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Zhou L, Zhu J, Liu Y, Zhou P, Gu Y. Mechanisms of radiation-induced tissue damage and response. MedComm (Beijing) 2024; 5:e725. [PMID: 39309694 PMCID: PMC11413508 DOI: 10.1002/mco2.725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Revised: 08/20/2024] [Accepted: 08/21/2024] [Indexed: 09/25/2024] Open
Abstract
Radiation-induced tissue injury (RITI) is the most common complication in clinical tumor radiotherapy. Due to the heterogeneity in the response of different tissues to radiation (IR), radiotherapy will cause different types and degrees of RITI, which greatly limits the clinical application of radiotherapy. Efforts are continuously ongoing to elucidate the molecular mechanism of RITI and develop corresponding prevention and treatment drugs for RITI. Single-cell sequencing (Sc-seq) has emerged as a powerful tool in uncovering the molecular mechanisms of RITI and for identifying potential prevention targets by enhancing our understanding of the complex intercellular relationships, facilitating the identification of novel cell phenotypes, and allowing for the assessment of cell heterogeneity and spatiotemporal developmental trajectories. Based on a comprehensive review of the molecular mechanisms of RITI, we analyzed the molecular mechanisms and regulatory networks of different types of RITI in combination with Sc-seq and summarized the targeted intervention pathways and therapeutic drugs for RITI. Deciphering the diverse mechanisms underlying RITI can shed light on its pathogenesis and unveil new therapeutic avenues to potentially facilitate the repair or regeneration of currently irreversible RITI. Furthermore, we discuss how personalized therapeutic strategies based on Sc-seq offer clinical promise in mitigating RITI.
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Affiliation(s)
- Lin Zhou
- Beijing Key Laboratory for RadiobiologyBeijing Institute of Radiation MedicineBeijingChina
| | - Jiaojiao Zhu
- Beijing Key Laboratory for RadiobiologyBeijing Institute of Radiation MedicineBeijingChina
| | - Yuhao Liu
- Beijing Key Laboratory for RadiobiologyBeijing Institute of Radiation MedicineBeijingChina
| | - Ping‐Kun Zhou
- Beijing Key Laboratory for RadiobiologyBeijing Institute of Radiation MedicineBeijingChina
| | - Yongqing Gu
- Beijing Key Laboratory for RadiobiologyBeijing Institute of Radiation MedicineBeijingChina
- Hengyang Medical CollegeUniversity of South ChinaHengyangHunanChina
- College of Life SciencesHebei UniversityBaodingChina
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2
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Xiao Y, Ni M, Zheng Z, Liu Y, Yin M, Mao S, Zhao Y, Tian B, Wang L, Xu H, Hua Y. POLM variant G312R promotes ovarian tumorigenesis through genomic instability and COL11A1-NF-κB axis. Am J Physiol Cell Physiol 2024; 327:C168-C183. [PMID: 38826139 DOI: 10.1152/ajpcell.00025.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Revised: 05/22/2024] [Accepted: 05/22/2024] [Indexed: 06/04/2024]
Abstract
In ovarian cancer (OC), identifying key molecular players in disease escalation and chemoresistance remains critical. Our investigation elucidates the role of the DNA polymerase mu (POLM), especially G312R mutation, in propelling oncogenesis through dual pathways. POLMG312R markedly augments the ribonucleotide insertion capability of POLM, precipitating genomic instability. In addition, our research reveals that POLMG312R perturbs collagen alpha-1 (XI) chain (COL11A1) expression-a gene that plays a key role in oncogenesis-and modulates the NF-κB signaling pathway, alters the secretion of downstream inflammatory cytokines, and promotes tumor-macrophage interactions. We illustrate a bidirectional regulatory interaction between POLM, particularly its G312R variant, and COL11A1. This interaction regulates NF-κB signaling, culminating in heightened malignancy and resistance to chemotherapy in OC cells. These insights position the POLM as a potential molecular target for OC therapy, shedding light on the intricate pathways underpinning POLM variant disease progression.NEW & NOTEWORTHY Our research reveals that POLM plays an important role in ovarian cancer development, especially the mutation G312R. We uncover the POLMG312R mutation as a driver of genomic instability in ovarian cancer via aberrant ribonucleotide incorporation. We reveal that POLMG312R upregulates COL11A1 and activates NF-κB signaling, contributing to tumor progression and chemoresistance. This study identifies the POLM-COL11A1-NF-κB axis as a novel oncogenic pathway.
