scholarly journals An enigmatic translocation of the vertebrate primordial eye field

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
R. G. Loosemore ◽  
S. D. Matthaei ◽  
T. C. Stanger
Keyword(s):  
Progenitor Cells ◽  
Neural Plate ◽  
Evolutionary Significance ◽  
Mapping Data ◽  
Retinal Progenitor ◽  
Vertebrate Embryo ◽  
Eye Field ◽  
Optic Vesicles ◽  
Contralateral Eye ◽  
Anterior Neural Plate

Abstract The primordial eye field of the vertebrate embryo is a single entity of retinal progenitor cells spanning the anterior neural plate before bifurcating to form bilateral optic vesicles. Here we review fate mapping data from zebrafish suggesting that prior to evagination of the optic vesicles the eye field may undergo a Maypole-plait migration of progenitor cells through the midline influenced by the anteriorly subducting diencephalon. Such an enigmatic translocation of scaffolding progenitors could have evolutionary significance if pointing, by way of homology, to an ancient mechanism for transition of the single eye field in chordates to contralateral eye fields in vertebrates.

Inductive interactions direct early regionalization of the mouse forebrain

Development ◽  
1997 ◽  
Vol 124 (14) ◽  
pp. 2709-2718 ◽  
Author(s):  
K. Shimamura ◽  
J.L. Rubenstein
Keyword(s):  
Sonic Hedgehog ◽  
Bone Morphogenetic Proteins ◽  
Molecular Mechanisms ◽  
Neural Plate ◽  
Gene Encoding ◽  
Prechordal Plate ◽  
Optic Vesicles ◽  
The Central Nervous System ◽  
Anterior Neural Plate ◽  
Anterior Posterior

The cellular and molecular mechanisms that regulate regional specification of the forebrain are largely unknown. We studied the expression of transcription factors in neural plate explants to identify tissues, and the molecules produced by these tissues, that regulate medial-lateral and local patterning of the prosencephalic neural plate. Molecular properties of the medial neural plate are regulated by the prechordal plate perhaps through the action of Sonic Hedgehog. By contrast, gene expression in the lateral neural plate is regulated by non-neural ectoderm and bone morphogenetic proteins. This suggests that the forebrain employs the same medial-lateral (ventral-dorsal) patterning mechanisms present in the rest of the central nervous system. We have also found that the anterior neural ridge regulates patterning of the anterior neural plate, perhaps through a mechanism that is distinct from those that regulate general medial-lateral patterning. The anterior neural ridge is essential for expression of BF1, a gene encoding a transcription factor required for regionalization and growth of the telencephalic and optic vesicles. In addition, the anterior neural ridge expresses Fgf8, and recombinant FGF8 protein is capable of inducing BF1, suggesting that FGF8 regulates the development of anterolateral neural plate derivatives. Furthermore, we provide evidence that the neural plate is subdivided into distinct anterior-posterior domains that have different responses to the inductive signals from the prechordal plate, Sonic Hedgehog, the anterior neural ridge and FGF8. In sum, these results suggest that regionalization of the forebrain primordia is established by several distinct patterning mechanisms: (1) anterior-posterior patterning creates transverse zones with differential competence within the neural plate, (2) patterning along the medial-lateral axis generates longitudinally aligned domains and (3) local inductive interactions, such as a signal(s) from the anterior neural ridge, further define the regional organization.

scholarly journals Hallmarks of primary neurulation are conserved in the zebrafish forebrain

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Jonathan M. Werner ◽  
Maraki Y. Negesse ◽  
Dominique L. Brooks ◽  
Allyson R. Caldwell ◽  
Jafira M. Johnson ◽  
...  
Keyword(s):  
Neural Tube ◽  
Time Lapse ◽  
Neural Plate ◽  
Neural Tube Closure ◽  
Developmental Studies ◽  
Underlying Causes ◽  
The Central Nervous System ◽  
Resolution Imaging ◽  
Fold Formation ◽  
Anterior Neural Plate

