Tn10のトランスポーゼーションは,DNAヘアピンの中間介質を介して行われます
A K Kennedy1, A Guhathakurta, N Kleckner
1Department of Biochemistry, University of Western Ontario, London, Canada.
Cell
|October 20, 1998
まとめ
非複製性トランポゾンTn10は,DNA切除のための3段階の化学メカニズムを使用しています. このプロセスは,ニッキング,ヘアピン形成,および解消を含み,V(D) J再結合と共通の進化的起源を示唆します.
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
- バイオケミストリー バイオケミストリー
背景:
- Tn10のようなトランスポーザブル要素は,ゲノム内の位置を変えることができる移動性DNA配列です.
- 転置の正確な分子メカニズムを理解することは,ゲノムダイナミクスと進化を理解するために不可欠です.
- V(D) J再結合は,抗体とT細胞受容体の多様性を生成するための適応性免疫システムの重要なプロセスです.
研究 の 目的:
- 非複製性トランポゾンTn10の切除に伴う詳細な化学的ステップを解明する.
- タンパク質の活性部位に対する観察されたメカニズムの機能的影響を調査する.
- Tn10トランスポーゼーションとV(D) J再結合の間の潜在的なメカニズム的リンクを調査する.
主な方法:
- この研究では,Tn10切除の酵素的ステップを解剖するための生化学的測定法が含まれていた可能性が高い.
- DNA中間産物と反応産物の分析が鍵となる.
- V(D) J再結合の既知のメカニズムとの比較分析.
主要な成果:
- 提示されたエビデンスは,Tn10の切除が3つの異なる化学的ステップを経由して進行することを示唆しています:最初の糸の切断,ヘアピン形成,ヘアピン解像度.
- このメカニズムは,単一の活性部位が,反対の極性を持つ両方のDNA鎖を分割することを可能にします.
- この発見は,活性部位内の二機能性の交替を示唆している.
- V(D) J再結合で使用されたヘアピンメカニズムとの類似点も指摘された.
結論:
- Tn10切除の3段階メカニズムは化学的にエレガントで,単一の活性部位によって二重鎖切断を可能にします.
- Tn10トランスポーゼーションとV(D) J再結合の間の共有された化学的ステップは,バクテリアのトランスポーゼーションシステムから潜在的に進化したV(D) J再結合の可能性がある進化的リンクを示唆しています.
関連する概念動画
Overview of Transposition and Recombination
19.0K
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...
19.0K
DNA-only Transposons
17.3K
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...
17.3K
DNA Helicases
23.9K
DNA unwinding helicase enzymes are a type of motor protein. Motor proteins can translocate along filaments or polymers using energy generated from ATP hydrolysis. Helicases are involved in all the important cellular processes where DNA unwinding is required, such as DNA replication, repair, recombination, and transcription. They are present in all living organisms, but vary in their structure, function, and mechanism of action. For example, in prokaryotes, DnaB helicase binds and translocates...
23.9K
Disassembly of Intermediate Filaments
2.6K
Intermediate filaments (IFs) do not undergo spontaneous disassembly. Enzymes, kinases, and phosphatases add and remove phosphates from specific sites to regulate their disassembly. The IF concentration in the cytoplasm also regulates the disassembly. If the concentration crosses a threshold, it activates the protein kinases in the vicinity, allowing the phosphorylation of IFs.
Keratin proteins, found at the cell periphery near cell junctions, undergo a cycle of assembly and disassembly. In Type...
Keratin proteins, found at the cell periphery near cell junctions, undergo a cycle of assembly and disassembly. In Type...
2.6K
Types of Intermediate Filaments
4.8K
The intermediate filaments are an essential component of the cytoskeleton. Presently six types of intermediate filament have been identified. Type I and II are acidic and basic keratin proteins. Type III is of mesodermal origin and comprises four proteins: vimentin, desmin, glial fibrillary acidic protein (GFAP), and peripherin. Vimentin is commonly found in mesenchymal cells, desmin in muscle cells, GFAP in astrocytes, while peripherin is found in peripheral nervous system neurons (PNS). Type...
4.8K
Formation of Intermediate Filaments
3.9K
Intermediate filaments are cytoskeletal proteins with higher tensile strength and flexibility than microfilaments and microtubules. Unlike the other two cytoskeletal proteins, intermediate filament formation lacks the enzymatic activity to hydrolyze nucleotides like ATP and GTP to generate energy for polymerization. Therefore, the formation of intermediate filaments is multistep self-assembly. The involvement of any accessory proteins in intermediate filament formation has not yet been...
3.9K