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Affiliation(s)
- Yue Xiao
- Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou, People's Republic of China
- MOE Key Laboratory of Biosystems Homeostasis & Protection, Hangzhou, People's Republic of China
| | - Maowei Ni
- Zhejiang Cancer Hospital, Hangzhou, People's Republic of China
- Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou, People's Republic of China
| | - Zhiguo Zheng
- Zhejiang Cancer Hospital, Hangzhou, People's Republic of China
- Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou, People's Republic of China
| | - Yufeng Liu
- Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou, People's Republic of China
- MOE Key Laboratory of Biosystems Homeostasis & Protection, Hangzhou, People's Republic of China
| | - Mingyu Yin
- Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou, People's Republic of China
- MOE Key Laboratory of Biosystems Homeostasis & Protection, Hangzhou, People's Republic of China
| | - Shuyu Mao
- Zhejiang Cancer Hospital, Hangzhou, People's Republic of China
- Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou, People's Republic of China
| | - Ye Zhao
- Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou, People's Republic of China
- MOE Key Laboratory of Biosystems Homeostasis & Protection, Hangzhou, People's Republic of China
- Cancer Center, Zhejiang University, Hangzhou, People's Republic of China
| | - Bing Tian
- Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou, People's Republic of China
- MOE Key Laboratory of Biosystems Homeostasis & Protection, Hangzhou, People's Republic of China
- Cancer Center, Zhejiang University, Hangzhou, People's Republic of China
| | - Liangyan Wang
- Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou, People's Republic of China
- MOE Key Laboratory of Biosystems Homeostasis & Protection, Hangzhou, People's Republic of China
- Cancer Center, Zhejiang University, Hangzhou, People's Republic of China
| | - Hong Xu
- Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou, People's Republic of China
- MOE Key Laboratory of Biosystems Homeostasis & Protection, Hangzhou, People's Republic of China
- Cancer Center, Zhejiang University, Hangzhou, People's Republic of China
| | - Yuejin Hua
- Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou, People's Republic of China
- MOE Key Laboratory of Biosystems Homeostasis & Protection, Hangzhou, People's Republic of China
- Cancer Center, Zhejiang University, Hangzhou, People's Republic of China
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3
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Gao A, Zhang M, Zhu SQ, Zou S, Chen H, Li X, He C, Zhou L, Mei Y, Ding W, Zhou J, Zhou Y, Cao Y. DNA polymerase iota promotes EMT and metastasis of esophageal squamous cell carcinoma by interacting with USP7 to stabilize HIF-1α. Cell Death Dis 2024; 15:171. [PMID: 38402183 PMCID: PMC10894303 DOI: 10.1038/s41419-024-06552-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 02/05/2024] [Accepted: 02/09/2024] [Indexed: 02/26/2024]
Abstract
Esophageal squamous cell carcinoma (ESCC) is one of the most lethal cancer types, with a low 5-year survival rate of ~20%. Our prior research has suggested that DNA Polymerase iota (Pol ι), a member of Y-family DNA polymerase, plays a crucial role in the invasion and metastasis of ESCC. However, the underlying mechanism is not well understood. In this study, we utilized ChIP-PCR and luciferase reporter assays to investigate the binding of HIF-1α to the promoter of the Pol ι gene. Transwell, wound healing, and mouse models were employed to assess the impact of Pol ι and HIF-1α on the motility of ESCC cells. Co-immunoprecipitation and Western blot were carried out to explore the interaction between Pol ι and HIF-1α, while qRT-PCR and Western blot were conducted to confirm the regulation of Pol ι and HIF-1α on their downstream targets. Our results demonstrate that HIF-1α activates the transcription of the Pol ι gene in ESCC cells under hypoxic conditions. Furthermore, the knockdown of Pol ι impeded HIF-1α-induced invasion and metastasis. Additionally, we found that Pol ι regulates the expression of genes involved in epithelial-mesenchymal transition (EMT) and initiates EMT through the stabilization of HIF-1α. Mechanistically, Pol ι maintains the protein stability of HIF-1α by recruiting USP7 to mediate the deubiquitination of HIF-1α, with the residues 446-578 of Pol being crucial for the interaction between Pol ι and USP7. Collectively, our findings unveil a novel feedforward molecular axis of HIF-1α- Pol ι -USP7 in ESCC that contributes to ESCC metastasis. Hence, our results present an attractive target for intervention in ESCC.
