1
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Crossley MP, Song C, Bocek MJ, Choi JH, Kousouros JN, Sathirachinda A, Lin C, Brickner JR, Bai G, Lans H, Vermeulen W, Abu-Remaileh M, Cimprich KA. Author Correction: R-loop-derived cytoplasmic RNA-DNA hybrids activate an immune response. Nature 2024; 626:E6. [PMID: 38263519 DOI: 10.1038/s41586-024-07064-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2024]
Affiliation(s)
- Magdalena P Crossley
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA, USA
| | - Chenlin Song
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA, USA
| | - Michael J Bocek
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA, USA
| | - Jun-Hyuk Choi
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA, USA
- Biometrology Group, Division of Chemical and Biological Metrology, Korea Research Institute of Standards and Science, Daejeon, South Korea
- Department of Bio-Analytical Science, University of Science & Technology, Daejeon, South Korea
| | - Joseph N Kousouros
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA, USA
| | - Ataya Sathirachinda
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA, USA
| | - Cindy Lin
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA
- Department of Genetics, Stanford University, Stanford, CA, USA
- The Institute for Chemistry, Engineering & Medicine for Human Health (ChEM-H), Stanford University, Stanford, CA, USA
| | - Joshua R Brickner
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA, USA
| | - Gongshi Bai
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA, USA
| | - Hannes Lans
- Department of Molecular Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Wim Vermeulen
- Department of Molecular Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Monther Abu-Remaileh
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA
- Department of Genetics, Stanford University, Stanford, CA, USA
- The Institute for Chemistry, Engineering & Medicine for Human Health (ChEM-H), Stanford University, Stanford, CA, USA
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA, USA.
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2
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Bai G, Endres T, Kühbacher U, Greer BH, Peacock EM, Crossley MP, Sathirachinda A, Cortez D, Eichman BF, Cimprich KA. HLTF Prevents G4 Accumulation and Promotes G4-induced Fork Slowing to Maintain Genome Stability. bioRxiv 2023:2023.10.27.563641. [PMID: 37961428 PMCID: PMC10634870 DOI: 10.1101/2023.10.27.563641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
G-quadruplexes (G4s) form throughout the genome and influence important cellular processes, but their deregulation can challenge DNA replication fork progression and threaten genome stability. Here, we demonstrate an unexpected, dual role for the dsDNA translocase HLTF in G4 metabolism. First, we find that HLTF is enriched at G4s in the human genome and suppresses G4 accumulation throughout the cell cycle using its ATPase activity. This function of HLTF affects telomere maintenance by restricting alternative lengthening of telomeres, a process stimulated by G4s. We also show that HLTF and MSH2, a mismatch repair factor that binds G4s, act in independent pathways to suppress G4s and to promote resistance to G4 stabilization. In a second, distinct role, HLTF restrains DNA synthesis upon G4 stabilization by suppressing PrimPol-dependent repriming. Together, the dual functions of HLTF in the G4 response prevent DNA damage and potentially mutagenic replication to safeguard genome stability.
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3
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Cimprich KA, Li GM, Demaria S, Gekara NO, Zha S, Chen Q. The crosstalk between DNA repair and immune responses. Mol Cell 2023; 83:3582-3587. [PMID: 37863025 DOI: 10.1016/j.molcel.2023.09.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 09/19/2023] [Accepted: 09/19/2023] [Indexed: 10/22/2023]
Abstract
In recent years, increasing evidence has highlighted the profound connection between DNA damage repair and the activation of immune responses. We spoke with researchers about their mechanistic interplays and the implications for cancer and other diseases.
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4
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Stoy H, Zwicky K, Kuster D, Lang KS, Krietsch J, Crossley MP, Schmid JA, Cimprich KA, Merrikh H, Lopes M. Direct visualization of transcription-replication conflicts reveals post-replicative DNA:RNA hybrids. Nat Struct Mol Biol 2023; 30:348-359. [PMID: 36864174 PMCID: PMC10023573 DOI: 10.1038/s41594-023-00928-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 01/23/2023] [Indexed: 03/04/2023]
Abstract
Transcription-replication collisions (TRCs) are crucial determinants of genome instability. R-loops were linked to head-on TRCs and proposed to obstruct replication fork progression. The underlying mechanisms, however, remained elusive due to the lack of direct visualization and of non-ambiguous research tools. Here, we ascertained the stability of estrogen-induced R-loops on the human genome, visualized them directly by electron microscopy (EM), and measured R-loop frequency and size at the single-molecule level. Combining EM and immuno-labeling on locus-specific head-on TRCs in bacteria, we observed the frequent accumulation of DNA:RNA hybrids behind replication forks. These post-replicative structures are linked to fork slowing and reversal across conflict regions and are distinct from physiological DNA:RNA hybrids at Okazaki fragments. Comet assays on nascent DNA revealed a marked delay in nascent DNA maturation in multiple conditions previously linked to R-loop accumulation. Altogether, our findings suggest that TRC-associated replication interference entails transactions that follow initial R-loop bypass by the replication fork.
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Affiliation(s)
- Henriette Stoy
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Katharina Zwicky
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Danina Kuster
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Kevin S Lang
- Vanderbilt University School of Medicine, Nashville, TN, USA
- Department of Veterinary and Biomedical Sciences, University of Minnesota, Saint Paul, MN, USA
| | - Jana Krietsch
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Magdalena P Crossley
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Jonas A Schmid
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Houra Merrikh
- Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Massimo Lopes
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland.
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5
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Crossley MP, Song C, Bocek MJ, Choi JH, Kousouros JN, Sathirachinda A, Lin C, Brickner JR, Bai G, Lans H, Vermeulen W, Abu-Remaileh M, Cimprich KA. R-loop-derived cytoplasmic RNA-DNA hybrids activate an immune response. Nature 2023; 613:187-194. [PMID: 36544021 PMCID: PMC9949885 DOI: 10.1038/s41586-022-05545-9] [Citation(s) in RCA: 74] [Impact Index Per Article: 74.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 11/08/2022] [Indexed: 12/24/2022]
Abstract
R-loops are RNA-DNA-hybrid-containing nucleic acids with important cellular roles. Deregulation of R-loop dynamics can lead to DNA damage and genome instability1, which has been linked to the action of endonucleases such as XPG2-4. However, the mechanisms and cellular consequences of such processing have remained unclear. Here we identify a new population of RNA-DNA hybrids in the cytoplasm that are R-loop-processing products. When nuclear R-loops were perturbed by depleting the RNA-DNA helicase senataxin (SETX) or the breast cancer gene BRCA1 (refs. 5-7), we observed XPG- and XPF-dependent cytoplasmic hybrid formation. We identify their source as a subset of stable, overlapping nuclear hybrids with a specific nucleotide signature. Cytoplasmic hybrids bind to the pattern recognition receptors cGAS and TLR3 (ref. 8), activating IRF3 and inducing apoptosis. Excised hybrids and an R-loop-induced innate immune response were also observed in SETX-mutated cells from patients with ataxia oculomotor apraxia type 2 (ref. 9) and in BRCA1-mutated cancer cells10. These findings establish RNA-DNA hybrids as immunogenic species that aberrantly accumulate in the cytoplasm after R-loop processing, linking R-loop accumulation to cell death through the innate immune response. Aberrant R-loop processing and subsequent innate immune activation may contribute to many diseases, such as neurodegeneration and cancer.
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Affiliation(s)
- Magdalena P Crossley
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA, USA
| | - Chenlin Song
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA, USA
| | - Michael J Bocek
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA, USA
| | - Jun-Hyuk Choi
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA, USA
- Biometrology Group, Division of Chemical and Biological Metrology, Korea Research Institute of Standards and Science, Daejeon, South Korea
- Department of Bio-Analytical Science, University of Science & Technology, Daejeon, South Korea
| | - Joseph N Kousouros
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA, USA
| | - Ataya Sathirachinda
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA, USA
| | - Cindy Lin
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA
- Department of Genetics, Stanford University, Stanford, CA, USA
- The Institute for Chemistry, Engineering & Medicine for Human Health (ChEM-H), Stanford University, Stanford, CA, USA
| | - Joshua R Brickner
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA, USA
| | - Gongshi Bai
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA, USA
| | - Hannes Lans
- Department of Molecular Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Wim Vermeulen
- Department of Molecular Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Monther Abu-Remaileh
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA
- Department of Genetics, Stanford University, Stanford, CA, USA
- The Institute for Chemistry, Engineering & Medicine for Human Health (ChEM-H), Stanford University, Stanford, CA, USA
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA, USA.
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Salvi JS, Kang J, Kim S, Colville AJ, de Morrée A, Billeskov TB, Larsen MC, Kanugovi A, van Velthoven CTJ, Cimprich KA, Rando TA. ATR activity controls stem cell quiescence via the cyclin F-SCF complex. Proc Natl Acad Sci U S A 2022; 119:e2115638119. [PMID: 35476521 PMCID: PMC9170012 DOI: 10.1073/pnas.2115638119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A key property of adult stem cells is their ability to persist in a quiescent state for prolonged periods of time. The quiescent state is thought to contribute to stem cell resilience by limiting accumulation of DNA replication–associated mutations. Moreover, cellular stress response factors are thought to play a role in maintaining quiescence and stem cell integrity. We utilized muscle stem cells (MuSCs) as a model of quiescent stem cells and find that the replication stress response protein, ATR (Ataxia Telangiectasia and Rad3-Related), is abundant and active in quiescent but not activated MuSCs. Concurrently, MuSCs display punctate RPA (replication protein A) and R-loop foci, both key triggers for ATR activation. To discern the role of ATR in MuSCs, we generated MuSC-specific ATR conditional knockout (ATRcKO) mice. Surprisingly, ATR ablation results in increased MuSC quiescence exit. Phosphoproteomic analysis of ATRcKO MuSCs reveals enrichment of phosphorylated cyclin F, a key component of the Skp1–Cul1–F-box protein (SCF) ubiquitin ligase complex and regulator of key cell-cycle transition factors, such as the E2F family of transcription factors. Knocking down cyclin F or inhibiting the SCF complex results in E2F1 accumulation and in MuSCs exiting quiescence, similar to ATR-deficient MuSCs. The loss of ATR could be counteracted by inhibiting casein kinase 2 (CK2), the kinase responsible for phosphorylating cyclin F. We propose a model in which MuSCs express cell-cycle progression factors but ATR, in coordination with the cyclin F–SCF complex, represses premature stem cell quiescence exit via ubiquitin–proteasome degradation of these factors.
