1
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Gall-Duncan T, Luo J, Jurkovic CM, Fischer LA, Fujita K, Deshmukh AL, Harding RJ, Tran S, Mehkary M, Li V, Leib DE, Chen R, Tanaka H, Mason AG, Lévesque D, Khan M, Razzaghi M, Prasolava T, Lanni S, Sato N, Caron MC, Panigrahi GB, Wang P, Lau R, Castel AL, Masson JY, Tippett L, Turner C, Spies M, La Spada AR, Campos EI, Curtis MA, Boisvert FM, Faull RLM, Davidson BL, Nakamori M, Okazawa H, Wold MS, Pearson CE. Antagonistic roles of canonical and Alternative-RPA in disease-associated tandem CAG repeat instability. Cell 2023; 186:4898-4919.e25. [PMID: 37827155 PMCID: PMC11209935 DOI: 10.1016/j.cell.2023.09.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 06/30/2023] [Accepted: 09/09/2023] [Indexed: 10/14/2023]
Abstract
Expansions of repeat DNA tracts cause >70 diseases, and ongoing expansions in brains exacerbate disease. During expansion mutations, single-stranded DNAs (ssDNAs) form slipped-DNAs. We find the ssDNA-binding complexes canonical replication protein A (RPA1, RPA2, and RPA3) and Alternative-RPA (RPA1, RPA3, and primate-specific RPA4) are upregulated in Huntington disease and spinocerebellar ataxia type 1 (SCA1) patient brains. Protein interactomes of RPA and Alt-RPA reveal unique and shared partners, including modifiers of CAG instability and disease presentation. RPA enhances in vitro melting, FAN1 excision, and repair of slipped-CAGs and protects against CAG expansions in human cells. RPA overexpression in SCA1 mouse brains ablates expansions, coincident with decreased ATXN1 aggregation, reduced brain DNA damage, improved neuron morphology, and rescued motor phenotypes. In contrast, Alt-RPA inhibits melting, FAN1 excision, and repair of slipped-CAGs and promotes CAG expansions. These findings suggest a functional interplay between the two RPAs where Alt-RPA may antagonistically offset RPA's suppression of disease-associated repeat expansions, which may extend to other DNA processes.
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Affiliation(s)
- Terence Gall-Duncan
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada; Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Jennifer Luo
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada; Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | | | - Laura A Fischer
- Developmental Biology and Center of Regenerative Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Kyota Fujita
- Neuropathology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Amit L Deshmukh
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Rachel J Harding
- Structural Genomics Consortium, University of Toronto, Toronto, ON M5G 1L7, Canada; Pharmacology and Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Stephanie Tran
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada; Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Mustafa Mehkary
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada; Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Vanessa Li
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada; Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - David E Leib
- Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19146, USA
| | - Ran Chen
- Pediatrics, Division of Hematology and Oncology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Hikari Tanaka
- Neuropathology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Amanda G Mason
- Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | - Dominique Lévesque
- Immunology and Cell Biology, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Mahreen Khan
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada; Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Mortezaali Razzaghi
- Biochemistry and Molecular Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Tanya Prasolava
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Stella Lanni
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Nozomu Sato
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Marie-Christine Caron
- CHU de Québec-Université Laval, Oncology Division, Molecular Biology, Medical Biochemistry, and Pathology, Laval University Cancer Research Center, Québec, QC, Canada
| | - Gagan B Panigrahi
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Peixiang Wang
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Rachel Lau
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | | | - Jean-Yves Masson
- CHU de Québec-Université Laval, Oncology Division, Molecular Biology, Medical Biochemistry, and Pathology, Laval University Cancer Research Center, Québec, QC, Canada
| | - Lynette Tippett
- School of Psychology, University of Auckland, Auckland, New Zealand; University Research Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Clinton Turner
- Anatomical Pathology, LabPlus, Auckland City Hospital, Auckland, New Zealand
| | - Maria Spies
- Biochemistry and Molecular Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Albert R La Spada
- Pathology & Laboratory Medicine, Neurology, and Biological Chemistry, University of California, Irvine School of Medicine, Irvine, CA, USA; Neurobiology & Behavior, University of California, Irvine, Irvine, CA, USA; Center for Neurotherapeutics, University of California, Irvine, Irvine, CA 92697, USA
| | - Eric I Campos
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada; Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Maurice A Curtis
- University Research Centre for Brain Research, University of Auckland, Auckland, New Zealand; Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
| | | | - Richard L M Faull
- University Research Centre for Brain Research, University of Auckland, Auckland, New Zealand; Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
| | - Beverly L Davidson
- Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19146, USA
| | - Masayuki Nakamori
- Neurology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Hitoshi Okazawa
- Neuropathology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Marc S Wold
- Biochemistry and Molecular Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Christopher E Pearson
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada; Structural Genomics Consortium, University of Toronto, Toronto, ON M5G 1L7, Canada.
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2
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Biber S, Pospiech H, Gottifredi V, Wiesmüller L. Multiple biochemical properties of the p53 molecule contribute to activation of polymerase iota-dependent DNA damage tolerance. Nucleic Acids Res 2020; 48:12188-12203. [PMID: 33166398 PMCID: PMC7708082 DOI: 10.1093/nar/gkaa974] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 10/05/2020] [Accepted: 10/09/2020] [Indexed: 11/29/2022] Open
Abstract
We have previously reported that p53 decelerates nascent DNA elongation in complex with the translesion synthesis (TLS) polymerase ι (POLι) which triggers a homology-directed DNA damage tolerance (DDT) pathway to bypass obstacles during DNA replication. Here, we demonstrate that this DDT pathway relies on multiple p53 activities, which can be disrupted by TP53 mutations including those frequently found in cancer tissues. We show that the p53-mediated DDT pathway depends on its oligomerization domain (OD), while its regulatory C-terminus is not involved. Mutation of residues S315 and D48/D49, which abrogate p53 interactions with the DNA repair and replication proteins topoisomerase I and RPA, respectively, and residues L22/W23, which disrupt formation of p53-POLι complexes, all prevent this DDT pathway. Our results demonstrate that the p53-mediated DDT requires the formation of a DNA binding-proficient p53 tetramer, recruitment of such tetramer to RPA-coated forks and p53 complex formation with POLι. Importantly, our mutational analysis demonstrates that transcriptional transactivation is dispensable for the POLι-mediated DDT pathway, which we show protects against DNA replication damage from endogenous and exogenous sources.
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Affiliation(s)
- Stephanie Biber
- Department of Obstetrics and Gynecology, Ulm University, Ulm 89075, Germany
| | - Helmut Pospiech
- Project group Biochemistry, Leibniz Institute on Aging - Fritz Lipmann Institute, D-07745 Jena, Germany.,Faculty of Biochemistry and Molecular Medicine, FIN-90014 University of Oulu, Finland
| | - Vanesa Gottifredi
- Cell Cycle and Genomic Stability Laboratory, Fundación Instituto Leloir, Buenos Aires C1405BWE, Argentina
| | - Lisa Wiesmüller
- Department of Obstetrics and Gynecology, Ulm University, Ulm 89075, Germany
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3
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Caldwell CC, Spies M. Dynamic elements of replication protein A at the crossroads of DNA replication, recombination, and repair. Crit Rev Biochem Mol Biol 2020; 55:482-507. [PMID: 32856505 PMCID: PMC7821911 DOI: 10.1080/10409238.2020.1813070] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 08/18/2020] [Accepted: 08/18/2020] [Indexed: 01/19/2023]
Abstract
The heterotrimeric eukaryotic Replication protein A (RPA) is a master regulator of numerous DNA metabolic processes. For a long time, it has been viewed as an inert protector of ssDNA and a platform for assembly of various genome maintenance and signaling machines. Later, the modular organization of the RPA DNA binding domains suggested a possibility for dynamic interaction with ssDNA. This modular organization has inspired several models for the RPA-ssDNA interaction that aimed to explain how RPA, the high-affinity ssDNA binding protein, is replaced by the downstream players in DNA replication, recombination, and repair that bind ssDNA with much lower affinity. Recent studies, and in particular single-molecule observations of RPA-ssDNA interactions, led to the development of a new model for the ssDNA handoff from RPA to a specific downstream factor where not only stability and structural rearrangements but also RPA conformational dynamics guide the ssDNA handoff. Here we will review the current knowledge of the RPA structure, its dynamic interaction with ssDNA, and how RPA conformational dynamics may be influenced by posttranslational modification and proteins that interact with RPA, as well as how RPA dynamics may be harnessed in cellular decision making.