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Affiliation(s)
- Aidi Gao
- Suzhou Cancer Center Core Laboratory, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, Jiangsu, P.R. China
| | - Mingxia Zhang
- Department of Radiation Oncology, the First Affiliated Hospital of Anhui Medical University, Hefei, P.R. China
| | - Shuang Qi Zhu
- Suzhou Cancer Center Core Laboratory, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, Jiangsu, P.R. China
| | - Shitao Zou
- Suzhou Cancer Center Core Laboratory, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, Jiangsu, P.R. China
| | - Hengrui Chen
- Suzhou Cancer Center Core Laboratory, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, Jiangsu, P.R. China
| | - Xiaoqin Li
- Suzhou Cancer Center Core Laboratory, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, Jiangsu, P.R. China
| | - Chao He
- Suzhou Cancer Center Core Laboratory, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, Jiangsu, P.R. China
| | - Liangsu Zhou
- Suzhou Cancer Center Core Laboratory, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, Jiangsu, P.R. China
| | - Yan Mei
- Suzhou Cancer Center Core Laboratory, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, Jiangsu, P.R. China
| | - Weiqun Ding
- Department of Pathology, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Jundong Zhou
- Suzhou Cancer Center Core Laboratory, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, Jiangsu, P.R. China.
| | - Yue Zhou
- Department of Thoracic Surgery, First Affiliated Hospital of Nanjing Medical University, Nanjing, P.R. China.
| | - Yuandong Cao
- Department of Radiation Oncology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, P.R. China.
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Zhuang X, Xiao R, Fu Y, Yang B, Fan J, Lu F, Qin T, Yang X, Hu X, Yin J, Li W, Kang X, Chen G, Hu D, Sun C. MRE11:p.K464R mutation mediates olaparib resistance by enhancing DNA damage repair in HGSOC. Cell Biosci 2023; 13:178. [PMID: 37759323 PMCID: PMC10537967 DOI: 10.1186/s13578-023-01117-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 08/28/2023] [Indexed: 09/29/2023] Open
Abstract
BACKGROUND Although the clinical application of PARP inhibitors has brought hope to ovarian cancer, the problem of its resistance has become increasingly prominent. Therefore, clinical experts have been focused on finding specific indicators and therapeutic targets that can be used for resistance monitoring of PARP inhibitors. RESULTS By cfDNA detecting during Olaparib maintenance therapy in platinum-sensitive relapsed ovarian cancer, we found the presence of MRE11:p.K464R mutation was strongly associated with acquired Olaparib resistance. Structural analysis revealed that the MRE11:p.K464R mutation is situated at a critical site where the MRE11 protein interacts with other biomolecules, leading to potential structural and functional abnormalities of MRE11 protein. Functionally, MRE11:p.K464R mutation enhanced the tolerance of Olaparib by reducing the DNA damage. Mechanistically, MRE11:p.K464R mutation improved the efficiency of DNA damage repair and induce Olaparib resistance by enhancing its binding activity with the interacting proteins (including RAD50 and RPS3). Among them, the enhanced binding of MRE11:p.K464R mutation to RAD50/RPS3 facilitated non-homologous end joining (NHEJ) repair in tumor cells, thereby expanding the scope of research into acquired resistance to PARP inhibitors. CONCLUSIONS Our findings provide a theoretical basis for MRE11:p.K464R mutation as a specific indicator of resistance monitoring in Olaparib treatment, and the exploration of its resistance mechanism provides a novel insights for the formulation of combination ther therapies after Olaparib resistance.