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Affiliation(s)
- Jayesh S. Salvi
- aPaul F. Glenn Center for the Biology of Aging, Stanford University School of Medicine, Stanford, CA 94305
- bDepartment of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305
| | - Jengmin Kang
- aPaul F. Glenn Center for the Biology of Aging, Stanford University School of Medicine, Stanford, CA 94305
- bDepartment of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305
| | - Soochi Kim
- aPaul F. Glenn Center for the Biology of Aging, Stanford University School of Medicine, Stanford, CA 94305
- bDepartment of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305
| | - Alex J. Colville
- aPaul F. Glenn Center for the Biology of Aging, Stanford University School of Medicine, Stanford, CA 94305
- bDepartment of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305
| | - Antoine de Morrée
- aPaul F. Glenn Center for the Biology of Aging, Stanford University School of Medicine, Stanford, CA 94305
- bDepartment of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305
| | - Tine Borum Billeskov
- aPaul F. Glenn Center for the Biology of Aging, Stanford University School of Medicine, Stanford, CA 94305
- bDepartment of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305
| | - Mikkel Christian Larsen
- aPaul F. Glenn Center for the Biology of Aging, Stanford University School of Medicine, Stanford, CA 94305
- bDepartment of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305
| | - Abhijnya Kanugovi
- aPaul F. Glenn Center for the Biology of Aging, Stanford University School of Medicine, Stanford, CA 94305
- bDepartment of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305
| | - Cindy T. J. van Velthoven
- aPaul F. Glenn Center for the Biology of Aging, Stanford University School of Medicine, Stanford, CA 94305
- bDepartment of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305
| | - Karlene A. Cimprich
- cDepartment of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305–5441
| | - Thomas A. Rando
- aPaul F. Glenn Center for the Biology of Aging, Stanford University School of Medicine, Stanford, CA 94305
- bDepartment of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305
- dNeurology Service, VA Palo Alto Health Care System, Palo Alto, CA 94304
- 6To whom correspondence may be addressed.
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7
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Brickner JR, Garzon JL, Cimprich KA. Walking a tightrope: The complex balancing act of R-loops in genome stability. Mol Cell 2022; 82:2267-2297. [PMID: 35508167 DOI: 10.1016/j.molcel.2022.04.014] [Citation(s) in RCA: 73] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 03/28/2022] [Accepted: 04/10/2022] [Indexed: 12/14/2022]
Abstract
Although transcription is an essential cellular process, it is paradoxically also a well-recognized cause of genomic instability. R-loops, non-B DNA structures formed when nascent RNA hybridizes to DNA to displace the non-template strand as single-stranded DNA (ssDNA), are partially responsible for this instability. Yet, recent work has begun to elucidate regulatory roles for R-loops in maintaining the genome. In this review, we discuss the cellular contexts in which R-loops contribute to genomic instability, particularly during DNA replication and double-strand break (DSB) repair. We also summarize the evidence that R-loops participate as an intermediate during repair and may influence pathway choice to preserve genomic integrity. Finally, we discuss the immunogenic potential of R-loops and highlight their links to disease should they become pathogenic.
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Affiliation(s)
- Joshua R Brickner
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jada L Garzon
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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8
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Crossley MP, Brickner JR, Song C, Zar SMT, Maw SS, Chédin F, Tsai MS, Cimprich KA. Catalytically inactive, purified RNase H1: A specific and sensitive probe for RNA-DNA hybrid imaging. J Cell Biol 2021; 220:212458. [PMID: 34232287 PMCID: PMC8266564 DOI: 10.1083/jcb.202101092] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 05/24/2021] [Accepted: 06/07/2021] [Indexed: 12/17/2022] Open
Abstract
R-loops are three-stranded nucleic acid structures with both physiological and pathological roles in cells. R-loop imaging generally relies on detection of the RNA-DNA hybrid component of these structures using the S9.6 antibody. We show that the use of this antibody for imaging can be problematic because it readily binds to double-stranded RNA (dsRNA) in vitro and in vivo, giving rise to nonspecific signal. In contrast, purified, catalytically inactive human RNase H1 tagged with GFP (GFP-dRNH1) is a more specific reagent for imaging RNA-DNA hybrids. GFP-dRNH1 binds strongly to RNA-DNA hybrids but not to dsRNA oligonucleotides in fixed human cells and is not susceptible to binding endogenous RNA. Furthermore, we demonstrate that purified GFP-dRNH1 can be applied to fixed cells to detect hybrids after their induction, thereby bypassing the need for cell line engineering. GFP-dRNH1 therefore promises to be a versatile tool for imaging and quantifying RNA-DNA hybrids under a wide range of conditions.
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Affiliation(s)
- Magdalena P Crossley
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA
| | - Joshua R Brickner
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA
| | - Chenlin Song
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA
| | - Su Mon Thin Zar
- Biological Systems and Engineering, Lawrence Berkeley National Laboratory, Berkeley, CA
| | - Su S Maw
- Biological Systems and Engineering, Lawrence Berkeley National Laboratory, Berkeley, CA
| | - Frédéric Chédin
- Department of Molecular and Cellular Biology and Genome Center, University of California, Davis, Davis, CA
| | - Miaw-Sheue Tsai
- Biological Systems and Engineering, Lawrence Berkeley National Laboratory, Berkeley, CA
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA
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9
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Mehibel M, Xu Y, Li CG, Moon EJ, Thakkar KN, Diep AN, Kim RK, Bloomstein JD, Xiao Y, Bacal J, Saldivar JC, Le QT, Cimprich KA, Rankin EB, Giaccia AJ. Eliminating hypoxic tumor cells improves response to PARP inhibitors in homologous recombination-deficient cancer models. J Clin Invest 2021; 131:146256. [PMID: 34060485 PMCID: PMC8266208 DOI: 10.1172/jci146256] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 04/21/2021] [Indexed: 12/21/2022] Open
Abstract
Hypoxia, a hallmark feature of the tumor microenvironment, causes resistance to conventional chemotherapy, but was recently reported to synergize with poly(ADP-ribose) polymerase inhibitors (PARPis) in homologous recombination-proficient (HR-proficient) cells through suppression of HR. While this synergistic killing occurs under severe hypoxia (<0.5% oxygen), our study shows that moderate hypoxia (2% oxygen) instead promotes PARPi resistance in both HR-proficient and -deficient cancer cells. Mechanistically, we identify reduced ROS-induced DNA damage as the cause for the observed resistance. To determine the contribution of hypoxia to PARPi resistance in tumors, we used the hypoxic cytotoxin tirapazamine to selectively kill hypoxic tumor cells. We found that the selective elimination of hypoxic tumor cells led to a substantial antitumor response when used with PARPi compared with that in tumors treated with PARPi alone, without enhancing normal tissue toxicity. Since human breast cancers with BRAC1/2 mutations have an increased hypoxia signature and hypoxia reduces the efficacy of PARPi, then eliminating hypoxic tumor cells should enhance the efficacy of PARPi therapy.
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Affiliation(s)
- Manal Mehibel
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, Stanford University Medical Center, Stanford, California, USA
| | - Yu Xu
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, Stanford University Medical Center, Stanford, California, USA
| | - Caiyun G. Li
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, Stanford University Medical Center, Stanford, California, USA
| | - Eui Jung Moon
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, Stanford University Medical Center, Stanford, California, USA
| | - Kaushik N. Thakkar
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, Stanford University Medical Center, Stanford, California, USA
| | - Anh N. Diep
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, Stanford University Medical Center, Stanford, California, USA
| | - Ryan K. Kim
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, Stanford University Medical Center, Stanford, California, USA
| | - Joshua D. Bloomstein
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, Stanford University Medical Center, Stanford, California, USA
| | - Yiren Xiao
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, Stanford University Medical Center, Stanford, California, USA
| | - Julien Bacal
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, California, USA
| | - Joshua C. Saldivar
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, California, USA
| | - Quynh-Thu Le
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, Stanford University Medical Center, Stanford, California, USA
| | - Karlene A. Cimprich
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, California, USA
| | - Erinn B. Rankin
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, Stanford University Medical Center, Stanford, California, USA
- Department of Obstetrics and Gynecology, Stanford University Medical Center, Stanford, California, USA
| | - Amato J. Giaccia
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, Stanford University Medical Center, Stanford, California, USA
- Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom
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10
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Crossley MP, Bocek MJ, Hamperl S, Swigut T, Cimprich KA. qDRIP: a method to quantitatively assess RNA-DNA hybrid formation genome-wide. Nucleic Acids Res 2020; 48:e84. [PMID: 32544226 PMCID: PMC7641308 DOI: 10.1093/nar/gkaa500] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 05/30/2020] [Accepted: 06/03/2020] [Indexed: 12/13/2022] Open
Abstract
R-loops are dynamic, co-transcriptional nucleic acid structures that facilitate physiological processes but can also cause DNA damage in certain contexts. Perturbations of transcription or R-loop resolution are expected to change their genomic distribution. Next-generation sequencing approaches to map RNA–DNA hybrids, a component of R-loops, have so far not allowed quantitative comparisons between such conditions. Here, we describe quantitative differential DNA–RNA immunoprecipitation (qDRIP), a method combining synthetic RNA–DNA-hybrid internal standards with high-resolution, strand-specific sequencing. We show that qDRIP avoids biases inherent to read-count normalization by accurately profiling signal in regions unaffected by transcription inhibition in human cells, and by facilitating accurate differential peak calling between conditions. We also use these quantitative comparisons to make the first estimates of the absolute count of RNA–DNA hybrids per cell and their half-lives genome-wide. Finally, we identify a subset of RNA–DNA hybrids with high GC skew which are partially resistant to RNase H. Overall, qDRIP allows for accurate normalization in conditions where R-loops are perturbed and for quantitative measurements that provide previously unattainable biological insights.
