Early posterior neural tissue is induced by FGF in the chick embryo

Development ◽  
1998 ◽  
Vol 125 (3) ◽  
pp. 473-484 ◽  
Author(s):  
K.G. Storey ◽  
A. Goriely ◽  
C.M. Sargent ◽  
J.M. Brown ◽  
H.D. Burns ◽  
...  
Keyword(s):  
Chick Embryo ◽  
Cell Fate ◽  
Neural Induction ◽  
Neural Tissue ◽  
Primitive Streak ◽  
Specific Aspect ◽  
Amphibian Embryo ◽  
Fgf Signalling ◽  
Unique Cell ◽  
Neural Cell Fate

Signals that induce neural cell fate in amniote embryos emanate from a unique cell population found at the anterior end of the primitive streak. Cells in this region express a number of fibroblast growth factors (FGFs), a group of secreted proteins implicated in the induction and patterning of neural tissue in the amphibian embryo. Here we exploit the large size and accessibility of the early chick embryo to analyse the function of FGF signalling specifically during neural induction. Our results demonstrate that extraembryonic epiblast cells previously shown to be responsive to endogenous neural-inducing signals express early posterior neural genes in response to local, physiological levels of FGF signal. This neural tissue does not express anterior neural markers or undergo neuronal differentiation and forms in the absence of axial mesoderm. Prospective mesodermal tissue is, however, induced and we present evidence for both the direct and indirect action of FGFs on prospective posterior neural tissue. These findings suggest that FGF signalling underlies a specific aspect of neural induction, the initiation of the programme that leads to the generation of the posterior central nervous system.

scholarly journals An early requirement for FGF signalling in the acquisition of neural cell fate in the chick embryo

2000 ◽  
Vol 10 (8) ◽  
pp. 421-429 ◽  
Author(s):  
Sara I Wilson ◽  
Enrique Graziano ◽  
Richard Harland ◽  
Thomas M Jessell ◽  
Thomas Edlund
Keyword(s):  
Chick Embryo ◽  
Cell Fate ◽  
Neural Cell ◽  
Fgf Signalling ◽  
Neural Cell Fate

Studies on self-differentiating and induction capacities of Hensen's node using intracoelomic grafting technique

Development ◽  
1972 ◽  
Vol 28 (3) ◽  
pp. 547-558
Author(s):  
J. R. Viswanath ◽  
Leela Mulherkar
Keyword(s):  
Chick Embryo ◽  
Neural Tissue ◽  
Primitive Streak ◽  
Germ Layer ◽  
Grafting Technique ◽  
Definite Combination

Living Hensen's node of the definitive primitive streak of chick embryo was prepared into ‘sandwiches’ with the competent ectoderm and the sandwich grafts were transplated into the 2·5 day chick embryo using the intracoelomic grafting technique of Hamburger. One hundred and twenty-four grafts were prepared and transplanted intracoelomically, 28 grafts were lost due to the death of the host embryos, 63 grafts did not differentiate at all, but 33 well-defined grafts were recovered, after cultivating the transplanted hosts for 12–14 days. All kinds of tissues from feather germs to neural tissue were found to have differentiated in the grafts. The more frequently occurring tissues were feather germs, epidermal vesicle, neural tissue, kidney and muscle. Other differentiations were the cartilage notochord and gut. No definite combination pattern has emerged from the tissues. But when the tissues were traced to their germ-layer derivation, 22 of them belonged to the mesodermal complex, 11 to the ectodermal complex and 8 to the endodermal complex. In the light of the above results, the probable existence of a mesodermal factor and an ectodermal factor independently responsible for the respective differentiations, as also the competence of the ectoderm, is discussed.

