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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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Conventional model and Proposed model of amphibian gastrulation. (A) Conventional mode of amphibian gastrulation. (B) Proposed model of amphibian gastrulation “S&Z movement”. The organizer and the prospective neuroectoderm are represented by red and blue, respectively. (A-1) Blastula embryo. (A-2, 3, 4, 5) The organizer which is derived from the dorsal marginal zone, invaginates, involutes into the body, and then migrates toward the animal pole on the inner surface of the blastocoel roof. (A-6) Anterior contact establishment (ACE) occurs around the animal pole area of mid- to late-gastrula embryo. (B-1) Blastula embryo. (B-2,3) The embryos undergo subduction movement. (B-4, 5) The zippering movement leads to physical contact between the blastocoel floor and the blastocoel roof. ACE occurs at equatorial region of very early gastrula. (B-6) The leading edge tissue migrates animally beyond the region of anterior contact. (B-7) An axial structure is progressively formed toward the posterior during the rest of the gastrulation movement. Curved arrows between A and P indicate the direction of axial structure formation. , organizer; , prospective neuroectoderm.
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fig10: Conventional model and Proposed model of amphibian gastrulation. (A) Conventional mode of amphibian gastrulation. (B) Proposed model of amphibian gastrulation “S&Z movement”. The organizer and the prospective neuroectoderm are represented by red and blue, respectively. (A-1) Blastula embryo. (A-2, 3, 4, 5) The organizer which is derived from the dorsal marginal zone, invaginates, involutes into the body, and then migrates toward the animal pole on the inner surface of the blastocoel roof. (A-6) Anterior contact establishment (ACE) occurs around the animal pole area of mid- to late-gastrula embryo. (B-1) Blastula embryo. (B-2,3) The embryos undergo subduction movement. (B-4, 5) The zippering movement leads to physical contact between the blastocoel floor and the blastocoel roof. ACE occurs at equatorial region of very early gastrula. (B-6) The leading edge tissue migrates animally beyond the region of anterior contact. (B-7) An axial structure is progressively formed toward the posterior during the rest of the gastrulation movement. Curved arrows between A and P indicate the direction of axial structure formation. , organizer; , prospective neuroectoderm.

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)

Conventional model and Proposed model of amphibian gastrulation. (A) Conventional mode of amphibian gastrulation. (B) Proposed model of amphibian gastrulation “S&Z movement”. The organizer and the prospective neuroectoderm are represented by red and blue, respectively. (A-1) Blastula embryo. (A-2, 3, 4, 5) The organizer which is derived from the dorsal marginal zone, invaginates, involutes into the body, and then migrates toward the animal pole on the inner surface of the blastocoel roof. (A-6) Anterior contact establishment (ACE) occurs around the animal pole area of mid- to late-gastrula embryo. (B-1) Blastula embryo. (B-2,3) The embryos undergo subduction movement. (B-4, 5) The zippering movement leads to physical contact between the blastocoel floor and the blastocoel roof. ACE occurs at equatorial region of very early gastrula. (B-6) The leading edge tissue migrates animally beyond the region of anterior contact. (B-7) An axial structure is progressively formed toward the posterior during the rest of the gastrulation movement. Curved arrows between A and P indicate the direction of axial structure formation. , organizer; , prospective neuroectoderm.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig10: Conventional model and Proposed model of amphibian gastrulation. (A) Conventional mode of amphibian gastrulation. (B) Proposed model of amphibian gastrulation “S&Z movement”. The organizer and the prospective neuroectoderm are represented by red and blue, respectively. (A-1) Blastula embryo. (A-2, 3, 4, 5) The organizer which is derived from the dorsal marginal zone, invaginates, involutes into the body, and then migrates toward the animal pole on the inner surface of the blastocoel roof. (A-6) Anterior contact establishment (ACE) occurs around the animal pole area of mid- to late-gastrula embryo. (B-1) Blastula embryo. (B-2,3) The embryos undergo subduction movement. (B-4, 5) The zippering movement leads to physical contact between the blastocoel floor and the blastocoel roof. ACE occurs at equatorial region of very early gastrula. (B-6) The leading edge tissue migrates animally beyond the region of anterior contact. (B-7) An axial structure is progressively formed toward the posterior during the rest of the gastrulation movement. Curved arrows between A and P indicate the direction of axial structure formation. , organizer; , prospective neuroectoderm.
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