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Affiliation(s)
- Magdalena P Crossley
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Michael J Bocek
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Stephan Hamperl
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Tomek Swigut
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
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11
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Bai G, Kermi C, Stoy H, Schiltz CJ, Bacal J, Zaino AM, Hadden MK, Eichman BF, Lopes M, Cimprich KA. HLTF Promotes Fork Reversal, Limiting Replication Stress Resistance and Preventing Multiple Mechanisms of Unrestrained DNA Synthesis. Mol Cell 2020; 78:1237-1251.e7. [PMID: 32442397 PMCID: PMC7305998 DOI: 10.1016/j.molcel.2020.04.031] [Citation(s) in RCA: 107] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 03/12/2020] [Accepted: 04/24/2020] [Indexed: 01/06/2023]
Abstract
DNA replication stress can stall replication forks, leading to genome instability. DNA damage tolerance pathways assist fork progression, promoting replication fork reversal, translesion DNA synthesis (TLS), and repriming. In the absence of the fork remodeler HLTF, forks fail to slow following replication stress, but underlying mechanisms and cellular consequences remain elusive. Here, we demonstrate that HLTF-deficient cells fail to undergo fork reversal in vivo and rely on the primase-polymerase PRIMPOL for repriming, unrestrained replication, and S phase progression upon limiting nucleotide levels. By contrast, in an HLTF-HIRAN mutant, unrestrained replication relies on the TLS protein REV1. Importantly, HLTF-deficient cells also exhibit reduced double-strand break (DSB) formation and increased survival upon replication stress. Our findings suggest that HLTF promotes fork remodeling, preventing other mechanisms of replication stress tolerance in cancer cells. This remarkable plasticity of the replication fork may determine the outcome of replication stress in terms of genome integrity, tumorigenesis, and response to chemotherapy.
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Affiliation(s)
- Gongshi Bai
- Department of Chemical and Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA 94305-5441, USA
| | - Chames Kermi
- Department of Chemical and Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA 94305-5441, USA
| | - Henriette Stoy
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Carl J Schiltz
- Department of Biological Sciences and Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Julien Bacal
- Department of Chemical and Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA 94305-5441, USA
| | - Angela M Zaino
- Department of Pharmaceutical Sciences, University of Connecticut, 69 North Eagleville Road, Storrs, CT 06029-3092, USA
| | - M Kyle Hadden
- Department of Pharmaceutical Sciences, University of Connecticut, 69 North Eagleville Road, Storrs, CT 06029-3092, USA
| | - Brandt F Eichman
- Department of Biological Sciences and Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Massimo Lopes
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA 94305-5441, USA.
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12
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Abstract
During transcription, the nascent RNA strand can base pair with its template DNA, displacing the non-template strand as ssDNA and forming a structure called an R-loop. R-loops are common across many domains of life and cause DNA damage in certain contexts. In this review, we summarize recent results implicating R-loops as important regulators of cellular processes such as transcription termination, gene regulation, and DNA repair. We also highlight recent work suggesting that R-loops can be problematic to cells as blocks to efficient transcription and replication that trigger the DNA damage response. Finally, we discuss how R-loops may contribute to cancer, neurodegeneration, and inflammatory diseases and compare the available next-generation sequencing-based approaches to map R-loops genome wide.
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Affiliation(s)
- Madzia P Crossley
- Department of Chemical and Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA 94305-5441, USA
| | - Michael Bocek
- Department of Chemical and Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA 94305-5441, USA
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA 94305-5441, USA.
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13
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Li CG, Mahon C, Sweeney NM, Verschueren E, Kantamani V, Li D, Hennigs JK, Marciano DP, Diebold I, Abu-Halawa O, Elliott M, Sa S, Guo F, Wang L, Cao A, Guignabert C, Sollier J, Nickel NP, Kaschwich M, Cimprich KA, Rabinovitch M. PPARγ Interaction with UBR5/ATMIN Promotes DNA Repair to Maintain Endothelial Homeostasis. Cell Rep 2019; 26:1333-1343.e7. [PMID: 30699358 PMCID: PMC6436616 DOI: 10.1016/j.celrep.2019.01.013] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 11/30/2018] [Accepted: 01/03/2019] [Indexed: 01/13/2023] Open
Abstract
Using proteomic approaches, we uncovered a DNA damage response (DDR) function for peroxisome proliferator activated receptor γ (PPARγ) through its interaction with the DNA damage sensor MRE11-RAD50-NBS1 (MRN) and the E3 ubiquitin ligase UBR5. We show that PPARγ promotes ATM signaling and is essential for UBR5 activity targeting ATM interactor (ATMIN). PPARγ depletion increases ATMIN protein independent of transcription and suppresses DDR-induced ATM signaling. Blocking ATMIN in this context restores ATM activation and DNA repair. We illustrate the physiological relevance of PPARγ DDR functions by using pulmonary arterial hypertension (PAH) as a model that has impaired PPARγ signaling related to endothelial cell (EC) dysfunction and unresolved DNA damage. In pulmonary arterial ECs (PAECs) from PAH patients, we observed disrupted PPARγ-UBR5 interaction, heightened ATMIN expression, and DNA lesions. Blocking ATMIN in PAH PAEC restores ATM activation. Thus, impaired PPARγ DDR functions may explain the genomic instability and loss of endothelial homeostasis in PAH.
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Affiliation(s)
- Caiyun G Li
- The Vera Moulton Wall Center for Pulmonary Vascular Disease, Department of Pediatrics and Cardiovascular Institute, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Cathal Mahon
- California Institute for Quantitative Biosciences, Department of Cellular and Molecular Pharmacology, University of California-San Francisco, San Francisco, CA 94158, USA; Department of Pharmaceutical Chemistry, University of California-San Francisco, San Francisco, CA 94158, USA
| | - Nathaly M Sweeney
- The Vera Moulton Wall Center for Pulmonary Vascular Disease, Department of Pediatrics and Cardiovascular Institute, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Erik Verschueren
- California Institute for Quantitative Biosciences, Department of Cellular and Molecular Pharmacology, University of California-San Francisco, San Francisco, CA 94158, USA
| | - Vivek Kantamani
- The Vera Moulton Wall Center for Pulmonary Vascular Disease, Department of Pediatrics and Cardiovascular Institute, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Dan Li
- The Vera Moulton Wall Center for Pulmonary Vascular Disease, Department of Pediatrics and Cardiovascular Institute, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Jan K Hennigs
- The Vera Moulton Wall Center for Pulmonary Vascular Disease, Department of Pediatrics and Cardiovascular Institute, Stanford School of Medicine, Stanford, CA 94305, USA
| | - David P Marciano
- Department of Genetics, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Isabel Diebold
- The Vera Moulton Wall Center for Pulmonary Vascular Disease, Department of Pediatrics and Cardiovascular Institute, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Ossama Abu-Halawa
- The Vera Moulton Wall Center for Pulmonary Vascular Disease, Department of Pediatrics and Cardiovascular Institute, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Matthew Elliott
- The Vera Moulton Wall Center for Pulmonary Vascular Disease, Department of Pediatrics and Cardiovascular Institute, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Silin Sa
- The Vera Moulton Wall Center for Pulmonary Vascular Disease, Department of Pediatrics and Cardiovascular Institute, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Feng Guo
- Department of Medicine, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Lingli Wang
- The Vera Moulton Wall Center for Pulmonary Vascular Disease, Department of Pediatrics and Cardiovascular Institute, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Aiqin Cao
- The Vera Moulton Wall Center for Pulmonary Vascular Disease, Department of Pediatrics and Cardiovascular Institute, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Christophe Guignabert
- The Vera Moulton Wall Center for Pulmonary Vascular Disease, Department of Pediatrics and Cardiovascular Institute, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Julie Sollier
- Department of Chemical and Systems Biology, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Nils P Nickel
- The Vera Moulton Wall Center for Pulmonary Vascular Disease, Department of Pediatrics and Cardiovascular Institute, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Mark Kaschwich
- The Vera Moulton Wall Center for Pulmonary Vascular Disease, Department of Pediatrics and Cardiovascular Institute, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Marlene Rabinovitch
- The Vera Moulton Wall Center for Pulmonary Vascular Disease, Department of Pediatrics and Cardiovascular Institute, Stanford School of Medicine, Stanford, CA 94305, USA.