Induction of primitive streak and Hensen's node by the posterior marginal zone in the early chick embryo

Development ◽  
1998 ◽  
Vol 125 (17) ◽  
pp. 3521-3534 ◽  
Author(s):  
R.F. Bachvarova ◽  
I. Skromne ◽  
C.D. Stern
Keyword(s):  
Chick Embryo ◽  
Marginal Zone ◽  
Lower Layer ◽  
Primitive Streak ◽  
Normal Embryo ◽  
Anterior Pole ◽  
Posterior Edge ◽  
Amphibian Embryo ◽  
Midline Cells ◽  
Marginal Zones

In the preprimitive streak chick embryo, the search for a region capable of inducing the organizer, equivalent to the Nieuwkoop Center of the amphibian embryo, has focused on Koller's sickle, the hypoblast and the posterior marginal zone. However, no clear evidence for induction of an organizer without contribution from the inducing tissue has been provided for any of these structures. We have used DiI/DiO labeling to establish the fate of midline cells in and around Koller's sickle in the normal embryo. In the epiblast, the boundary between cells that contribute to the streak and those that do not lies at the posterior edge of Koller's sickle, except at stage X when it lies slightly more posteriorly in the epiblast. Hypoblast and endoblast (a second lower layer formed under the streak) have distinct origins in the lower layer, and goosecoid expression distinguishes between them. We then used anterior halves of chick prestreak embryos as recipients for grafts of quail posterior marginal zone; quail cells can be identified subsequently with a quail-specific antibody. Anterior halves alone usually formed a streak, most often from the posterior edge. Quail posterior marginal zones without Koller's sickle were grafted to the anterior side of anterior halves. These grafts were able to increase significantly the frequency of streaks arising from the anterior pole of stage X-XI anterior halves without contributing to the streak or node. Stage XII anterior halves no longer responded. A goosecoid-expressing hypoblast did not form under the induced streak, indicating that it is not required for streak formation. We conclude that the marginal zone posterior to Koller's sickle can induce a streak and node, without contributing cells to the induced streak.

The L5 epitope: an early marker for neural induction in the chick embryo and its involvement in inductive interactions

Development ◽  
1991 ◽  
Vol 112 (4) ◽  
pp. 959-970 ◽  
Author(s):  
C. Roberts ◽  
N. Platt ◽  
A. Streit ◽  
M. Schachner ◽  
C.D. Stern
Keyword(s):  
Nervous System ◽  
Chick Embryo ◽  
Neural Induction ◽  
Primitive Streak ◽  
Hybridoma Cells ◽  
Minor Components ◽  
Lower Molecular Mass ◽  
Host Embryo ◽  
Donor Embryo ◽  
Developing Nervous System

The pattern of expression of the carbohydrate epitope L5 was studied during early development of the chick neuroepithelium. Immunoreactivity first appears during gastrulation, at mid-primitive streak stage, and persists until at least 3.5 days of development. The epitope is expressed on all the components of the developing nervous system, both central and peripheral. In immunoblots, the antibody recognises a major component of about Mr 500,000 and several more minor components of lower molecular mass. If a Hensen's node from a donor embryo is transplanted into the area opaca of a host embryo, L5 immunoreactivity appears in the epiblast surrounding the graft. If hybridoma cells secreting the antibody are grafted together with Hensen's node into a host chick embryo, the induction of a supernumerary nervous system is inhibited. We suggest that the L5 epitope is an early and general marker for neural induction and that it may be involved directly in inductive interactions.

Chordin regulates primitive streak development and the stability of induced neural cells, but is not sufficient for neural induction in the chick embryo

Development ◽  
1998 ◽  
Vol 125 (3) ◽  
pp. 507-519 ◽  
Author(s):  
A. Streit ◽  
K.J. Lee ◽  
I. Woo ◽  
C. Roberts ◽  
T.M. Jessell ◽  
...  
Keyword(s):  
Neural Induction ◽  
Neural Tissue ◽  
Primitive Streak ◽  
Neural Plate ◽  
Neural Cells ◽  
Morphogenetic Protein ◽  
Neural Markers ◽  
Bmp Signalling ◽  
The Stability ◽  
Area Pellucida