AbstractPrimary neurulation is the process by which the neural tube, the central nervous system precursor, is formed from the neural plate. Incomplete neural tube closure occurs frequently, yet underlying causes remain poorly understood. Developmental studies in amniotes and amphibians have identified hingepoint and neural fold formation as key morphogenetic events and hallmarks of primary neurulation, the disruption of which causes neural tube defects. In contrast, the mode of neurulation in teleosts has remained highly debated. Teleosts are thought to have evolved a unique mode of neurulation, whereby the neural plate infolds in absence of hingepoints and neural folds, at least in the hindbrain/trunk where it has been studied. Using high-resolution imaging and time-lapse microscopy, we show here the presence of these morphological landmarks in the zebrafish anterior neural plate. These results reveal similarities between neurulation in teleosts and other vertebrates and hence the suitability of zebrafish to understand human neurulation.

Different characteristics of rat retinal progenitor cells from different culture periods

2003 ◽  
Vol 341 (3) ◽  
pp. 213-216 ◽  
Author(s):  
Tadamichi Akagi ◽  
Masatoshi Haruta ◽  
Joe Akita ◽  
Akihiro Nishida ◽  
Yoshihito Honda ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Retinal Progenitor Cells ◽  
Retinal Progenitor ◽  
Different Characteristics

scholarly journals A gene regulatory network that underlies the derivation of the anterior neural plate from the epiblast

2010 ◽  
Vol 344 (1) ◽  
pp. 495
Author(s):  
Makiko Iwafuchi-Doi ◽  
Tatsuya Takemoto ◽  
Yuzo Yoshida ◽  
Isao Matsuo ◽  
Jun Aruga ◽  
...  
Keyword(s):  
Gene Regulatory Network ◽  
Regulatory Network ◽  
Neural Plate ◽  
Gene Regulatory ◽  
Anterior Neural Plate

scholarly journals Experiments on the Development of the Head of the Chick Embryo

1936 ◽  
Vol 13 (2) ◽  
pp. 219-236
Author(s):  
C. H. WADDINGTON ◽  
A. COHEN
Keyword(s):  
Thin Sheet ◽  
Neural Tissue ◽  
Primitive Streak ◽  
Neural Plate ◽  
Head Region ◽  
Process Stage ◽  
Optic Vesicles ◽  
Lens Formation ◽  
Embryonic Ectoderm

1. Experiments were made on the development of the head of chicken embryos cultivated in vitro. 2. Defects in the presumptive head region of primitive streak embryos are regulated completely if the wound fills up before the histogenesis of neural tissue begins in the head-process stage. Different methods by which the hole is filled are described. 3. No repair occurs in the head-process and head-fold stages, and in this period two masses of neural tissue cannot heal together. 4. Median defects, even if repaired as regards neural tissue, cause a failure of the ventral closure of the foregut. The lateral evaginations of the gut develop typically in atypical situations. The headfold may break through and join up with the endoderm in such a way that the gut acquires an anterior opening. 5. The paired heart rudiments may develop separately. The separate vesicles begin to contract at a time appropriate to the development of the embryo as a whole. The two hearts are mirror images, the left one having the normal curvature, but the embryos do not survive long enough for the hearts to acquire a very definite shape. 6. The forebrain has a considerable capacity for repair in the early somite stages (five to twenty-five somites). One-half of the forebrain can remodel itself into a complete forebrain. In some cases the neural plate and epidermis grow together over the wound, in others the epidermis and mesenchyme make the first covering, leaving a space along the inside of which the neural tissue grows. The neural tissue may become a very thin sheet. 7. The repaired forebrain may induce the formation of a nasal placode from the non-presumptive nasal epidermis which covers the wound. 8. If the optic vesicle is entirely removed, a new one is not formed, but parts of the vesicle can regulate to complete eye-cups, either when still attached to the forebrain or after being isolated in the extra-embryonic regions of another embryo. 9. Injured optic vesicles induce lenses from the non-presumptive epidermis which grows over the wound. Transplanted optic neural tissue from embryos of about five somites induces the formation of lentoids from extra-embryonic ectoderm, but only in a small proportion of cases. 10. The presumptive lens epidermis can produce a slight thickening even when contact with the optic cup is prevented. 11. The significance of periods of minimum regulatory power for the concept of determination is discussed. 12. The data concerning lens formation are discussed in terms of the field concept.

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