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Kovács ZJ, Harami GM, Pálinkás J, Kuljanishvili N, Hegedüs J, Harami‐Papp H, Mahmudova L, Khamisi L, Szakács G, Kovács M. DNA-dependent phase separation by human SSB2 (NABP1/OBFC2A) protein points to adaptations to eukaryotic genome repair processes. Protein Sci 2024; 33:e4959. [PMID: 38511671 PMCID: PMC10955726 DOI: 10.1002/pro.4959] [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: 10/19/2023] [Revised: 02/04/2024] [Accepted: 02/21/2024] [Indexed: 03/22/2024]
Abstract
Single-stranded DNA binding proteins (SSBs) are ubiquitous across all domains of life and play essential roles via stabilizing and protecting single-stranded (ss) DNA as well as organizing multiprotein complexes during DNA replication, recombination, and repair. Two mammalian SSB paralogs (hSSB1 and hSSB2 in humans) were recently identified and shown to be involved in various genome maintenance processes. Following our recent discovery of the liquid-liquid phase separation (LLPS) propensity of Escherichia coli (Ec) SSB, here we show that hSSB2 also forms LLPS condensates under physiologically relevant ionic conditions. Similar to that seen for EcSSB, we demonstrate the essential contribution of hSSB2's C-terminal intrinsically disordered region (IDR) to condensate formation, and the selective enrichment of various genome metabolic proteins in hSSB2 condensates. However, in contrast to EcSSB-driven LLPS that is inhibited by ssDNA binding, hSSB2 phase separation requires single-stranded nucleic acid binding, and is especially facilitated by ssDNA. Our results reveal an evolutionarily conserved role for SSB-mediated LLPS in the spatiotemporal organization of genome maintenance complexes. At the same time, differential LLPS features of EcSSB and hSSB2 point to functional adaptations to prokaryotic versus eukaryotic genome metabolic contexts.
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Affiliation(s)
- Zoltán J. Kovács
- ELTE‐MTA “Momentum” Motor Enzymology Research Group, Department of BiochemistryEötvös Loránd UniversityBudapestHungary
- HUN‐REN–ELTE Motor Pharmacology Research Group, Department of BiochemistryEötvös Loránd UniversityBudapestHungary
| | - Gábor M. Harami
- ELTE‐MTA “Momentum” Motor Enzymology Research Group, Department of BiochemistryEötvös Loránd UniversityBudapestHungary
| | - János Pálinkás
- ELTE‐MTA “Momentum” Motor Enzymology Research Group, Department of BiochemistryEötvös Loránd UniversityBudapestHungary
| | - Natalie Kuljanishvili
- ELTE‐MTA “Momentum” Motor Enzymology Research Group, Department of BiochemistryEötvös Loránd UniversityBudapestHungary
| | - József Hegedüs
- ELTE‐MTA “Momentum” Motor Enzymology Research Group, Department of BiochemistryEötvös Loránd UniversityBudapestHungary
| | - Hajnalka Harami‐Papp
- ELTE‐MTA “Momentum” Motor Enzymology Research Group, Department of BiochemistryEötvös Loránd UniversityBudapestHungary
| | - Lamiya Mahmudova
- ELTE‐MTA “Momentum” Motor Enzymology Research Group, Department of BiochemistryEötvös Loránd UniversityBudapestHungary
| | - Lana Khamisi
- ELTE‐MTA “Momentum” Motor Enzymology Research Group, Department of BiochemistryEötvös Loránd UniversityBudapestHungary
| | - Gergely Szakács
- HUN‐REN Institute of Molecular Life Sciences, Research Centre for Natural Sciences, Hungarian Academy of SciencesBudapestHungary
- Center for Cancer ResearchMedical University of ViennaWienAustria
| | - Mihály Kovács
- ELTE‐MTA “Momentum” Motor Enzymology Research Group, Department of BiochemistryEötvös Loránd UniversityBudapestHungary
- HUN‐REN–ELTE Motor Pharmacology Research Group, Department of BiochemistryEötvös Loránd UniversityBudapestHungary
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2
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Xu C, Li C, Chen J, Xiong Y, Qiao Z, Fan P, Li C, Ma S, Liu J, Song A, Tao B, Xu T, Xu W, Chi Y, Xue J, Wang P, Ye D, Gu H, Zhang P, Wang Q, Xiao R, Cheng J, Zheng H, Yu X, Zhang Z, Wu J, Liang K, Liu YJ, Lu H, Chen FX. R-loop-dependent promoter-proximal termination ensures genome stability. Nature 2023; 621:610-619. [PMID: 37557913 PMCID: PMC10511320 DOI: 10.1038/s41586-023-06515-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 08/03/2023] [Indexed: 08/11/2023]
Abstract
The proper regulation of transcription is essential for maintaining genome integrity and executing other downstream cellular functions1,2. Here we identify a stable association between the genome-stability regulator sensor of single-stranded DNA (SOSS)3 and the transcription regulator Integrator-PP2A (INTAC)4-6. Through SSB1-mediated recognition of single-stranded DNA, SOSS-INTAC stimulates promoter-proximal termination of transcription and attenuates R-loops associated with paused RNA polymerase II to prevent R-loop-induced genome instability. SOSS-INTAC-dependent attenuation of R-loops is enhanced by the ability of SSB1 to form liquid-like condensates. Deletion of NABP2 (encoding SSB1) or introduction of cancer-associated mutations into its intrinsically disordered region leads to a pervasive accumulation of R-loops, highlighting a genome surveillance function of SOSS-INTAC that enables timely termination of transcription at promoters to constrain R-loop accumulation and ensure genome stability.
