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The Spemann organizer meets the anterior-most neuroectoderm at the equator of early gastrulae in amphibian species.

Yanagi T, Ito K, Nishihara A, Minamino R, Mori S, Sumida M, Hashimoto C - Dev. Growth Differ. (2015)

Bottom Line: However, we found that this physical contact was already established at the equatorial region of very early gastrula in a wide variety of amphibian species.After the contact is established, the dorsal axis is formed posteriorly, but not anteriorly.The model also implies the possibility of constructing a common model of gastrulation among chordate species.

View Article: PubMed Central - PubMed

Affiliation: JT Biohistory Research Hall, 1-1 Murasaki-cho, Takatsuki, Osaka, 569-1125, Japan; Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan.

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Expression patterns of chordin during early gastrulation in Xenopus laevis and Cynops pyrrhogaster. (A–E) Expression patterns of X. laevis chordin from late blastula to anterior contact establishment (ACE) (3 h after blastopore appearance). (F–J) Expression patterns of C. pyrrhogaster chordin from late blastula to ACE (7 h after blastopore appearance). (A, F) Expression in late blastula embryos. Chordin expression is first detected in the dorsal blastocoel roof. (B, G) Expression at the onset of gastrulation. Chordin is expressed not only in the surface layer (dorsal lip) but also internally in the blastocoel floor. (C, H) Expression in X. laevis 1 h after blastopore appearance, and in C. pyrrhogaster 2 h after blastopore appearance. A trench (red arrowheads) is formed between chordin-positive blastocoel floor and chordin-negative blastocoel roof. (D, I) Expression in X. laevis 2 h after blastopore appearance, and in C. pyrrhogaster 4 h after blastopore appearance. (E, J) Expression in ACE embryos (in X. laevis 3 h after blastopore appearance, and in C. pyrrhogaster 7 h after blastopore appearance). Insets are schematic drawings of the expression pattern. The developmental stages are shown at the bottom of each panel. Black arrowheads indicate blastopore. The outline of the embryo is shown by broken lines in panel (A). Note that the boundary between chordin-positive and -negative tissues corresponds to the bottom of the trench, and contributes to the tip of Brachet's cleft (red arrows).
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fig08: Expression patterns of chordin during early gastrulation in Xenopus laevis and Cynops pyrrhogaster. (A–E) Expression patterns of X. laevis chordin from late blastula to anterior contact establishment (ACE) (3 h after blastopore appearance). (F–J) Expression patterns of C. pyrrhogaster chordin from late blastula to ACE (7 h after blastopore appearance). (A, F) Expression in late blastula embryos. Chordin expression is first detected in the dorsal blastocoel roof. (B, G) Expression at the onset of gastrulation. Chordin is expressed not only in the surface layer (dorsal lip) but also internally in the blastocoel floor. (C, H) Expression in X. laevis 1 h after blastopore appearance, and in C. pyrrhogaster 2 h after blastopore appearance. A trench (red arrowheads) is formed between chordin-positive blastocoel floor and chordin-negative blastocoel roof. (D, I) Expression in X. laevis 2 h after blastopore appearance, and in C. pyrrhogaster 4 h after blastopore appearance. (E, J) Expression in ACE embryos (in X. laevis 3 h after blastopore appearance, and in C. pyrrhogaster 7 h after blastopore appearance). Insets are schematic drawings of the expression pattern. The developmental stages are shown at the bottom of each panel. Black arrowheads indicate blastopore. The outline of the embryo is shown by broken lines in panel (A). Note that the boundary between chordin-positive and -negative tissues corresponds to the bottom of the trench, and contributes to the tip of Brachet's cleft (red arrows).

Mentions: Chordin is initially expressed in the dorsal blastocoel roof at the blastula stage in both species (Fig.8A,F; Kuroda et al. 2004) The chordin-negative ectoderm animally located relative to the organizer (chordin-positive) tissue should correspond to the prospective neuroectoderm, meaning that the prospective neuroectoderm and the organizer are aligned in tandem in the blastocoel roof of late blastula (Fig.9A), as indicated by the fate map of amphibian late blastula/early gastrula embryos (Vogt 1929; Nakamura 1942; Keller 1975).


