アネリドのアクソコードの発達: ノトコードの進化に関する洞察

Antonella Lauri¹, Thibaut Brunet¹, Mette Handberg-Thorsager²

¹Developmental Biology Unit, European Molecular Biology Laboratory (EMBL), D-69117 Heidelberg.

Science (New York, N.Y.)

|September 13, 2014

まとめ

研究者らは,Platynereis dumeriliiの新種の細胞集団を特定し,コード状ノトコルドの進化的起源に光を当てました. この発見は,初期の動物の発達と進化に関する新しい洞察を提供します.

科学分野:

進化的発達生物学進化的発達生物学
比較ゲノミクスとは
海洋無脊椎動物生物学

背景:

コルド類,特にノトコルド類の進化的起源は,生物学における長年の議論であり続けています.
脊椎動物のノトコルドの発達には,特殊なミッドライン細胞 (コルドメソダーム) の収束と拡張が含まれる.

研究の目的:

ノトコルドの起源の基礎となる細胞および分子機構を調査する.
無脊椎動物のモデルにおけるコード状ノトコルドの潜在的祖先前駆者を特定する.

主な方法:

海洋アネリド Platynereis dumeriliiにおけるメソダーマ細胞集団の識別と特徴付け.
ノトコルド特有のマーカーを含む遺伝子発現パターンの分析.
進化的関係を推論するために,先祖状態の再構築.

主要な成果:

Platynereis dumerilii の中皮細胞の集団が特定され,中線に向かって収束的な拡張を示しています.
これらの細胞は,ノトコルドの発達に関連した遺伝子のユニークな組み合わせを表現し,縦筋の筋肉であるアクソコルドに微分化します.
アクソコードは,中枢神経系と軸性血管の間に位置し,コラーゲン状の細胞外マトリックスを分泌する.

結論:

収縮性メソダーマルミドルライン細胞は,双子の祖先に存在していた可能性が高い.
Platynereis axochordは,祖先のノトコルド前駆者の機能的および分子的性質を理解するためのモデルを提供します.
これらの祖先細胞の真空化と硬化が,状ノトコルドの進化の重要なステップとして提案されています.

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