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Affiliation(s)
- Congling Xu
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Medical Epigenetics, Shanghai Key Laboratory of Radiation Oncology, Human Phenome Institute, Fudan University, Shanghai, China
| | - Chengyu Li
- Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, China
| | - Jiwei Chen
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Medical Epigenetics, Shanghai Key Laboratory of Radiation Oncology, Human Phenome Institute, Fudan University, Shanghai, China
| | - Yan Xiong
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Medical Epigenetics, Shanghai Key Laboratory of Radiation Oncology, Human Phenome Institute, Fudan University, Shanghai, China
| | - Zhibin Qiao
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Medical Epigenetics, Shanghai Key Laboratory of Radiation Oncology, Human Phenome Institute, Fudan University, Shanghai, China
- Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Fudan University, Shanghai, China
| | - Pengyu Fan
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Medical Epigenetics, Shanghai Key Laboratory of Radiation Oncology, Human Phenome Institute, Fudan University, Shanghai, China
- Department of Thoracic Surgery, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Conghui Li
- Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Shuangyu Ma
- Department of Histoembryology, Genetics and Developmental Biology, Shanghai Key Laboratory of Reproductive Medicine, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jin Liu
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Medical Epigenetics, Shanghai Key Laboratory of Radiation Oncology, Human Phenome Institute, Fudan University, Shanghai, China
| | - Aixia Song
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Medical Epigenetics, Shanghai Key Laboratory of Radiation Oncology, Human Phenome Institute, Fudan University, Shanghai, China
| | - Bolin Tao
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Medical Epigenetics, Shanghai Key Laboratory of Radiation Oncology, Human Phenome Institute, Fudan University, Shanghai, China
| | - Tao Xu
- Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, China
| | - Wei Xu
- Department of Orthopedic Oncology, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Yayun Chi
- Department of Breast Surgery, Fudan University Shanghai Cancer Center, Shanghai, China
| | - Jingyan Xue
- Department of Breast Surgery, Fudan University Shanghai Cancer Center, Shanghai, China
| | - Pu Wang
- Huashan Hospital, Fudan University, Shanghai Key Laboratory of Medical Epigenetics, Molecular and Cell Biology Lab, Institutes of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Dan Ye
- Huashan Hospital, Fudan University, Shanghai Key Laboratory of Medical Epigenetics, Molecular and Cell Biology Lab, Institutes of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Hongzhou Gu
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Medical Epigenetics, Shanghai Key Laboratory of Radiation Oncology, Human Phenome Institute, Fudan University, Shanghai, China
| | - Peng Zhang
- Department of Thoracic Surgery, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Qiong Wang
- Department of Histoembryology, Genetics and Developmental Biology, Shanghai Key Laboratory of Reproductive Medicine, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ruijing Xiao
- Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Jingdong Cheng
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Medical Epigenetics, Shanghai Key Laboratory of Radiation Oncology, Human Phenome Institute, Fudan University, Shanghai, China
| | - Hai Zheng
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Medical Epigenetics, Shanghai Key Laboratory of Radiation Oncology, Human Phenome Institute, Fudan University, Shanghai, China
| | - Xiaoli Yu
- Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Fudan University, Shanghai, China
| | - Zhen Zhang
- Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Fudan University, Shanghai, China
| | - Jiong Wu
- Department of Breast Surgery, Fudan University Shanghai Cancer Center, Shanghai, China
| | - Kaiwei Liang
- Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Yan-Jun Liu
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Medical Epigenetics, Shanghai Key Laboratory of Radiation Oncology, Human Phenome Institute, Fudan University, Shanghai, China
| | - Huasong Lu
- Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, China.
| | - Fei Xavier Chen
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Medical Epigenetics, Shanghai Key Laboratory of Radiation Oncology, Human Phenome Institute, Fudan University, Shanghai, China.
- Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Fudan University, Shanghai, China.
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3
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Guo JT, Malik F. Single-Stranded DNA Binding Proteins and Their Identification Using Machine Learning-Based Approaches. Biomolecules 2022; 12:biom12091187. [PMID: 36139026 PMCID: PMC9496475 DOI: 10.3390/biom12091187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 08/11/2022] [Accepted: 08/24/2022] [Indexed: 11/25/2022] Open
Abstract
Single-stranded DNA (ssDNA) binding proteins (SSBs) are critical in maintaining genome stability by protecting the transient existence of ssDNA from damage during essential biological processes, such as DNA replication and gene transcription. The single-stranded region of telomeres also requires protection by ssDNA binding proteins from being attacked in case it is wrongly recognized as an anomaly. In addition to their critical roles in genome stability and integrity, it has been demonstrated that ssDNA and SSB-ssDNA interactions play critical roles in transcriptional regulation in all three domains of life and viruses. In this review, we present our current knowledge of the structure and function of SSBs and the structural features for SSB binding specificity. We then discuss the machine learning-based approaches that have been developed for the prediction of SSBs from double-stranded DNA (dsDNA) binding proteins (DSBs).
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4
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hSSB2 (NABP1) is required for the recruitment of RPA during the cellular response to DNA UV damage. Sci Rep 2021; 11:20256. [PMID: 34642383 PMCID: PMC8511049 DOI: 10.1038/s41598-021-99355-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 09/15/2021] [Indexed: 11/17/2022] Open
Abstract
Maintenance of genomic stability is critical to prevent diseases such as cancer. As such, eukaryotic cells have multiple pathways to efficiently detect, signal and repair DNA damage. One common form of exogenous DNA damage comes from ultraviolet B (UVB) radiation. UVB generates cyclobutane pyrimidine dimers (CPD) that must be rapidly detected and repaired to maintain the genetic code. The nucleotide excision repair (NER) pathway is the main repair system for this type of DNA damage. Here, we determined the role of the human Single-Stranded DNA Binding protein 2, hSSB2, in the response to UVB exposure. We demonstrate that hSSB2 levels increase in vitro and in vivo after UVB irradiation and that hSSB2 rapidly binds to chromatin. Depletion of hSSB2 results in significantly decreased Replication Protein A (RPA32) phosphorylation and impaired RPA32 localisation to the site of UV-induced DNA damage. Delayed recruitment of NER protein Xeroderma Pigmentosum group C (XPC) was also observed, leading to increased cellular sensitivity to UVB. Finally, hSSB2 was shown to have affinity for single-strand DNA containing a single CPD and for duplex DNA with a two-base mismatch mimicking a CPD moiety. Altogether our data demonstrate that hSSB2 is involved in the cellular response to UV exposure.
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5
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Sinha D, Nag P, Nanayakkara D, Duijf PHG, Burgess A, Raninga P, Smits VAJ, Bain AL, Subramanian G, Wall M, Finnie JW, Kalimutho M, Khanna KK. Cep55 overexpression promotes genomic instability and tumorigenesis in mice. Commun Biol 2020; 3:593. [PMID: 33087841 PMCID: PMC7578791 DOI: 10.1038/s42003-020-01304-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 09/17/2020] [Indexed: 12/16/2022] Open
Abstract
High expression of centrosomal protein CEP55 has been correlated with clinico-pathological parameters across multiple human cancers. Despite significant in vitro studies and association of aberrantly overexpressed CEP55 with worse prognosis, its causal role in vivo tumorigenesis remains elusive. Here, using a ubiquitously overexpressing transgenic mouse model, we show that Cep55 overexpression causes spontaneous tumorigenesis and accelerates Trp53+/− induced tumours in vivo. At the cellular level, using mouse embryonic fibroblasts (MEFs), we demonstrate that Cep55 overexpression induces proliferation advantage by modulating multiple cellular signalling networks including the hyperactivation of the Pi3k/Akt pathway. Notably, Cep55 overexpressing MEFs have a compromised Chk1-dependent S-phase checkpoint, causing increased replication speed and DNA damage, resulting in a prolonged aberrant mitotic division. Importantly, this phenotype was rescued by pharmacological inhibition of Pi3k/Akt or expression of mutant Chk1 (S280A) protein, which is insensitive to regulation by active Akt, in Cep55 overexpressing MEFs. Moreover, we report that Cep55 overexpression causes stabilized microtubules. Collectively, our data demonstrates causative effects of deregulated Cep55 on genome stability and tumorigenesis which have potential implications for tumour initiation and therapy development. Sinha et al. demonstrate that overexpression of centrosomal protein Cep55 in mice is sufficient to cause a wide-spectrum of cancer via multiple mechanisms including hyperactivation of the Pi3k/Akt pathway, stabilized microtubules and a defective replication checkpoint response. These findings are relevant to human cancers as high CEP55 expression is associated with worse prognosis across multiple cancer types.