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Affiliation(s)
- Xucui Zhuang
- Department of Gynecological Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- National Clinical Research Center for Obstetrics and Gynecology, Cancer Biology Research Center (Key Laboratory of the Ministry of Education), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Rourou Xiao
- Department of Gynecological Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- National Clinical Research Center for Obstetrics and Gynecology, Cancer Biology Research Center (Key Laboratory of the Ministry of Education), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yu Fu
- Department of Gynecological Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- National Clinical Research Center for Obstetrics and Gynecology, Cancer Biology Research Center (Key Laboratory of the Ministry of Education), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Bin Yang
- Department of Gynecological Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- National Clinical Research Center for Obstetrics and Gynecology, Cancer Biology Research Center (Key Laboratory of the Ministry of Education), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Junpeng Fan
- Department of Gynecological Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- National Clinical Research Center for Obstetrics and Gynecology, Cancer Biology Research Center (Key Laboratory of the Ministry of Education), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Funian Lu
- Department of Gynecological Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- National Clinical Research Center for Obstetrics and Gynecology, Cancer Biology Research Center (Key Laboratory of the Ministry of Education), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Tianyu Qin
- Department of Gynecological Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- National Clinical Research Center for Obstetrics and Gynecology, Cancer Biology Research Center (Key Laboratory of the Ministry of Education), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaohang Yang
- Department of Gynecological Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- National Clinical Research Center for Obstetrics and Gynecology, Cancer Biology Research Center (Key Laboratory of the Ministry of Education), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xingyuan Hu
- Department of Gynecological Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- National Clinical Research Center for Obstetrics and Gynecology, Cancer Biology Research Center (Key Laboratory of the Ministry of Education), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jingjing Yin
- Department of Gynecological Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- National Clinical Research Center for Obstetrics and Gynecology, Cancer Biology Research Center (Key Laboratory of the Ministry of Education), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Wenting Li
- Department of Gynecological Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- National Clinical Research Center for Obstetrics and Gynecology, Cancer Biology Research Center (Key Laboratory of the Ministry of Education), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaoyan Kang
- Department of Gynecological Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- National Clinical Research Center for Obstetrics and Gynecology, Cancer Biology Research Center (Key Laboratory of the Ministry of Education), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Gang Chen
- Department of Gynecological Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- National Clinical Research Center for Obstetrics and Gynecology, Cancer Biology Research Center (Key Laboratory of the Ministry of Education), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Dianxing Hu
- Department of Gynecological Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
- National Clinical Research Center for Obstetrics and Gynecology, Cancer Biology Research Center (Key Laboratory of the Ministry of Education), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Chaoyang Sun
- Department of Gynecological Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
- National Clinical Research Center for Obstetrics and Gynecology, Cancer Biology Research Center (Key Laboratory of the Ministry of Education), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
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5
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Guo S, Zhu X, Huang Z, Wei C, Yu J, Zhang L, Feng J, Li M, Li Z. Genomic instability drives tumorigenesis and metastasis and its implications for cancer therapy. Biomed Pharmacother 2023; 157:114036. [PMID: 36436493 DOI: 10.1016/j.biopha.2022.114036] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 11/19/2022] [Indexed: 11/27/2022] Open
Abstract
Genetic instability can be caused by external factors and may also be associated with intracellular damage. At the same time, there is a large body of research investigating the mechanisms by which genetic instability occurs and demonstrating the relationship between genomic stability and tumors. Nowadays, tumorigenesis development is one of the hottest research areas. It is a vital factor affecting tumor treatment. Mechanisms of genomic stability and tumorigenesis development are relatively complex. Researchers have been working on these aspects of research. To explore the research progress of genomic stability and tumorigenesis, development, and treatment, the authors searched PubMed with the keywords "genome instability" "chromosome instability" "DNA damage" "tumor spread" and "cancer treatment". This extracts the information relevant to this study. Results: This review introduces genomic stability, drivers of tumor development, tumor cell characteristics, tumor metastasis, and tumor treatment. Among them, immunotherapy is more important in tumor treatment, which can effectively inhibit tumor metastasis and kill tumor cells. Breakthroughs in tumorigenesis development studies and discoveries in tumor metastasis will provide new therapeutic techniques. New tumor treatment methods can effectively prevent tumor metastasis and improve the cure rate of tumors.
