関連する実験動画
Updated: Jun 18, 2026

11:32
Analysis of mRNA Nuclear Export Kinetics in Mammalian Cells by Microinjection
Published on: December 4, 2010
プレミクロRNA核輸出機械の高解像度構造
Chimari Okada1, Eiki Yamashita, Soo Jae Lee
1Institute for Protein Research, Osaka University, 3-2 Yamada-oka, Suita, Osaka 565-0871, Japan.
まとめ
前駆微RNA (pre-miRNA) の核輸出には,エキスポートイン-5 (Exp-5) とランGTP.が含まれています. この研究は,この複合体の構造を明らかにし,輸出のためのプレミRNAを認識し,保護する方法を示しています.
科学分野:
- 分子生物学は分子生物学である.
- 構造生物学 構造生物学とは
- バイオケミストリー バイオケミストリー
背景:
- マイクロRNA (miRNA) の核輸出は,miRNAの生殖にとって極めて重要です.
- エクスポートイン-5 (Exp-5) は,前駆体miRNAs (pre-miRNAs) とRanGTPと相互作用することで,このエクスポートを促進します.
研究 の 目的:
- プレミRNA核輸出機械の高解像度構造を決定する.
- Exp-5,RanGTP,およびpre-miRNAの間の分子相互作用を解明する.
主な方法:
- 2.9アングストームの解像度のX線結晶学.
- 前ミRNA:Exp-5:RanGTP複合体の構造分析.
主要な成果:
- この構造は,Exp-5:RanGTPが,プリミRNAの2核酸3'オーバーハングと二重鎖の幹を認識する方法を示しています.
- 複合体は,プリミRNA幹の周りに保護的な"ベースボール・マット"と,3'オーバーハングのための"トンネル"を形成します.
- 認識は配列独立であり,様々なプレミRNAに広く適用できることを示唆しています.
結論:
- この構造は,プリミRNA核輸出のための詳細な分子機構を提供します.
- Exp-5:RanGTPの保護シールドと3'オーバーハングとの特定の相互作用は,その機能の鍵です.
- 配列独立認識メカニズムは,miRNAバイオゲネシスにおけるExp-5:RanGTPの適応性を強調しています.
関連する概念動画
Nuclear Export
The nucleus restricts several proteins within and allows others to pass. The restricted proteins possess a nuclear retention sequence or NRS, anchoring them to the nuclear lamins and preventing their transport to the cytosol. The non-restricted proteins, after their synthesis, are transported to their site of action, such as the cytosol or other organelles, with the help of nuclear export signals or NES.
NES are of three types- the canonical 10-residue long leucine-rich signal and other...
NES are of three types- the canonical 10-residue long leucine-rich signal and other...
Nuclear Export of mRNA
Before mRNAs are exported to the cytoplasm, it is crucial to check each mRNA for structural and functional integrity. Eukaryotic cells use several different mechanisms, collectively known as mRNA surveillance, to look for irregularities in mRNAs. Irregular or aberrant mRNA are rapidly degraded by various enzymes. If a defective mRNA escapes the surveillance, it would be translated into a protein which would either be non-functional or not function properly. One of the primary irregularities in...
Nuclear Export of mRNA
Before mRNAs are exported to the cytoplasm, it is crucial to check each mRNA for structural and functional integrity. Eukaryotic cells use several different mechanisms, collectively known as mRNA surveillance, to look for irregularities in mRNAs. Irregular or aberrant mRNA are rapidly degraded by various enzymes. If a defective mRNA escapes the surveillance, it would be translated into a protein which would either be non-functional or not function properly. One of the primary irregularities in...
Nuclear Protein Sorting
Nuclear protein sorting is the selective trafficking of histones, polymerases, gene regulatory proteins into the nucleus and exporting RNAs and ribosomes to the cytosol. It is a tightly controlled process that regulates gene expression within a cell.
Proteins targeted to the nucleus carry nuclear localization signals or NLS recognized by import receptors in the cytosol. Similarly, proteins with nuclear export signals are recognized by export receptors. Import and export receptors are...
Proteins targeted to the nucleus carry nuclear localization signals or NLS recognized by import receptors in the cytosol. Similarly, proteins with nuclear export signals are recognized by export receptors. Import and export receptors are...
Regulated mRNA Transport
In eukaryotes, transcription and translation are compartmentalized; an mRNA is first synthesized in the nucleus and then selectively transported to the cytoplasm for protein synthesis. Before transport, a pre-mRNA undergoes several steps of post-transcriptional modifications including splicing, 5' capping, and the addition of a poly-adenine tail. Various proteins bind to the pre-mRNA during these modifications. The mRNA transport takes place with the help of multiple proteins playing specific...
Directionality of Nuclear Transport
Ras-related nuclear protein or Ran is a small G protein that cycles between its GTP and GDP bound states. Ran specific regulators, a Ran GTPase Activating Protein or RanGAP present in the cytosol and a Ran guanine nucleotide exchange factor or RanGEF present inside the nucleus regulate GTP/GDP exchange. A high concentration of GTP inside the cells, in addition to this asymmetric distribution of Ran-specific regulators, leads to a higher RanGTP concentration inside the nucleus. This...