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14
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Saldivar JC, Hamperl S, Bocek MJ, Chung M, Bass TE, Cisneros-Soberanis F, Samejima K, Xie L, Paulson JR, Earnshaw WC, Cortez D, Meyer T, Cimprich KA. An intrinsic S/G 2 checkpoint enforced by ATR. Science 2018; 361:806-810. [PMID: 30139873 DOI: 10.1126/science.aap9346] [Citation(s) in RCA: 178] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 02/07/2018] [Accepted: 07/13/2018] [Indexed: 12/12/2022]
Abstract
The cell cycle is strictly ordered to ensure faithful genome duplication and chromosome segregation. Control mechanisms establish this order by dictating when a cell transitions from one phase to the next. Much is known about the control of the G1/S, G2/M, and metaphase/anaphase transitions, but thus far, no control mechanism has been identified for the S/G2 transition. Here we show that cells transactivate the mitotic gene network as they exit the S phase through a CDK1 (cyclin-dependent kinase 1)-directed FOXM1 phosphorylation switch. During normal DNA replication, the checkpoint kinase ATR (ataxia-telangiectasia and Rad3-related) is activated by ETAA1 to block this switch until the S phase ends. ATR inhibition prematurely activates FOXM1, deregulating the S/G2 transition and leading to early mitosis, underreplicated DNA, and DNA damage. Thus, ATR couples DNA replication with mitosis and preserves genome integrity by enforcing an S/G2 checkpoint.
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Affiliation(s)
- Joshua C Saldivar
- Department of Chemical and Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA 94305-5441, USA
| | - Stephan Hamperl
- Department of Chemical and Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA 94305-5441, USA
| | - Michael J Bocek
- Department of Chemical and Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA 94305-5441, USA
| | - Mingyu Chung
- Department of Chemical and Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA 94305-5441, USA
| | - Thomas E Bass
- Department of Biochemistry, Vanderbilt University School of Medicine, 2215 Garland Avenue, Nashville, TN 37232, USA
| | - Fernanda Cisneros-Soberanis
- Wellcome Centre for Cell Biology, University of Edinburgh, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, Scotland, UK.,Unidad de Investigación Biomédica en Cáncer, Instituto de Investigaciones Biomédicas-Universidad Nacional Autónoma de México; Insituto Nacional de Cancerología, México City 14080, Mexico
| | - Kumiko Samejima
- Wellcome Centre for Cell Biology, University of Edinburgh, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, Scotland, UK
| | - Linfeng Xie
- Department of Chemistry, University of Wisconsin-Oshkosh, 800 Algoma Boulevard, Oshkosh, WI 54901, USA
| | - James R Paulson
- Department of Chemistry, University of Wisconsin-Oshkosh, 800 Algoma Boulevard, Oshkosh, WI 54901, USA
| | - William C Earnshaw
- Wellcome Centre for Cell Biology, University of Edinburgh, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, Scotland, UK
| | - David Cortez
- Department of Biochemistry, Vanderbilt University School of Medicine, 2215 Garland Avenue, Nashville, TN 37232, USA
| | - Tobias Meyer
- Department of Chemical and Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA 94305-5441, USA
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA 94305-5441, USA.
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15
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Daigh LH, Liu C, Chung M, Cimprich KA, Meyer T. Stochastic Endogenous Replication Stress Causes ATR-Triggered Fluctuations in CDK2 Activity that Dynamically Adjust Global DNA Synthesis Rates. Cell Syst 2018; 7:17-27.e3. [PMID: 29909278 PMCID: PMC6436092 DOI: 10.1016/j.cels.2018.05.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 04/06/2018] [Accepted: 05/18/2018] [Indexed: 12/21/2022]
Abstract
Faithful DNA replication is challenged by stalling of replication forks during S phase. Replication stress is further increased in cancer cells or in response to genotoxic insults. Using live single-cell image analysis, we found that CDK2 activity fluctuates throughout an unperturbed S phase. We show that CDK2 fluctuations result from transient ATR signals triggered by stochastic replication stress events. In turn, fluctuating endogenous CDK2 activity causes corresponding decreases and increases in DNA synthesis rates, linking changes in stochastic replication stress to fluctuating global DNA replication rates throughout S phase. Moreover, cells that reenter the cell cycle after mitogen stimulation have increased CDK2 fluctuations and prolonged S phase resulting from increased replication stress-induced CDK2 suppression. Thus, our study reveals a dynamic control principle for DNA replication whereby CDK2 activity is suppressed and fluctuates throughout S phase to continually adjust global DNA synthesis rates in response to recurring stochastic replication stress events. Live single-cell microscopy reveals a control principal that helps maintain proper duplication of genetic material. Upon inevitable DNA replication stress during S phase, cells signal through ATR to attenuate CDK2 activity, which then decreases global DNA synthesis rate. This feedback enables dynamic modulation of S-phase progression.
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Affiliation(s)
- Leighton H Daigh
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Chad Liu
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Mingyu Chung
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Tobias Meyer
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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16
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Affiliation(s)
- Joshua C Saldivar
- Department of Chemical and Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA 94305-5441, USA
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA 94305-5441, USA.
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17
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Saldivar JC, Cortez D, Cimprich KA. Publisher correction: The essential kinase ATR: ensuring faithful duplication of a challenging genome. Nat Rev Mol Cell Biol 2017; 18:783. [PMID: 29115300 DOI: 10.1038/nrm.2017.116] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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18
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Hamperl S, Bocek MJ, Saldivar JC, Swigut T, Cimprich KA. Transcription-Replication Conflict Orientation Modulates R-Loop Levels and Activates Distinct DNA Damage Responses. Cell 2017; 170:774-786.e19. [PMID: 28802045 DOI: 10.1016/j.cell.2017.07.043] [Citation(s) in RCA: 367] [Impact Index Per Article: 52.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2017] [Revised: 05/09/2017] [Accepted: 07/25/2017] [Indexed: 12/19/2022]
Abstract
Conflicts between transcription and replication are a potent source of DNA damage. Co-transcriptional R-loops could aggravate such conflicts by creating an additional barrier to replication fork progression. Here, we use a defined episomal system to investigate how conflict orientation and R-loop formation influence genome stability in human cells. R-loops, but not normal transcription complexes, induce DNA breaks and orientation-specific DNA damage responses during conflicts with replication forks. Unexpectedly, the replisome acts as an orientation-dependent regulator of R-loop levels, reducing R-loops in the co-directional (CD) orientation but promoting their formation in the head-on (HO) orientation. Replication stress and deregulated origin firing increase the number of HO collisions leading to genome-destabilizing R-loops. Our findings connect DNA replication to R-loop homeostasis and suggest a mechanistic basis for genome instability resulting from deregulated DNA replication, observed in cancer and other disease states.
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Affiliation(s)
- Stephan Hamperl
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Michael J Bocek
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Joshua C Saldivar
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Tomek Swigut
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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19
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Abstract
One way to preserve a rare book is to lock it away from all potential sources of damage. Of course, an inaccessible book is also of little use, and the paper and ink will continue to degrade with age in any case. Like a book, the information stored in our DNA needs to be read, but it is also subject to continuous assault and therefore needs to be protected. In this Review, we examine how the replication stress response that is controlled by the kinase ataxia telangiectasia and Rad3-related (ATR) senses and resolves threats to DNA integrity so that the DNA remains available to read in all of our cells. We discuss the multiple data that have revealed an elegant yet increasingly complex mechanism of ATR activation. This involves a core set of components that recruit ATR to stressed replication forks, stimulate kinase activity and amplify ATR signalling. We focus on the activities of ATR in the control of cell cycle checkpoints, origin firing and replication fork stability, and on how proper regulation of these processes is crucial to ensure faithful duplication of a challenging genome.
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Affiliation(s)
- Joshua C Saldivar
- Department of Chemical and Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, California 94305-5441, USA
| | - David Cortez
- Department of Biochemistry, School of Medicine, Vanderbilt University, Nashville, Tennessee 37232, USA
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, California 94305-5441, USA
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20
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Hess GT, Frésard L, Han K, Lee CH, Li A, Cimprich KA, Montgomery SB, Bassik MC. Directed evolution using dCas9-targeted somatic hypermutation in mammalian cells. Nat Methods 2016; 13:1036-1042. [PMID: 27798611 PMCID: PMC5557288 DOI: 10.1038/nmeth.4038] [Citation(s) in RCA: 319] [Impact Index Per Article: 39.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 09/27/2016] [Indexed: 12/23/2022]
Abstract
Engineering and study of protein function by directed evolution has been limited by the technical requirement to use global mutagenesis or introduce DNA libraries. Here, we develop CRISPR-X, a strategy to repurpose the somatic hypermutation machinery for protein engineering in situ. Using catalytically inactive dCas9 to recruit variants of cytidine deaminase (AID) with MS2-modified sgRNAs, we can specifically mutagenize endogenous targets with limited off-target damage. This generates diverse libraries of localized point mutations and can target multiple genomic locations simultaneously. We mutagenize GFP and select for spectrum-shifted variants, including EGFP. Additionally, we mutate the target of the cancer therapeutic bortezomib, PSMB5, and identify known and novel mutations that confer bortezomib resistance. Finally, using a hyperactive AID variant, we mutagenize loci both upstream and downstream of transcriptional start sites. These experiments illustrate a powerful approach to create complex libraries of genetic variants in native context, which is broadly applicable to investigate and improve protein function.
