産後哺乳類の卵巣における生殖系幹細胞と卵泡の再生
Joshua Johnson1, Jacqueline Canning, Tomoko Kaneko
1Vincent Center for Reproductive Biology, Vincent Obstetrics and Gynecology Service, Massachusetts General Hospital, and Department of Obstetrics, Gynecology and Reproductive Biology, Harvard Medical School, Boston, Massachusetts 02114, USA.
Nature
|March 12, 2004
まとめ
哺乳類の卵巣には,生涯にわたって卵の供給を補う,積極的に分裂する生殖細胞が含まれています. この発見は,出生時に確立された固定的卵子貯蔵量という長年にわたる信念に異議を唱え,継続的な更新プロセスを明らかにしています.
科学分野:
- 生殖生物学 生殖生物学
- 発達生物学 発達生物学について
- 細胞生物学 細胞生物学
背景:
- 繁殖生物学における支配的な見解は,雌性哺乳類は,産後における更なる生殖細胞の更新なし,限られた数の卵細胞で生まれているというものです.
- この学説は,卵巣の固定リザーブが時間とともに減少し,生育能力に影響を及ぼすことを示唆しています.
研究 の 目的:
- 幼生および成人哺乳類の卵巣におけるミトーシス活性生殖細胞の存在と機能を調査する.
- 卵巣の固定リザーブという既成の教義に異議を唱え,卵泡プール補給のメカニズムを探求する.
主な方法:
- マウスの卵巣における卵細胞変性 (アトレシア) とクリアランスの分析.
- 発芽前の雌マウスを,生殖細胞に毒性のあるブスルファンで治療する.
- 卵巣細胞におけるシナプトネマル複合タンパク質3 (メオティックマーカー) の検出.
- 緑色光タンパク質 (GFP) を発現するトランス遺伝子マウスを用いた卵巣移植実験.
主要な成果:
- 幼生マウスの卵巣と成人マウスの卵巣でミトーシス的に活発な生殖細胞の証拠が発見され,これは毛細血管の補充に不可欠である.
- ブスルファン治療は,アトレシアを増加させることなく,原始の卵泡の準備を枯渇させ,ミトスの生殖細胞の役割をサポートしました.
- 成人卵巣では,メヨティックエントリーマーカーを発現する細胞が特定されました.
- 移植された野生型の卵巣は,GFP陽性生殖細胞に浸透し,新しい卵泡を形成しました.
結論:
- 哺乳類の卵巣は,産後,卵細胞と卵泡の生産を継続的に行うことができる増殖性生殖細胞の集団を保持しています.
- この発見は,卵巣の準備量と女性の生殖能力に関する生殖生物学における基本的な概念の見直しを必要としています.
- この発見は,哺乳類の生殖生涯を通じて内生性生殖細胞の再生の可能性を示しています.
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