scholarly journals Induction by the Primitive Streak and its Derivatives in the Chick

1933 ◽  
Vol 10 (1) ◽  
pp. 38-46 ◽  
Author(s):  
C. H. WADDINGTON
Keyword(s):  
Anterior Part ◽  
Primitive Streak ◽  
Neural Plate ◽  
Embryonic Axis ◽  
Host Embryo

1. Specimens are described which demonstrate the induction of neural plateby (a) the mesodermal part of the primitive streak, (b) the head process and sinus rhomboidalis, and (c) neural plate. 2. The neural plate which was induced by the mesodermal part of the primitive streak was in reversed orientation as regards the host embryo. Thus the orientation of the embryo must be already fixed in the mesodermal part of the streak, and must in this case have overcome any influence which the host may be able to exert. 3. The same embryo was more complete than indicated by the presumptive fate of the tissue which induced it, whence it is concluded that the chick organiser,like the amphibian, shows a tendency to complete itself, and to this extent behaves like part of a harmonious equipotential system. 4. Grafts of the anterior part of the embryonic axis (head process and neuralplate) into the anterior part of the host blastoderm, have induced structures which in nearly all cases give indications of being heads. Inductions by posterior parts of the axis (sinus rhomboidalis) have never given such indications. 5. Grafts of the notochord have not, as yet, given satisfactory inductions.

scholarly journals Segregating expression domains of two goosecoid genes during the transition from gastrulation to neurulation in chick embryos

Development ◽  
1997 ◽  
Vol 124 (8) ◽  
pp. 1443-1452 ◽  
Author(s):  
L. Lemaire ◽  
T. Roeser ◽  
J.C. Izpisua-Belmonte ◽  
M. Kessel
Keyword(s):  
Posterior Margin ◽  
Anterior Part ◽  
Primitive Streak ◽  
Neural Plate ◽  
Chick Embryos ◽  
Positive Part ◽  
Full Extension ◽  
Isolation And Characterization ◽  
Chick Embryogenesis

We report the isolation and characterization of a chicken gene, GSX, containing a homeobox similar to that of the goosecoid gene. The structure of the GSX gene and the deduced GSX protein are highly related to the previously described goosecoid gene. The two homeodomains are 74% identical. In the first few hours of chick embryogenesis, the expression pattern of GSX is similar to GSC, in the posterior margin of the embryo and the young primitive streak. Later during gastrulation, expression of the two genes segregate. GSC is expressed in the anterior part of the primitive streak, then in the node, and finally in the pre-chordal plate. GSX is expressed in the primitive streak excluding the node, and then demarcating the early neural plate around the anterior streak and overlying the pre-chordal plate. We demonstrate that the GSX-positive part of the primitive streak induces gastrulation, while the GSC-expressing part induces neurulation. After full extension of the streak, the fate of cells now characterized by GSX is to undergo neurulation, while those expressing GSC undergo gastrulation. We discuss the effect of a duplicated basic goosecoid identity for the generation of a chordate nervous system in ontogeny and phylogeny.

Clonal analysis of epiblast fate during germ layer formation in the mouse embryo

Development ◽  
1991 ◽  
Vol 113 (3) ◽  
pp. 891-911 ◽  
Author(s):  
K.A. Lawson ◽  
J.J. Meneses ◽  
R.A. Pedersen
Keyword(s):  
Single Cells ◽  
Primitive Streak ◽  
Clonal Analysis ◽  
Neural Plate ◽  
Embryonic Axis ◽  
Population Doubling ◽  
Germ Layer ◽  
Layer Formation ◽  
Fate Map ◽  
Germ Layer Formation

