アラビドプシスの小さなRNA経路による雌性ゲメット形成の制御
Vianey Olmedo-Monfil1, Noé Durán-Figueroa, Mario Arteaga-Vázquez
1Grupo de Desarrollo Reproductivo y Apomixis, Laboratorio Nacional de Genómica para la Biodiversidad y Departamento de Ingeniería Genética de Plantas, Cinvestav Irapuato CP36500 Guanajuato, México.
Nature
|March 9, 2010
まとめ
アラビドプシスのARGONAUTE 9 (AGO9) タンパク質は,ゲメトファイットの前駆体を制御することによって,雌性ゲメト形成を制限する. このプロセスは,同伴細胞からの小さなRNA (sRNA) サイレンシングに依存し,卵子内の細胞運命を指定するために不可欠です.
科学分野:
- 植物の生殖生物学 植物の生殖生物学
- エピジェネティクス エピジェネティクス
- 分子遺伝学 分子遺伝学
背景:
- 花咲く植物の雌性ゲメトゲネシスは,通常,メガスポア母細胞 (MMC) から派生した単一の機能的なメガスポアから始まります.
- いくつかの種や突然変異が複数のMMCを形成したり,アポミクチカル (メオシスなし) でゲメットを産生したりすることで,多様性が存在します.
- これは,卵子内の体細胞がゲメトゲネシスを決定する信号に反応できることを示唆しています.
研究 の 目的:
- アラビドプシス・アルゴナウテ9 (AGO9) が雌性ゲメット形成を制御する役割を調査する.
- AGO9がゲメトファイト前駆体特異を調節するメカニズムを解明する.
主な方法:
- アラビドプシスの変異体,特にago9,遺伝子静止抑制剤3 (sgs3),RNA依存型RNAポリメラーゼ6 (rdp6) の分析.
- 卵巣組織内のAGO9のタンパク質発現パターンの調査.
- 小型RNA (sRNA) とAGO9の相互作用とその起源,特に移植可能な元素 (TEs) を研究する.
主要な成果:
- AGO9の変異は,ゲメトゲネシスを開始できる複数のゲメティック細胞の形成につながります.
- AGO9タンパク質は,ゲメト系ではなく,体細胞の仲間細胞に局所されています.
- SGS3とRDP6の欠陥はago9変異体と同様の表型を示し,仲間細胞からのsRNA移動の重要性を強調しています.
- AGO9は,TEsからの24核酸sRNAと相互作用し,ゲメットと付属細胞のTEsを静止するのに不可欠です.
結論:
- AGO9に依存するsRNAサイレンシングは,アラビドプシスの卵巣発達の過程で細胞運命を特定するために重要である.
- 植物ゲメットの有効なsRNA依存性静止には,伴生細胞における表遺伝子再プログラムが必要である.
- このメカニズムは,単一の細胞系から女性のゲメトゲネシスの正しい開始を保証します.
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