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Affiliation(s)
- Gaelen T Hess
- Department of Genetics, Stanford University, Stanford, California, USA
| | - Laure Frésard
- Department of Pathology, Stanford University, Stanford, California, USA
| | - Kyuho Han
- Department of Genetics, Stanford University, Stanford, California, USA
| | - Cameron H Lee
- Department of Genetics, Stanford University, Stanford, California, USA
| | - Amy Li
- Department of Genetics, Stanford University, Stanford, California, USA
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University, Stanford, California, USA
| | - Stephen B Montgomery
- Department of Genetics, Stanford University, Stanford, California, USA
- Department of Pathology, Stanford University, Stanford, California, USA
| | - Michael C Bassik
- Department of Genetics, Stanford University, Stanford, California, USA
- Stanford University Chemistry, Engineering, and Medicine for Human Health (ChEM-H), Stanford, California, USA
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21
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Stork CT, Bocek M, Crossley MP, Sollier J, Sanz LA, Chédin F, Swigut T, Cimprich KA. Co-transcriptional R-loops are the main cause of estrogen-induced DNA damage. eLife 2016; 5. [PMID: 27552054 PMCID: PMC5030092 DOI: 10.7554/elife.17548] [Citation(s) in RCA: 180] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 08/18/2016] [Indexed: 12/19/2022] Open
Abstract
The hormone estrogen (E2) binds the estrogen receptor to promote transcription of E2-responsive genes in the breast and other tissues. E2 also has links to genomic instability, and elevated E2 levels are tied to breast cancer. Here, we show that E2 stimulation causes a rapid, global increase in the formation of R-loops, co-transcriptional RNA-DNA products, which in some instances have been linked to DNA damage. We show that E2-dependent R-loop formation and breast cancer rearrangements are highly enriched at E2-responsive genomic loci and that E2 induces DNA replication-dependent double-strand breaks (DSBs). Strikingly, many DSBs that accumulate in response to E2 are R-loop dependent. Thus, R-loops resulting from the E2 transcriptional response are a significant source of DNA damage. This work reveals a novel mechanism by which E2 stimulation leads to genomic instability and highlights how transcriptional programs play an important role in shaping the genomic landscape of DNA damage susceptibility. DOI:http://dx.doi.org/10.7554/eLife.17548.001 The hormone estrogen controls the development of breast tissue. However too much estrogen can damage the DNA in human cells and may be linked to an increased risk of breast cancer. In breast cells, estrogen activates many genes via a process called transcription. The transcription process results in the production of an RNA molecule that contains a copy of the instructions encoded within the gene. Previous studies have found that, in certain cases, a new RNA molecule can stick to the matching DNA from which it was made. This creates a structure known as an R-loop, which can lead the DNA to break. DNA breaks are particularly harmful because they can dramatically alter the cell’s genome in ways that allow it to become cancerous. However, it was not clear if the large increase in transcription triggered by estrogen causes an increase in R-loops, which could help to explain the DNA damage that has been reported to occur when cells are treated with estrogen. Now, Stork et al. show that treating human breast cancer cells with estrogen causes an increase in R-loops and DNA breaks. The R-loops occurred particularly in regions of the genome that contain estrogen-activated genes. Stork et al. also found that regions of estrogen-activated transcription were more frequently mutated in breast cancers, and further experiments confirmed that the R-loops were responsible for many of the DNA breaks that occurred following estrogen treatment. Taken together, these findings demonstrate that the changes in transcription due to estrogen lead to increased R-loops and DNA breaks, which may make the cells vulnerable to becoming cancerous. The next challenge is to determine precisely where these DNA breaks that result from estrogen occur on the DNA. Knowing the location of the DNA breaks will be useful in determining what additional factors or genomic features make an R-loop more prone to being broken. This in turn might help explain how the R-loops lead to DNA damage. In addition, further studies are also needed to determine if tumor samples from breast cancer patients also contain increased levels of R-loops. DOI:http://dx.doi.org/10.7554/eLife.17548.002
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Affiliation(s)
- Caroline Townsend Stork
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, United States
| | - Michael Bocek
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, United States
| | - Madzia P Crossley
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, United States
| | - Julie Sollier
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, United States
| | - Lionel A Sanz
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, United States
| | - Frédéric Chédin
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, United States
| | - Tomek Swigut
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, United States
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, United States
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22
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Slaats GG, Saldivar JC, Bacal J, Zeman MK, Kile AC, Hynes AM, Srivastava S, Nazmutdinova J, den Ouden K, Zagers MS, Foletto V, Verhaar MC, Miles C, Sayer JA, Cimprich KA, Giles RH. DNA replication stress underlies renal phenotypes in CEP290-associated Joubert syndrome. J Clin Invest 2015; 125:3657-66. [PMID: 26301811 DOI: 10.1172/jci80657] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 07/10/2015] [Indexed: 11/17/2022] Open
Abstract
Juvenile ciliopathy syndromes that are associated with renal cysts and premature renal failure are commonly the result of mutations in the gene encoding centrosomal protein CEP290. In addition to centrosomes and the transition zone at the base of the primary cilium, CEP290 also localizes to the nucleus; however, the nuclear function of CEP290 is unknown. Here, we demonstrate that reduction of cellular CEP290 in primary human and mouse kidney cells as well as in zebrafish embryos leads to enhanced DNA damage signaling and accumulation of DNA breaks ex vivo and in vivo. Compared with those from WT mice, primary kidney cells from Cep290-deficient mice exhibited supernumerary centrioles, decreased replication fork velocity, fork asymmetry, and increased levels of cyclin-dependent kinases (CDKs). Treatment of Cep290-deficient cells with CDK inhibitors rescued DNA damage and centriole number. Moreover, the loss of primary cilia that results from CEP290 dysfunction was rescued in 3D cell culture spheroids of primary murine kidney cells after exposure to CDK inhibitors. Together, our results provide a link between CEP290 and DNA replication stress and suggest CDK inhibition as a potential treatment strategy for a wide range of ciliopathy syndromes.
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23
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Kile AC, Chavez DA, Bacal J, Eldirany S, Korzhnev DM, Bezsonova I, Eichman BF, Cimprich KA. HLTF's Ancient HIRAN Domain Binds 3' DNA Ends to Drive Replication Fork Reversal. Mol Cell 2015; 58:1090-100. [PMID: 26051180 DOI: 10.1016/j.molcel.2015.05.013] [Citation(s) in RCA: 147] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 04/29/2015] [Accepted: 05/01/2015] [Indexed: 12/20/2022]
Abstract
Stalled replication forks are a critical problem for the cell because they can lead to complex genome rearrangements that underlie cell death and disease. Processes such as DNA damage tolerance and replication fork reversal protect stalled forks from these events. A central mediator of these DNA damage responses in humans is the Rad5-related DNA translocase, HLTF. Here, we present biochemical and structural evidence that the HIRAN domain, an ancient and conserved domain found in HLTF and other DNA processing proteins, is a modified oligonucleotide/oligosaccharide (OB) fold that binds to 3' ssDNA ends. We demonstrate that the HIRAN domain promotes HLTF-dependent fork reversal in vitro through its interaction with 3' ssDNA ends found at forks. Finally, we show that HLTF restrains replication fork progression in cells in a HIRAN-dependent manner. These findings establish a mechanism of HLTF-mediated fork reversal and provide insight into the requirement for distinct fork remodeling activities in the cell.
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Affiliation(s)
- Andrew C Kile
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Diana A Chavez
- Department of Biological Sciences and Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Julien Bacal
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Sherif Eldirany
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT 06032, USA
| | - Dmitry M Korzhnev
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT 06032, USA
| | - Irina Bezsonova
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT 06032, USA
| | - Brandt F Eichman
- Department of Biological Sciences and Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA.
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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24
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Abstract
R-loops, nucleic acid structures consisting of an RNA-DNA hybrid and displaced single-stranded (ss) DNA, are ubiquitous in organisms from bacteria to mammals. First described in bacteria where they initiate DNA replication, it now appears that R-loops regulate diverse cellular processes such as gene expression, immunoglobulin (Ig) class switching, and DNA repair. Changes in R-loop regulation induce DNA damage and genome instability, and recently it was shown that R-loops are associated with neurodegenerative disorders. We discuss recent developments in the field; in particular, the regulation and effects of R-loops in cells, their effect on genomic and epigenomic stability, and their potential contribution to the origin of diseases including cancer and neurodegenerative disorders.
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Affiliation(s)
- Julie Sollier
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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Sollier J, Stork CT, García-Rubio ML, Paulsen RD, Aguilera A, Cimprich KA. Transcription-coupled nucleotide excision repair factors promote R-loop-induced genome instability. Mol Cell 2014; 56:777-85. [PMID: 25435140 DOI: 10.1016/j.molcel.2014.10.020] [Citation(s) in RCA: 379] [Impact Index Per Article: 37.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 10/07/2014] [Accepted: 10/22/2014] [Indexed: 11/19/2022]
Abstract
R-loops, consisting of an RNA-DNA hybrid and displaced single-stranded DNA, are physiological structures that regulate various cellular processes occurring on chromatin. Intriguingly, changes in R-loop dynamics have also been associated with DNA damage accumulation and genome instability; however, the mechanisms underlying R-loop-induced DNA damage remain unknown. Here we demonstrate in human cells that R-loops induced by the absence of diverse RNA processing factors, including the RNA/DNA helicases Aquarius (AQR) and Senataxin (SETX), or by the inhibition of topoisomerase I, are actively processed into DNA double-strand breaks (DSBs) by the nucleotide excision repair endonucleases XPF and XPG. Surprisingly, DSB formation requires the transcription-coupled nucleotide excision repair (TC-NER) factor Cockayne syndrome group B (CSB), but not the global genome repair protein XPC. These findings reveal an unexpected and potentially deleterious role for TC-NER factors in driving R-loop-induced DNA damage and genome instability.
