostral or caudal parts of the mesencephalic vesicle. Taken together, these results are compatible with a prolonged role of Wnt-1 in the specification and/or development of the met-mesencephalic region, and show that Wnt-1 could be directly or indirectly involved in the regulation of En-2 expression around the Wnt-1-positive ring during this time. We also provide data on the position of the Wnt-1-positive ring relative to anatomical boundaries in the neural tube, which suggest a more general role for the Wnt-1 protein as a positional signal involved in organizing the met-mesencephalic domain.

Sonic hedgehog and the molecular regulation of mouse neural tube closure

Development ◽  
2002 ◽  
Vol 129 (10) ◽  
pp. 2507-2517 ◽  
Author(s):  
Patricia Ybot-Gonzalez ◽  
Patricia Cogram ◽  
Dianne Gerrelli ◽  
Andrew J. Copp
Keyword(s):  
Sonic Hedgehog ◽  
Neural Tube ◽  
Hedgehog Signaling ◽  
Neural Plate ◽  
Neural Tube Closure ◽  
Molecular Regulation ◽  
Sonic Hedgehog Signaling ◽  
Surface Ectoderm ◽  
Necessary And Sufficient ◽  
Tube Closure

Neural tube closure is a fundamental embryonic event whose molecular regulation is poorly understood. As mouse neurulation progresses along the spinal axis, there is a shift from midline neural plate bending to dorsolateral bending. Here, we show that midline bending is not essential for spinal closure since, in its absence, the neural tube can close by a ‘default’ mechanism involving dorsolateral bending, even at upper spinal levels. Midline and dorsolateral bending are regulated by mutually antagonistic signals from the notochord and surface ectoderm. Notochordal signaling induces midline bending and simultaneously inhibits dorsolateral bending. Sonic hedgehog is both necessary and sufficient to inhibit dorsolateral bending, but is neither necessary nor sufficient to induce midline bending, which seems likely to be regulated by another notochordal factor. Attachment of surface ectoderm cells to the neural plate is required for dorsolateral bending, which ensures neural tube closure in the absence of sonic hedgehog signaling.

Wnt signaling from the dorsal neural tube is required for the formation of the medial dermomyotome

Development ◽  
1998 ◽  
Vol 125 (24) ◽  
pp. 4969-4976 ◽  
Author(s):  
M. Ikeya ◽  
S. Takada
Keyword(s):  
Neural Tube ◽  
Marker Gene ◽  
Mouse Embryos ◽  
Medial Compartment ◽  
Dorsoventral Patterning ◽  
Dorsal Midline ◽  
Dorsal Neural Tube ◽  
Dorsal Portion ◽  
Lines Of Evidence

Signals originating from tissues surrounding somites are involved in mediolateral and dorsoventral patterning of somites and in the differentiation of the myotome. Wnt-1 and Wnt-3a, which encode members of the Wnt family of cystein-rich secreted signaling molecules, are coexpressed at the dorsal midline of the developing neural tube, an area adjacent to the dorsomedial portion of the somite. Several lines of evidence indicate that Wnt-1 and Wnt-3a have the ability to induce the development of the medial and dorsal portion of somites, as well as to induce myogenesis. To address whether these Wnt signalings are really essential for the development of somites during normal embryogenesis, we investigated the development of somites in mouse embryos lacking both Wnt-1 and Wnt-3a. Here we demonstrate that the medial compartment of the dermomyotome is not formed and the expression of a lateral dermomyotome marker gene, Sim-1, is expanded more medially in the absence of these Wnt signalings. In addition, the expression of a myogenic gene, Myf-5, is decreased at 9.5 days post coitum whereas the level of expression of a number of myogenic genes in the later stage appeared normal. These results indicate that Wnt-1 and Wnt-3a signalings actually regulate the formation of the medial compartment of the dermomyotome and the early part of myogenesis.

Mouse-chick chimera: a developmental model of murine neurogenic cells

Development ◽  
1997 ◽  
Vol 124 (16) ◽  
pp. 3025-3036 ◽  
Author(s):  
J. Fontaine-Perus ◽  
P. Halgand ◽  
Y. Cheraud ◽  
T. Rouaud ◽  
M.E. Velasco ◽  
...  
Keyword(s):  
Nervous System ◽  
Neural Tube ◽  
Mammalian Cells ◽  
Mouse Embryos ◽  
Developmental Model ◽  
Sensory Ganglia ◽  
Chick Embryos ◽  
In Ovo ◽  
Neuroepithelial Cells ◽  
Cellular Compartments