We have investigated the role of Bone Morphogenetic Protein 4 (BMP-4) and a BMP antagonist, chordin, in primitive streak formation and neural induction in amniote embryos. We show that both BMP-4 and chordin are expressed before primitive streak formation, and that BMP-4 expression is downregulated as the streak starts to form. When BMP-4 is misexpressed in the posterior area pellucida, primitive streak formation is inhibited. Misexpression of BMP-4 also arrests further development of Hensen's node and axial structures. In contrast, misexpression of chordin in the anterior area pellucida generates an ectopic primitive streak that expresses mesoderm and organizer markers. We also provide evidence that chordin is not sufficient to induce neural tissue in the chick. Misexpression of chordin in regions outside the future neural plate does not induce the early neural markers L5, Sox-3 or Sox-2. Furthermore, neither BMP-4 nor BMP-7 interfere with neural induction when misexpressed in the presumptive neural plate before or after primitive streak formation. However, chordin can stabilise the expression of early neural markers in cells that have already received neural inducing signals. These results suggest that the regulation of BMP signalling by chordin plays a role in primitive streak formation and that chordin is not sufficient to induce neural tissue.

scholarly journals The Behaviour of Epiblast Grafts Beneath the Primitive Streak of the Chick

1937 ◽  
Vol 14 (3) ◽  
pp. 302-318
Author(s):  
M. ABERCROMBIE
Keyword(s):  
Neural Induction ◽  
Neural Tissue ◽  
Primitive Streak ◽  
Active Movement ◽  
Side Plate ◽  
Long Time ◽  
Epithelial Structure ◽  
Break Up ◽  
High Degree

1. Grafts consisting of area opaca ectoderm, presumptive epidermis, presumptive neural tissue, or presumptive mesoderm (axial or side-plate), were transplanted to a position immediately under the primitive streak of chick blastoderms in the primitive streak stage. 2. The grafts, though they sometimes remained as a non-neural epithelium, were usually neurally induced, contemporaneously and co-extensively with the neural induction of the host. The graft-derived neural tissue is often much thicker than the host neural tissue, and though usually forming an autonomous structure, it is frequently arranged with a high degree of symmetry relative to the host. If, however, the graft remains for a long time uninduced, lying in the host mesenchyme, it tends to break up into mesenchyme itself. 3. It is probable that all parts of the epiblast, whatever their presumptive fate, are competent to form neural tissue, provided their epithelial structure is maintained; and it is notable that this is true of presumptive mesoderm. 4. The dorso-ventral polarity of the grafts is maintained whatever their orientation in the host; but the irreversible determination of this polarity was probably not tested. The antero-posterior polarity of the grafts was without effect on their differentiation. 5. An elongation of the graft along the antero-posterior axis of the host usually occurred. It was often very marked, and generally consisted in the posterior end of the graft accompanying the host primitive node as it moved backwards. It is believed to be due to the induction of an active movement in the graft itself. 6. The host is considerably modified by the presence of the graft. In particular, the head-fold is usually suppressed. The formation of the foregut is frequently upset, but the closed foregut shows a considerable power of regulation.

Neural induction and regionalisation by different subpopulations of cells in Hensen's node

Development ◽  
1995 ◽  
Vol 121 (2) ◽  
pp. 417-428 ◽  
Author(s):  
K.G. Storey ◽  
M.A. Selleck ◽  
C.D. Stern
Keyword(s):  
Chick Embryo ◽  
Cell Lineage ◽  
Neural Induction ◽  
Neural Tissue ◽  
Cell Types ◽  
Neural Cells ◽  
Cell Type ◽  
Prechordal Plate ◽  
Gut Endoderm ◽  
Lineage Analysis

Cell lineage analysis has revealed that the amniote organizer, Hensen's node, is subdivided into distinct regions, each containing a characteristic subpopulation of cells with defined fates. Here, we address the question of whether the inducing and regionalising ability of Hensen's node is associated with a specific subpopulation. Quail explants from Hensen's node are grafted into an extraembryonic site in a host chick embryo allowing host- and donor-derived cells to be distinguished. Cell-type- and region-specific markers are used to assess the fates of the mesodermal and neural cells that develop. We find that neural inducing ability is localised in the epiblast layer and the mesendoderm (deep portion) of the medial sector of the node. The deep portion of the posterolateral part of the node does not have neural inducing ability. Neural induction also correlates with the presence of particular prospective cell types in our grafts: chordamesoderm (notochord/head process), definitive (gut) endoderm or neural tissue. However, only grafts that include the epiblast layer of the node induce neural tissue expressing a complete range of anteroposterior characteristics, although prospective prechordal plate cells may also play a role in specification of the forebrain.

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