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Affiliation(s)
- Julie Sollier
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Caroline Townsend Stork
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - María L García-Rubio
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla, Avenida Américo Vespucio, 41092 Seville, Spain
| | - Renee D Paulsen
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla, Avenida Américo Vespucio, 41092 Seville, Spain
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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26
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de Jesus Perez VA, Yuan K, Lyuksyutova MA, Dewey F, Orcholski ME, Shuffle EM, Mathur M, Yancy L, Rojas V, Li CG, Cao A, Alastalo TP, Khazeni N, Cimprich KA, Butte AJ, Ashley E, Zamanian RT. Whole-exome sequencing reveals TopBP1 as a novel gene in idiopathic pulmonary arterial hypertension. Am J Respir Crit Care Med 2014; 189:1260-72. [PMID: 24702692 DOI: 10.1164/rccm.201310-1749oc] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Idiopathic pulmonary arterial hypertension (IPAH) is a life-threatening disorder characterized by progressive loss of pulmonary microvessels. Although mutations in the bone morphogenetic receptor 2 (BMPR2) are found in 80% of heritable and ∼15% of patients with IPAH, their low penetrance (∼20%) suggests that other unidentified genetic modifiers are required for manifestation of the disease phenotype. Use of whole-exome sequencing (WES) has recently led to the discovery of novel susceptibility genes in heritable PAH, but whether WES can also accelerate gene discovery in IPAH remains unknown. OBJECTIVES To determine whether WES can help identify novel gene modifiers in patients with IPAH. METHODS Exome capture and sequencing was performed on genomic DNA isolated from 12 unrelated patients with IPAH lacking BMPR2 mutations. Observed genetic variants were prioritized according to their pathogenic potential using ANNOVAR. MEASUREMENTS AND MAIN RESULTS A total of nine genes were identified as high-priority candidates. Our top hit was topoisomerase DNA binding II binding protein 1 (TopBP1), a gene involved in the response to DNA damage and replication stress. We found that TopBP1 expression was reduced in vascular lesions and pulmonary endothelial cells isolated from patients with IPAH. Although TopBP1 deficiency made endothelial cells susceptible to DNA damage and apoptosis in response to hydroxyurea, its restoration resulted in less DNA damage and improved cell survival. CONCLUSIONS WES led to the discovery of TopBP1, a gene whose deficiency may increase susceptibility to small vessel loss in IPAH. We predict that use of WES will help identify gene modifiers that influence an individual's risk of developing IPAH.
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27
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Abstract
Deubiquitination of Rad18 drives its localization to sites of DNA damage and formation of the Rad18–SHPRH complexes necessary for error-free lesion bypass. Deoxyribonucleic acid (DNA) lesions encountered during replication are often bypassed using DNA damage tolerance (DDT) pathways to avoid prolonged fork stalling and allow for completion of DNA replication. Rad18 is a central E3 ubiquitin ligase in DDT, which exists in a monoubiquitinated (Rad18•Ub) and nonubiquitinated form in human cells. We find that Rad18 is deubiquitinated when cells are treated with methyl methanesulfonate or hydrogen peroxide. The ubiquitinated form of Rad18 does not interact with SNF2 histone linker plant homeodomain RING helicase (SHPRH) or helicase-like transcription factor, two downstream E3 ligases needed to carry out error-free bypass of DNA lesions. Instead, it interacts preferentially with the zinc finger domain of another, nonubiquitinated Rad18 and may inhibit Rad18 function in trans. Ubiquitination also prevents Rad18 from localizing to sites of DNA damage, inducing proliferating cell nuclear antigen monoubiquitination, and suppressing mutagenesis. These data reveal a new role for monoubiquitination in controlling Rad18 function and suggest that damage-specific deubiquitination promotes a switch from Rad18•Ub–Rad18 complexes to the Rad18–SHPRH complexes necessary for error-free lesion bypass in cells.
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Affiliation(s)
- Michelle K Zeman
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305
| | - Jia-Ren Lin
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305
| | - Raimundo Freire
- Unidad de Investigación, Hospital Universitario de Canarias, Instituto de Tecnologias Biomedicas, 38320 Tenerife, Spain
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305
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28
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Abstract
Accurate DNA replication and DNA repair are crucial for the maintenance of genome stability, and it is generally accepted that failure of these processes is a major source of DNA damage in cells. Intriguingly, recent evidence suggests that DNA damage is more likely to occur at genomic loci with high transcriptional activity. Furthermore, loss of certain RNA processing factors in eukaryotic cells is associated with increased formation of co-transcriptional RNA:DNA hybrid structures known as R-loops, resulting in double-strand breaks (DSBs) and DNA damage. However, the molecular mechanisms by which R-loop structures ultimately lead to DNA breaks and genome instability is not well understood. In this review, we summarize the current knowledge about the formation, recognition and processing of RNA:DNA hybrids, and discuss possible mechanisms by which these structures contribute to DNA damage and genome instability in the cell.
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Affiliation(s)
- Stephan Hamperl
- Department of Chemical, Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA 94305-5441, USA
| | - Karlene A Cimprich
- Department of Chemical, Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA 94305-5441, USA.
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29
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Abstract
Replication stress is a complex phenomenon that has serious implications for genome stability, cell survival and human disease. Generation of aberrant replication fork structures containing single-stranded DNA activates the replication stress response, primarily mediated by the kinase ATR (ATM- and Rad3-related). Along with its downstream effectors, ATR stabilizes and helps to restart stalled replication forks, avoiding the generation of DNA damage and genome instability. Understanding this response may be key to diagnosing and treating human diseases caused by defective responses to replication stress.
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Affiliation(s)
- Michelle K Zeman
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, California 94305, USA
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, California 94305, USA
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30
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Abstract
Replication stress is a complex phenomenon that has serious implications for genome stability, cell survival and human disease. Generation of aberrant replication fork structures containing single-stranded DNA activates the replication stress response, primarily mediated by the kinase ATR (ATM- and Rad3-related). Along with its downstream effectors, ATR stabilizes and helps to restart stalled replication forks, avoiding the generation of DNA damage and genome instability. Understanding this response may be key to diagnosing and treating human diseases caused by defective responses to replication stress.
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Affiliation(s)
- Michelle K Zeman
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, California 94305, USA
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, California 94305, USA
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31
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Couch FB, Bansbach CE, Driscoll R, Luzwick JW, Glick GG, Bétous R, Carroll CM, Jung SY, Qin J, Cimprich KA, Cortez D. ATR phosphorylates SMARCAL1 to prevent replication fork collapse. Genes Dev 2013; 27:1610-23. [PMID: 23873943 DOI: 10.1101/gad.214080.113] [Citation(s) in RCA: 299] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The DNA damage response kinase ataxia telangiectasia and Rad3-related (ATR) coordinates much of the cellular response to replication stress. The exact mechanisms by which ATR regulates DNA synthesis in conditions of replication stress are largely unknown, but this activity is critical for the viability and proliferation of cancer cells, making ATR a potential therapeutic target. Here we use selective ATR inhibitors to demonstrate that acute inhibition of ATR kinase activity yields rapid cell lethality, disrupts the timing of replication initiation, slows replication elongation, and induces fork collapse. We define the mechanism of this fork collapse, which includes SLX4-dependent cleavage yielding double-strand breaks and CtIP-dependent resection generating excess single-stranded template and nascent DNA strands. Our data suggest that the DNA substrates of these nucleases are generated at least in part by the SMARCAL1 DNA translocase. Properly regulated SMARCAL1 promotes stalled fork repair and restart; however, unregulated SMARCAL1 contributes to fork collapse when ATR is inactivated in both mammalian and Xenopus systems. ATR phosphorylates SMARCAL1 on S652, thereby limiting its fork regression activities and preventing aberrant fork processing. Thus, phosphorylation of SMARCAL1 is one mechanism by which ATR prevents fork collapse, promotes the completion of DNA replication, and maintains genome integrity.
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Affiliation(s)
- Frank B Couch
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
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32
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Choi HJC, Lin JR, Vannier JB, Slaats GG, Kile AC, Paulsen RD, Manning DK, Beier DR, Giles RH, Boulton SJ, Cimprich KA. NEK8 links the ATR-regulated replication stress response and S phase CDK activity to renal ciliopathies. Mol Cell 2013; 51:423-39. [PMID: 23973373 PMCID: PMC3790667 DOI: 10.1016/j.molcel.2013.08.006] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 06/09/2013] [Accepted: 07/24/2013] [Indexed: 01/03/2023]
Abstract
Renal ciliopathies are a leading cause of kidney failure, but their exact etiology is poorly understood. NEK8/NPHP9 is a ciliary kinase associated with two renal ciliopathies in humans and mice, nephronophthisis (NPHP) and polycystic kidney disease. Here, we identify NEK8 as a key effector of the ATR-mediated replication stress response. Cells lacking NEK8 form spontaneous DNA double-strand breaks (DSBs) that further accumulate when replication forks stall, and they exhibit reduced fork rates, unscheduled origin firing, and increased replication fork collapse. NEK8 suppresses DSB formation by limiting cyclin A-associated CDK activity. Strikingly, a mutation in NEK8 that is associated with renal ciliopathies affects its genome maintenance functions. Moreover, kidneys of NEK8 mutant mice accumulate DNA damage, and loss of NEK8 or replication stress similarly disrupts renal cell architecture in a 3D-culture system. Thus, NEK8 is a critical component of the DNA damage response that links replication stress with cystic kidney disorders.
