プロモーターおよび強化剤に依存するコヘシン負荷は,長距離リコンビネーションのためのTcrbロシウムの折りたたみに染色体のループを開始する
Brittney M Allyn1, Katharina E Hayer2, Clement Oyeniran3
1Immunology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
Cell reports
|August 20, 2025
まとめ
コヘシン媒介の染色体ループは,抗原受容体遺伝子組立を誘導する. この研究は,Tcrbロカス全体でのコヘシン負荷とループエクストルーションが,多様なT細胞受容体レパートリーを組み立てるのに不可欠な長距離コンタクトを作成する方法を示しています.
科学分野:
- 遺伝学
- 分子生物学
- ゲノミクス
背景:
- コヘシン媒介の染色体ループは,様々な細胞プロセスにとって極めて重要です.
- V(D) J再結合は,複雑なゲノム相互作用を含む抗原受容体 (AgR) 遺伝子を組み立てます.
研究 の 目的:
- T細胞受容体β (Tcrb) ゲノムアセンブリにおけるゲノムトポロジーの調整メカニズムを解明する.
- Tcrb ロカスアーキテクチャの調整におけるコヘシン・ロードとループ・エクストルーション (LE) の役割を調査する.
主な方法:
- 遺伝子操作可能なTcrbの位置をモデルシステムとして利用した.
- CTCF結合要素 (CBE) と超強化器がループの流出を調節する機能を調査した.
- V ((D)) J再結合中の長距離接触とコヘシン動態を分析した.
主要な成果:
- 5'Vbのプロモーターに依存し,下流のDJbセグメントと接触する.
- リコンビネーションセンター (RC) の側面にあるCTCF結合要素は,LEの終結,開始,および強化器の隔離を媒介する.
- 超強化器の消去はRCループの流出に影響したが,遠距離接触は影響せず,一方的なLEが十分であることを示唆している.
結論:
- Vbのプロモーターとエンハンサーに依存するコヘシン負荷は,Tcrbの位置に双方向のLEを駆動する.
- この調整されたループの挤出は,多様なTcrbレパートリーを組み立てるのに不可欠です.
- この発見は,Tcrb遺伝子組立を超えた意味を持つゲノム構造と機能の洞察を提供します.
関連する概念動画
Cohesins
4.7K
Cohesin protein complexes are a molecular glue that holds two sister chromatids together. They play an important role both in mitosis and meiosis. In mitosis, all cohesin complexes present on the chromosomes are removed before the start of the anaphase stage.
Cohesin complexes in Meiotic Division
Meiosis involves two distinct rounds of chromosomal segregation and cell divisions— Meiosis I followed by Meiosis II – producing four daughter cells. Meiosis I includes the separation of...
Cohesin complexes in Meiotic Division
Meiosis involves two distinct rounds of chromosomal segregation and cell divisions— Meiosis I followed by Meiosis II – producing four daughter cells. Meiosis I includes the separation of...
4.7K
Crossing Over
4.7K
Crossing over is the exchange of genetic information between homologous chromosomes during prophase I of meiosis I. Genetic recombination gives rise to allelic diversity in the newly formed daughter cells. In humans, crossing over produces genetically distinct haploid egg and sperm cells that undergo fertilization to produce unique offspring. Before cell division starts, the germ cell’s chromosome(s) undergo duplication in the S phase of the cell cycle. As the cells enter prophase I,...
4.7K
Homologous Recombination
51.7K
The basic reaction of homologous recombination (HR) involves two chromatids that contain DNA sequences sharing a significant stretch of identity. One of these sequences uses a strand from another as a template to synthesize DNA in an enzyme-catalyzed reaction. The final product is a novel amalgamation of the two substrates. To ensure an accurate recombination of sequences, HR is restricted to the S and G2 phases of the cell cycle. At these stages, the DNA has been replicated already and the...
51.7K
Conservative Site-specific Recombination and Phase Variation
6.1K
Because the DNA segments are cut and reorganized in a direction-specific manner, site-specific recombination has emerged as an efficient genetic engineering technique. Flippase and Cyclization recombinases or Flp and Cre, respectively, are two members of the tyrosine recombinase family derived from bacteriophages, that are used to mediate site-specific DNA insertions, deletions, and targeted expression of proteins in mammalian cell lines.
The recognition sites for Cre recombinase called LoxP...
The recognition sites for Cre recombinase called LoxP...
6.1K
Replication in Eukaryotes
14.5K
In eukaryotic cells, DNA replication is highly conserved and tightly regulated. Multiple linear chromosomes must be duplicated with high fidelity before cell division, so there are many proteins that fulfill specialized roles in the replication process. Replication occurs in three phases: initiation, elongation, and termination, and ends with two complete sets of chromosomes in the nucleus.
Many Proteins Orchestrate Replication at the Origin
Eukaryotic replication follows many of the same...
Many Proteins Orchestrate Replication at the Origin
Eukaryotic replication follows many of the same...
14.5K
Condensins
3.6K
Condensins are large protein complexes that use ATP to fuel the assembly of chromosomes during mitosis. They transform the tangled, shapeless mass of post-interphase DNA into individualized chromosomes by compacting, organizing, and segregating chromosomal DNA.
The plant and animal cells contain two types of condensin complexes—condensin I and condensin II. Both complexes have five subunits: two SMC (Structural Maintenance of Chromosomes) subunits, a kleisin subunit, and two HEAT-repeat...
The plant and animal cells contain two types of condensin complexes—condensin I and condensin II. Both complexes have five subunits: two SMC (Structural Maintenance of Chromosomes) subunits, a kleisin subunit, and two HEAT-repeat...
3.6K