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Affiliation(s)
- Debottam Sinha
- QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, 4006, QLD, Australia.,School of Environment and Sciences, Griffith University, Nathan, 4111, QLD, Australia
| | - Purba Nag
- QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, 4006, QLD, Australia.,School of Environment and Sciences, Griffith University, Nathan, 4111, QLD, Australia.,Conjoint Internal Medicine Laboratory, Chemical Pathology, Pathology Queensland and Kidney Health Service, Royal Brisbane and Women's Hospital, Brisbane, 4029, QLD, Australia
| | - Devathri Nanayakkara
- QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, 4006, QLD, Australia
| | - Pascal H G Duijf
- University of Queensland Diamantina Institute, The University of Queensland, Translational Research Institute, Brisbane, 4102, QLD, Australia.,Institute of Health and Biomedical Innovation and School of Biomedical Sciences, Queensland University of Technology, Brisbane, Australia
| | - Andrew Burgess
- ANZAC Research Institute, University of Sydney, Sydney, NSW, Australia
| | - Prahlad Raninga
- QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, 4006, QLD, Australia
| | - Veronique A J Smits
- Unidad de Investigación, Hospital Universitario de Canarias, Tenerife, Spain.,Instituto de Tecnologías Biomédicas, Universidad de La Laguna, Tenerife, Spain.,Universidad Fernando Pessoa Canarias, Las Palmas de Gran Canaria, Spain
| | - Amanda L Bain
- QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, 4006, QLD, Australia
| | - Goutham Subramanian
- QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, 4006, QLD, Australia
| | - Meaghan Wall
- Victorian Cancer Cytogenetics Service, St. Vincent's Hospital, Fitzroy, Melbourne, Australia
| | - John W Finnie
- Discipline of Anatomy and Pathology, Adelaide Medical School, University of Adelaide and SA Pathology, Adelaide, Australia
| | - Murugan Kalimutho
- QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, 4006, QLD, Australia.
| | - Kum Kum Khanna
- QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, 4006, QLD, Australia.
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6
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Pfeifer M, Brem R, Lippert TP, Boulianne B, Ho HN, Robinson ME, Stebbing J, Feldhahn N. SSB1/SSB2 Proteins Safeguard B Cell Development by Protecting the Genomes of B Cell Precursors. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2019; 202:3423-3433. [PMID: 31085591 PMCID: PMC6545462 DOI: 10.4049/jimmunol.1801618] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 04/12/2019] [Indexed: 12/22/2022]
Abstract
Induction of programmed DNA damage and its recognition and repair are fundamental for B cell development. The ssDNA-binding protein SSB1 has been described in human cells as essential for the recognition and repair of DNA damage. To study its relevance for B cells, we recently developed Ssb1 -/- and conditional Ssb1 -/- mice. Although SSB1 loss did not affect B cell development, Ssb1 -/- cells exhibited compensatory expression of its homolog SSB2. We have now generated Ssb2 -/- mice and show in this study that SSB2 is also dispensable for B cell development and DNA damage response activation. In contrast to the single loss of Ssb1 or Ssb2, however, combined SSB1/2 deficiency caused a defect in early B cell development. We relate this to the sensitivity of B cell precursors as mature B cells largely tolerated their loss. Toxicity of combined genetic SSB1/2 loss can be rescued by ectopic expression of either SSB1 or SSB2, mimicked by expression of SSB1 ssDNA-binding mutants, and attenuated by BCL2-mediated suppression of apoptosis. SSB1/2 loss in B cell precursors further caused increased exposure of ssDNA associated with disruption of genome fragile sites, inefficient cell cycle progression, and increased DNA damage if apoptosis is suppressed. As such, our results establish SSB1/2 as safeguards of B cell development and unveil their differential requirement in immature and mature B lymphocytes.
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Affiliation(s)
- Matthias Pfeifer
- Centre for Hematology, Department of Medicine, Imperial College London, W12 0NN London, United Kingdom; and
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, W12 0NN London, United Kingdom
| | - Reto Brem
- Centre for Hematology, Department of Medicine, Imperial College London, W12 0NN London, United Kingdom; and
| | - Timothy P Lippert
- Centre for Hematology, Department of Medicine, Imperial College London, W12 0NN London, United Kingdom; and
| | - Bryant Boulianne
- Centre for Hematology, Department of Medicine, Imperial College London, W12 0NN London, United Kingdom; and
| | - Howin Ng Ho
- Centre for Hematology, Department of Medicine, Imperial College London, W12 0NN London, United Kingdom; and
| | - Mark E Robinson
- Centre for Hematology, Department of Medicine, Imperial College London, W12 0NN London, United Kingdom; and
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, W12 0NN London, United Kingdom
| | - Justin Stebbing
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, W12 0NN London, United Kingdom
| | - Niklas Feldhahn
- Centre for Hematology, Department of Medicine, Imperial College London, W12 0NN London, United Kingdom; and
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7
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Croft LV, Bolderson E, Adams MN, El-Kamand S, Kariawasam R, Cubeddu L, Gamsjaeger R, Richard DJ. Human single-stranded DNA binding protein 1 (hSSB1, OBFC2B), a critical component of the DNA damage response. Semin Cell Dev Biol 2019; 86:121-128. [DOI: 10.1016/j.semcdb.2018.03.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 03/21/2018] [Accepted: 03/22/2018] [Indexed: 12/18/2022]
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8
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Zhang RR, Koido M, Tadokoro T, Ouchi R, Matsuno T, Ueno Y, Sekine K, Takebe T, Taniguchi H. Human iPSC-Derived Posterior Gut Progenitors Are Expandable and Capable of Forming Gut and Liver Organoids. Stem Cell Reports 2018; 10:780-793. [PMID: 29429958 PMCID: PMC5919071 DOI: 10.1016/j.stemcr.2018.01.006] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 01/10/2018] [Accepted: 01/11/2018] [Indexed: 02/06/2023] Open