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Affiliation(s)
- Hyo Jei Claudia Choi
- Stanford University School of Medicine, Department of Chemical and Systems Biology, Stanford, CA 94025
| | - Jia-Ren Lin
- Stanford University School of Medicine, Department of Chemical and Systems Biology, Stanford, CA 94025
| | - Jean-Baptiste Vannier
- London Research Institute, Clare Hall Laboratories, Blanche Lane, South Mimms, EN6 3LD, UK
| | - Gisela G. Slaats
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Heidelberglaan 100, 3584CX Utrecht, the Netherlands
| | - Andrew C. Kile
- Stanford University School of Medicine, Department of Chemical and Systems Biology, Stanford, CA 94025
| | - Renee D. Paulsen
- Stanford University School of Medicine, Department of Chemical and Systems Biology, Stanford, CA 94025
| | | | - David R. Beier
- Brigham and Women's Hospital, Division of Genetics, Boston MA, 02115
| | - Rachel H. Giles
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Heidelberglaan 100, 3584CX Utrecht, the Netherlands
| | - Simon J. Boulton
- London Research Institute, Clare Hall Laboratories, Blanche Lane, South Mimms, EN6 3LD, UK
| | - Karlene A. Cimprich
- Stanford University School of Medicine, Department of Chemical and Systems Biology, Stanford, CA 94025
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33
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Machado LEF, Pustovalova Y, Kile AC, Pozhidaeva A, Cimprich KA, Almeida FCL, Bezsonova I, Korzhnev DM. PHD domain from human SHPRH. J Biomol NMR 2013; 56:393-399. [PMID: 23907177 PMCID: PMC3905319 DOI: 10.1007/s10858-013-9758-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Accepted: 06/22/2013] [Indexed: 06/02/2023]
Abstract
SHPRH (SNF2, histone linker, PHD, RING, helicase) is a SWI2/SNF2-family ATP-dependent chromatin remodeling factor, and one of E3 ubiquitin ligases responsible for Ubc13-Mms2-dependent K63 poly-ubiquitination of PCNA (proliferating cell nuclear antigen) that promotes error-free DNA damage tolerance in eukaryotes. In contrast to its functional homologues, S. cerevisiae Rad5 and human HLTF (helicase like transcription factor), SHPRH contains a PHD (plant homeodomain) finger embedded in the ‘minor’ insert region of the core helicase-like domain. PHD fingers are often found in proteins involved in chromatin remodeling and transcription regulation, and are generally considered as ‘readers’ of methylation state of histone tails, primarily the lysine 4 (K4) residue of histone H3 (H3K4). Here we report the solution NMR structure of the SHPRH PHD domain and investigate whether this domain is capable of recognizing H3K4 modifications. The domain adopts a canonical PHD-finger fold with a central two-stranded anti-parallel β-sheet flanked on both sides by the two interleaved zinc-binding sites. Despite the presence of a subset of aromatic residues characteristic for PHD-fingers that preferentially bind methylated H3K4, NMR titration experiments reveal that SHPRH PHD does not specifically interact with the H3-derived peptides irrespective of K4 methylation. This result suggests that the SHPRH PHD domain might have evolved a different function other than recognizing histone modifications.
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Affiliation(s)
- Luciana E. F. Machado
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, Farmington, CT 06030, USA
- Centro Nacional de Ressonância Magnética Nuclear de Macromoléculas, Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil
| | - Yulia Pustovalova
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, Farmington, CT 06030, USA
| | - Andrew C. Kile
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA 94305, USA
| | - Alexandra Pozhidaeva
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, Farmington, CT 06030, USA
| | - Karlene A. Cimprich
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA 94305, USA
| | - Fabio C. L. Almeida
- Centro Nacional de Ressonância Magnética Nuclear de Macromoléculas, Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil
| | - Irina Bezsonova
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, Farmington, CT 06030, USA
| | - Dmitry M. Korzhnev
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, Farmington, CT 06030, USA
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34
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Duursma AM, Driscoll R, Elias JE, Cimprich KA. A role for the MRN complex in ATR activation via TOPBP1 recruitment. Mol Cell 2013; 50:116-22. [PMID: 23582259 DOI: 10.1016/j.molcel.2013.03.006] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 02/11/2013] [Accepted: 03/05/2013] [Indexed: 12/17/2022]
Abstract
The MRN (MRE11-RAD50-NBS1) complex has been implicated in many aspects of the DNA damage response. It has key roles in sensing and processing DNA double-strand breaks, as well as in activation of ATM (ataxia telangiectasia mutated). We reveal a function for MRN in ATR (ATM- and RAD3-related) activation by using defined ATR-activating DNA structures in Xenopus egg extracts. Strikingly, we demonstrate that MRN is required for recruitment of TOPBP1 to an ATR-activating structure that contains a single-stranded DNA (ssDNA) and a double-stranded DNA (dsDNA) junction and that this recruitment is necessary for phosphorylation of CHK1. We also show that the 911 (RAD9-RAD1-HUS1) complex is not required for TOPBP1 recruitment but is essential for TOPBP1 function. Thus, whereas MRN is required for TOPBP1 recruitment at an ssDNA-to-dsDNA junction, 911 is required for TOPBP1 "activation." These findings provide molecular insights into how ATR is activated.
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Affiliation(s)
- Anja M Duursma
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA 94305, USA
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35
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Abstract
Studies from Ciccia et al. (2012) and Yuan et al. (2012) in this issue of Molecular Cell, together with Weston et al. (2012), reveal that the translocase ZRANB3/AH2 can recognize K63-linked polyubiquitinated PCNA and plays an important role in restarting stalled replication forks.
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Affiliation(s)
- Michelle K Zeman
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA 94305, USA
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36
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Lin JR, Zeman MK, Chen JY, Yee MC, Cimprich KA. SHPRH and HLTF act in a damage-specific manner to coordinate different forms of postreplication repair and prevent mutagenesis. Mol Cell 2011; 42:237-49. [PMID: 21396873 DOI: 10.1016/j.molcel.2011.02.026] [Citation(s) in RCA: 138] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2010] [Revised: 10/29/2010] [Accepted: 02/23/2011] [Indexed: 12/27/2022]
Abstract
Postreplication repair (PRR) pathways play important roles in restarting stalled replication forks and regulating mutagenesis. In yeast, Rad5-mediated damage avoidance and Rad18-mediated translesion synthesis (TLS) are two forms of PRR. Two Rad5-related proteins, SHPRH and HLTF, have been identified in mammalian cells, but their specific roles in PRR are unclear. Here, we show that HLTF and SHPRH suppress mutagenesis in a damage-specific manner, preventing mutations induced by UV and MMS, respectively. Following UV, HLTF enhances PCNA monoubiquitination and recruitment of TLS polymerase η, while also inhibiting SHPRH function. In contrast, MMS promotes the degradation of HLTF and the interactions of SHPRH with Rad18 and polymerase κ. Our data suggest not only that cells differentially utilize HLTF and SHPRH for different forms of DNA damage, but also, surprisingly, that HLTF and SHPRH may coordinate the two main branches of PRR to choose the proper bypass mechanism for minimizing mutagenesis.
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Affiliation(s)
- Jia-Ren Lin
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA 94305, USA
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37
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Abstract
An increased number of primer–template junctions generated by PCNA, Pol-δ, and Pol-ε at stalled replication forks activates Chk1. Stalled replication forks activate and are stabilized by the ATR (ataxia-telangiectasia mutated and Rad3 related)-mediated checkpoint, but ultimately, they must also recover from the arrest. Although primed single-stranded DNA (ssDNA) is sufficient for checkpoint activation, it is still unknown how this signal is generated at a stalled replication fork. Furthermore, it is not clear how recovery and fork restart occur in higher eukaryotes. Using Xenopus laevis egg extracts, we show that DNA replication continues at a stalled fork through the synthesis and elongation of new primers independent of the checkpoint. This synthesis is dependent on the activity of proliferating cell nuclear antigen, Pol-δ, and Pol-ε, and it contributes to the phosphorylation of Chk1. We also used defined DNA structures to show that for a fixed amount of ssDNA, increasing the number of primer–template junctions strongly enhances Chk1 phosphorylation. These results suggest that new primers are synthesized at stalled replication forks by the leading and lagging strand polymerases and that accumulation of these primers may contribute to checkpoint activation.
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Affiliation(s)
- Christopher Van
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA 94305, USA
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38
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Abstract
In this issue of Genes & Development, four papers report that the annealing helicase HepA-related protein (HARP, also known as SMARCAL1 [SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily a-like 1]) binds directly to the ssDNA-binding protein Replication protein A (RPA) and is recruited to sites of replicative stress. Knockdown of HARP results in hypersensitivity to multiple DNA-damaging agents and defects in fork stability or restart. These exciting insights reveal a key new player in the S-phase DNA damage response.
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Affiliation(s)
- Robert Driscoll
- Department of Chemical and Systems Biology, Stanford University, Stanford, California 94305, USA
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39
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Paulsen RD, Soni DV, Wollman R, Hahn AT, Yee MC, Guan A, Hesley JA, Miller SC, Cromwell EF, Solow-Cordero DE, Meyer T, Cimprich KA. A genome-wide siRNA screen reveals diverse cellular processes and pathways that mediate genome stability. Mol Cell 2009; 35:228-39. [PMID: 19647519 DOI: 10.1016/j.molcel.2009.06.021] [Citation(s) in RCA: 418] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2009] [Revised: 05/21/2009] [Accepted: 06/26/2009] [Indexed: 12/26/2022]
Abstract
Signaling pathways that respond to DNA damage are essential for the maintenance of genome stability and are linked to many diseases, including cancer. Here, a genome-wide siRNA screen was employed to identify additional genes involved in genome stabilization by monitoring phosphorylation of the histone variant H2AX, an early mark of DNA damage. We identified hundreds of genes whose downregulation led to elevated levels of H2AX phosphorylation (gammaH2AX) and revealed links to cellular complexes and to genes with unclassified functions. We demonstrate a widespread role for mRNA-processing factors in preventing DNA damage, which in some cases is caused by aberrant RNA-DNA structures. Furthermore, we connect increased gammaH2AX levels to the neurological disorder Charcot-Marie-Tooth (CMT) syndrome, and we find a role for several CMT proteins in the DNA-damage response. These data indicate that preservation of genome stability is mediated by a larger network of biological processes than previously appreciated.
