DNA Repair最新文献

英文中文

B cell receptor stimulation inhibits class switch recombination through elevated DNA repair B细胞受体刺激通过提高DNA修复抑制类开关重组

IF 2.7 3区生物学 Q2 GENETICS & HEREDITY

DNA Repair

Pub Date : 2026-03-01 Epub Date: 2026-03-08 DOI: 10.1016/j.dnarep.2026.103931

Robert W. Maul , Rhonda L. McFleder , Zheng Cao , Darrell D. Norton , Jana Ridani , Philip Barbulescu , Alberto Martin , Javier M. Di Noia , Patricia J. Gearhart

Antibody diversity in B cells arises from the activity of activation-induced deaminase (AID), which introduces uracils into DNA of the immunoglobulin loci. The presence of uracil initiates a cascade of mutagenic events, resulting in somatic hypermutation and class switch recombination (CSR). To produce CSR, uracils are removed from DNA by uracil DNA glycosylase (UNG), resulting in formation of an abasic site, which is subsequently transformed into a double-stand break and promotes recombination to another constant gene. While the classical model indicates that B cells are activated when the IgM receptor binds antigen, stimulation of cells ex vivo with anti-IgM is insufficient for CSR. In fact, anti-IgM stimulation has a strong inhibitory effect on CSR when added together with lipopolysaccharide (LPS). To determine the mechanism of anti-IgM inhibition of CSR, we examined the known components required for CSR: AID and UNG. After stimulation with anti-IgM and LPS, AID was expressed and recruited to the immunoglobulin loci, and UNG levels increased and prevented uracil accumulation. We also linked the increased expression of UNG to the cell-cycle, as the presence of anti-IgM allowed cells to enter S-phase sooner. Therefore, for efficient CSR, AID-induced uracils must accumulate to sufficient levels before initiating S-phase, to provide more substrate for UNG and endonuclease to generate mutagenic strand breaks. If cell division occurs too early, as in the case of stimulation with anti-IgM and LPS, UNG is quickly upregulated and removes the uracils before they can accumulate, resulting in faithful DNA repair and less CSR.

B细胞中的抗体多样性源于激活诱导脱氨酶（AID）的活性，它将尿嘧啶引入免疫球蛋白位点的DNA中。尿嘧啶的存在引发一系列诱变事件，导致体细胞超突变和类开关重组（CSR）。为了产生CSR，尿嘧啶通过尿嘧啶DNA糖基化酶（UNG）从DNA中去除，导致形成一个基本位点，随后转化为双支架断裂，并促进重组为另一个恒定基因。虽然经典模型表明，当IgM受体结合抗原时，B细胞被激活，但体外用抗IgM刺激细胞不足以引起CSR。事实上，当与脂多糖（LPS）一起添加抗igm刺激时，对CSR具有较强的抑制作用。为了确定抗igm抑制CSR的机制，我们检查了CSR所需的已知成分：AID和UNG。在抗igm和LPS刺激后，AID被表达并募集到免疫球蛋白位点，UNG水平升高并阻止尿嘧啶积聚。我们还将UNG的表达增加与细胞周期联系起来，因为抗igm的存在使细胞更快地进入s期。因此，为了实现有效的CSR，艾滋病诱导的尿嘧啶必须在启动s期之前积累到足够的水平，以便为UNG和内切酶提供更多的底物来产生诱变链断裂。如果细胞分裂发生得太早，如在抗igm和LPS刺激的情况下，UNG会迅速上调，并在尿嘧啶积聚之前将其清除，从而导致DNA的可靠修复和较少的CSR。

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引用次数: 0

Dss1 facilitates Rad51 recruitment downstream of BRCA2/Brh2 in response to DNA damage Dss1在响应DNA损伤时促进BRCA2/Brh2下游的Rad51募集。

IF 2.7 3区生物学 Q2 GENETICS & HEREDITY

DNA Repair

Pub Date : 2026-02-01 Epub Date: 2026-01-22 DOI: 10.1016/j.dnarep.2026.103923

Louise Juhl , Linea Busch , Jonas Bagge , Ruiqi Xu , Milorad Kojic , Mira Milisavljevic , Vibe H. Oestergaard , William K. Holloman , Michael Lisby