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Affiliation(s)
- Colleen C. Caldwell
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242
| | - Maria Spies
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242
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4
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Hedglin M, Aitha M, Pedley A, Benkovic SJ. Replication protein A dynamically regulates monoubiquitination of proliferating cell nuclear antigen. J Biol Chem 2019; 294:5157-5168. [PMID: 30700555 DOI: 10.1074/jbc.ra118.005297] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 01/17/2019] [Indexed: 11/06/2022] Open
Abstract
DNA damage tolerance permits bypass of DNA lesions encountered during S-phase and may be carried out by translesion DNA synthesis (TLS). Human TLS requires selective monoubiquitination of proliferating cell nuclear antigen (PCNA) sliding clamps encircling damaged DNA. This posttranslational modification (PTM) is catalyzed by Rad6/Rad18. Recent studies revealed that replication protein A (RPA), the major ssDNA-binding protein, is involved in the regulation of PCNA monoubiquitination and interacts directly with Rad18 on chromatin and in the nucleoplasm. However, it is unclear how RPA regulates this critical PTM and what functional role(s) these interactions serve. Here, we developed an in vitro assay to quantitatively monitor PCNA monoubiquitination under in vivo scenarios. Results from extensive experiments revealed that RPA regulates Rad6/Rad18 activity in an ssDNA-dependent manner. We found that "DNA-free" RPA inhibits monoubiquitination of free PCNA by directly interacting with Rad18. This interaction is promoted under native conditions when there is an overabundance of free RPA in the nucleoplasm where Rad6/Rad18 and a significant fraction of PCNA reside. During DNA replication stress, RPA binds the ssDNA exposed downstream of stalled primer/template (P/T) junctions, releasing Rad6/Rad18. RPA restricted the resident PCNAs to the upstream duplex regions by physically blocking diffusion of PCNA along ssDNA, and this activity was required for efficient monoubiquitination of PCNA on DNA. Furthermore, upon binding ssDNA, RPA underwent a conformational change that increased its affinity for Rad18. Rad6/Rad18 complexed with ssDNA-bound RPA was active, and this interaction may selectively promote monoubiquitination of PCNA on long RPA-coated ssDNA.
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Affiliation(s)
- Mark Hedglin
- From the Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Mahesh Aitha
- From the Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Anthony Pedley
- From the Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Stephen J Benkovic
- From the Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
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5
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The silencing of replication protein A1 induced cell apoptosis via regulating Caspase 3. Life Sci 2018; 201:141-149. [DOI: 10.1016/j.lfs.2018.03.054] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 03/23/2018] [Accepted: 03/26/2018] [Indexed: 01/15/2023]
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6
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Glanzer JG, Carnes KA, Soto P, Liu S, Parkhurst LJ, Oakley GG. A small molecule directly inhibits the p53 transactivation domain from binding to replication protein A. Nucleic Acids Res 2012; 41:2047-59. [PMID: 23267009 PMCID: PMC3561959 DOI: 10.1093/nar/gks1291] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Replication protein A (RPA), essential for DNA replication, repair and DNA damage signalling, possesses six ssDNA-binding domains (DBDs), including DBD-F on the N-terminus of the largest subunit, RPA70. This domain functions as a binding site for p53 and other DNA damage and repair proteins that contain amphipathic alpha helical domains. Here, we demonstrate direct binding of both ssDNA and the transactivation domain 2 of p53 (p53TAD2) to DBD-F, as well as DBD-F-directed dsDNA strand separation by RPA, all of which are inhibited by fumaropimaric acid (FPA). FPA binds directly to RPA, resulting in a conformational shift as determined through quenching of intrinsic tryptophan fluorescence in full length RPA. Structural analogues of FPA provide insight on chemical properties that are required for inhibition. Finally, we confirm the inability of RPA possessing R41E and R43E mutations to bind to p53, destabilize dsDNA and quench tryptophan fluorescence by FPA, suggesting that protein binding, DNA modulation and inhibitor binding all occur within the same site on DBD-F. The disruption of p53–RPA interactions by FPA may disturb the regulatory functions of p53 and RPA, thereby inhibiting cellular pathways that control the cell cycle and maintain the integrity of the human genome.
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Affiliation(s)
- Jason G Glanzer
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, NE 68583, USA
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7
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Replication-mediated disassociation of replication protein A-XPA complex upon DNA damage: implications for RPA handing off. Cell Biol Int 2012; 36:713-20. [PMID: 22578086 DOI: 10.1042/cbi20110633] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
RPA (replication protein A), the eukaryotic ssDNA (single-stranded DNA)-binding protein, participates in most cellular processes in response to genotoxic insults, such as NER (nucleotide excision repair), DNA, DSB (double-strand break) repair and activation of cell cycle checkpoint signalling. RPA interacts with XPA (xeroderma pigmentosum A) and functions in early stage of NER. We have shown that in cells the RPA-XPA complex disassociated upon exposure of cells to high dose of UV irradiation. The dissociation required replication stress and was partially attributed to tRPA hyperphosphorylation. Treatment of cells with CPT (camptothecin) and HU (hydroxyurea), which cause DSB DNA damage and replication fork collapse respectively and also leads to the disruption of RPA-XPA complex. Purified RPA and XPA were unable to form complex in vitro in the presence of ssDNA. We propose that the competition-based RPA switch among different DNA metabolic pathways regulates the dissociation of RPA with XPA in cells after DNA damage. The biological significances of RPA-XPA complex disruption in relation with checkpoint activation, DSB repair and RPA hyperphosphorylation are discussed.
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8
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Serrano MA, Li Z, Dangeti M, Musich PR, Patrick S, Roginskaya M, Cartwright B, Zou Y. DNA-PK, ATM and ATR collaboratively regulate p53-RPA interaction to facilitate homologous recombination DNA repair. Oncogene 2012; 32:2452-62. [PMID: 22797063 PMCID: PMC3651755 DOI: 10.1038/onc.2012.257] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Homologous recombination (HR) and nonhomologous end-joining (NHEJ) are two distinct DNA double-strand break (DSB) repair pathways. Here we report that DNA-dependent protein kinase (DNA-PK), the core component of NHEJ, partnering with DNA-damage checkpoint kinases ataxia telangiectasia mutated (ATM) and ATM- and Rad3-related (ATR), regulates HR repair of DSBs. The regulation was accomplished through modulation of the p53 and replication protein A (RPA) interaction. We show that upon DNA damage, p53 and RPA were freed from a p53-RPA complex by simultaneous phosphorylations of RPA at the N-terminus of RPA32 subunit by DNA-PK and of p53 at Ser37 and Ser46 in a Chk1/Chk2-independent manner by ATR and ATM, respectively. Neither the phosphorylation of RPA nor of p53 alone could dissociate p53 and RPA. Furthermore, disruption of the release significantly compromised HR repair of DSBs. Our results reveal a mechanism for the crosstalk between HR repair and NHEJ through the co-regulation of p53-RPA interaction by DNA-PK, ATM and ATR.
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Affiliation(s)
- M A Serrano
- Department of Biochemistry and Molecular Biology, JH Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, USA
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9
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Ezeokonkwo C, Zhelkovsky A, Lee R, Bohm A, Moore CL. A flexible linker region in Fip1 is needed for efficient mRNA polyadenylation. RNA (NEW YORK, N.Y.) 2011; 17:652-664. [PMID: 21282348 PMCID: PMC3062176 DOI: 10.1261/rna.2273111] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Accepted: 12/21/2010] [Indexed: 05/30/2023]
Abstract
Synthesis of the poly(A) tail of mRNA in Saccharomyces cerevisiae requires recruitment of the polymerase Pap1 to the 3' end of cleaved pre-mRNA. This is made possible by the tethering of Pap1 to the Cleavage/Polyadenylation Factor (CPF) by Fip1. We have recently reported that Fip1 is an unstructured protein in solution, and proposed that it might maintain this conformation as part of CPF, when bound to Pap1. However, the role that this feature of Fip1 plays in 3' end processing has not been investigated. We show here that Fip1 has a flexible linker in the middle of the protein, and that removal or replacement of the linker affects the efficiency of polyadenylation. However, the point of tethering is not crucial, as a fusion protein of Pap1 and Fip1 is fully functional in cells lacking genes encoding the essential individual proteins, and directly tethering Pap1 to RNA increases the rate of poly(A) addition. We also find that the linker region of Fip1 provides a platform for critical interactions with other parts of the processing machinery. Our results indicate that the Fip1 linker, through its flexibility and protein/protein interactions, allows Pap1 to reach the 3' end of the cleaved RNA and efficiently initiate poly(A) addition.