The Spemann organizer meets the anterior-most neuroectoderm at the equator of early gastrulae in amphibian species.

Yanagi T, Ito K, Nishihara A, Minamino R, Mori S, Sumida M, Hashimoto C - Dev. Growth Differ. (2015)

Expression patterns of chordin during early gastrulation in Xenopus laevis and Cynops pyrrhogaster. (A–E) Expression patterns of X. laevis chordin from late blastula to anterior contact establishment (ACE) (3 h after blastopore appearance). (F–J) Expression patterns of C. pyrrhogaster chordin from late blastula to ACE (7 h after blastopore appearance). (A, F) Expression in late blastula embryos. Chordin expression is first detected in the dorsal blastocoel roof. (B, G) Expression at the onset of gastrulation. Chordin is expressed not only in the surface layer (dorsal lip) but also internally in the blastocoel floor. (C, H) Expression in X. laevis 1 h after blastopore appearance, and in C. pyrrhogaster 2 h after blastopore appearance. A trench (red arrowheads) is formed between chordin-positive blastocoel floor and chordin-negative blastocoel roof. (D, I) Expression in X. laevis 2 h after blastopore appearance, and in C. pyrrhogaster 4 h after blastopore appearance. (E, J) Expression in ACE embryos (in X. laevis 3 h after blastopore appearance, and in C. pyrrhogaster 7 h after blastopore appearance). Insets are schematic drawings of the expression pattern. The developmental stages are shown at the bottom of each panel. Black arrowheads indicate blastopore. The outline of the embryo is shown by broken lines in panel (A). Note that the boundary between chordin-positive and -negative tissues corresponds to the bottom of the trench, and contributes to the tip of Brachet's cleft (red arrows).
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4402005&req=5

fig08: Expression patterns of chordin during early gastrulation in Xenopus laevis and Cynops pyrrhogaster. (A–E) Expression patterns of X. laevis chordin from late blastula to anterior contact establishment (ACE) (3 h after blastopore appearance). (F–J) Expression patterns of C. pyrrhogaster chordin from late blastula to ACE (7 h after blastopore appearance). (A, F) Expression in late blastula embryos. Chordin expression is first detected in the dorsal blastocoel roof. (B, G) Expression at the onset of gastrulation. Chordin is expressed not only in the surface layer (dorsal lip) but also internally in the blastocoel floor. (C, H) Expression in X. laevis 1 h after blastopore appearance, and in C. pyrrhogaster 2 h after blastopore appearance. A trench (red arrowheads) is formed between chordin-positive blastocoel floor and chordin-negative blastocoel roof. (D, I) Expression in X. laevis 2 h after blastopore appearance, and in C. pyrrhogaster 4 h after blastopore appearance. (E, J) Expression in ACE embryos (in X. laevis 3 h after blastopore appearance, and in C. pyrrhogaster 7 h after blastopore appearance). Insets are schematic drawings of the expression pattern. The developmental stages are shown at the bottom of each panel. Black arrowheads indicate blastopore. The outline of the embryo is shown by broken lines in panel (A). Note that the boundary between chordin-positive and -negative tissues corresponds to the bottom of the trench, and contributes to the tip of Brachet's cleft (red arrows).
Mentions: Chordin is initially expressed in the dorsal blastocoel roof at the blastula stage in both species (Fig.8A,F; Kuroda et al. 2004) The chordin-negative ectoderm animally located relative to the organizer (chordin-positive) tissue should correspond to the prospective neuroectoderm, meaning that the prospective neuroectoderm and the organizer are aligned in tandem in the blastocoel roof of late blastula (Fig.9A), as indicated by the fate map of amphibian late blastula/early gastrula embryos (Vogt 1929; Nakamura 1942; Keller 1975).

Bottom Line: However, we found that this physical contact was already established at the equatorial region of very early gastrula in a wide variety of amphibian species.After the contact is established, the dorsal axis is formed posteriorly, but not anteriorly.The model also implies the possibility of constructing a common model of gastrulation among chordate species.

View Article: PubMed Central - PubMed

Affiliation: JT Biohistory Research Hall, 1-1 Murasaki-cho, Takatsuki, Osaka, 569-1125, Japan; Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan.

Show MeSH
Related in: MedlinePlus