Homologous recombination (HR) is a major pathway for repair of DNA double-strand breaks (DSB), recovery of broken replication forks and formation of meiotic crossovers. HR provides a mechanism to precisely repair damaged DNA in a template-dependent process. The defining step in HR is homologous strand exchange directed by the RecA-related recombinase Rad51. BRCA2 and Brh2, the BRCA2 orthologue in Ustilago maydis, enable recombinational repair of DNA by controlling Rad51. In turn, Dss1, a small intrinsically disordered protein that binds to the C-terminal region of BRCA2/Brh2, regulates BRCA2/Brh2. In the present study, we dissect the interdependency of HR proteins for recruitment to DNA-damage induced foci using fluorescence microscopy and genetics. In U. maydis, Brh2 and Dss1 colocalize at DNA damage-induced foci. Dss1 recruitment to foci is dependent on interaction with full-length Brh2 and Dss1-Brh2 interaction is required for resistance to DNA damage. Further, Dss1 is required for Rad51 and Rec2 focus formation. Interestingly, we find that Rad52 is required for Brh2, Rec2 and Dss1 focus formation. In avian DT40 cells, we likewise show that endogenously tagged DSS1 redistributes into subnuclear foci in response to DNA damaging agents. However, DSS1 foci rarely colocalize with BRCA2 foci. Finally, Dss1 focus formation is inhibited by treatment with the proteasome inhibitor MG132, in both U. maydis and DT40 cells, suggesting a role of ubiquitin in homology-dependent repair.

同源重组（HR）是DNA双链断裂（DSB）修复、断裂复制叉恢复和减数分裂交叉形成的主要途径。HR提供了一种在模板依赖过程中精确修复受损DNA的机制。HR的决定性步骤是由reca相关重组酶Rad51引导的同源链交换。黑穗病菌BRCA2同源基因BRCA2和Brh2通过控制Rad51实现DNA的重组修复。反过来，Dss1，一种结合BRCA2/Brh2 c端区域的小的内在无序蛋白，调节BRCA2/Brh2。在本研究中，我们使用荧光显微镜和遗传学分析了HR蛋白在dna损伤诱导的病灶招募中的相互依赖性。在美国，Brh2和Dss1在DNA损伤诱导的病灶上共定位。Dss1向病灶的募集依赖于与全长Brh2的相互作用，Dss1-Brh2相互作用是抵抗DNA损伤所必需的。此外，Dss1是Rad51和Rec2焦点形成所必需的。有趣的是，我们发现Rad52是Brh2， Rec2和Dss1焦点形成所必需的。在禽类DT40细胞中，我们同样发现内源性标记的DSS1在DNA损伤剂的作用下重新分布到亚核病灶。然而，DSS1位点很少与BRCA2位点共定位。最后，在U. maydis和DT40细胞中，蛋白酶体抑制剂MG132可以抑制Dss1病灶的形成，这表明泛素在同源依赖性修复中的作用。

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引用次数: 0

Editorial: DNA crosslink repair: From molecules to mankind 社论：DNA交联修复：从分子到人类。

IF 2.7 3区生物学 Q2 GENETICS & HEREDITY

DNA Repair

Pub Date : 2026-02-01 Epub Date: 2026-01-29 DOI: 10.1016/j.dnarep.2026.103927

Penny Jeggo , Puck Knipscheer , Peter J. McHugh

引用次数: 0

Tribute to life and science of Grigory (Gosha) Dianov 向格里戈里·迪亚诺夫的生命和科学致敬。

IF 2.7 3区生物学 Q2 GENETICS & HEREDITY

DNA Repair

Pub Date : 2026-02-01 Epub Date: 2026-01-30 DOI: 10.1016/j.dnarep.2026.103925

Alexander V. Mazin , Andrei Kuzminov , Murat Saparbaev , Svetlana Khoronenkova , Jason Parsons , Sarah Allinson

引用次数: 0

Search, verify and excise-lesion recognition in NER 在NER中搜索、验证和切除病变识别

IF 2.7 3区生物学 Q2 GENETICS & HEREDITY

DNA Repair

Pub Date : 2026-02-01 Epub Date: 2026-01-12 DOI: 10.1016/j.dnarep.2026.103922

Jochen Kuper, Caroline Kisker

Nucleotide excison repair (NER) is a highly versatile template-based DNA repair mechanism that can address lesions ranging from cyclo butane pyrimdine dimers, to cisplatinum crosslinks, and bulky adducts like acetyl amino flourenes. Eukaryotic NER employs more than thirty different proteins that coordinate and facilitate the search, verification, incision, and DNA re-synthesis of the various lesions with extremely high precision. High resolution structures of key complexes combined with biochemistry and computational biology have greatly enhanced our understanding of the NER process. In this review we will highlight recent discoveries in NER research concerning lesion search and handover of complex assemblies, lesion verification, and potential mechanisms providing the signal for incision with a focus on structural biology.