The fate of cells in the epiblast at prestreak and early primitive streak stages has been studied by injecting horseradish peroxidase (HRP) into single cells in situ of 6.7-day mouse embryos and identifying the labelled descendants at midstreak to neural plate stages after one day of culture. Ectoderm was composed of descendants of epiblast progenitors that had been located in the embryonic axis anterior to the primitive streak. Embryonic mesoderm was derived from all areas of the epiblast except the distal tip and the adjacent region anterior to it: the most anterior mesoderm cells originated posteriorly, traversing the primitive streak early; labelled cells in the posterior part of the streak at the neural plate stage were derived from extreme anterior axial and paraxial epiblast progenitors; head process cells were derived from epiblast at or near the anterior end of the primitive streak. Endoderm descendants were most frequently derived from a region that included, but extended beyond, the region producing the head process: descendants of epiblast were present in endoderm by the midstreak stage, as well as at later stages. Yolk sac and amnion mesoderm developed from posterolateral and posterior epiblast. The resulting fate map is essentially the same as those of the chick and urodele and indicates that, despite geometrical differences, topological fate relationships are conserved among these vertebrates. Clonal descendants were not necessarily confined to a single germ layer or to extraembryonic mesoderm, indicating that these lineages are not separated at the beginning of gastrulation. The embryonic axis lengthened up to the neural plate stage by (1) elongation of the primitive streak through progressive incorporation of the expanding lateral and initially more anterior regions of epiblast and, (2) expansion of the region of epiblast immediately cranial to the anterior end of the primitive streak. The population doubling time of labelled cells was 7.5 h; a calculated 43% were in, or had completed, a 4th cell cycle, and no statistically significant regional differences in the number of descendants were found. This clonal analysis also showed that (1) growth in the epiblast was noncoherent and in most regions anisotropic and directed towards the primitive streak and (2) the midline did not act as a barrier to clonal spread, either in the epiblast in the anterior half of the axis or in the primitive streak. These results taken together with the fate map indicate that, while individual cells in the epiblast sheet behave independently with respect to their neighbours, morphogenetic movement during germ layer formation is coordinated in the population as a whole.

Primordial germ cells in normal and transected duck blastoderms

Development ◽  
1968 ◽  
Vol 20 (3) ◽  
pp. 247-260
Author(s):  
Teresa Rogulska
Keyword(s):  
Chick Embryo ◽  
Blood Vessels ◽  
Germ Cells ◽  
Anterior Part ◽  
Primordial Germ Cells ◽  
Primitive Streak ◽  
Experimental Investigations ◽  
Suggestive Evidence ◽  
Area Pellucida

Suggestive evidence for the extragonadal origin of germ cells in birds was first presented by Swift (1914), who described primordial germ cells in the chick embryo at as early a stage as the primitive streak. According to Swift, primordial germ cells are originally located extra-embryonically in the anterior part of the blastoderm and occupy a crescent-shaped region (‘germinal crescent’) on the boundary between area opaca and area pellucida. Swift also found that primordial germ cells later enter into the blood vessels, circulate together with the blood throughout the whole blastoderm and finally penetrate into the genital ridges, where they become definitive germ cells. Swift's views have been confirmed in numerous descriptive and experimental investigations. Among the latter, the publications of Willier (1937), Simon (1960) and Dubois (1964a, b, 1965a, b, 1966) merit special attention. Dubois finally proved that the genital ridges exert a strong chemotactic influence on the primordial germ cells.

A developmental pathway controlling outgrowth of the Xenopus tail bud

Development ◽  
1999 ◽  
Vol 126 (8) ◽  
pp. 1611-1620 ◽  
Author(s):  
C.W. Beck ◽  
J.M. Slack
Keyword(s):  
Normal Development ◽  
Posterior Part ◽  
Neural Plate ◽  
General Mechanism ◽  
Developmental Pathway ◽  
Tail Bud ◽  
Neural Tubes ◽  
Tailbud Stage ◽  
Tail Tip ◽  
Host Embryo

