ドロシャの処理をバイパスする腸内マイクロRNA前駆体.
J Graham Ruby1, Calvin H Jan, David P Bartel
1Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, Massachusetts 02142, USA.
Nature
|June 26, 2007
まとめ
科学者たちは,ミルトロンと呼ばれる,枝分かれしたイントロンを用いて新しいマイクロRNA (miRNA) 経路を発見しました. これらはドロシャの処理をバイパスし,動物におけるmiRNA生殖のための代替ルートを提供します.
科学分野:
- 分子生物学は分子生物学である.
- 遺伝学 遺伝学とは
- RNA 生物学 RNA 生物学
背景:
- マイクロRNA (miRNA) は,メッセンジャーRNAを抑制することによって遺伝子発現を調節する小さな内生RNAである.
- カノニカルなmiRNAバイオゲネシスには,pre-miRNAヘアピンのドロシャとディッサーの処理が含まれています.
- miRNA生殖経路の正確なメカニズムと進化的起源は,現在活発に研究されている分野です.
研究 の 目的:
- マイクロRNAバイオゲネシスの代替経路を特定する.
- miRNA生成におけるイントロンの役割を調査する.
- マイクロRNAの進化的起源を探求する.
主な方法:
- 潜在的なmiRNA前駆体を特定するためのバイオ情報分析.
- 進化的保存を評価するための比較ゲノミクス.
- 特定されたミルトロンの機能的特徴.
主要な成果:
- "ミートロン"の発見,ミートロン前RNAを模倣する分断されたイントロンの発見.
- ドロソフィラ・メラノガスターのミルトロン14個,カエノラブディティス・エレガンスのミルトロン4個を特定した.
- 進化的保存の証拠は,ミルトロンの規制的役割を示唆しています.
結論:
- 新しいmiRNAバイオゲネシス経路が存在し,脱枝されたイントロン (ミートロン) を利用しています.
- ミルトロンは,正規のドロシャ依存の処理ステップをバイパスします.
- この経路は,Drosha.より前のmiRNA進化の古代のメカニズムを表している可能性があります.
関連する概念動画
01:22MicroRNAs
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02:01pre-mRNA Processing
In eukaryotic cells, transcripts made by RNA polymerase are modified and processed before exiting the nucleus. Unprocessed RNA is called precursor mRNA or pre-mRNA to distinguish it from mature mRNA.
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a “cap” to the 5’ end of the growing transcript. In this process, a 5’ phosphate is replaced by modified guanosine that has a methyl group attached to it (7-Methyl guanosine). This 5’ cap helps the...
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a “cap” to the 5’ end of the growing transcript. In this process, a 5’ phosphate is replaced by modified guanosine that has a methyl group attached to it (7-Methyl guanosine). This 5’ cap helps the...
01:23RNA Interference
RNA interference (RNAi) is a process in which a small non-coding RNA molecule blocks the post-transcriptional expression of a gene by binding to its messenger RNA (mRNA) and preventing the protein from being translated.
This process occurs naturally in cells, often through the activity of genomically-encoded microRNAs. Researchers can take advantage of this mechanism by introducing synthetic RNAs to deactivate specific genes for research or therapeutic purposes. For example, RNAi could be used...
This process occurs naturally in cells, often through the activity of genomically-encoded microRNAs. Researchers can take advantage of this mechanism by introducing synthetic RNAs to deactivate specific genes for research or therapeutic purposes. For example, RNAi could be used...
01:22MicroRNAs
MicroRNA (miRNA) are short, regulatory RNA transcribed from introns—non-coding regions of a gene—or intergenic regions—stretches of DNA present between genes. Several processing steps are required to form biologically active, mature miRNA. The initial transcript, called primary miRNA (pri-mRNA), base-pairs with itself forming a stem-loop structure. Within the nucleus, an endonuclease enzyme, called Drosha, shortens the stem-loop structure into hairpin-shaped pre-miRNA. After the pre-miRNA ends...
01:22MicroRNAs
MicroRNA (miRNA) are short, regulatory RNA transcribed from introns (non-coding regions of a gene) or intergenic regions (stretches of DNA present between genes). Several processing steps are required to form biologically active, mature miRNA. The initial transcript, called primary miRNA (pri-mRNA), base-pairs with itself, forming a stem-loop structure. Within the nucleus, an endonuclease enzyme, called Drosha, shortens the stem-loop structure into hairpin-shaped pre-miRNA. After the pre-miRNA...