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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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Prospective neuroectoderm and lining mesoderm are continuously associated with each other during gastrulation in Cynops pyrrhogaster. (A) Schematic illustration of the experimental procedure for internal and external labeling. At the beginning, the external surface of the equatorial region was labeled with Nile blue 30 min before anterior contact establishment (ACE) (6.5 h after blastopore appearance), and then a bead was placed in the internal tissue at the same location as the labeled external surface, which can be seen from the internal side. (A) If the internal and the external tissues do not slide in tandem, the bead is under the labeled tissue at the end of gastrulation. (B) A labeled embryo 24 h after blastopore appearance (sagittal section). White bracket indicates the Nile blue labeled region. The bead in the internal tissue was found below the surface layer labeled with Nile blue. White arrowhead in panel B indicates blastopore.
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fig06: Prospective neuroectoderm and lining mesoderm are continuously associated with each other during gastrulation in Cynops pyrrhogaster. (A) Schematic illustration of the experimental procedure for internal and external labeling. At the beginning, the external surface of the equatorial region was labeled with Nile blue 30 min before anterior contact establishment (ACE) (6.5 h after blastopore appearance), and then a bead was placed in the internal tissue at the same location as the labeled external surface, which can be seen from the internal side. (A) If the internal and the external tissues do not slide in tandem, the bead is under the labeled tissue at the end of gastrulation. (B) A labeled embryo 24 h after blastopore appearance (sagittal section). White bracket indicates the Nile blue labeled region. The bead in the internal tissue was found below the surface layer labeled with Nile blue. White arrowhead in panel B indicates blastopore.

Mentions: Anterior terminal neural tissue is determined when the anterior tip of the axial mesoderm reaches the anterior-most portion of the prospective neuroectoderm at the blastocoel roof. In this work, the establishment of this physical contact is called “anterior contact establishment” (ACE) (cf. Fig. 10A-6). The establishment of physical contact between the organizer and the prospective neuroectoderm is one of the important steps for axis formation. As the prospective head neuroectoderm is known to locate around the animal pole in fate maps of early gastrula (Vogt 1929; Nakamura 1942; Keller 1975), ACE should occur around the animal pole area of mid- to late-gastrula embryo.


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)

Prospective neuroectoderm and lining mesoderm are continuously associated with each other during gastrulation in Cynops pyrrhogaster. (A) Schematic illustration of the experimental procedure for internal and external labeling. At the beginning, the external surface of the equatorial region was labeled with Nile blue 30 min before anterior contact establishment (ACE) (6.5 h after blastopore appearance), and then a bead was placed in the internal tissue at the same location as the labeled external surface, which can be seen from the internal side. (A) If the internal and the external tissues do not slide in tandem, the bead is under the labeled tissue at the end of gastrulation. (B) A labeled embryo 24 h after blastopore appearance (sagittal section). White bracket indicates the Nile blue labeled region. The bead in the internal tissue was found below the surface layer labeled with Nile blue. White arrowhead in panel B indicates blastopore.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig06: Prospective neuroectoderm and lining mesoderm are continuously associated with each other during gastrulation in Cynops pyrrhogaster. (A) Schematic illustration of the experimental procedure for internal and external labeling. At the beginning, the external surface of the equatorial region was labeled with Nile blue 30 min before anterior contact establishment (ACE) (6.5 h after blastopore appearance), and then a bead was placed in the internal tissue at the same location as the labeled external surface, which can be seen from the internal side. (A) If the internal and the external tissues do not slide in tandem, the bead is under the labeled tissue at the end of gastrulation. (B) A labeled embryo 24 h after blastopore appearance (sagittal section). White bracket indicates the Nile blue labeled region. The bead in the internal tissue was found below the surface layer labeled with Nile blue. White arrowhead in panel B indicates blastopore.
Mentions: Anterior terminal neural tissue is determined when the anterior tip of the axial mesoderm reaches the anterior-most portion of the prospective neuroectoderm at the blastocoel roof. In this work, the establishment of this physical contact is called “anterior contact establishment” (ACE) (cf. Fig. 10A-6). The establishment of physical contact between the organizer and the prospective neuroectoderm is one of the important steps for axis formation. As the prospective head neuroectoderm is known to locate around the animal pole in fate maps of early gastrula (Vogt 1929; Nakamura 1942; Keller 1975), ACE should occur around the animal pole area of mid- to late-gastrula embryo.

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