核苷酸切除修复（NER）是一种高度通用的基于模板的DNA修复机制，可以解决从环丁烷嘧啶二聚体到顺铂交联和大体积加合物如乙酰基氨基芴的损伤。真核生物NER使用超过30种不同的蛋白质，以极高的精度协调和促进各种病变的搜索、验证、切割和DNA重新合成。关键配合物的高分辨率结构与生物化学和计算生物学相结合，极大地增强了我们对NER过程的理解。在这篇综述中，我们将重点介绍最近在NER研究中的发现，包括病变搜索和复杂组件的移交、病变验证以及为切口提供信号的潜在机制，重点是结构生物学。

引用次数: 0

A special issue: DNA damage response in disease and therapy 特刊：疾病和治疗中的DNA损伤反应。

IF 2.7 3区生物学 Q2 GENETICS & HEREDITY

DNA Repair

Pub Date : 2026-02-01 Epub Date: 2026-01-22 DOI: 10.1016/j.dnarep.2026.103924

Guo-Min Li, Zhao-Qi Wang

引用次数: 0

DNA Repair Special Issue: Genome maintenance pathways in cancer - etiology, biomarkers and targets DNA修复特刊：癌症的基因组维持途径——病因学、生物标志物和靶标。

IF 2.7 3区生物学 Q2 GENETICS & HEREDITY

DNA Repair

Pub Date : 2026-02-01 Epub Date: 2026-01-29 DOI: 10.1016/j.dnarep.2026.103926

Robert W. Sobol , Gianluca Tell

引用次数: 0

Genetic analysis reveals a timing-dependent functional interplay between Polζ and Polη in translesion DNA synthesis upon UV damage 遗传分析揭示了在UV损伤下翻译DNA合成中Polζ和Polη之间的时间依赖功能相互作用。

IF 2.7 3区生物学 Q2 GENETICS & HEREDITY

DNA Repair

Pub Date : 2026-01-01 Epub Date: 2025-12-24 DOI: 10.1016/j.dnarep.2025.103919

Mone Okuda, Minori Fujii, Ryotaro Kawasumi, Kouji Hirota

Translesion DNA synthesis (TLS) plays a crucial role in restarting stalled replication at damaged templates. This process is facilitated by specialized DNA polymerases, such as Polη and Polζ, where Polη inserts nucleotides opposite the damaged template, and Polζ extends the primer following insertion. TLS occurring at the stalled replication fork is termed "on-the-fly" TLS, whereas TLS that fills gaps remaining after fork progression is referred to as "post-replicative gap-filling" TLS. However, the roles of Polη and Polζ in these two phases of TLS remain unclear. Here, we demonstrate the functional relationship between Polη and Polζ in these TLS pathways through genetic studies in human cells. We established POLH^−/−, REV3L^−/− (deficient in Polζ catalytic subunit, Rev3), and POLH^−/−/REV3L^−/− cells from human TK6 cells and evaluated the sensitivity of these cell lines to ultraviolet (UV). We found that the loss of Polη in REV3L^−/− cells led to the synergistic increase of the UV sensitivity, accompanied by a marked rise in UV-induced chromosomal aberrations. However, such synergistic effects were not observed in the rate of replication fork stalling after UV damage in POLH^−/−/REV3L^−/− cells. In marked contrast, the number of unrepaired gaps following UV irradiation was significantly increased in the double mutant. These findings suggest that Polη and Polζ function complementarily in promoting post-replicative gap-filling TLS while they act collaboratively in on-the-fly TLS. Our current genetic study in human cells revealed a previously unappreciated functional relationship between Polη and Polζ and showed the pivotal role of "post-replicative gap-filling" TLS in UV-tolerance.

翻译DNA合成（TLS）在重新启动受损模板的停滞复制中起着至关重要的作用。这一过程是由特殊的DNA聚合酶促进的，如Polη和Polζ，其中Polη插入与受损模板相反的核苷酸，Polζ在插入后延伸引物。发生在停止复制分叉处的TLS被称为“即时”TLS，而在分叉进展后填补剩余空白的TLS被称为“复制后填补空白”TLS。然而，Polη和Polζ在这两相TLS中的作用尚不清楚。在这里，我们通过人类细胞的遗传研究证明了Polη和Polζ在这些TLS通路中的功能关系。我们从人TK6细胞中建立了POLH-/-， REV3L-/-（缺乏Polζ催化亚基，Rev3）和POLH-/-/REV3L-/-细胞，并评估了这些细胞系对紫外线（UV）的敏感性。我们发现，在REV3L-/-细胞中Polη的缺失导致紫外线敏感性的协同增加，并伴随着紫外线诱导的染色体畸变的显著增加。然而，在紫外线损伤后POLH-/-/REV3L-/-细胞的复制叉停滞率中没有观察到这种协同效应。与此形成鲜明对比的是，双突变体在紫外线照射后未修复的间隙数量显著增加。这些发现表明，Polη和Polζ在促进复制后补隙的TLS中是互补的，而在动态TLS中是协同作用的。我们目前在人类细胞中的遗传学研究揭示了Polη和Polζ之间以前未被认识到的功能关系，并显示了“复制后间隙填充”TLS在紫外线耐受性中的关键作用。

