Jeon Bong Chan, Kim Yu-Ji, Park Ae Kyung, Song Mi-Ran, Na Ki Myeong, Lee Juwon, An Dasom, Park Yeseul, Hwang Heeyoun, Kim Tae-Don, Lim Junghyun, Park Sung-Kyun
Infectious Disease Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Republic of Korea.
Department of Functional Genomics, KRIBB School of Bioscience, Korea University of Science and Technology (UST), Daejeon, Republic of Korea.
Cell Mol Immunol. 2025 Jan;22(1):68-82. doi: 10.1038/s41423-024-01236-9. Epub 2024 Dec 3.
V(D)J recombination secures the production of functional immunoglobulin (Ig) genes and antibody diversity during the early stages of B-cell development through long-distance interactions mediated by cis-regulatory elements and trans-acting factors. O-GlcNAcylation is a dynamic and reversible posttranslational modification of nuclear and cytoplasmic proteins that regulates various protein functions, including DNA-binding affinity and protein-protein interactions. However, the effects of O-GlcNAcylation on proteins involved in V(D)J recombination remain largely unknown. To elucidate this relationship, we downregulated O-GlcNAcylation in a mouse model by administering an O-GlcNAc inhibitor or restricting the consumption of a regular diet. Interestingly, the inhibition of O-GlcNAcylation in mice severely impaired Ig heavy-chain (IgH) gene rearrangement. We identified several factors crucial for V(D)J recombination, including YY1, CTCF, SMC1, and SMC3, as direct targets of O-GlcNAc modification. Importantly, O-GlcNAcylation regulates the physical interaction between SMC1 and SMC3 and the DNA-binding patterns of YY1 at the IgH gene locus. Moreover, O-GlcNAc inhibition downregulated DDX5 protein expression, affecting the functional association of CTCF with its DNA-binding sites at the IgH locus. Our results showed that locus contraction and long-range interactions throughout the IgH locus are disrupted in a manner dependent on the cellular O-GlcNAc level. In this study, we established that V(D)J recombination relies on the O-GlcNAc status of stage-specific proteins during early B-cell development and identified O-GlcNAc-dependent mechanisms as new regulatory components for the development of a diverse antibody repertoire.
V(D)J重排通过顺式调控元件和反式作用因子介导的长距离相互作用，确保在B细胞发育早期产生功能性免疫球蛋白（Ig）基因并实现抗体多样性。O-GlcNAcylation是一种对核蛋白和胞质蛋白进行的动态可逆的翻译后修饰，可调节各种蛋白质功能，包括DNA结合亲和力和蛋白质-蛋白质相互作用。然而，O-GlcNAcylation对参与V(D)J重排的蛋白质的影响在很大程度上仍不清楚。为了阐明这种关系，我们通过给予O-GlcNAc抑制剂或限制常规饮食的摄入，在小鼠模型中下调了O-GlcNAcylation。有趣的是，小鼠中O-GlcNAcylation的抑制严重损害了Ig重链（IgH）基因重排。我们确定了几个对V(D)J重排至关重要的因子，包括YY1、CTCF、SMC1和SMC3，作为O-GlcNAc修饰的直接靶点。重要的是，O-GlcNAcylation调节SMC1和SMC3之间的物理相互作用以及YY1在IgH基因座处的DNA结合模式。此外，O-GlcNAc抑制下调了DDX5蛋白表达，影响了CTCF与其在IgH基因座处的DNA结合位点的功能关联。我们的结果表明，整个IgH基因座的基因座收缩和长距离相互作用以依赖于细胞O-GlcNAc水平的方式被破坏。在这项研究中，我们确定V(D)J重排在早期B细胞发育过程中依赖于阶段特异性蛋白质的O-GlcNAc状态，并确定O-GlcNAc依赖的机制是产生多样化抗体库的新调控成分。