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Affiliation(s)
- Chukwudi Ezeokonkwo
- Department of Biochemistry, Tufts University School of Medicine and the Sackler Graduate School of Biomedical Sciences, Boston, Massachusetts 02111, USA
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10
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Shlomai J. Redox control of protein-DNA interactions: from molecular mechanisms to significance in signal transduction, gene expression, and DNA replication. Antioxid Redox Signal 2010; 13:1429-76. [PMID: 20446770 DOI: 10.1089/ars.2009.3029] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Protein-DNA interactions play a key role in the regulation of major cellular metabolic pathways, including gene expression, genome replication, and genomic stability. They are mediated through the interactions of regulatory proteins with their specific DNA-binding sites at promoters, enhancers, and replication origins in the genome. Redox signaling regulates these protein-DNA interactions using reactive oxygen species and reactive nitrogen species that interact with cysteine residues at target proteins and their regulators. This review describes the redox-mediated regulation of several master regulators of gene expression that control the induction and suppression of hundreds of genes in the genome, regulating multiple metabolic pathways, which are involved in cell growth, development, differentiation, and survival, as well as in the function of the immune system and cellular response to intracellular and extracellular stimuli. It also discusses the role of redox signaling in protein-DNA interactions that regulate DNA replication. Specificity of redox regulation is discussed, as well as the mechanisms providing several levels of redox-mediated regulation, from direct control of DNA-binding domains through the indirect control, mediated by release of negative regulators, regulation of redox-sensitive protein kinases, intracellular trafficking, and chromatin remodeling.
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Affiliation(s)
- Joseph Shlomai
- Department of Microbiology and Molecular Genetics, The Kuvin Center for the Study of Tropical and Infectious Diseases, Institute for Medical Research Canada-Israel, The Hebrew University-Hadassah Medical School, Jerusalem, Israel.
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11
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Sakaguchi K, Ishibashi T, Uchiyama Y, Iwabata K. The multi-replication protein A (RPA) system--a new perspective. FEBS J 2009; 276:943-63. [PMID: 19154342 DOI: 10.1111/j.1742-4658.2008.06841.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Replication protein A (RPA) complex has been shown, using both in vivo and in vitro approaches, to be required for most aspects of eukaryotic DNA metabolism: replication, repair, telomere maintenance and homologous recombination. Here, we review recent data concerning the function and biological importance of the multi-RPA complex. There are distinct complexes of RPA found in the biological kingdoms, although for a long time only one type of RPA complex was believed to be present in eukaryotes. Each complex probably serves a different role. In higher plants, three distinct large and medium subunits are present, but only one species of the smallest subunit. Each of these protein subunits forms stable complexes with their respective partners. They are paralogs as complex. Humans possess two paralogs and one analog of RPA. The multi-RPA system can be regarded as universal in eukaryotes. Among eukaryotic kingdoms, paralogs, orthologs, analogs and heterologs of many DNA synthesis-related factors, including RPA, are ubiquitous. Convergent evolution seems to be ubiquitous in these processes. Using recent findings, we review the composition and biological functions of RPA complexes.
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Affiliation(s)
- Kengo Sakaguchi
- Department of Applied Biological Science, Tokyo University of Science, Chiba, Japan.
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12
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Abstract
Convergent studies demonstrated that p53 regulates homologous recombination (HR) independently of its classic tumour-suppressor functions in transcriptionally transactivating cellular target genes that are implicated in growth control and apoptosis. In this review, we summarise the analyses of the involvement of p53 in spontaneous and double-strand break (DSB)-triggered HR and in alternative DSB repair routes. Molecular characterisation indicated that p53 controls the fidelity of Rad51-dependent HR and represses aberrant processing of replication forks after stalling at unrepaired DNA lesions. These findings established a genome stabilising role of p53 in counteracting error-prone DSB repair. However, recent work has also unveiled a stimulatory role for p53 in topoisomerase I-induced recombinative repair events that may have implications for a gain-of-function phenotype of cancer-related p53 mutants. Additional evidence will be discussed which suggests that p53 and/or p53-regulated gene products also contribute to nucleotide excision, base excision, and mismatch repair.
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Affiliation(s)
- S A Gatz
- Universitätsklinik für Kinder- und Jugendmedizin, Eythstr. 24, 89075 Ulm, Germany
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13
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Givalos N, Gakiopoulou H, Skliri M, Bousboukea K, Konstantinidou AE, Korkolopoulou P, Lelouda M, Kouraklis G, Patsouris E, Karatzas G. Replication protein A is an independent prognostic indicator with potential therapeutic implications in colon cancer. Mod Pathol 2007; 20:159-66. [PMID: 17361204 DOI: 10.1038/modpathol.3800719] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Replication protein A (RPA), a component of the origin recognition complex, is required for stabilization of single-stranded DNA at early and later stages of DNA replication being thus critical for eukaryotic DNA replication. Experimental studies in colon cancer cell lines have shown that RPA protein may be the target of cytotoxins designed to inhibit cellular proliferation. This is the first study to investigate the expression of RPA1 and RPA2 subunits of RPA protein and assess their prognostic value in colon cancer patients. We analyzed immunohistochemically the expression of RPA1 and RPA2 proteins in a series of 130 colon cancer resection specimens in relation to conventional clinicopathological parameters and patients' survival. Statistical significant positive associations emerged between: (a) RPA1 and RPA2 protein expressions (P=0.0001), (b) RPA1 and RPA2 labelling indices (LIs) and advanced stage of the disease (P=0.001 and 0.003, respectively), (c) RPA1 and RPA2 LIs and the presence of lymph node metastasis (P=0.002 and 0.004, respectively), (d) RPA1 LI and the number of infiltrated lymph nodes (P=0.021), (e) RPA2 LI and histological grade of carcinomas (P=0.05). Moreover, a statistical significant higher RPA1 LI was observed in the metastatic sites compared to the original ones (P=0.012). RPA1 and RPA2 protein expression associated with adverse patients' outcome in both univariate (log rank test: P<0.00001 and 0.00001, respectively) and multivariate (Cox model: P=0.092 and 0.0001, respectively) statistical analysis. Statistical significant differences according to the expression of RPA1 and RPA2 proteins were also noticed in the survival of stage II (P<0.00001 and 0.0016, respectively) and stage III (P=0.0029 and 0.0079, respectively) patients. In conclusion, RPA1 and RPA2 proteins appear to be useful prognostic indicators in colon cancer patients and attractive therapeutic targets for regulation by tumor suppressors or other proteins involved in the control of cell proliferation.
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Affiliation(s)
- Nikolaos Givalos
- Department of Surgery, Medical School, National Kapodistrian University of Athens, Athens, Greece.
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14
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Kumaran S, Kozlov AG, Lohman TM. Saccharomyces cerevisiae replication protein A binds to single-stranded DNA in multiple salt-dependent modes. Biochemistry 2006; 45:11958-73. [PMID: 17002295 PMCID: PMC2516750 DOI: 10.1021/bi060994r] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have examined the single-stranded DNA (ssDNA) binding properties of the Saccharomyces cerevisiae replication protein A (scRPA) using fluorescence titrations, isothermal titration calorimetry, and sedimentation equilibrium to determine whether scRPA can bind to ssDNA in multiple binding modes. We measured the occluded site size for scRPA binding poly(dT), as well as the stoichiometry, equilibrium binding constants, and binding enthalpy of scRPA-(dT)L complexes as a function of the oligodeoxynucleotide length, L. Sedimentation equilibrium studies show that scRPA is a stable heterotrimer over the range of [NaCl] examined (0.02-1.5 M). However, the occluded site size, n, undergoes a salt-dependent transition between values of n = 18-20 nucleotides at low [NaCl] and values of n = 26-28 nucleotides at high [NaCl], with a transition midpoint near 0.36 M NaCl (25.0 degrees C, pH 8.1). Measurements of the stoichiometry of scRPA-(dT)L complexes also show a [NaCl]-dependent change in stoichiometry consistent with the observed change in the occluded site size. Measurements of the deltaH(obsd) for scRPA binding to (dT)L at 1.5 M NaCl yield a contact site size of 28 nucleotides, similar to the occluded site size determined at this [NaCl]. Altogether, these data support a model in which scRPA can bind to ssDNA in at least two binding modes, a low site size mode (n = 18 +/- 1 nucleotides), stabilized at low [NaCl], in which only three of its oligonucleotide/oligosaccharide binding folds (OB-folds) are used, and a higher site size mode (n = 27 +/- 1 nucleotides), stabilized at higher [NaCl], which uses four of its OB-folds. No evidence for highly cooperative binding of scRPA to ssDNA was found under any conditions examined. Thus, scRPA shows some behavior similar to that of the E. coli SSB homotetramer, which also shows binding mode transitions, but some significant differences also exist.
