KAP1は,胚性幹細胞の内生レトロウイルスを制御する
Helen M Rowe1, Johan Jakobsson, Daniel Mesnard
1School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
Nature
|January 16, 2010
まとめ
KRAB関連タンパク質1 (KAP1) は,発達の初期に内生レトロウイルス (ERV) を制御する. ネズミの胚性幹細胞および胚におけるKAP1の欠失は,ERVの有意なアップレギュレーションを引き起こし,ゲノム完全性におけるその役割を強調する.
科学分野:
- 遺伝学 遺伝学とは
- エピジェネティクス エピジェネティクス
- 発達生物学 発達生物学について
背景:
- 哺乳類のゲノムには,内生レトロウイルス (ERV) を含む40%以上のレトロエレメントが含まれています.
- ERVは,ゲノム整合性を維持するために,DNAとヒストンのメチル化を経由して,初期胚形成の間に転写的に静止されます.
- ERV静音化の正確なメカニズムと始動者は,ほとんど不明のままです.
研究 の 目的:
- 胚の発達初期における内生レトロエレメントの転写制御におけるKRAB関連タンパク質1 (KAP1) の役割を調査する.
- KAP1媒介による抑制が,マウスの胚性幹細胞および早期胚におけるERVの静止に寄与するかどうかを決定する.
主な方法:
- マウスの胚性幹細胞 (ES細胞) と初期の胚におけるKAP1の欠損.
- 定量的な方法を使用して内生レトロウイルス (ERV) 発現の分析.
- ヒストン変異 (H3K9me3) とKAP1濃縮を評価するためのクロマチンの免疫プレシピテーション.
- Reporterは,ERV配列の抑圧的機能を評価するためのアッセイである.
主要な成果:
- KAP1の消去は,マウスのES細胞と初期の胚で,様々なERV,特に内A型粒子 (IAP) の有意なアップレギュレーションをもたらしました.
- KAP1は,IAP元素を静止するためにDNAメチル化と連携して作用する.
- KAP1はIAPゲノムの5'未翻訳領域 (5'UTR) で濃縮され,その削除によりH3K9me3.3が失われる.
- IAP 5'UTR配列は,異質なプロモーターにKAP1依存の抑制を与える.
結論:
- KAP1は,哺乳類の発達初期における内生的なレトロエレメントサイレンシングの重要な調節体である.
- KAP1媒介による抑制は,DNAメチル化と組み合わせて,ERVの活動を制御し,ゲノムの安定性を維持するために不可欠です.
さらに関連する動画
11:40Retroviral Infection of Murine Embryonic Stem Cell Derived Embryoid Body Cells for Analysis of Hematopoietic Differentiation
Published on: October 20, 2014
07:28Transfection, Selection, and Colony-picking of Human Induced Pluripotent Stem Cells TALEN-targeted with a GFP Gene into the AAVS1 Safe Harbor
Published on: February 1, 2015
関連する概念動画
Retrovirus Life Cycles
Retroviruses have a single-stranded RNA genome that undergoes a special form of replication. Once the retrovirus has entered the host cell, an enzyme called reverse transcriptase synthesizes double-stranded DNA from the retroviral RNA genome. This DNA copy of the genome is then integrated into the host’s genome inside the nucleus via an enzyme called integrase. Consequently, the retroviral genome is transcribed into RNA whenever the host’s genome is transcribed, allowing the retrovirus to...
Retroviruses
Retroviruses and retrotransposons both insert copies of their genetic elements into the genome of the host cell. Thus, the viral genes are passed on when the host genome is replicated or translated. A typical retroviral DNA sequence contains 3-4 genes that encode the different proteins required for its structural assembly and function as a molecular parasite. This DNA is transcribed into a single mRNA, which is very similar in structure to conventional mRNAs, i.e., it is capped at the 5’...
LTR Retrotransposons
LTR retrotransposons are class I transposable elements with long terminal repeats flanking an internal coding region. These elements are less abundant in mammals compared to other class I transposable elements. About 8 percent of human genomic DNA comprises LTR retrotransposons. Some of the common examples of LTR retrotransposons are Ty elements in yeast and Copia elements in Drosophila.
The internal coding region of LTR retrotransposons and their mechanism of transposition closely resembles a...
The internal coding region of LTR retrotransposons and their mechanism of transposition closely resembles a...
Mechanisms of Retrovirus-induced Cancers
Retroviruses are RNA viruses that have been shown to cause cancers in diverse species, including chickens, mice, cats, and monkeys. The RNA genomes of these viruses are first reverse-transcribed into single and then double-stranded DNA (dsDNA) copies. This dsDNA called proviral DNA then integrates into the host genome. Subsequently, the host cell transcribes the proviral DNA in concert with the chromosomal DNA. This leads to the production of viral RNA and proteins that assemble at the host...
Maintenance of the ES Cell State
The cells of the blastocyst inner cell mass only remain pluripotent for a short time. This state of pluripotency and self-renewal can be maintained in embryonic stem (ES) cell culture by adding specific chemicals or growth factors to ensure the cells can continue dividing and later differentiate into different cell types. In some cases, the cells are grown on a feeder layer of differentiated cells, which provides the growth factors and extracellular matrix components necessary for stem cell...
