ホロCRISPRRNA誘導トランポゾン統合複合体の構造
Jung-Un Park1, Amy Wei-Lun Tsai1, Alexandrea N Rizo1
1Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA.
Nature
|November 28, 2022
まとめ
研究者は,Scythonema hofmanniiのCRISPR関連トランポゾン (CAST) トランポソームの構造を決定した. これは,CAST要素がDNAを統合する方法を明らかにし,精密なゲノム編集アプリケーションの洞察を提供します.
科学分野:
- 分子生物学
- 遺伝学
- 構造生物学
背景:
- CRISPR関連トランポゾン (CAST) は,大きなDNAペイロードを挿入するためにRNA誘導メカニズムを使用する移動性遺伝子要素です.
- CASTシステムは,CRISPRエフェクタ,AAA+レギュレータ,トランポゼ,ターゲットサイト関連因子を含む複数の保存されたタンパク質で構成され,トランポゼーション統合複合体 (トランポゾーム) を形成します.
研究 の 目的:
- Scytonema hofmannii (ShCAST) のV-K CAST型トランポソームの高解像度構造を再構成し,決定する.
- ShCASTトランポソーム内の分子構造とタンパク質とDNAの相互作用を解明し,CASTトランポシションに関する機械的洞察を提供すること.
主な方法:
- 単粒子の冷凍電子顕微鏡 (cryo-EM) を用いて,約1MDaのShCASTトランポソームの構造を決定した.
- タンパク質-タンパク質とタンパク質-DNAの相互作用とそのトランスポーゼーション活動への影響を調査するために,生化学的測定法を使用した.
主要な成果:
- 凍結-EM構造は,ShCASTトランポゾームのモジュール構造を明らかにし,Cas12k,TniQ,TnsC,TnsBの相互作用を詳細に示した.
- Cas12kはRループ構造を安定させ,TnsCはTniQとTnsBと相互作用し,TnsC-TnsBの相互作用はATPアゼの活性を刺激する.
- 構造は,変化したTnsC結合DNA構造と,トランスポーゼーションに不可欠な新しいタンパク質-DNA相互作用,そして柔軟なCRISPRエフェクター関連の証拠を示している.
結論:
- 決定されたShCASTトランポソーム構造は,V-K型CASTシステムの組立と機能に関する前例のない詳細を提供します.
- これらの分子メカニズムの理解は,ゲノム編集アプリケーションの精度を高めるために CAST システムを設計するための道を開きます.
関連する概念動画
Overview of Transposition and Recombination
16.0K
Transposons make up a significant part of genomes of various organisms. Therefore, it is believed that transposition played a major evolutionary role in speciation by changing genome sizes and modifying gene expression patterns. For example, in bacteria, transposition can lead to conferring antibiotic resistance. Movement of transposable elements within the genetic pool of pathogenic bacteria can aid in transfer of antibiotic-resistant genetic elements. In eukaryotes, transposons can carry out...
16.0K
DNA-only Transposons
14.6K
DNA-only transposons are called autonomous transposons since they code for the enzyme transposase that is required for the transposition mechanism. Insertion of transposons can alter gene functions in multiple ways. They can mutate the gene, alter gene expression by introducing a novel promoter or insulator sequence, introduce new splice sites, and change the mRNA transcripts produced, or remodel chromatin structure.
The donor site from where the transposon is excised is either degraded or...
The donor site from where the transposon is excised is either degraded or...
14.6K
LTR Retrotransposons
17.7K
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...
17.7K
CRISPR
52.7K
Genome editing technologies allow scientists to modify an organism’s DNA via the addition, removal, or rearrangement of genetic material at specific genomic locations. These types of techniques could potentially be used to cure genetic disorders such as hemophilia and sickle cell anemia. One popular and widely used DNA-editing research tool that could lead to safe and effective cures for genetic disorders is the CRISPR-Cas9 system. CRISPR-Cas9 stands for Clustered Regularly Interspaced...
52.7K
Transposons
97
Transposons, or "jumping genes," are small mobile genetic elements (MGEs) that range from 700 to 40,000 base pairs in length. They are found in all organisms and can move within the same chromosome or transfer to different chromosomes. In some cases, transposons can also jump between different host DNA molecules, such as plasmids or viruses, contributing to genetic variability.Barbara McClintock first discovered these mobile genetic elements in the 1940s while studying maize genetics, and she...
97
Protein Translocation Machinery on the ER Membrane
4.8K
The translocon complex situated on the ER membrane is the main gateway for the protein secretory pathway. It facilitates the transport of nascent peptides into the ER lumen and their insertion into the ER membrane.
Sec61 protein conducting channel
In eukaryotes, the translocon complex comprises a core heterotrimeric translocator channel called the Sec61 complex. This channel includes three transmembrane proteins, Sec61α, Sec61β, and Sec61γ, and is the largest subunit of the...
Sec61 protein conducting channel
In eukaryotes, the translocon complex comprises a core heterotrimeric translocator channel called the Sec61 complex. This channel includes three transmembrane proteins, Sec61α, Sec61β, and Sec61γ, and is the largest subunit of the...
4.8K