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Affiliation(s)
| | | | - Timothy M. Lohman
- Address correspondence to: Department of Biochemistry and Molecular Biophysics, Box 8231 Washington University School of Medicine 660 South Euclid Ave. St. Louis, M0 63110 E-mail: Tel: (314)-362−4393 FAX: (314)-362−7183
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15
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Bochkareva E, Kaustov L, Ayed A, Yi GS, Lu Y, Pineda-Lucena A, Liao JCC, Okorokov AL, Milner J, Arrowsmith CH, Bochkarev A. Single-stranded DNA mimicry in the p53 transactivation domain interaction with replication protein A. Proc Natl Acad Sci U S A 2005; 102:15412-7. [PMID: 16234232 PMCID: PMC1266094 DOI: 10.1073/pnas.0504614102] [Citation(s) in RCA: 233] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2005] [Accepted: 09/08/2005] [Indexed: 12/30/2022] Open
Abstract
One of many protein-protein interactions modulated upon DNA damage is that of the single-stranded DNA-binding protein, replication protein A (RPA), with the p53 tumor suppressor. Here we report the crystal structure of RPA residues 1-120 (RPA70N) bound to the N-terminal transactivation domain of p53 (residues 37-57; p53N) and, by using NMR spectroscopy, characterize two mechanisms by which the RPA/p53 interaction can be modulated. RPA70N forms an oligonucleotide/oligosaccharide-binding fold, similar to that previously observed for the ssDNA-binding domains of RPA. In contrast, the N-terminal p53 transactivation domain is largely disordered in solution, but residues 37-57 fold into two amphipathic helices, H1 and H2, upon binding with RPA70N. The H2 helix of p53 structurally mimics the binding of ssDNA to the oligonucleotide/oligosaccharide-binding fold. NMR experiments confirmed that both ssDNA and an acidic peptide mimicking a phosphorylated form of RPA32N can independently compete the acidic p53N out of the binding site. Taken together, our data suggest a mechanism for DNA damage signaling that can explain a threshold response to DNA damage.
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Affiliation(s)
- Elena Bochkareva
- Banting and Best Department of Medical Research & Department of Medical Genetics and Microbiology, University of Toronto, 112 College Street, Toronto, Ontario, Canada M5G 1L6
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16
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Vise PD, Baral B, Latos AJ, Daughdrill GW. NMR chemical shift and relaxation measurements provide evidence for the coupled folding and binding of the p53 transactivation domain. Nucleic Acids Res 2005; 33:2061-77. [PMID: 15824059 PMCID: PMC1075921 DOI: 10.1093/nar/gki336] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2005] [Revised: 03/16/2005] [Accepted: 03/16/2005] [Indexed: 01/10/2023] Open
Abstract
The interaction between the acidic transactivation domain of the human tumor suppressor protein p53 (p53TAD) and the 70 kDa subunit of human replication protein A (hRPA70) was investigated using heteronuclear magnetic resonance spectroscopy. A 1H-15N heteronuclear single quantum coherence (HSQC) titration experiment was performed on a 15N-labeled fragment of hRPA70, containing the N-terminal 168 residues (hRPA701-168) and p53TAD. HRPA701-168 residues important for binding were identified and found to be localized to a prominent basic cleft. This binding site overlapped with a previously identified single-stranded DNA-binding site, suggesting that a competitive binding mechanism may regulate the formation of p53TAD-hRPA70 complex. The amide 1H and 15N chemical shifts of an uniformly 15N-labeled sample of p53TAD were also monitored before and after the addition of unlabeled hRPA701-168. In the presence of unlabeled hRPA701-168, resonance lineshapes increased and corresponding intensity reductions were observed for specific p53TAD residues. The largest intensity reductions were observed for p53TAD residues 42-56. Minimal binding was observed between p53TAD and a mutant form of hRPA701-168, where the basic cleft residue R41 was changed to a glutamic acid (R41E), demonstrating that ionic interactions play an important role in specifying the binding interface. The region of p53TAD most affected by binding hRPA701-168 was found to have some residual alpha helical and beta strand structure; however, this structure was not stabilized by binding hRPA701-168. 15N relaxation experiments were performed to monitor changes in backbone dynamics of p53TAD when bound to hRPA701-168. Large changes in both the transverse (R2) and rotating frame (R1) relaxation rates were observed for a subset of the p53TAD residues that had 1H-15N HSQC resonance intensity reductions during the complex formation. The folding of p53TAD upon complex formation is suggested by the pattern of changes observed for both R2 and R1. A model that couples the formation of a weak encounter complex between p53TAD and hRPA701-168 to the folding of p53TAD is discussed in the context of a functional role for the p53-hRPA70 complex in DNA repair.
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Affiliation(s)
- Pamela D. Vise
- Department of Microbiology, Molecular Biology and Biochemistry, University of IdahoPO Box 443052, Life Science South Room 142, Moscow 83844-3052, Idaho
| | - Bharat Baral
- Department of Microbiology, Molecular Biology and Biochemistry, University of IdahoPO Box 443052, Life Science South Room 142, Moscow 83844-3052, Idaho
| | - Andrew J. Latos
- Department of Microbiology, Molecular Biology and Biochemistry, University of IdahoPO Box 443052, Life Science South Room 142, Moscow 83844-3052, Idaho
| | - Gary W. Daughdrill
- Department of Microbiology, Molecular Biology and Biochemistry, University of IdahoPO Box 443052, Life Science South Room 142, Moscow 83844-3052, Idaho
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17
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Loo YM, Melendy T. Recruitment of replication protein A by the papillomavirus E1 protein and modulation by single-stranded DNA. J Virol 2004; 78:1605-15. [PMID: 14747526 PMCID: PMC369418 DOI: 10.1128/jvi.78.4.1605-1615.2004] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
With the exception of viral proteins E1 and E2, papillomaviruses depend heavily on host replication machinery for replication of their viral genome. E1 and E2 are known to recruit many of the necessary cellular replication factors to the viral origin of replication. Previously, we reported a physical interaction between E1 and the major human single-stranded DNA (ssDNA)-binding protein, replication protein A (RPA). E1 was determined to bind to the 70-kDa subunit of RPA, RPA70. In this study, using E1-affinity coprecipitation and enzyme-linked immunosorbent assay-based interaction assays, we show that E1 interacts with the major ssDNA-binding domain of RPA. Consistent with our previous report, no measurable interaction between E1 and the two smaller subunits of RPA was detected. The interaction of E1 with RPA was substantially inhibited by ssDNA. The extent of this inhibition was dependent on the length of the DNA. A 31-nucleotide (nt) oligonucleotide strongly inhibited the E1-RPA interaction, while a 16-nt oligonucleotide showed an intermediate level of inhibition. In contrast, a 10-nt oligonucleotide showed no observable effect on the E1-RPA interaction. This inhibition was not dependent on the sequence of the DNA. Furthermore, ssDNA also inhibited the interaction of RPA with papillomavirus E2, simian virus 40 T antigen, human polymerase alpha-primase, and p53. Taken together, our results suggest a potential role for ssDNA in modulating RPA-protein interactions, in particular, the RPA-E1 interactions during papillomavirus DNA replication. A model for recruitment of RPA by E1 during papillomavirus DNA replication is proposed.
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Affiliation(s)
- Yueh-Ming Loo
- Department of Microbiology, and Witebsky Center for Microbial Pathogenesis and Immunology, School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York 14214, USA
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18
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Theobald DL, Schultz SC. Nucleotide shuffling and ssDNA recognition in Oxytricha nova telomere end-binding protein complexes. EMBO J 2003; 22:4314-24. [PMID: 12912928 PMCID: PMC175804 DOI: 10.1093/emboj/cdg415] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2003] [Revised: 06/27/2003] [Accepted: 07/02/2003] [Indexed: 12/25/2022] Open
Abstract
Sequence-specific protein recognition of single-stranded nucleic acids is critical for many fundamental cellular processes, such as DNA replication, DNA repair, transcription, translation, recombination, apoptosis and telomere maintenance. To explore the mechanisms of sequence-specific ssDNA recognition, we determined the crystal structures of 10 different non-cognate ssDNAs complexed with the Oxytricha nova telomere end-binding protein (OnTEBP) and evaluated their corresponding binding affinities (PDB ID codes 1PH1-1PH9 and 1PHJ). The thermodynamic and structural effects of these sequence perturbations could not have been predicted based solely upon the cognate structure. OnTEBP accommodates non-cognate nucleotides by both subtle adjustments and surprisingly large structural rearrangements in the ssDNA. In two complexes containing ssDNA intermediates that occur during telomere extension by telomerase, entire nucleotides are expelled from the complex. Concurrently, the sequence register of the ssDNA shifts to re-establish a more cognate-like pattern. This phenomenon, termed nucleotide shuffling, may be of general importance in protein recognition of single-stranded nucleic acids. This set of structural and thermodynamic data highlights a fundamental difference between protein recognition of ssDNA versus dsDNA.
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Affiliation(s)
- Douglas L Theobald
- Department of Chemistry and Biochemistry, University of Colorado at Boulder, Boulder, CO 80309-0215, USA.