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引用次数: 0

Cutting edge perspectives in genome maintenance XII 基因组维持的前沿观点。

IF 2.7 3区生物学 Q2 GENETICS & HEREDITY

DNA Repair

Pub Date : 2026-01-01 Epub Date: 2025-12-24 DOI: 10.1016/j.dnarep.2025.103920

Penny Jeggo

引用次数: 0

A tale of two mechanisms: Clarification of the pathway for MBD4 catalyzed glycosidic bond cleavage using MD and QM/MM calculations 通过MD和QM/MM计算，阐明了MBD4催化糖苷键裂解的途径

IF 2.7 3区生物学 Q2 GENETICS & HEREDITY

DNA Repair

Pub Date : 2026-01-01 Epub Date: 2025-12-19 DOI: 10.1016/j.dnarep.2025.103917

Dylan J. Nikkel, Stacey D. Wetmore

DNA methylation to yield 5-methylcytosine (5mC) in CpG motifs plays a vital role in epigenetic regulation. However, deamination of 5mC results in canonical thymine (T) that requires methyl-CpG-binding domain protein 4 (MBD4) for repair. This important function has resulted in MBD4 being implicated in various human health disorders including MBD4-associated neoplasia syndrome and cancer resistance to 5-fluorouracil treatment. Nevertheless, the catalytic mechanism of MBD4 is poorly understood, with conflicting experimental observations resulting in multiple proposals. To provide atomic level structural details of the active site conformation and clarify the mechanistic pathway, this study uses a combination of adaptively biased molecular dynamics (abMD) simulations and quantum mechanics/molecular mechanics (QM/MM) calculations to map the MBD4 catalytic mechanism. Although our data indicate that the catalytic D560 residue is flexible in the active site, only one conformation facilitates 5mC excision. Despite some literature proposing the formation of a DNA−protein crosslinked intermediate, our modeling suggests catalysis is only viable through a deglycosylation mechanism that involves a water nucleophile attacking C1′ of T, with D560 activating the nucleophile and stabilizing the transition state and nucleobase departure facilitated by a network of hydrogen bonds. This proposal is fully consistent with experimental crystallographic, mutagenic, stereoscopic, and kinetic data, and aligns the MBD4 catalytic pathway with that characterized for several other monofunctional DNA glycosylases. By furthering our knowledge of MBD4 catalysis, this work will aid in the future development of treatments for MBD4-related genetic disorders and the rational design of transition state mimic inhibitors to enhance existing cancer therapies.

CpG基序中DNA甲基化产生5-甲基胞嘧啶（5mC）在表观遗传调控中起着至关重要的作用。然而，5mC的脱胺导致典型胸腺嘧啶(T)的产生，这需要甲基- cpg结合结构域蛋白4 （MBD4）进行修复。这一重要功能导致MBD4与多种人类健康疾病有关，包括MBD4相关的瘤变综合征和对5-氟尿嘧啶治疗的癌症耐药性。然而，人们对MBD4的催化机制知之甚少，实验观察结果相互矛盾，导致多种建议。为了提供活性位点构象的原子水平结构细节和阐明机理途径，本研究采用自适应偏态分子动力学（abMD）模拟和量子力学/分子力学（QM/MM）计算相结合的方法来绘制MBD4的催化机理。虽然我们的数据表明催化D560残基在活性位点是灵活的，但只有一种构象有利于5mC的切除。尽管一些文献提出了DNA -蛋白质交联中间体的形成，但我们的模型表明，催化作用只能通过一种脱糖基化机制来实现，该机制涉及一种水亲核试剂攻击T的C1 '， D560激活亲核试剂并稳定过渡态和氢键网络促进的核碱基离开。这一建议与实验晶体学、诱变、立体和动力学数据完全一致，并使MBD4的催化途径与其他几种单功能DNA糖基酶的催化途径一致。通过进一步了解MBD4的催化作用，这项工作将有助于MBD4相关遗传疾病的治疗方法的未来发展，以及过渡状态模拟抑制剂的合理设计，以增强现有的癌症治疗。

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