We have developed a new assay to identify factors promoting formation and outgrowth of the tail bud. A piece of animal cap filled with the test mRNAs is grafted into the posterior region of the neural plate of a host embryo. With this assay we show that expression of a constitutively active Notch (Notch ICD) in the posterior neural plate is sufficient to produce an ectopic tail consisting of neural tube and fin. The ectopic tails express the evenskipped homologue Xhox3, a marker for the distal tail tip. Xhox3 will also induce formation of an ectopic tail in our assay. We show that an antimorphic version of Xhox3, Xhox3VP16, will prevent tail formation by Notch ICD, showing that Xhox3 is downstream of Notch signalling. An inducible version of this reagent, Xhox3VP16GR, specifically blocks tail formation when induced in tailbud stage embryos, comfirming the importance of Xhox3 for tail bud outgrowth in normal development. Grafts containing Notch ICD will only form tails if placed in the posterior part of the neural plate. However, if Xwnt3a is also present in the grafts they can form tails at any anteroposterior level. Since Xwnt3a expression is localised appropriately in the posterior at the time of tail bud formation it is likely to be responsible for restricting tail forming competence to the posterior neural plate in our assay. Combined expression of Xwnt3a and active Notch in animal cap explants is sufficient to induce Xhox3, provoke elongation and form neural tubes. Conservation of gene expression in the tail bud of other vertebrates suggests that this pathway may describe a general mechanism controlling tail outgrowth and secondary neurulation.

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.

The spatial and temporal dynamics of Sax1 (CHox3) homeobox gene expression in the chick's spinal cord

Development ◽  
1994 ◽  
Vol 120 (7) ◽  
pp. 1817-1828 ◽  
Author(s):  
P. Spann ◽  
M. Ginsburg ◽  
Z. Rangini ◽  
A. Fainsod ◽  
H. Eyal-Giladi ◽  
...  
Keyword(s):  
Temporal Dynamics ◽  
Homeobox Gene ◽  
Primitive Streak ◽  
Neural Plate ◽  
Transverse Plane ◽  
Posterior Border ◽  
Anterior Border ◽  
Spatial And Temporal Dynamics ◽  
Specific Localization

Sax1 (previously CHox3) is a chicken homeobox gene belonging to the same homeobox gene family as the Drosophila NK1 and the honeybee HHO genes. Sax1 transcripts are present from stage 2 H&H until at least 5 days of embryonic development. However, specific localization of Sax1 transcripts could not be detected by in situ hybridization prior to stage 8-, when Sax1 transcripts are specifically localized in the neural plate, posterior to the hindbrain. From stages 8- to 15 H&H, Sax1 continues to be expressed only in the spinal part of the neural plate. The anterior border of Sax1 expression was found to be always in the transverse plane separating the youngest somite from the yet unsegmented mesodermal plate and to regress with similar dynamics to that of the segregation of the somites from the mesodermal plate. The posterior border of Sax1 expression coincides with the posterior end of the neural plate. In order to study a possible regulation of Sax1 expression by its neighboring tissues, several embryonic manipulation experiments were performed. These manipulations included: removal of somites, mesodermal plate or notochord and transplantation of a young ectopic notochord in the vicinity of the neural plate or transplantation of neural plate sections into the extraembryonic area. The results of these experiments revealed that the induction of the neural plate by the mesoderm has already occurred in full primitive streak embryos, after which Sax1 is autonomously regulated within the spinal part of the neural plate.

The histogenetic capacity of tissues in the caudal end of the embryonic axis of the mouse

Development ◽  
1984 ◽  
Vol 82 (1) ◽  
pp. 253-266
Author(s):  
P. P. L. Tam
Keyword(s):  
Developmental Stages ◽  
Primitive Streak ◽  
Mouse Embryos ◽  
Embryonic Axis ◽  
Tail Bud ◽  
Germ Layers ◽  
Kidney Capsule ◽  
Caudal Region ◽  
Caudal Portion ◽  
Adult Body