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19
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Sukhodolets KE, Hickman AB, Agarwal SK, Sukhodolets MV, Obungu VH, Novotny EA, Crabtree JS, Chandrasekharappa SC, Collins FS, Spiegel AM, Burns AL, Marx SJ. The 32-kilodalton subunit of replication protein A interacts with menin, the product of the MEN1 tumor suppressor gene. Mol Cell Biol 2003; 23:493-509. [PMID: 12509449 PMCID: PMC151531 DOI: 10.1128/mcb.23.2.493-509.2003] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Menin is a 70-kDa protein encoded by MEN1, the tumor suppressor gene disrupted in multiple endocrine neoplasia type 1. In a yeast two-hybrid system based on reconstitution of Ras signaling, menin was found to interact with the 32-kDa subunit (RPA2) of replication protein A (RPA), a heterotrimeric protein required for DNA replication, recombination, and repair. The menin-RPA2 interaction was confirmed in a conventional yeast two-hybrid system and by direct interaction between purified proteins. Menin-RPA2 binding was inhibited by a number of menin missense mutations found in individuals with multiple endocrine neoplasia type 1, and the interacting regions were mapped to the N-terminal portion of menin and amino acids 43 to 171 of RPA2. This region of RPA2 contains a weak single-stranded DNA-binding domain, but menin had no detectable effect on RPA-DNA binding in vitro. Menin bound preferentially in vitro to free RPA2 rather than the RPA heterotrimer or a subcomplex consisting of RPA2 bound to the 14-kDa subunit (RPA3). However, the 70-kDa subunit (RPA1) was coprecipitated from HeLa cell extracts along with RPA2 by menin-specific antibodies, suggesting that menin binds to the RPA heterotrimer or a novel RPA1-RPA2-containing complex in vivo. This finding was consistent with the extensive overlap in the nuclear localization patterns of endogenous menin, RPA2, and RPA1 observed by immunofluorescence.
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Affiliation(s)
- Karen E Sukhodolets
- Metabolic Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-1802, USA.
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20
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Schmitt O, Schubert C, Feyerabend T, Hellwig-Bürgel T, Weiss C, Kühnel W. Preferential topography of proteins regulating vascularization and apoptosis in a MX1 xenotransplant after treatment with hypoxia, hyperthermia, ifosfamide, and irradiation. Am J Clin Oncol 2002; 25:325-36. [PMID: 12151958 DOI: 10.1097/00000421-200208000-00001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The MX1 xenotransplant growing in nude mice was used as a model for estrogen- and progesterone-receptor-negative breast cancer. The effects of different therapeutic regimens-combinations of hyperthermia, chemotherapy, and irradiation-on the expression of proteins playing a role in tumor vascularization and apoptosis were investigated. Additionally, MX-1 tumors were exposed to hypoxia to investigate changes in protein expression related to angiogenesis. This is of particular importance with respect to antiangiogenic therapies that may be combined with the treatments mentioned before. Endothelial and adhesion factors, extracellular matrix (ECM) factors, apoptosis-regulating factors, and neuronal factors were examined by immunohistochemical techniques. Concerning vascularization, the most prominent changes were seen in the expression of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF), which increased strongly after hypoxia. The other cytokines, adhesion and ECM molecules, were either little affected or unaffected by the therapy. At the ultrastructural level, the walls of the tumor vessels are of the sinusoidal type, possessing many fenestrations. With regard to the second focus of this investigation, apoptosis, tumor cells again exerted the strongest differences after hypoxia where c-myc was clearly enhanced, whereas the effects on p53, bcl-2, and CD95 were extremely weak or not detectable. Furthermore, the neurotransmitter somatostatin, a possible "external" regulator of apoptosis, did not show treatment-related changes. In summary, it was shown that 1) within the group of apoptosis-regulating proteins c-myc was particularly affected by hypoxia, indicating a possible role for an activation-induced pathway of apoptosis in this context; 2) minor changes seen after treatment combined with hyperthermia point to a more acute vascular reaction (=dilatation), causing an increase of tissue pO2 rather than angiogenesis; and 3) the concentrations of the angiogenic factors VEGF and bFGF rose strongly under hypoxia, thereby possibly exerting counterproductive effects to antiangiogenic therapy but not to thermochemotherapy or irradiation. This supports the concept of a combined antiangiogenic, hyperthermia, chemo- and irradiation therapy.
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Affiliation(s)
- Oliver Schmitt
- Departments of Anatomy, Medical University of Lübeck, Lübeck, Germany
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21
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Dziegielewski J, Beerman TA. Cellular responses to the DNA strand-scission enediyne C-1027 can be independent of ATM, ATR, and DNA-PK kinases. J Biol Chem 2002; 277:20549-54. [PMID: 11927575 DOI: 10.1074/jbc.m109897200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The current paradigm based upon ionizing radiation (IR) studies states that cells deficient in either ataxia-telangiectasia-mutated kinase (ATM) or related phosphatidylinositol 3 (PI 3) -kinases (ATR and DNA-PK) are hypersensitive to DNA strand breaks because they are unable to rapidly activate downstream effectors such as p53. Here we have contrasted cell responses to IR and C-1027, a radiomimetic antibiotic that induces DNA strand breaks. At equal levels of DNA double strand breaks, cell lines with inactive ATM or other phosphatidylinositol 3-kinases displayed classical hypersensitivity to IR but not to C-1027. Moreover, phosphorylation of p53 Ser-15 induced by C-1027 was independent of ATM, ATR, or DNA-PK function. We have concluded that the model based on IR studies cannot always be directly applied to DNA damage induced by other strand-scission agents.
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Affiliation(s)
- Jaroslaw Dziegielewski
- Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, New York 14263, USA
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22
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Tomkiel JE, Alansari H, Tang N, Virgin JB, Yang X, VandeVord P, Karvonen RL, Granda JL, Kraut MJ, Ensley JF, Fernández-Madrid F. Autoimmunity to the M(r) 32,000 subunit of replication protein A in breast cancer. Clin Cancer Res 2002; 8:752-8. [PMID: 11895905 PMCID: PMC5604237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
PURPOSE We sought to identify autoantigens recognized by antibodies in breast cancer patient sera with potential diagnostic or prognostic significance. EXPERIMENTAL DESIGN Serum from a female breast cancer patient exhibiting a high titer antinuclear antibody was used to screen a HeLa cDNA expression library, leading to the cloning of a cDNA for the M(r) 32,000 subunit of replication protein A (RPA32). RPA32 expression and localization were assayed in autologous tumor by monoclonal antibody staining. A specific ELISA using recombinant protein was used to screen sera from 801 breast cancer patients and 65 controls. RESULTS A relationship between anti-replication protein A (RPA) antibodies and the ductal breast carcinoma of the proband was suggested by overexpression and aberrant localization of RPA32 in tumor cells as compared with surrounding normal ductal tissue and by the presence of anti-RPA32 antibodies before the diagnosis. The prevalence of anti-RPA32 antibodies was significantly higher (P < 0.01) among breast cancer patients (87 of 801 patients) than among noncancer controls (0 of 65 controls). Similarly, anti-RPA32 antibodies were present in 4 of 39 patients with intraductal in situ carcinoma. No associations were found between anti-RPA antibodies and survival, occurrence of a second tumor, metastases, or antibodies to p53. Reactivity to RPA32 also was detected in sera from 3 of 47 patients with other cancers. CONCLUSIONS In view of the central role of RPA in DNA replication, recombination, and repair, we suggest that autoimmunity to RPA32 may reflect molecular changes involved in the process of tumorigenesis. The finding of antibodies to RPA32 before diagnosis and their prevalence in in situ carcinoma suggest that they are potentially useful markers of early disease.