Abstract
Early endoderm progenitors naturally possess robust propagating potential to develop a majority of meter-long gastrointestinal tracts and are therefore considered as a promising source for therapy. Here, we demonstrated the reproducible generation of human CDX2+ posterior gut endoderm cells (PGECs) from five induced pluripotent stem cell clones by manipulating FGF, TGF, and WNT signaling. Transcriptome analysis suggested that putative PGECs harbored an intermediate signature profile between definitive endoderm and organ-specific endoderm. We found that combinatorial EGF, VEGF, FGF2, Chir99021, and A83-01 treatments selectively amplify storable PGECs up to 1021 cell scale without any gene transduction or feeder use. PGECs, compared with induced pluripotent stem cells, showed stable differentiation propensity into multiple endodermal lineages without teratoma formation. Furthermore, transplantation of PGEC-derived liver bud organoids showed therapeutic potential against fulminant liver failure. Together, the robustly amplified PGECs may be a promising cellular source for endoderm-derived organoids in studying human development, modeling disease, and, ultimately, therapy. Successful activation of posteriorization program using human iPSC-derived endoderm CDX2+ PGECs exhibit a robust amplification potential after passaging and freezing PGECs with differentiation potential into hindgut and liver bud organoids PGEC liver bud transplant is therapeutically effective for acute liver failure
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Affiliation(s)
- Ran-Ran Zhang
- Department of Regenerative Medicine, Yokohama City University Graduate School of Medicine, Kanazawa-ku 3-9, Yokohama, Kanagawa 236-0004, Japan; Division of Gastroenterology, Hepatology & Nutrition, Developmental Biology, Center for Stem Cell and Organoid Medicine (CuSTOM), Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229-3039, USA
| | - Masaru Koido
- Department of Regenerative Medicine, Yokohama City University Graduate School of Medicine, Kanazawa-ku 3-9, Yokohama, Kanagawa 236-0004, Japan
| | - Tomomi Tadokoro
- Department of Regenerative Medicine, Yokohama City University Graduate School of Medicine, Kanazawa-ku 3-9, Yokohama, Kanagawa 236-0004, Japan
| | - Rie Ouchi
- Division of Gastroenterology, Hepatology & Nutrition, Developmental Biology, Center for Stem Cell and Organoid Medicine (CuSTOM), Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229-3039, USA
| | - Tatsuya Matsuno
- Department of Regenerative Medicine, Yokohama City University Graduate School of Medicine, Kanazawa-ku 3-9, Yokohama, Kanagawa 236-0004, Japan
| | - Yasuharu Ueno
- Department of Regenerative Medicine, Yokohama City University Graduate School of Medicine, Kanazawa-ku 3-9, Yokohama, Kanagawa 236-0004, Japan
| | - Keisuke Sekine
- Department of Regenerative Medicine, Yokohama City University Graduate School of Medicine, Kanazawa-ku 3-9, Yokohama, Kanagawa 236-0004, Japan
| | - Takanori Takebe
- Department of Regenerative Medicine, Yokohama City University Graduate School of Medicine, Kanazawa-ku 3-9, Yokohama, Kanagawa 236-0004, Japan; Division of Gastroenterology, Hepatology & Nutrition, Developmental Biology, Center for Stem Cell and Organoid Medicine (CuSTOM), Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229-3039, USA; Advanced Medical Research Center, Yokohama City University, Kanazawa-ku 3-9, Yokohama, Kanagawa 236-0004, Japan; PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
| | - Hideki Taniguchi
- Department of Regenerative Medicine, Yokohama City University Graduate School of Medicine, Kanazawa-ku 3-9, Yokohama, Kanagawa 236-0004, Japan; Division of Gastroenterology, Hepatology & Nutrition, Developmental Biology, Center for Stem Cell and Organoid Medicine (CuSTOM), Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229-3039, USA.
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9
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Li Q, Qu F, Li R, He X, Zhai Y, Chen W, Zheng Y. A functional polymorphism of SSBP1 gene predicts prognosis and response to chemotherapy in resected gastric cancer patients. Oncotarget 2017; 8:110861-110876. [PMID: 29340022 PMCID: PMC5762290 DOI: 10.18632/oncotarget.22864] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 11/03/2017] [Indexed: 12/17/2022] Open
Abstract
Growing evidence has indicated that single-stranded DNA-binding proteins 1 (SSBP1) is involved in tumor initiation and progression. However, effects of single nucleotide polymorphisms (SNPs) in SSBP1 gene on gastric cancer (GC) prognosis are still unknown. In present study, two functional SNPs from SSBP1 were selected and genotyped in a large cohorts of 1030 resected GC patients (326 in the training set, 704 in the validation set) to explore the association of SNPs with patients’ survival. The rs6976500 G allele (CG/GG) genotypes were found significantly associated with both worse overall survival (OS) and recurrence-free survival (RFS) in the training and the independent validation set when compared to C allele genotype, which reaching a more robust statistical significance in the pooled analysis. Furthermore, integration of rs6976500 genotypes and TNM stage significantly improved the prognosis prediction models based on TNM stage alone. In addition, only carriers with at least one G allele of rs6976500 gained significant survival benefit from FOLFOX-based ACT. Mechanistically, SNP rs6976500 G allele genotype could significantly decrease promoter transcriptional activity and markedly reduce expression level of SSBP1 compared with the C allele genotype in GC cells. This was further substantiated by immunohistochemical assay in 70 GC tissue samples. Our study presents the first evidence that SNP rs6976500 G allele genotypes might contribute to GC prognosis by attenuating SSBP1 promoter activity and gene expression, and provides the guidance in refining therapeutic decisions of GC patients. Further exploration on its function is needed to clarify the exact biological mechanism behind.
