イーストのノンコーディングRNAの進化は,広範囲に広がるイントロン喪失の代替メカニズムを明らかにする
Quinn M Mitrovich1, Brian B Tuch, Francisco M De La Vega
1Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143-2200, USA.
まとめ
イントロン損失のメカニズムは,酵母菌の系統によって異なります. カンジダ・アルビカンスのスノRNA (small nucleolar RNA) 遺伝子は,スノRNAをイントロン内に保持し,サッカロマイセスの酵母はスプライシング信号変性によってイントロンを失います.
科学分野:
- 進化生物学の進化生物学について
- 分子遺伝学 分子遺伝学
- ゲノミクスゲノミクスとは
背景:
- イントロン喪失の進化的原動力は,ほとんど不明のままである.
- 以前の研究では,主にタンパク質をコードする遺伝子のイントロン損失を調査した.
- イントロンがしばしば機能する小核核RNA (snoRNA) 遺伝子は,独特のモデルシステムを提供します.
研究 の 目的:
- ノンコーディングスノRNA遺伝子におけるイントロンの喪失の進化的メカニズムを調査する.
- 異なった酵母系,特にCandida albicansとSaccharomycesの異なった酵母系におけるsnoRNA遺伝子におけるイントロン損失パターンを比較する.
- コーディング対非コーディング遺伝子のイントロン損失の独特の進化軌道を明らかにする.
主な方法:
- 遺伝子発現を分析し,スプライス・ジャンクションを特定するために,ディープRNAシーケンシングを使用した.
- スプライス・ジャンクションの全ゲノムアノテーションは,イントロン-エクソン構造をマッピングするために行われました.
- 異なる酵母系にわたる比較ゲノム解析が行われました.
主要な成果:
- Candida albicansの系統では,snoRNA遺伝子は極端な圧縮とエクソンの損失を示したが,機能的なsnoRNAを含むイントロンを保持した.
- Saccharomycesの系統では,本質的なスプライシング信号の退化により,イントロンが大幅に失われました.
- スノRNA遺伝子におけるこのイントロンの損失は,タンパク質をコードする遺伝子で観察されたものとは,機構的および時間的に異なる.
結論:
- スノRNA遺伝子のイントロン喪失は,タンパク質をコードする遺伝子と比較して,異なる進化の経路をたどります.
- SaccharomycesのsnoRNA遺伝子のイントロンの喪失は,新しいsnoRNA処理メカニズムによって促進される可能性があります.
- 非コーディングRNAにおけるイントロン損失を理解することは,ゲノム進化に関する重要な洞察を提供します.
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