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MESH Headings
- Antigens, Neoplasm/immunology
- Autoantibodies/blood
- Autoantigens/immunology
- Autoimmunity
- Biomarkers, Tumor/blood
- Breast Neoplasms/blood
- Breast Neoplasms/genetics
- Breast Neoplasms/immunology
- Breast Neoplasms/pathology
- Carcinoma in Situ/blood
- Carcinoma in Situ/immunology
- Carcinoma in Situ/pathology
- Carcinoma, Ductal, Breast/blood
- Carcinoma, Ductal, Breast/immunology
- Carcinoma, Ductal, Breast/pathology
- Carcinoma, Squamous Cell/blood
- Carcinoma, Squamous Cell/immunology
- Carcinoma, Squamous Cell/pathology
- Case-Control Studies
- Cloning, Molecular
- DNA-Binding Proteins/immunology
- Enzyme-Linked Immunosorbent Assay
- Female
- Gene Library
- HeLa Cells
- Head and Neck Neoplasms/blood
- Head and Neck Neoplasms/immunology
- Head and Neck Neoplasms/pathology
- Humans
- Immunoenzyme Techniques
- Lung Neoplasms/blood
- Lung Neoplasms/immunology
- Lung Neoplasms/pathology
- Male
- Middle Aged
- Molecular Weight
- Nuclear Family
- Reference Values
- Replication Protein A
- Tumor Suppressor Protein p53/immunology
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - F. Fernández-Madrid
- To whom requests for reprints should be addressed, at Hutzel Hospital, Department of Internal Medicine, Division of Rheumatology, Wayne State University, 4707 Saint Antoine Boulevard, Detroit, MI 48201. Phone: (313) 577-1134;
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23
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Oakley GG, Loberg LI, Yao J, Risinger MA, Yunker RL, Zernik-Kobak M, Khanna KK, Lavin MF, Carty MP, Dixon K. UV-induced hyperphosphorylation of replication protein a depends on DNA replication and expression of ATM protein. Mol Biol Cell 2001; 12:1199-213. [PMID: 11359916 PMCID: PMC34578 DOI: 10.1091/mbc.12.5.1199] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Exposure to DNA-damaging agents triggers signal transduction pathways that are thought to play a role in maintenance of genomic stability. A key protein in the cellular processes of nucleotide excision repair, DNA recombination, and DNA double-strand break repair is the single-stranded DNA binding protein, RPA. We showed previously that the p34 subunit of RPA becomes hyperphosphorylated as a delayed response (4-8 h) to UV radiation (10-30 J/m(2)). Here we show that UV-induced RPA-p34 hyperphosphorylation depends on expression of ATM, the product of the gene mutated in the human genetic disorder ataxia telangiectasia (A-T). UV-induced RPA-p34 hyperphosphorylation was not observed in A-T cells, but this response was restored by ATM expression. Furthermore, purified ATM kinase phosphorylates the p34 subunit of RPA complex in vitro at many of the same sites that are phosphorylated in vivo after UV radiation. Induction of this DNA damage response was also dependent on DNA replication; inhibition of DNA replication by aphidicolin prevented induction of RPA-p34 hyperphosphorylation by UV radiation. We postulate that this pathway is triggered by the accumulation of aberrant DNA replication intermediates, resulting from DNA replication fork blockage by UV photoproducts. Further, we suggest that RPA-p34 is hyperphosphorylated as a participant in the recombinational postreplication repair of these replication products. Successful resolution of these replication intermediates reduces the accumulation of chromosomal aberrations that would otherwise occur as a consequence of UV radiation.
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Affiliation(s)
- G G Oakley
- Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
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24
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Daughdrill GW, Ackerman J, Isern NG, Botuyan MV, Arrowsmith C, Wold MS, Lowry DF. The weak interdomain coupling observed in the 70 kDa subunit of human replication protein A is unaffected by ssDNA binding. Nucleic Acids Res 2001; 29:3270-6. [PMID: 11470885 PMCID: PMC55822 DOI: 10.1093/nar/29.15.3270] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Replication protein A (RPA) is a heterotrimeric, multi-functional protein that binds single-stranded DNA (ssDNA) and is essential for eukaryotic DNA metabolism. Using heteronuclear NMR methods we have investigated the domain interactions and ssDNA binding of a fragment from the 70 kDa subunit of human RPA (hRPA70). This fragment contains an N-terminal domain (NTD), which is important for hRPA70-protein interactions, connected to a ssDNA-binding domain (SSB1) by a flexible linker (hRPA70(1-326)). Correlation analysis of the amide (1)H and (15)N chemical shifts was used to compare the structure of the NTD and SSB1 in hRPA70(1-326) with two smaller fragments that corresponded to the individual domains. High correlation coefficients verified that the NTD and SSB1 maintained their structures in hRPA70(1-326), indicating weak interdomain coupling. Weak interdomain coupling was also suggested by a comparison of the transverse relaxation rates for hRPA70(1-326) and one of the smaller hRPA70 fragments containing the NTD and the flexible linker (hRPA70(1-168)). We also examined the structure of hRPA70(1-326) after addition of three different ssDNA substrates. Each of these substrates induced specific amide (1)H and/or (15)N chemical shift changes in both the NTD and SSB1. The NTD and SSB1 have similar topologies, leading to the possibility that ssDNA binding induced the chemical shift changes observed for the NTD. To test this hypothesis we monitored the amide (1)H and (15)N chemical shift changes of hRPA70(1-168) after addition of ssDNA. The same amide (1)H and (15)N chemical shift changes were observed for the NTD in hRPA70(1-168) and hRPA70(1-326). The NTD residues with the largest amide (1)H and/or (15)N chemical shift changes were localized to a basic cleft that is important for hRPA70-protein interactions. Based on this relationship, and other available data, we propose a model where binding between the NTD and ssDNA interferes with hRPA70-protein interactions.
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Affiliation(s)
- G W Daughdrill
- Department of Microbiology, Molecular Biology and Biochemistry, University of Idaho, PO Box 443052, Life Science South Room 142, Moscow, ID 83844-3052, USA.
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25
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Maga G, Frouin I, Spadari S, Hubscher U. Replication protein A as a "fidelity clamp" for DNA polymerase alpha. J Biol Chem 2001; 276:18235-42. [PMID: 11278525 DOI: 10.1074/jbc.m009599200] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The current view of DNA replication in eukaryotes predicts that DNA polymerase alpha (pol alpha)-primase synthesizes the first 10-ribonucleotide-long RNA primer on the leading strand and at the beginning of each Okazaki fragment on the lagging strand. Subsequently, pol alpha elongates such an RNA primer by incorporating about 20 deoxynucleotides. pol alpha displays a low processivity and, because of the lack of an intrinsic or associated 3'--> 5' exonuclease activity, it is more error-prone than other replicative pols. Synthesis of the RNA/DNA primer catalyzed by pol alpha-primase is a critical step in the initiation of DNA synthesis, but little is known about the role of the DNA replication accessory proteins in its regulation. In this paper we provide evidences that the single-stranded DNA-binding protein, replication protein A (RP-A), acts as an auxiliary factor for pol alpha playing a dual role: (i) it stabilizes the pol alpha/primer complex, thus acting as a pol clamp; and (ii) it significantly reduces the misincorporation efficiency by pol alpha. Based on these results, we propose a hypothetical model in which RP-A is involved in the regulation of the early events of DNA synthesis by acting as a "fidelity clamp" for pol alpha.
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Affiliation(s)
- G Maga
- Istituto di Genetica Biochimica ed Evoluzionistica-Consiglio Nazionale delle Ricerche, I-27100 Pavia, Italy
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26
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Offer H, Milyavsky M, Erez N, Matas D, Zurer I, Harris CC, Rotter V. Structural and functional involvement of p53 in BER in vitro and in vivo. Oncogene 2001; 20:581-9. [PMID: 11313990 DOI: 10.1038/sj.onc.1204120] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2000] [Revised: 11/14/2000] [Accepted: 11/16/2000] [Indexed: 11/09/2022]
Abstract
p53 is involved in several DNA repair pathways. Some of these require the specific transactivation of p53-dependent genes and others involve direct interactions between the p53 protein and DNA repair associated proteins. Previously, we have shown that p53 acts directly in Base Excision Repair (BER) when assayed under in vitro conditions. Our present data indicate that this involvement is independent of the transcriptional activity of the p53 molecule. We found that under both in vitro and in vivo conditions, a p53 transactivation-deficient molecule, p53-22-23 was more efficient in BER activity than was wild type p53. However, mutations in the core domain or C-terminal alterations strongly reduced p53-mediated BER activity. These results are consistent with the hypothesis that the involvement of p53 in BER activity, a housekeeping DNA repair pathway, is a prompt and immediate one that does not involve the activation of p53 transactivation-dependent mechanisms, but rather concerns with the p53 protein itself. In an endogenous DNA damage status p53 is active in BER pathways as a protein and not as a transcription factor.
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Affiliation(s)
- H Offer
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
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27
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Bochkareva E, Belegu V, Korolev S, Bochkarev A. Structure of the major single-stranded DNA-binding domain of replication protein A suggests a dynamic mechanism for DNA binding. EMBO J 2001; 20:612-8. [PMID: 11157767 PMCID: PMC133470 DOI: 10.1093/emboj/20.3.612] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Although structures of single-stranded (ss)DNA-binding proteins (SSBs) have been reported with and without ssDNA, the mechanism of ssDNA binding in eukarya remains speculative. Here we report a 2.5 Angstroms structure of the ssDNA-binding domain of human replication protein A (RPA) (eukaryotic SSB), for which we previously reported a structure in complex with ssDNA. A comparison of free and bound forms of RPA revealed that ssDNA binding is associated with a major reorientation between, and significant conformational changes within, the structural modules--OB-folds--which comprise the DNA-binding domain. Two OB-folds, whose tandem orientation was stabilized by the presence of DNA, adopted multiple orientations in its absence. Within the OB-folds, extended loops implicated in DNA binding significantly changed conformation in the absence of DNA. Analysis of intermolecular contacts suggested the possibility that other RPA molecules and/or other proteins could compete with DNA for the same binding site. Using this mechanism, protein-protein interactions can regulate, and/or be regulated by DNA binding. Combined with available biochemical data, this structure also suggested a dynamic model for the DNA-binding mechanism.