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Affiliation(s)
- Qiuchen Li
- Department of Gastroenterology, First Affiliated Hospital of the Medical College, Shihezi University, Shihezi, Xinjiang, 832008, China
| | - Falin Qu
- Department of General Surgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, 710038, China
| | - Renli Li
- Department of General Surgery, The Fourth Hospital of Chinese PLA, Xining, Qinghai, 810007, China
| | - Xianli He
- Department of General Surgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, 710038, China
| | - Yulong Zhai
- Department of General Surgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, 710038, China
| | - Weigang Chen
- Department of Gastroenterology, First Affiliated Hospital of the Medical College, Shihezi University, Shihezi, Xinjiang, 832008, China
| | - Yong Zheng
- Department of Gastroenterology, First Affiliated Hospital of the Medical College, Shihezi University, Shihezi, Xinjiang, 832008, China
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10
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Ssb1 and Ssb2 cooperate to regulate mouse hematopoietic stem and progenitor cells by resolving replicative stress. Blood 2017; 129:2479-2492. [PMID: 28270450 DOI: 10.1182/blood-2016-06-725093] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 02/26/2017] [Indexed: 12/14/2022] Open
Abstract
Hematopoietic stem and progenitor cells (HSPCs) are vulnerable to endogenous damage and defects in DNA repair can limit their function. The 2 single-stranded DNA (ssDNA) binding proteins SSB1 and SSB2 are crucial regulators of the DNA damage response; however, their overlapping roles during normal physiology are incompletely understood. We generated mice in which both Ssb1 and Ssb2 were constitutively or conditionally deleted. Constitutive Ssb1/Ssb2 double knockout (DKO) caused early embryonic lethality, whereas conditional Ssb1/Ssb2 double knockout (cDKO) in adult mice resulted in acute lethality due to bone marrow failure and intestinal atrophy featuring stem and progenitor cell depletion, a phenotype unexpected from the previously reported single knockout models of Ssb1 or Ssb2 Mechanistically, cDKO HSPCs showed altered replication fork dynamics, massive accumulation of DNA damage, genome-wide double-strand breaks enriched at Ssb-binding regions and CpG islands, together with the accumulation of R-loops and cytosolic ssDNA. Transcriptional profiling of cDKO HSPCs revealed the activation of p53 and interferon (IFN) pathways, which enforced cell cycling in quiescent HSPCs, resulting in their apoptotic death. The rapid cell death phenotype was reproducible in in vitro cultured cDKO-hematopoietic stem cells, which were significantly rescued by nucleotide supplementation or after depletion of p53. Collectively, Ssb1 and Ssb2 control crucial aspects of HSPC function, including proliferation and survival in vivo by resolving replicative stress to maintain genomic stability.
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11
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Wu Y, Lu J, Kang T. Human single-stranded DNA binding proteins: guardians of genome stability. Acta Biochim Biophys Sin (Shanghai) 2016; 48:671-7. [PMID: 27217471 DOI: 10.1093/abbs/gmw044] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Accepted: 04/15/2016] [Indexed: 01/03/2023] Open
Abstract
Single-stranded DNA-binding proteins (SSBs) are essential for maintaining the integrity of the genome in all organisms. All processes related to DNA, such as replication, excision, repair, and recombination, require the participation of SSBs whose oligonucleotide/oligosaccharide-binding (OB)-fold domain is responsible for the interaction with single-stranded DNA (ssDNA). For a long time, the heterotrimeric replication protein A (RPA) complex was believed to be the only nuclear SSB in eukaryotes to participate in ssDNA processing, while mitochondrial SSBs that are conserved with prokaryotic SSBs were shown to be essential for maintaining genome stability in eukaryotic mitochondria. In recent years, two new proteins, hSSB1 and hSSB2 (human SSBs 1/2), were identified and have better sequence similarity to bacterial and archaeal SSBs than RPA. This review summarizes the current understanding of these human SSBs in DNA damage repair and in cell-cycle checkpoint activation following DNA damage, as well as their relationships with cancer.
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Affiliation(s)
- Yuanzhong Wu
- State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
| | - Jinping Lu
- State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
| | - Tiebang Kang
- State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
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12
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Vidhyasagar V, He Y, Guo M, Ding H, Talwar T, Nguyen V, Nwosu J, Katselis G, Wu Y. C-termini are essential and distinct for nucleic acid binding of human NABP1 and NABP2. Biochim Biophys Acta Gen Subj 2015; 1860:371-83. [PMID: 26550690 DOI: 10.1016/j.bbagen.2015.11.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 10/30/2015] [Accepted: 11/04/2015] [Indexed: 01/03/2023]
Abstract
BACKGROUND Human Nucleic Acid Binding Protein 1 and 2 (hNABP1 and 2; also known as hSSB2 and 1, respectively) are two newly identified single-stranded (ss) DNA binding proteins (SSB). Both NABP1 and NABP2 have a conserved oligonucleotide/oligosaccharide-binding (OB)-fold domain and a divergent carboxy-terminal domain, the functional importance of which is unknown. METHODS Recombinant hNABP1/2 proteins were purified using affinity and size exclusion chromatography and their identities confirmed by mass spectrometry. Oligomerization state was checked by sucrose gradient centrifugation. Secondary structure was determined by circular dichroism spectroscopy. Nucleic acid binding ability was examined by EMSA and ITC. RESULTS Both hNABP1 and hNABP2 exist as monomers in solution; however, hNABP2 exhibits anomalous behavior. CD spectroscopy revealed that the C-terminus of hNABP2 is highly disordered. Deletion of the C-terminal tail diminishes the DNA binding ability and protein stability of hNABP2. Although both hNABP1 and hNABP2 prefer to bind ssDNA than double-stranded (ds) DNA, hNABP1 has a higher affinity for ssDNA than hNABP2. Unlike hNABP2, hNABP1 protein binds and multimerizes on ssDNA with the C-terminal tail responsible for its multimerization. Both hNABP1 and hNABP2 are able to bind single-stranded RNA, with hNABP2 having a higher affinity than hNABP1. CONCLUSIONS Biochemical evidence suggests that the C-terminal region of NABP1 and NABP2 is essential for their functionality and may lead to different roles in DNA and RNA metabolism. GENERAL SIGNIFICANCE This is the first report demonstrating the regulation and functional properties of the C-terminal domain of hNABP1/2, which might be a general characteristic of OB-fold proteins.
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Affiliation(s)
- Venkatasubramanian Vidhyasagar
- Department of Biochemistry, University of Saskatchewan, Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Yujiong He
- Department of Biochemistry, University of Saskatchewan, Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Manhong Guo
- Department of Biochemistry, University of Saskatchewan, Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Hao Ding
- Department of Biochemistry, University of Saskatchewan, Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Tanu Talwar
- Department of Biochemistry, University of Saskatchewan, Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Vi Nguyen
- Department of Biochemistry, University of Saskatchewan, Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Jessica Nwosu
- Department of Biochemistry, University of Saskatchewan, Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - George Katselis
- Department of Medicine, University of Saskatchewan, Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada; Canadian Centre for Health and Safety in Agriculture, University of Saskatchewan, Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Yuliang Wu
- Department of Biochemistry, University of Saskatchewan, Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada.
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13
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Funato N, Nakamura M, Yanagisawa H. Molecular basis of cleft palates in mice. World J Biol Chem 2015; 6:121-138. [PMID: 26322171 PMCID: PMC4549757 DOI: 10.4331/wjbc.v6.i3.121] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 05/26/2015] [Accepted: 07/14/2015] [Indexed: 02/05/2023] Open
Abstract
Cleft palate, including complete or incomplete cleft palates, soft palate clefts, and submucosal cleft palates, is the most frequent congenital craniofacial anomaly in humans. Multifactorial conditions, including genetic and environmental factors, induce the formation of cleft palates. The process of palatogenesis is temporospatially regulated by transcription factors, growth factors, extracellular matrix proteins, and membranous molecules; a single ablation of these molecules can result in a cleft palate in vivo. Studies on knockout mice were reviewed in order to identify genetic errors that lead to cleft palates. In this review, we systematically describe these mutant mice and discuss the molecular mechanisms of palatogenesis.
