Cancer Research Institute, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong Province 510515, China.
Department of Immunology, School of Basic Medical, Zhengzhou University, Zhengzhou 450001, China.
Nucleic Acids Res. 2023 Sep 22;51(17):8987-9000. doi: 10.1093/nar/gkad641.
The generation of highly diverse antigen receptors in T and B lymphocytes relies on V(D)J recombination. The enhancer Eα has been implicated in regulating the accessibility of Vα and Jα genes through long-range interactions during rearrangements of the T-cell antigen receptor gene Tcra. However, direct evidence for Eα physically mediating the interaction of Vα and Jα genes is still lacking. In this study, we utilized the 3C-HTGTS assay, a chromatin interaction technique based on 3C, to analyze the higher order chromatin structure of the Tcra locus. Our analysis revealed the presence of sufficient information in the 3C-HTGTS data to detect multiway contacts. Three-way contact analysis of the Tcra locus demonstrated the co-occurrence of the proximal Jα genes, Vα genes and Eα in CD4+CD8+ double-positive thymocytes. Notably, the INT2-TEAp loop emerged as a prominent structure likely to be responsible for bringing the proximal Jα genes and the Vα genes into proximity. Moreover, the enhancer Eα utilizes this loop to establish physical proximity with the proximal Vα gene region. This study provides insights into the higher order chromatin structure of the Tcra locus, shedding light on the spatial organization of chromatin and its impact on V(D)J recombination.
在 T 和 B 淋巴细胞中产生高度多样化的抗原受体依赖于 V(D)J 重组。增强子 Eα 被认为通过 T 细胞抗原受体基因 Tcra 重排过程中的长距离相互作用来调节 Vα 和 Jα 基因的可及性。然而，Eα 物理介导 Vα 和 Jα 基因相互作用的直接证据仍然缺乏。在这项研究中，我们利用了基于 3C 的染色质相互作用技术 3C-HTGTS，分析了 Tcra 基因座的高级染色质结构。我们的分析表明，3C-HTGTS 数据中存在足够的信息来检测多方式接触。对 Tcra 基因座的三向接触分析表明，在 CD4+CD8+双阳性胸腺细胞中，近端 Jα 基因、Vα 基因和 Eα 同时存在。值得注意的是，INT2-TEAp 环作为一种突出的结构出现，可能负责使近端 Jα 基因和 Vα 基因接近。此外，增强子 Eα 利用这个环与近端 Vα 基因区域建立物理接近性。这项研究提供了对 Tcra 基因座高级染色质结构的深入了解，揭示了染色质的空间组织及其对 V(D)J 重组的影响。