Chimeras were prepared by transplanting fragments of neural primordium from 8- to 8.5- and 9-day postcoital mouse embryos into 1.5- and 2-day-old chick embryos at different axial levels. Mouse neuroepithelial cells differentiated in ovo and organized to form the different cellular compartments normally constituting the central nervous system.The graft also entered into the development of the peripheral nervous system through migration of neural crest cells associated with mouse neuroepithelium. Depending on the graft level, mouse crest cells participated in the formation of various derivatives such as head components, sensory ganglia, orthosympathetic ganglionic chain, nerves and neuroendocrine glands. Tenascin knockout mice, which express lacZ instead of tenascin and show no tenascin production (Saga, Y., Yagi, J., Ikawa, Y., Sakakura, T. and Aizawa, S. (1992) Genes and Development 6, 1821–1838), were specifically used to label Schwann cells lining nerves derived from the implant. Although our experiments do not consider how mouse neural tube can participate in the mechanism required to maintain myogenesis in the host somites, they show that the grafted neural tube behaves in the same manner as the chick host neural tube. Together with our previous results on somite development (Fontaine-Perus, J., Jarno, V., Fournier Le Ray, C., Li, Z. and Paulin, D. (1995) Development 121, 1705–1718), this study shows that chick embryo constitutes a privileged environment, facilitating access to the developmental potentials of normal or defective mammalian cells. It allows the study of the histogenesis and precise timing of a known structure, as well as the implication of a given gene at all equivalent mammalian embryonic stages.

scholarly journals Regulation of cell protrusions by small GTPases during fusion of the neural folds

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Ana Rolo ◽  
Dawn Savery ◽  
Sarah Escuin ◽  
Sandra C de Castro ◽  
Hannah EJ Armer ◽  
...  
Keyword(s):  
Neural Tube ◽  
Small Gtpases ◽  
Mouse Embryos ◽  
Neural Tube Closure ◽  
Molecular Regulation ◽  
Mammalian Development ◽  
Surface Ectoderm ◽  
Late Closure ◽  
Membrane Protrusions ◽  
Epithelial Fusion

Epithelial fusion is a crucial process in embryonic development, and its failure underlies several clinically important birth defects. For example, failure of neural fold fusion during neurulation leads to open neural tube defects including spina bifida. Using mouse embryos, we show that cell protrusions emanating from the apposed neural fold tips, at the interface between the neuroepithelium and the surface ectoderm, are required for completion of neural tube closure. By genetically ablating the cytoskeletal regulators Rac1 or Cdc42 in the dorsal neuroepithelium, or in the surface ectoderm, we show that these protrusions originate from surface ectodermal cells and that Rac1 is necessary for the formation of membrane ruffles which typify late closure stages, whereas Cdc42 is required for the predominance of filopodia in early neurulation. This study provides evidence for the essential role and molecular regulation of membrane protrusions prior to fusion of a key organ primordium in mammalian development.

Gli1 is a target of Sonic hedgehog that induces ventral neural tube development

Development ◽  
1997 ◽  
Vol 124 (13) ◽  
pp. 2537-2552 ◽  
Author(s):  
J. Lee ◽  
K.A. Platt ◽  
P. Censullo ◽  
A. Ruiz i Altaba
Keyword(s):  
Sonic Hedgehog ◽  
Neural Tube ◽  
Transcriptional Regulator ◽  
Floor Plate ◽  
Neural Plate ◽  
Mouse Embryos ◽  
Human Glioma ◽  
Cubitus Interruptus ◽  
Ventral Neural Tube ◽  
Neural Tube Development

The vertebrate zinc finger genes of the Gli family are homologs of the Drosophila gene cubitus interruptus. In frog embryos, Gli1 is expressed transiently in the prospective floor plate during gastrulation and in cells lateral to the midline during late gastrula and neurula stages. In contrast, Gli2 and Gli3 are absent from the neural plate midline with Gli2 expressed widely and Gli3 in a graded fashion with highest levels in lateral regions. In mouse embryos, the three Gli genes show a similar pattern of expression in the neural tube but are coexpressed throughout the early neural plate. Because Gli1 is the only Gli gene expressed in prospective floor plate cells of frog embryos, we have investigated a possible involvement of this gene in ventral neural tube development. Here we show that Shh signaling activates Gli1 transcription and that widespread expression of endogenous frog or human glioma Gli1, but not Gli3, in developing frog embryos results in the ectopic differentiation of floor plate cells and ventral neurons within the neural tube. Floor-plate-inducing ability is retained when cytoplasmic Gli1 proteins are forced into the nucleus or are fused to the VP16 transactivating domain. Thus, our results identify Gli1 as a midline target of Shh and suggest that it mediates the induction of floor plate cells and ventral neurons by Shh acting as a transcriptional regulator.

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