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14
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Boucher D, Vu T, Bain AL, Tagliaro‐Jahns M, Shi W, Lane SW, Khanna KK. Ssb2/Nabp1
is dispensable for thymic maturation, male fertility, and DNA repair in mice. FASEB J 2015; 29:3326-3334. [DOI: 10.1096/fj.14-269944] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Affiliation(s)
- Didier Boucher
- Signal Transduction LaboratoryQIMR Berghofer Medical Research InstituteHerstonQueenslandAustralia
| | - Therese Vu
- Translational Leukaemia ResearchQIMR Berghofer Medical Research InstituteHerstonQueenslandAustralia
- University of QueenslandBrisbaneQueenslandAustralia
| | - Amanda L. Bain
- Signal Transduction LaboratoryQIMR Berghofer Medical Research InstituteHerstonQueenslandAustralia
| | - Marina Tagliaro‐Jahns
- Signal Transduction LaboratoryQIMR Berghofer Medical Research InstituteHerstonQueenslandAustralia
- Institut National De La Recherche AgronomiqueInstitut Jean‐Pierre BourginUnité Mixte de Recherche 1318, Équipes de Recherche Labellisées Centre National de la Recherche Scientifique 3559, Saclay Plant SciencesVersaillesFrance
| | - Wei Shi
- Signal Transduction LaboratoryQIMR Berghofer Medical Research InstituteHerstonQueenslandAustralia
| | - Steven W. Lane
- Translational Leukaemia ResearchQIMR Berghofer Medical Research InstituteHerstonQueenslandAustralia
| | - Kum Kum Khanna
- Signal Transduction LaboratoryQIMR Berghofer Medical Research InstituteHerstonQueenslandAustralia
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15
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Abstract
DNA double-strand breaks (DSBs) in cells can undergo nucleolytic degradation to generate long 3' single-stranded DNA tails. This process is termed DNA end resection, and its occurrence effectively commits to break repair via homologous recombination, which entails the acquisition of genetic information from an intact, homologous donor DNA sequence. Recent advances, prompted by the identification of the nucleases that catalyze resection, have revealed intricate layers of functional redundancy, interconnectedness, and regulation. Here, we review the current state of the field with an emphasis on the major questions that remain to be answered. Topics addressed will include how resection initiates via the introduction of an endonucleolytic incision close to the break end, the molecular mechanism of the conserved MRE11 complex in conjunction with Sae2/CtIP within such a model, the role of BRCA1 and 53BP1 in regulating resection initiation in mammalian cells, the influence of chromatin in the resection process, and potential roles of novel factors.
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Affiliation(s)
- James M Daley
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA.
| | - Hengyao Niu
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, IN 47405, USA
| | - Adam S Miller
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Patrick Sung
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA
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16
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Abstract
Genome instability is a hallmark of cancer, and DNA replication is the most vulnerable cellular process that can lead to it. Any condition leading to high levels of DNA damage will result in replication stress, which is a source of genome instability and a feature of pre-cancerous and cancerous cells. Therefore, understanding the molecular basis of replication stress is crucial to the understanding of tumorigenesis. Although a negative aspect of replication stress is its prominent role in tumorigenesis, a positive aspect is that it provides a potential target for cancer therapy. In this Review, we discuss the link between persistent replication stress and tumorigenesis, with the goal of shedding light on the mechanisms underlying the initiation of an oncogenic process, which should open up new possibilities for cancer diagnostics and treatment.
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Affiliation(s)
- Hélène Gaillard
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla, Av. Américo Vespucio s/n, Sevilla 41092, Spain
| | - Tatiana García-Muse
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla, Av. Américo Vespucio s/n, Sevilla 41092, Spain
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla, Av. Américo Vespucio s/n, Sevilla 41092, Spain
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17
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Kar A, Kaur M, Ghosh T, Khan MM, Sharma A, Shekhar R, Varshney A, Saxena S. RPA70 depletion induces hSSB1/2-INTS3 complex to initiate ATR signaling. Nucleic Acids Res 2015; 43:4962-74. [PMID: 25916848 PMCID: PMC4446429 DOI: 10.1093/nar/gkv369] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 04/08/2015] [Indexed: 01/12/2023] Open
Abstract
The primary eukaryotic single-stranded DNA-binding protein, Replication protein A (RPA), binds to single-stranded DNA at the sites of DNA damage and recruits the apical checkpoint kinase, ATR via its partner protein, ATRIP. It has been demonstrated that absence of RPA incapacitates the ATR-mediated checkpoint response. We report that in the absence of RPA, human single-stranded DNA-binding protein 1 (hSSB1) and its partner protein INTS3 form sub-nuclear foci, associate with the ATR-ATRIP complex and recruit it to the sites of genomic stress. The ATRIP foci formed after RPA depletion are abrogated in the absence of INTS3, establishing that hSSB-INTS3 complex recruits the ATR-ATRIP checkpoint complex to the sites of genomic stress. Depletion of homologs hSSB1/2 and INTS3 in RPA-deficient cells attenuates Chk1 phosphorylation, indicating that the cells are debilitated in responding to stress. We have identified that TopBP1 and the Rad9-Rad1-Hus1 complex are essential for the alternate mode of ATR activation. In summation, we report that the single-stranded DNA-binding protein complex, hSSB1/2-INTS3 can recruit the checkpoint complex to initiate ATR signaling.
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Affiliation(s)
- Ananya Kar
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Manpreet Kaur
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Tanushree Ghosh
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Md Muntaz Khan
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Aparna Sharma
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Ritu Shekhar
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Akhil Varshney
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Sandeep Saxena
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi-110067, India
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18
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Skaar JR, Ferris AL, Wu X, Saraf A, Khanna KK, Florens L, Washburn MP, Hughes SH, Pagano M. The Integrator complex controls the termination of transcription at diverse classes of gene targets. Cell Res 2015; 25:288-305. [PMID: 25675981 PMCID: PMC4349240 DOI: 10.1038/cr.2015.19] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 11/22/2014] [Accepted: 12/25/2014] [Indexed: 02/08/2023] Open
Abstract
Complexes containing INTS3 and either NABP1 or NABP2 were initially characterized in DNA damage responses, but their biochemical function remained unknown. Using affinity purifications and HIV Integration targeting-sequencing (HIT-Seq), we find that these complexes are part of the Integrator complex, which binds RNA Polymerase II and regulates specific target genes. Integrator cleaves snRNAs as part of their processing to their mature form in a mechanism that is intimately coupled with transcription termination. However, HIT-Seq reveals that Integrator also binds to the 3' end of replication-dependent histones and promoter proximal regions of genes with polyadenylated transcripts. Depletion of Integrator subunits results in transcription termination failure, disruption of histone mRNA processing, and polyadenylation of snRNAs and histone mRNAs. Furthermore, promoter proximal binding of Integrator negatively regulates expression of genes whose transcripts are normally polyadenylated. Integrator recruitment to all three gene classes is DSIF-dependent, suggesting that Integrator functions as a termination complex at DSIF-dependent RNA Polymerase II pause sites.
