LTR-レトロトランスポソン tRNA 派生小RNAによる制御
Andrea J Schorn1, Michael J Gutbrod2, Chantal LeBlanc3
1Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
Cell
|July 1, 2017
まとめ
tRNA由来断片 (tRFs) と呼ばれる小さなRNAは,その複製機構を標的として,内生レトロウイルス (ERVs) を抑制する. この発見により 細胞内のトランポゾン活性を制御する 新しいメカニズムが明らかになりました
科学分野:
- 分子生物学
- 遺伝学
- エピジェネティクス
背景:
- エピジェネティック・サイレンシングが失われると 細胞の再プログラム中に トランポゾン再活性化が危険です
- ロング・ターミナル・リピート (LTR) - レトロトランスポゾンまたは内生レトロウイルス (ERV) は,特定のヒストン変異を欠いたマウス細胞に新しい挿入の主要な源である.
研究 の 目的:
- 内生レトロウイルス (ERV) の活性制御におけるtRNA由来小RNA (tRFs) の役割を調査する.
- tRF がレトロトランスポゾン移動性を制御する特定のターゲットとメカニズムを特定する.
主な方法:
- 植入前の幹細胞の小さなRNA群の分析
- tRFによるERV阻害を評価するためのin vitro逆転移測定法.
- ERV配列内のtRNA由来小RNA (tRF) ターゲットの特定
主要な成果:
- 豊富に発現する18ntと,あらゆるところに発現する22ntのtRFが特定された.
- これらのtRFは,ERVの逆転転写に不可欠なプライマー結合部位 (PBS) を標的とする.
- tRFは主要なERVファミリー (IAP,MusD/ ETn) の逆転転移を有意に抑制した.
結論:
- tRFは,ERV複製に干渉することによって,トランポゾン再活性化に対する防御メカニズムとして作用する.
- 22 nt tRFは,転写後の暗号化ERVを静止し,18 nt tRFは,逆転写と移動性を阻害する.
- PBSを標的にすることは,LTR-レトロトランスポゾンを阻害する特定の戦略であり,保存された小さなRNA媒介トランスポゾン制御メカニズムを示唆する.
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