The caudal end of the embryonic axis consists of the primitive streak and the tail bud. Small fragments of this caudal tissue were transplanted from mouse embryos of various developmental stages to the kidney capsule in order to test their histogenetic capacity. The variety of mature tissues obtained from these small fragments was similar to that obtained by grafting a larger caudal portion of the embryo. Initially, the grafted tissue broke up into loose masses of embryonic mesenchyme and this was later re-organized into more compact tissues and into cysts that were lined with various types of epithelia. After 14 days in the ectopic site, grafted tissues coming from embryos of the primitive-streak, the early-somite and the forelimb-bud stages differentiated into structures that has presumably originated from the three embryonic germ layers. Many of these structures were related to the caudal region of the adult body, such as the mid- and hindgut segments and urogenital derivatives. The histogenetic capacity for endodermal tissues and urogenital organs was lost when the grafted tissue consisted entirely of the tail bud of the hindlimb-bud-stage embryos. The behaviour of the caudal tissues suggested that (1) the primordia for the various parts of embryonic body were derived from a small progenitor population in the primitive streak and the tail bud, and (2) the histogenetic capacity of this population changed during development.

Ectodermal patterning in the avian embryo: epidermis versus neural plate

Development ◽  
1999 ◽  
Vol 126 (1) ◽  
pp. 63-73 ◽  
Author(s):  
E. Pera ◽  
S. Stein ◽  
M. Kessel
Keyword(s):  
Chick Embryo ◽  
Neural Crest ◽  
Plate Boundary ◽  
Homeobox Gene ◽  
Primitive Streak ◽  
Neural Plate ◽  
Avian Embryo ◽  
Neural Fate ◽  
Early Stages ◽  
Two Factors

Ectodermal patterning of the chick embryo begins in the uterus and continues during gastrulation, when cells with a neural fate become restricted to the neural plate around the primitive streak, and cells fated to become the epidermis to the periphery. The prospective epidermis at early stages is characterized by the expression of the homeobox gene DLX5, which remains an epidermal marker during gastrulation and neurulation. Later, some DLX5-expressing cells become internalized into the ventral forebrain and the neural crest at the hindbrain level. We studied the mechanism of ectodermal patterning by transplantation of Hensen's nodes and prechordal plates. The DLX5 marker indicates that not only a neural plate, but also a surrounding epidermis is induced in such operations. Similar effects can be obtained with neural plate grafts. These experiments demonstrate that the induction of a DLX5-positive epidermis is triggered by the midline, and the effect is transferred via the neural plate to the periphery. By repeated extirpations of the endoderm we suppressed the formation of an endoderm/mesoderm layer under the epiblast. This led to the generation of epidermis, and to the inhibition of neuroepithelium in the naked ectoderm. This suggests a signal necessary for neural, but inhibitory for epidermal development, normally coming from the lower layers. Finally, we demonstrate that BMP4, as well as BMP2, is capable of inducing epidermal fate by distorting the epidermis-neural plate boundary. This, however, does not happen independently within the neural plate or outside the normal DLX5 domain. In the area opaca, the co-transplantation of a BMP4 bead with a node graft leads to the induction of DLX5, thus indicating the cooperation of two factors. We conclude that ectodermal patterning is achieved by signalling both from the midline and from the periphery, within the upper but also from the lower layers.

scholarly journals Anterior neural plate regionalization in cripto null mutant mouse embryos in the absence of node and primitive streak

2003 ◽  
Vol 264 (2) ◽  
pp. 537-549 ◽  
Author(s):  
Giovanna L Liguori ◽  
Diego Echevarría ◽  
Raffaele Improta ◽  
Massimo Signore ◽  
Eileen Adamson ◽  
...  
Keyword(s):  
Mutant Mouse ◽  
Primitive Streak ◽  
Neural Plate ◽  
Mouse Embryos ◽  
Null Mutant ◽  
Mutant Mouse Embryos ◽  
Anterior Neural Plate ◽  
Null Mutant Mouse
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