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Affiliation(s)
- Jeffrey R Skaar
- Department of Pathology, Laura and Isaac Perlmutter Cancer Center, New York University School of Medicine, 522 First Avenue, New York, NY 10016, USA
| | - Andrea L Ferris
- HIV Drug Resistance Program, National Cancer Institute, Frederick, MD 21702, USA
| | - Xiaolin Wu
- Cancer Research Technology Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Anita Saraf
- The Stowers Institute for Medical Research, Kansas City, MO 6411, USA
| | - Kum Kum Khanna
- QIMR Berghofer Medical Research Institute, Herston, Brisbane, Queensland 4006, Australia
| | - Laurence Florens
- The Stowers Institute for Medical Research, Kansas City, MO 6411, USA
| | - Michael P Washburn
- The Stowers Institute for Medical Research, Kansas City, MO 6411, USA
- Department of Pathology and Laboratory Medicine, The University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Stephen H Hughes
- HIV Drug Resistance Program, National Cancer Institute, Frederick, MD 21702, USA
| | - Michele Pagano
- Department of Pathology, Laura and Isaac Perlmutter Cancer Center, New York University School of Medicine, 522 First Avenue, New York, NY 10016, USA
- Howard Hughes Medical Institute, 522 First Avenue New York, NY 10016, USA
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19
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Pandita RK, Chow TT, Udayakumar D, Bain AL, Cubeddu L, Hunt CR, Shi W, Horikoshi N, Zhao Y, Wright WE, Khanna KK, Shay JW, Pandita TK. Single-strand DNA-binding protein SSB1 facilitates TERT recruitment to telomeres and maintains telomere G-overhangs. Cancer Res 2015; 75:858-69. [PMID: 25589350 DOI: 10.1158/0008-5472.can-14-2289] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Proliferating mammalian stem and cancer cells express telomerase [telomerase reverse transcriptase (TERT)] in an effort to extend chromosomal G-overhangs and maintain telomere ends. Telomerase-expressing cells also have higher levels of the single-stranded DNA-binding protein SSB1, which has a critical role in DNA double-strand break (DSB) repair. Here, we report that SSB1 binds specifically to G-strand telomeric DNA in vitro and associates with telomeres in vivo. SSB1 interacts with the TERT catalytic subunit and regulates its interaction with telomeres. Deletion of SSB1 reduces TERT interaction with telomeres and leads to G-overhang loss. Although SSB1 is recruited to DSB sites, we found no corresponding change in TERT levels at these sites, implying that SSB1-TERT interaction relies upon a specific chromatin structure or context. Our findings offer an explanation for how telomerase is recruited to telomeres to facilitate G-strand DNA extension, a critical step in maintaining telomere ends and cell viability in all cancer cells. Cancer Res; 75(5); 858-69. ©2015 AACR.
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Affiliation(s)
- Raj K Pandita
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas. Department of Radiation Oncology, The Houston Methodist Research Institute, Houston, Texas
| | - Tracy T Chow
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Durga Udayakumar
- Department of Radiation Oncology, The Houston Methodist Research Institute, Houston, Texas. Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Amanda L Bain
- QIMR Berghofer Medical Research Institute, Herston, Brisbane, Australia
| | - Liza Cubeddu
- School of Science and Health, University of Western Sydney, Sydney, Australia
| | - Clayton R Hunt
- Department of Radiation Oncology, The Houston Methodist Research Institute, Houston, Texas. Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Wei Shi
- QIMR Berghofer Medical Research Institute, Herston, Brisbane, Australia
| | - Nobuo Horikoshi
- Department of Radiation Oncology, The Houston Methodist Research Institute, Houston, Texas. Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Yong Zhao
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Woodring E Wright
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Kum Kum Khanna
- QIMR Berghofer Medical Research Institute, Herston, Brisbane, Australia
| | - Jerry W Shay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas. Center for Excellence in Genomics Medicine Research, King Abdulaziz University, Jeddah, Saudi Arabia.
| | - Tej K Pandita
- Department of Radiation Oncology, The Houston Methodist Research Institute, Houston, Texas. Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas.
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20
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Bacrot S, Doyard M, Huber C, Alibeu O, Feldhahn N, Lehalle D, Lacombe D, Marlin S, Nitschke P, Petit F, Vazquez MP, Munnich A, Cormier-Daire V. Mutations in SNRPB, encoding components of the core splicing machinery, cause cerebro-costo-mandibular syndrome. Hum Mutat 2014; 36:187-90. [PMID: 25504470 DOI: 10.1002/humu.22729] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 10/31/2014] [Indexed: 11/08/2022]
Abstract
Cerebro-costo-mandibular syndrome (CCMS) is a developmental disorder characterized by the association of Pierre Robin sequence and posterior rib defects. Exome sequencing and Sanger sequencing in five unrelated CCMS patients revealed five heterozygous variants in the small nuclear ribonucleoprotein polypeptides B and B1 (SNRPB) gene. This gene includes three transcripts, namely transcripts 1 and 2, encoding components of the core spliceosomal machinery (SmB' and SmB) and transcript 3 undergoing nonsense-mediated mRNA decay. All variants were located in the premature termination codon (PTC)-introducing alternative exon of transcript 3. Quantitative RT-PCR analysis revealed a significant increase in transcript 3 levels in leukocytes of CCMS individuals compared to controls. We conclude that CCMS is due to heterozygous mutations in SNRPB, enhancing inclusion of a SNRPB PTC-introducing alternative exon, and show that this developmental disease is caused by defects in the splicing machinery. Our finding confirms the report of SNRPB mutations in CCMS patients by Lynch et al. (2014) and further extends the clinical and molecular observations.
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Affiliation(s)
- Séverine Bacrot
- Department of Genetics, INSERM U1163, Université Paris Descartes - Sorbonne Paris Cité, Institut Imagine, Hôpital Necker-Enfants Malades (AP-HP), Paris, France
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21
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Raymann K, Forterre P, Brochier-Armanet C, Gribaldo S. Global phylogenomic analysis disentangles the complex evolutionary history of DNA replication in archaea. Genome Biol Evol 2014; 6:192-212. [PMID: 24398374 PMCID: PMC3914693 DOI: 10.1093/gbe/evu004] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The archaeal machinery responsible for DNA replication is largely homologous to that of eukaryotes and is clearly distinct from its bacterial counterpart. Moreover, it shows high diversity in the various archaeal lineages, including different sets of components, heterogeneous taxonomic distribution, and a large number of additional copies that are sometimes highly divergent. This has made the evolutionary history of this cellular system particularly challenging to dissect. Here, we have carried out an exhaustive identification of homologs of all major replication components in over 140 complete archaeal genomes. Phylogenomic analysis allowed assigning them to either a conserved and probably essential core of replication components that were mainly vertically inherited, or to a variable and highly divergent shell of extra copies that have likely arisen from integrative elements. This suggests that replication proteins are frequently exchanged between extrachromosomal elements and cellular genomes. Our study allowed clarifying the history that shaped this key cellular process (ancestral components, horizontal gene transfers, and gene losses), providing important evolutionary and functional information. Finally, our precise identification of core components permitted to show that the phylogenetic signal carried by DNA replication is highly consistent with that harbored by two other key informational machineries (translation and transcription), strengthening the existence of a robust organismal tree for the Archaea.