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Affiliation(s)
| | | | - Sergey Korolev
- Department of Biochemistry and Molecular Biology, The University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC-466, Oklahoma City, OK 73190 and
Structural Biology Center, Argonne National Laboratory, 9700 Cass Avenue, Argonne, IL 60439, USA Corresponding author e-mail:
| | - Alexey Bochkarev
- Department of Biochemistry and Molecular Biology, The University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC-466, Oklahoma City, OK 73190 and
Structural Biology Center, Argonne National Laboratory, 9700 Cass Avenue, Argonne, IL 60439, USA Corresponding author e-mail:
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28
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Allio T, Donner EM, Preston RJ. A comparison of the roles of p53 mutation and AraC inhibition in the enhancement of bleomycin-induced chromatid aberrations in mouse and human cells. Mutat Res 2000; 447:227-37. [PMID: 10751606 DOI: 10.1016/s0027-5107(99)00212-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Previous studies have shown that p53 is involved in the repair of bleomycin-induced DNA damage, and that the frequency of bleomycin-induced chromatid aberrations is elevated in G(2)-treated p53 null transgenic mouse embryo fibroblasts (MEF) as compared to isogenic controls. To further characterize p53-mediated DNA repair, we studied the effect of p53 status on the ability of the DNA repair inhibitor 1-ss-D-arabinofuranosylcytosine (AraC) to sensitize MEF to bleomycin-induced chromatid aberrations. Both p53+/+ and p53-/- MEF were treated in G(2) with 0 to 7.5 microg/ml bleomycin in the presence or absence of AraC (5x10(-5) M). The frequency of bleomycin-induced chromatid aberrations was significantly higher in p53-/- cells than wild-type cells in the absence of AraC. AraC treatment significantly increased the frequency of bleomycin-induced chromatid aberrations in p53+/+ MEF to the levels in p53-/- (no AraC) but had no effect in p53-/- MEF. These results suggest that an AraC-sensitive DNA repair component is altered or absent in p53-/- cells. Similar results were observed in p53-mutant WTK1 and wild-type TK6 human lymphoblast cells exposed to 0 to 3 microg/ml bleomycin in G(2). However, AraC did cause a small increase in bleomycin sensitivity in WTK1 cells. This difference from the p53-/- MEF response may be due to differences in p53-mutant phenotype. To determine whether mutation of p53 alters DNA replication fidelity, p53+/+ and p53-/- MEF were exposed to 0 to 1 microg/ml mitomycin C (MMC). MMC did not induce chromosome aberrations in either cell line treated in G(2) but did with the same effectiveness in both cell lines treated in S-phase. Thus, p53 deficiency does not affect DNA replication fidelity or the repair of MMC-induced DNA damage.
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Affiliation(s)
- T Allio
- Chemical Industry Institute of Toxicology, Research Triangle Park, NC 27709, USA
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29
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Liu JS, Kuo SR, McHugh MM, Beerman TA, Melendy T. Adozelesin triggers DNA damage response pathways and arrests SV40 DNA replication through replication protein A inactivation. J Biol Chem 2000; 275:1391-7. [PMID: 10625690 DOI: 10.1074/jbc.275.2.1391] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The cyclopropylpyrroloindole anti-cancer drug, adozelesin, binds to and alkylates DNA. Treatment of human cells with low levels of adozelesin results in potent inhibition of both cellular and simian virus 40 (SV40) DNA replication. Extracts were prepared from adozelesin-treated cells and shown to be deficient in their ability to support SV40 DNA replication in vitro. This effect on in vitro DNA replication was dependent on both the concentration of adozelesin used and the time of treatment but was not due to the presence of adozelesin in the in vitro assay. Adozelesin treatment of cells was shown to result in the following: induction of p53 protein levels, hyperphosphorylation of replication protein A (RPA), and disruption of the p53-RPA complex (but not disruption of the RPA-cdc2 complex), indicating that adozelesin treatment triggers cellular DNA damage response pathways. Interestingly, in vitro DNA replication could be rescued in extracts from adozelesin-treated cells by the addition of exogenous RPA. Therefore, whereas adozelesin and other anti-cancer therapeutics trigger common DNA damage response markers, adozelesin causes DNA replication arrest through a unique mechanism. The S phase checkpoint response triggered by adozelesin acts by inactivating RPA in some function essential for SV40 DNA replication.
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Affiliation(s)
- J S Liu
- Department of Microbiology and the Center for Microbial Pathogenesis, State University of New York School of Medicine and Biomedical Sciences, Buffalo, New York 14214, USA
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30
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Courtemanche C, Anderson A. Multiple mutations in a shuttle vector modified by ultraviolet irradiation, (+/-)-7 beta,8 alpha-dihydroxy-9 alpha,10 alpha-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene, and aflatoxin B(1) have different properties than single mutations and may be generated during translesion synthesis. Mutat Res 1999; 430:23-36. [PMID: 10592315 DOI: 10.1016/s0027-5107(99)00113-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Shuttle vector-based systems are extensively employed to study the mutational properties of various mutagens in mammalian cells. Such vectors are designed for the detection of point mutations, that is small deletions and single base and tandem substitutions. However, mutant target genes carrying two or more point mutations, referred to as multiple mutations, can also be found in various proportions depending on the mutagen and the cells used. To evaluate the frequency and characteristics of multiple mutations, we used a system where the plasmid, pYZ289, was treated by ultraviolet irradiation, aflatoxin B(1) or (+/-)-7 beta,8 alpha-dihydroxy-9 alpha, 10 alpha-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene before transfection into mouse fibroblast cells. The kinds of mutations and the mutational spectra were different for single and multiple mutations. In addition, in at least 75% of the cases, mutations of multiples appeared to arise in the same strand. Furthermore, mutational spectra for multiple mutations were different for 5' and 3' members of multiple sets. These observations suggest that multiple mutations arise via a different mechanism than single mutations. Moreover, these findings suggest that multiples arise during translesion DNA synthesis and involve an error-prone polymerase able to introduce a base opposite misinstructive or noninstructional DNA lesions and subject to subsequent misincorporation errors.
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Affiliation(s)
- C Courtemanche
- Centre de recherche en cancérologie de l'Université Laval, Pavillon L'Hôtel-Dieu de Québec, Centre hospitalier universitaire de Québec, Quebec, Canada
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31
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Affiliation(s)
- E A Fortunato
- Department of Biology and Center for Molecular Genetics, University of California, San Diego, La Jolla 92093-0366, USA
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32
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Kohn KW. Molecular interaction map of the mammalian cell cycle control and DNA repair systems. Mol Biol Cell 1999; 10:2703-34. [PMID: 10436023 PMCID: PMC25504 DOI: 10.1091/mbc.10.8.2703] [Citation(s) in RCA: 280] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Eventually to understand the integrated function of the cell cycle regulatory network, we must organize the known interactions in the form of a diagram, map, and/or database. A diagram convention was designed capable of unambiguous representation of networks containing multiprotein complexes, protein modifications, and enzymes that are substrates of other enzymes. To facilitate linkage to a database, each molecular species is symbolically represented only once in each diagram. Molecular species can be located on the map by means of indexed grid coordinates. Each interaction is referenced to an annotation list where pertinent information and references can be found. Parts of the network are grouped into functional subsystems. The map shows how multiprotein complexes could assemble and function at gene promoter sites and at sites of DNA damage. It also portrays the richness of connections between the p53-Mdm2 subsystem and other parts of the network.
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Affiliation(s)
- K W Kohn
- Laboratory of Molecular Pharmacology, Division of Basic Sciences, National Cancer Institute, Bethesda, Maryland 20892, USA.
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33
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Offer H, Wolkowicz R, Matas D, Blumenstein S, Livneh Z, Rotter V. Direct involvement of p53 in the base excision repair pathway of the DNA repair machinery. FEBS Lett 1999; 450:197-204. [PMID: 10359074 DOI: 10.1016/s0014-5793(99)00505-0] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The p53 tumor suppressor that plays a central role in the cellular response to genotoxic stress was suggested to be associated with the DNA repair machinery which mostly involves nucleotide excision repair (NER). In the present study we show for the first time that p53 is also directly involved in base excision repair (BER). These experiments were performed with p53 temperature-sensitive (ts) mutants that were previously studied in in vivo experimental models. We report here that p53 ts mutants can also acquire wild-type activity under in vitro conditions. Using ts mutants of murine and human origin, it was observed that cell extracts overexpressing p53 exhibited an augmented BER activity measured in an in vitro assay. Depletion of p53 from the nuclear extracts abolished this enhanced activity. Together, this suggests that p53 is involved in more than one DNA repair pathway.
