乳芽原始線は,胃化の前の上皮細胞のインターカレーションによって定義されます
Octavian Voiculescu1, Federica Bertocchini, Lewis Wolpert
1Department of Anatomy & Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK. o.voiculescu@ucl.ac.uk
Nature
|October 12, 2007
まとめ
乳芽原始線形形成は,繊維細胞成長因子とWntシグナル伝達によって誘導される,胃化の前の新しい外皮細胞のインターキャレーションを含みます. このメカニズムは,原始的な線をミドルラインに配置し,胎児の発達と異なる.
科学分野:
- 発達生物学 発達生物学とは
- 細胞生物学 細胞生物学
- 進化的発達生物学 進化的発達生物学
背景:
- 胃化は,エクトダームから生殖層 (メソダーム,エンドダーム) を形成する.
- アムニオート (鳥,哺乳類) の中皮は,外皮細胞の移動が先行する原始的な線状経由で形成されます.
- 胎盤の原始的な線形形成を制御するメカニズムは,ほとんど不明のままです.
研究 の 目的:
- アムニオットにおける原始的なストライク形成を制御する細胞および分子メカニズムを解明する.
- 細胞のインターカレーションとシグナル伝達経路が,原始的な線条の位置づけにおける役割を調査する.
- 胎児の原始的な線状形成と,胎児の胃化の過程を比較する.
主な方法:
- チキン (Gallus gallus) の胚のマルチフォトンタイムラップ顕微鏡.
- エクトodermal 細胞のインターキャレーションダイナミクスの分析.
- 線維芽生殖成長因子 (FGF) とWnt平面細胞対極性 (PCP) 経路の関与の調査.
主要な成果:
- 原始的なストライク形成前のエクトダームで,新しい中側側細胞インターキャレーションが発生します.
- このインターカレーションは,ヒポブラストからの線維芽細胞成長因子によって指揮され,Wnt経路の成分を調節します.
- Wntのシグナル伝達の障害は,ミッドラインの原始的なストライク発達とは異なり,外周性メゼンドームの形成につながります.
結論:
- 羊膜原始線は,祖先のブラストポアから進化した可能性が高い.
- 加えて,プレガストゥルレーション前の中間横断のイベントにより,乳芽原始線が中間線に位置する.
- この胞特異的なインターカレーションメカニズムは,メゼンドルマ形成とは独立して動作する.
関連する概念動画
Cleavage and Blastulation
After a large-single-celled zygote is produced via fertilization, the process of cleavage occurs while zygotes travel through the uterine tube. Cleavage is a mitotic cell division that does not result in growth. With each round of successive cell division, daughter cells get increasingly smaller.
Gastrulation
Gastrulation establishes the three primary tissues of an embryo: the ectoderm, mesoderm, and endoderm. This developmental process relies on a series of intricate cellular movements, which in humans transforms a flat, “bilaminar disc” composed of two cell sheets into a three-tiered structure. In the resulting embryo, the endoderm serves as the bottom layer, and stacked directly above it is the intermediate mesoderm, and then the uppermost ectoderm. Respectively, these tissue strata will form...
Neurulation
Neurulation is the embryological process which forms the precursors of the central nervous system and occurs after gastrulation has established the three primary cell layers of the embryo: ectoderm, mesoderm, and endoderm. In humans, the majority of this system is formed via primary neurulation, in which the central portion of the ectoderm—originally appearing as a flat sheet of cells—folds upwards and inwards, sealing off to form a hollow neural tube. As development proceeds, the anterior...
Zygotic Development And Stem Cell Formation
The development of all multicellular organisms starts with the fusion of haploid cells called sperm and egg to form a diploid zygote. A zygote is a totipotent cell that can develop into a complete organism. The zygote undergoes cell division or cleavage to form an 8-cell mass. Until this stage, the cells are spherical, loosely attached, and remain totipotent. Totipotent cells are capable of developing both the embryonic and the extraembryonic tissues. However, as they continue to divide, they...
Renewal of Intestinal Stem Cells
The intestinal epithelial lining rapidly renews every 4 to 5 days. The renewal is facilitated by intestinal stem cells (ISCs) located at the base of the crypt– a gland located at the bottom of each villus. ISCs divide asymmetrically to form new stem cells and progenitor daughter cells. The daughter cells are called transit-amplifying (TA) cells which move upwards along the crypt and either differentiate into absorptive cells– the enterocytes or secretory cells– including the goblet,...
Embryonic Connective Tissues
During early development, the embryo forms two types of connective tissues— the mesenchyme and mucoid connective tissue.
The mesenchyme is the first connective tissue that emerges in the developing embryo. It consists of loosely arranged multipotent mesenchymal cells and reticular fibers in the extracellular matrix. This loose arrangement allows easy migration of cells, which is essential for germ layer positioning, patterning, and organ morphogenesis during embryonic development. Mesenchyme is...
The mesenchyme is the first connective tissue that emerges in the developing embryo. It consists of loosely arranged multipotent mesenchymal cells and reticular fibers in the extracellular matrix. This loose arrangement allows easy migration of cells, which is essential for germ layer positioning, patterning, and organ morphogenesis during embryonic development. Mesenchyme is...