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Affiliation(s)
- Kasie Raymann
- Département de Microbiologie, Institut Pasteur, Unité Biologie Moléculaire du Gene chez les Extrêmophiles, Paris, France
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22
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Bolderson E, Petermann E, Croft L, Suraweera A, Pandita RK, Pandita TK, Helleday T, Khanna KK, Richard DJ. Human single-stranded DNA binding protein 1 (hSSB1/NABP2) is required for the stability and repair of stalled replication forks. Nucleic Acids Res 2014; 42:6326-36. [PMID: 24753408 PMCID: PMC4041449 DOI: 10.1093/nar/gku276] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Aberrant DNA replication is a primary cause of mutations that are associated with pathological disorders including cancer. During DNA metabolism, the primary causes of replication fork stalling include secondary DNA structures, highly transcribed regions and damaged DNA. The restart of stalled replication forks is critical for the timely progression of the cell cycle and ultimately for the maintenance of genomic stability. Our previous work has implicated the single-stranded DNA binding protein, hSSB1/NABP2, in the repair of DNA double-strand breaks via homologous recombination. Here, we demonstrate that hSSB1 relocates to hydroxyurea (HU)-damaged replication forks where it is required for ATR and Chk1 activation and recruitment of Mre11 and Rad51. Consequently, hSSB1-depleted cells fail to repair and restart stalled replication forks. hSSB1 deficiency causes accumulation of DNA strand breaks and results in chromosome aberrations observed in mitosis, ultimately resulting in hSSB1 being required for survival to HU and camptothecin. Overall, our findings demonstrate the importance of hSSB1 in maintaining and repairing DNA replication forks and for overall genomic stability.
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Affiliation(s)
- Emma Bolderson
- Genome Stability Laboratory, Cancer and Ageing Research Program, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Woolloongabba, Queensland, 4102, Australia
| | - Eva Petermann
- School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Laura Croft
- Genome Stability Laboratory, Cancer and Ageing Research Program, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Woolloongabba, Queensland, 4102, Australia
| | - Amila Suraweera
- Genome Stability Laboratory, Cancer and Ageing Research Program, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Woolloongabba, Queensland, 4102, Australia
| | - Raj K Pandita
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Tej K Pandita
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Thomas Helleday
- Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, S-171 21 Stockholm, Sweden
| | - Kum Kum Khanna
- Signal Transduction Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Queensland 4029, Australia
| | - Derek J Richard
- Genome Stability Laboratory, Cancer and Ageing Research Program, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Woolloongabba, Queensland, 4102, Australia
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23
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Baudat F, Imai Y, de Massy B. Meiotic recombination in mammals: localization and regulation. Nat Rev Genet 2013; 14:794-806. [PMID: 24136506 DOI: 10.1038/nrg3573] [Citation(s) in RCA: 390] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
During meiosis, a programmed induction of DNA double-strand breaks (DSBs) leads to the exchange of genetic material between homologous chromosomes. These exchanges increase genome diversity and are essential for proper chromosome segregation at the first meiotic division. Recent findings have highlighted an unexpected molecular control of the distribution of meiotic DSBs in mammals by a rapidly evolving gene, PR domain-containing 9 (PRDM9), and genome-wide analyses have facilitated the characterization of meiotic DSB sites at unprecedented resolution. In addition, the identification of new players in DSB repair processes has allowed the delineation of recombination pathways that have two major outcomes, crossovers and non-crossovers, which have distinct mechanistic roles and consequences for genome evolution.
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Affiliation(s)
- Frédéric Baudat
- Institute of Human Genetics, Unité Propre de Recherche 1142, Centre National de la Recherche Scientifique, 141 rue de la Cardonille, 34396 Montpellier, France
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24
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Baumann M, Bodis S, Dikomey E, van der Kogel A, Overgaard J, Rodemann HP, Wouters B. Molecular radiation biology/oncology at its best: Cutting edge research presented at the 13th International Wolfsberg Meeting on Molecular Radiation Biology/Oncology. Radiother Oncol 2013; 108:357-61. [DOI: 10.1016/j.radonc.2013.10.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 10/02/2013] [Indexed: 10/26/2022]
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25
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Abstract
Three recently published reports, including one in Cell Research, generated Ssb1 knockout mice and demonstrated critical roles of this protein in regulating skeletogenesis, telomere homeostasis and tumor suppression.
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Affiliation(s)
- Amanda L Bain
- Queensland Institute of Medical Research, Herston, Australia
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26
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Ashton NW, Bolderson E, Cubeddu L, O'Byrne KJ, Richard DJ. Human single-stranded DNA binding proteins are essential for maintaining genomic stability. BMC Mol Biol 2013; 14:9. [PMID: 23548139 PMCID: PMC3626794 DOI: 10.1186/1471-2199-14-9] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 03/20/2013] [Indexed: 12/25/2022] Open
Abstract
The double-stranded conformation of cellular DNA is a central aspect of DNA stabilisation and protection. The helix preserves the genetic code against chemical and enzymatic degradation, metabolic activation, and formation of secondary structures. However, there are various instances where single-stranded DNA is exposed, such as during replication or transcription, in the synthesis of chromosome ends, and following DNA damage. In these instances, single-stranded DNA binding proteins are essential for the sequestration and processing of single-stranded DNA. In order to bind single-stranded DNA, these proteins utilise a characteristic and evolutionary conserved single-stranded DNA-binding domain, the oligonucleotide/oligosaccharide-binding (OB)-fold. In the current review we discuss a subset of these proteins involved in the direct maintenance of genomic stability, an important cellular process in the conservation of cellular viability and prevention of malignant transformation. We discuss the central roles of single-stranded DNA binding proteins from the OB-fold domain family in DNA replication, the restart of stalled replication forks, DNA damage repair, cell cycle-checkpoint activation, and telomere maintenance.
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Affiliation(s)
- Nicholas W Ashton
- Genome Stability Laboratory, Cancer and Ageing Research Program, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Woolloongabba, Queensland, 4102, Australia
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