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Affiliation(s)
- Shihui Guo
- Computational Oncology Lab, The Marine Biomedical Research Institute, Guangdong Medical University, Zhanjiang 524023, China
| | - Xiao Zhu
- Computational Oncology Lab, The Marine Biomedical Research Institute, Guangdong Medical University, Zhanjiang 524023, China
| | - Ziyuan Huang
- Computational Oncology Lab, The Marine Biomedical Research Institute, Guangdong Medical University, Zhanjiang 524023, China
| | - Chuzhong Wei
- Computational Oncology Lab, The Marine Biomedical Research Institute, Guangdong Medical University, Zhanjiang 524023, China
| | - Jiaao Yu
- Computational Oncology Lab, The Marine Biomedical Research Institute, Guangdong Medical University, Zhanjiang 524023, China
| | - Lin Zhang
- Computational Oncology Lab, The Marine Biomedical Research Institute, Guangdong Medical University, Zhanjiang 524023, China
| | - Jinghua Feng
- Computational Oncology Lab, The Marine Biomedical Research Institute, Guangdong Medical University, Zhanjiang 524023, China
| | - Mingdong Li
- Department of Gastroenterology, Zibo Central Hospital, Zibo 255000, China.
| | - Zesong Li
- Guangdong Provincial Key Laboratory of Systems Biology and Synthetic Biology for Urogenital Tumors, Shenzhen Key Laboratory of Genitourinary Tumor, Department of Urology, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital (Shenzhen Institute of Translational Medicine), Shenzhen, China.
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6
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Tang Q, Gulkis M, McKenna R, Çağlayan M. Structures of LIG1 that engage with mutagenic mismatches inserted by polβ in base excision repair. Nat Commun 2022; 13:3860. [PMID: 35790757 PMCID: PMC9256674 DOI: 10.1038/s41467-022-31585-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 06/23/2022] [Indexed: 11/09/2022] Open
Abstract
DNA ligase I (LIG1) catalyzes the ligation of the nick repair intermediate after gap filling by DNA polymerase (pol) β during downstream steps of the base excision repair (BER) pathway. However, how LIG1 discriminates against the mutagenic 3'-mismatches incorporated by polβ at atomic resolution remains undefined. Here, we determine the X-ray structures of LIG1/nick DNA complexes with G:T and A:C mismatches and uncover the ligase strategies that favor or deter the ligation of base substitution errors. Our structures reveal that the LIG1 active site can accommodate a G:T mismatch in the wobble conformation, where an adenylate (AMP) is transferred to the 5'-phosphate of a nick (DNA-AMP), while it stays in the LIG1-AMP intermediate during the initial step of the ligation reaction in the presence of an A:C mismatch at the 3'-strand. Moreover, we show mutagenic ligation and aberrant nick sealing of dG:T and dA:C mismatches, respectively. Finally, we demonstrate that AP-endonuclease 1 (APE1), as a compensatory proofreading enzyme, removes the mismatched bases and interacts with LIG1 at the final BER steps. Our overall findings provide the features of accurate versus mutagenic outcomes coordinated by a multiprotein complex including polβ, LIG1, and APE1 to maintain efficient repair.
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Affiliation(s)
- Qun Tang
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, 32610, USA
| | - Mitchell Gulkis
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, 32610, USA
| | - Robert McKenna
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, 32610, USA
| | - Melike Çağlayan
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, 32610, USA.
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