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Affiliation(s)
- H Offer
- Department of Molecular Cell Biology, The Weizmann Institute of Science, Rehovot, Israel
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34
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Shao RG, Cao CX, Zhang H, Kohn KW, Wold MS, Pommier Y. Replication-mediated DNA damage by camptothecin induces phosphorylation of RPA by DNA-dependent protein kinase and dissociates RPA:DNA-PK complexes. EMBO J 1999; 18:1397-406. [PMID: 10064605 PMCID: PMC1171229 DOI: 10.1093/emboj/18.5.1397] [Citation(s) in RCA: 279] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
UNLABELLED Replication protein A (RPA) is a DNA single-strand binding protein essential for DNA replication, recombination and repair. In human cells treated with the topoisomerase inhibitors camptothecin or etoposide (VP-16), we find that RPA2, the middle-sized subunit of RPA, becomes rapidly phosphorylated. This response appears to be due to DNA-dependent protein kinase (DNA-PK) and to be independent of p53 or the ataxia telangiectasia mutated (ATM) protein. RPA2 phosphorylation in response to camptothecin required ongoing DNA replication. Camptothecin itself partially inhibited DNA synthesis, and this inhibition followed the same kinetics as DNA-PK activation and RPA2 phosphorylation. DNA-PK activation and RPA2 phosphorylation were prevented by the cell-cycle checkpoint abrogator 7-hydroxystaurosporine (UCN-01), which markedly potentiates camptothecin cytotoxicity. The DNA-PK catalytic subunit (DNA-PKcs) was found to bind RPA which was replaced by the Ku autoantigen upon camptothecin treatment. DNA-PKcs interacted directly with RPA1 in vitro. We propose that the encounter of a replication fork with a topoisomerase-DNA cleavage complex could lead to a juxtaposition of replication fork-associated RPA and DNA double-strand end-associated DNA-PK, leading to RPA2 phosphorylation which may signal the presence of DNA damage to an S-phase checkpoint mechanism. KEYWORDS camptothecin/DNA damage/DNA-dependent protein kinase/RPA2 phosphorylation
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Affiliation(s)
- R G Shao
- Laboratory of Molecular Pharmacology, Division of Basic Sciences, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4255, USA
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Salles-Passador I, Fotedar A, Fotedar R. Cellular response to DNA damage. Link between p53 and DNA-PK. COMPTES RENDUS DE L'ACADEMIE DES SCIENCES. SERIE III, SCIENCES DE LA VIE 1999; 322:113-20. [PMID: 10196661 DOI: 10.1016/s0764-4469(99)80032-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Cells which lack DNA-activated protein kinase (DNA-PK) are very susceptible to ionizing radiation and display an inability to repair double strand DNA breaks. DNA-PK is a member of a protein kinase family that includes ATR and ATM which have strong homology in their carboxy-terminal kinase domain with PL-3 kinase. ATM has been proposed to act upstream of p53 in cellular response to ionizing radiation. DNA-PK may similarly interact with p53 in cellular growth control and in mediation of the response to ionizing radiation.
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Hedge SP, Kumar A, Kurschner C, Shapiro LH. c-Maf interacts with c-Myb to regulate transcription of an early myeloid gene during differentiation. Mol Cell Biol 1998; 18:2729-37. [PMID: 9566892 PMCID: PMC110652 DOI: 10.1128/mcb.18.5.2729] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/1997] [Accepted: 02/18/1998] [Indexed: 02/07/2023] Open
Abstract
The MafB transcriptional activator plays a pivotal role in regulating lineage-specific gene expression during hematopoiesis by repressing Ets-1-mediated transcription of key erythroid-specific genes in myeloid cells. To determine the effects of Maf family proteins on the transactivation of myeloid-specific genes in myeloid cells, we tested the ability of c-Maf to influence Ets-1- and c-Myb-dependent CD13/APN transcription. Expression of c-Maf in human immature myeloblastic cells inhibited CD13/APN-driven reporter gene activity (85 to 95% reduction) and required the binding of both c-Myb and Ets, but not Maf, to the promoter fragment. c-Maf's inhibition of CD13/APN expression correlates with its ability to physically associate with c-Myb. While c-Maf mRNA and protein levels remain constant during myeloid differentiation, formation of inhibitory Myb-Maf complexes was developmentally regulated, with their levels being highest in immature myeloid cell lines and markedly decreased in cell lines representing later developmental stages. This pattern matched that of CD13/APN reporter gene expression, indicating that Maf modulation of c-Myb activity may be an important mechanism for the control of gene transcription during hematopoietic cell development.
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Affiliation(s)
- S P Hedge
- Department of Experimental Oncology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
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37
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Fortunato EA, Spector DH. p53 and RPA are sequestered in viral replication centers in the nuclei of cells infected with human cytomegalovirus. J Virol 1998; 72:2033-9. [PMID: 9499057 PMCID: PMC109496 DOI: 10.1128/jvi.72.3.2033-2039.1998] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Previously, we reported that human cytomegalovirus (HCMV) infection of fibroblasts markedly affects p53 and other regulatory proteins and inhibits transit through the cell cycle (F. M. Jault, J.-M. Jault, F. Ruchti, E. A. Fortunato, C. Clark, J. Corbeil, D. D. Richman, and D. H. Spector, J. Virol. 69:6697-6704, 1995). Although the p53 steady-state levels are elevated throughout the infection, evidence suggests that the ability of p53 to transactivate some of its downstream targets is compromised. To elucidate the mechanisms governing the accumulation of p53, we examined the synthesis, stability, and localization of the protein in HCMV-infected fibroblasts. Synthesis of p53 was not increased in the infected cells during the first 24 h postinfection. In fact, pulse-chase experiments revealed that synthesis of p53 in infected fibroblasts was lower than in mock-infected cells. However, after an initial decay, the p53 was stabilized. In addition, beginning at approximately 30 h postinfection, p53 was localized to discrete foci within the nuclei of infected cells. The morphology of these foci suggested that they were replication centers. We confirmed that these are sites of DNA replication by demonstrating both incorporation of bromodeoxyuridine and localization of UL44 (the viral polymerase processivity factor) into these centers. The single-stranded DNA binding protein RPA was also sequestered. In contrast, Rb and HCMV IE1 72 remained distributed throughout the infected cell nuclei, indicating specific targeting of certain proteins. Taken together, our results provide two alternative mechanisms to account for the increased steady-state levels of p53 observed in HCMV-infected fibroblasts.
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Affiliation(s)
- E A Fortunato
- Department of Biology, University of California, San Diego, La Jolla 92093-0357, USA
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38
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Anderson ME, Woelker B, Reed M, Wang P, Tegtmeyer P. Reciprocal interference between the sequence-specific core and nonspecific C-terminal DNA binding domains of p53: implications for regulation. Mol Cell Biol 1997; 17:6255-64. [PMID: 9343386 PMCID: PMC232476 DOI: 10.1128/mcb.17.11.6255] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The tumor suppressor p53 has two DNA binding domains: a central sequence-specific domain and a C-terminal sequence-independent domain. Here, we show that binding of large but not small DNAs by the C terminus of p53 negatively regulates sequence-specific DNA binding by the central domain. Four previously described mechanisms for activation of specific DNA binding operate by blocking negative regulation. Deletion of the C terminus of p53 activates specific DNA binding only in the presence of large DNA. Three activator molecules (a small nucleic acid, a monoclonal antibody against the p53 C terminus, and a C-terminal peptide of p53) stimulate sequence-specific DNA binding only in the presence of both large DNA and p53 with an intact C terminus. Our findings argue that interactions of the C terminus of p53 with genomic DNA in vivo would prevent p53 binding to specific promoters and that cellular mechanisms to block C-terminal DNA binding would be required.
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Affiliation(s)
- M E Anderson
- Department of Molecular Genetics and Microbiology, State University of New York, Stony Brook 11794-5222, USA
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39
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Abramova NA, Russell J, Botchan M, Li R. Interaction between replication protein A and p53 is disrupted after UV damage in a DNA repair-dependent manner. Proc Natl Acad Sci U S A 1997; 94:7186-91. [PMID: 9207066 PMCID: PMC23787 DOI: 10.1073/pnas.94.14.7186] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Replication protein A (RPA) is required for both DNA replication and nucleotide excision repair. Previous studies have shown that RPA interacts with the tumor suppressor p53. Herein, we have mapped a 20-amino acid region in the N-terminal part of p53 that is essential for its binding to RPA. This region is distinct from the minimal activation domain of p53 previously identified. We also demonstrate that UV radiation of cells greatly reduces the ability of RPA to bind to p53. Interestingly, damage-induced hyperphosphorylated RPA does not associate with p53. Furthermore, down-regulation of the RPA/p53 interaction is dependent upon the capability of cells to perform global genome repair. On the basis of these data, we propose that RPA may participate in the coordination of DNA repair with the p53-dependent checkpoint control by sensing UV damage and releasing p53 to activate its downstream targets.
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Affiliation(s)
- N A Abramova
- Department of Biochemistry, Health Sciences Center, University of Virginia, Charlottesville, VA 22908, USA
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