の形成に欠かせないのは,外皮の頂上部へのソミティックな寄与である
Nature
|July 21, 2016
まとめ
ゼブラフィッシュの新発見のソマイト系細胞は 頂上折り形成を制御し 羽根から四肢への移行の重要なステップです テトラポッドの四肢が 進化の過程で失われてしまったことを 説明できるかもしれません
科学分野:
- 発達生物学
- 進化的発達生物学
- 比較解剖学
背景:
- 羽根から手足への移行は 陸上の生命にとって重要な進化的適応です
- この移行の既存のモデルは,アピカル外皮脊 (AER) と付属体の成長中のシグナリング分子に焦点を当てています.
- 翼のAERは迅速にアピカルフォールドを形成し,四肢とは異なり,骨格の前駆体増殖を促進する信号を停止します.
研究 の 目的:
- 手足の進化の理解が乏しいアスペクトであるアピカルフォールド誘導を制御する発達メカニズムを調査する.
- AERからアピカル・フォールドへの移行は,四肢の進化に不可欠であるという仮説を検証する.
- 羽根から四肢への発達シフトの調整に関与する細胞および分子プレーヤーを特定する.
主な方法:
- 付属体の発達を研究するモデル生物としてゼブラフィッシュを使用した.
- AERに侵入した新しいソミット系細胞を特定し特徴づけました.
- これらの細胞がアピカルフォールド形成とAER活動に果たす役割を評価するために,細胞剥離実験を行った.
- これらの細胞の進化的存在を gnathostome 種で調べました
主要な成果:
- AERに特定のソミット系細胞の侵入がゼブラフィッシュの頂点折り誘導を調節することを実証した.
- これらの細胞の消去により,頂点折り形成,AER活性が延長され,芽メゼンキームが増加しました.
- これらのアピカルフォールド誘発細胞は,グナトストームの進化の間に徐々に失われることが示された.
- この細胞は四足の肢に 欠けていて 足の発達に 繋がっていることを示唆しています
結論:
- 新しいソマイト由来の細胞系は,頂上折り形成のタイミングメカニズムとして作用し,ソルグッドの翼から四肢への移行の時計モデルを潜在的に説明します.
- これらのアピカルフォールド誘発細胞の進化的喪失は,四足の四肢構造の発達の前提条件であるようです.
- この発見は,脊椎動物の歴史における主要な進化的移行に関する新しい発展的視点を提供します.
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