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Affiliation(s)
- Renee D Paulsen
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA 94305, USA
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40
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Kochaniak AB, Habuchi S, Loparo JJ, Chang DJ, Cimprich KA, Walter JC, van Oijen AM. Proliferating cell nuclear antigen uses two distinct modes to move along DNA. J Biol Chem 2009; 284:17700-10. [PMID: 19411704 PMCID: PMC2719409 DOI: 10.1074/jbc.m109.008706] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Indexed: 02/06/2023] Open
Abstract
Proliferating cell nuclear antigen (PCNA) plays an important role in eukaryotic genomic maintenance by topologically binding DNA and recruiting replication and repair proteins. The ring-shaped protein forms a closed circle around double-stranded DNA and is able to move along the DNA in a random walk. The molecular nature of this diffusion process is poorly understood. We use single-molecule imaging to visualize the movement of individual, fluorescently labeled PCNA molecules along stretched DNA. Measurements of diffusional properties as a function of viscosity and protein size suggest that PCNA moves along DNA using two different sliding modes. Most of the time, the clamp moves while rotationally tracking the helical pitch of the DNA duplex. In a less frequently used second mode of diffusion, the movement of the protein is uncoupled from the helical pitch, and the clamp diffuses at much higher rates.
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Affiliation(s)
- Anna B. Kochaniak
- From the Graduate Program in Biophysics, Harvard University, Cambridge, Massachusetts 02138
- the Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115
| | - Satoshi Habuchi
- the Graduate School of Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8552, Japan, and
| | - Joseph J. Loparo
- the Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115
| | - Debbie J. Chang
- the Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, California 94305
| | - Karlene A. Cimprich
- the Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, California 94305
| | - Johannes C. Walter
- the Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115
| | - Antoine M. van Oijen
- the Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115
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41
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Abstract
Genome maintenance is a constant concern for cells, and a coordinated response to DNA damage is required to maintain cellular viability and prevent disease. The ataxia-telangiectasia mutated (ATM) and ATM and RAD3-related (ATR) protein kinases act as master regulators of the DNA-damage response by signalling to control cell-cycle transitions, DNA replication, DNA repair and apoptosis. Recent studies have provided new insights into the mechanisms that control ATR activation, have helped to explain the overlapping but non-redundant activities of ATR and ATM in DNA-damage signalling, and have clarified the crucial functions of ATR in maintaining genome integrity.
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Affiliation(s)
- Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Clark Center, 318 Campus Drive, W350B, Stanford, California 94305-5441, USA.
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42
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Cimprich KA, McDougall C, Lin J. Mechanisms for Maintaining Genome Stability at the Replication Fork. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.246.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | - Jia‐Ren Lin
- Chemical and Systems BiologyStanford UniversityStanfordCA
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43
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Abstract
The ATR kinase is a critical upstream component of a checkpoint pathway that responds to many forms of damaged and incompletely replicated DNA. Cellular processes such as DNA replication and repair are thought to convert these DNA lesions into a common DNA intermediate that activates this signaling pathway. Indeed, numerous studies have shown that two DNA structures formed during these processes--single-stranded DNA (ssDNA) and junctions between double-stranded DNA (dsDNA) and ssDNA--are important components of the ATR-activating structure. However, an unanswered question is whether primed ssDNA is sufficient for activation of the ATR response. We recently demonstrated that primed ssDNA is sufficient to induce a bona fide checkpoint response in Xenopus egg extracts. This is the first well-defined DNA structure capable of eliciting ATR activation. Using this structure, we examined the contribution of ds/ssDNA junctions and ssDNA to checkpoint activation. Our results indicate the context in which the checkpoint-activating structure is generated may contribute significantly to its signaling properties. Here we discuss the implications of our findings, in the context of other recent work in the field, on our understanding of checkpoint signaling.
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Affiliation(s)
- Karlene A Cimprich
- Stanford University, Department of Chemical and Systems Biology, Stanford, California 94305-5441, USA.
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44
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Abstract
The proper detection and repair of DNA damage is essential to the maintenance of genomic stability. The genome is particularly vulnerable during DNA replication, when endogenous and exogenous events can hinder replication fork progression. Stalled replication forks can fold into deleterious conformations and are also unstable structures that are prone to collapse or break. These events can lead to inappropriate processing of the DNA, ultimately resulting in genomic instability, chromosomal alterations and cancer. To cope with stalled replication forks, the cell relies on the replication checkpoint to block cell cycle progression, downregulate origin firing, stabilize the fork itself, and restart replication. The ATR (ATM and Rad3-related) kinase and its downstream effector kinase, Chk1, are central regulators of the replication checkpoint. Loss of these checkpoint proteins causes replication fork collapse and chromosomal rearrangements which may ultimately predispose affected individuals to cancer. This review summarizes our current understanding of how the ATR pathway recognizes and stabilizes stalled replication forks.
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Affiliation(s)
- Renee D Paulsen
- Department of Chemical and Systems Biology, Stanford University, 318 Campus Drive, Stanford, CA 94305-5441, USA
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45
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Abstract
Here, we demonstrate that primed, single-stranded DNA (ssDNA) is sufficient for activation of the ATR-dependent checkpoint pathway in Xenopus egg extracts. Using this structure, we define the contribution of the 5'- and 3'-primer ends to Chk1 activation when replication is blocked and ongoing. In addition, we show that although ssDNA is not sufficient for checkpoint activation, the amount of ssDNA adjacent to the primer influences the level of Chk1 phosphorylation. These observations define the minimal DNA requirements for checkpoint activation and suggest that primed ssDNA represents a common checkpoint activating-structure formed following many types of damage.
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Affiliation(s)
- Christina A. MacDougall
- Department of Chemical and Systems Biology, Stanford University, Stanford, California 94305, USA
| | - Tony S. Byun
- Department of Chemical and Systems Biology, Stanford University, Stanford, California 94305, USA
| | - Christopher Van
- Department of Chemical and Systems Biology, Stanford University, Stanford, California 94305, USA
| | - Muh-ching Yee
- Department of Chemical and Systems Biology, Stanford University, Stanford, California 94305, USA
| | - Karlene A. Cimprich
- Department of Chemical and Systems Biology, Stanford University, Stanford, California 94305, USA
- Corresponding author.E-MAIL ; FAX (650) 725-4665
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46
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Abstract
Our knowledge of cell cycle events such as DNA replication and mitosis has been advanced significantly through the use of Xenopus egg extracts as a model system. More recently, Xenopus extracts have been used to investigate the cellular mechanisms that ensure accurate and complete duplication of the genome, processes otherwise known as the DNA damage and replication checkpoints. Here we describe several Xenopus extract methods that have advanced the study of the ATR-mediated checkpoints. These include a protocol for the preparation of nucleoplasmic extract (NPE), which is a soluble extract system useful for studying nuclear events such as DNA replication and checkpoints. In addition, we describe several key assays for studying checkpoint activation as well as methods for using small DNA structures to activate ATR.
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Affiliation(s)
- Patrick J. Lupardus
- Department of Molecular Pharmacology, Stanford University, 318 Campus Drive, Stanford, CA 94305-5441, USA
| | - Christopher Van
- Department of Molecular Pharmacology, Stanford University, 318 Campus Drive, Stanford, CA 94305-5441, USA
| | - Karlene A. Cimprich
- Department of Molecular Pharmacology, Stanford University, 318 Campus Drive, Stanford, CA 94305-5441, USA
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47
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Chang DJ, Lupardus PJ, Cimprich KA. Monoubiquitination of proliferating cell nuclear antigen induced by stalled replication requires uncoupling of DNA polymerase and mini-chromosome maintenance helicase activities. J Biol Chem 2006; 281:32081-8. [PMID: 16959771 DOI: 10.1074/jbc.m606799200] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Proliferating cell nuclear antigen (PCNA) is a homotrimeric, ring-shaped protein complex that functions as a processivity factor for DNA polymerases. Following genotoxic stress, PCNA is modified at a conserved site by either a single ubiquitin moiety or a polyubiquitin chain. These modifications are required to coordinate DNA damage tolerance processes with ongoing replication. The molecular mechanisms responsible for inducing PCNA ubiquitination are not well understood. Using Xenopus egg extracts, we show that ultraviolet radiation and aphidicolin treatment induce the mono- and diubiquitination of PCNA. PCNA ubiquitination is replication-dependent and coincides with activation of the ataxia telangiectasia mutated and Rad3-related (ATR)-dependent DNA damage checkpoint pathway. However, loss of ATR signaling by depletion of the ATR-interacting protein (ATRIP) or Rad1, a component of the 911 checkpoint clamp, does not impair PCNA ubiquitination. Primed single-stranded DNA generated by uncoupling of mini-chromosome maintenance helicase and DNA polymerase activities has been shown previously to be necessary for ATR activation. Here we show that PCNA ubiquitination also requires uncoupling of helicase and polymerase activities. We further demonstrate that replicating single-stranded DNA, which mimics the structure produced upon uncoupling, is sufficient to induce PCNA monoubiquitination. Our results suggest that PCNA ubiquitination and ATR activation are two independent events that occur in response to a common single-stranded DNA intermediate generated by functional uncoupling of mini-chromosome maintenance (MCM) helicase and DNA polymerase activities.
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Affiliation(s)
- Debbie J Chang
- Department of Molecular Pharmacology, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA 94305-5441, USA
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48
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Bomgarden RD, Lupardus PJ, Soni DV, Yee MC, Ford JM, Cimprich KA. Opposing effects of the UV lesion repair protein XPA and UV bypass polymerase eta on ATR checkpoint signaling. EMBO J 2006; 25:2605-14. [PMID: 16675950 PMCID: PMC1478198 DOI: 10.1038/sj.emboj.7601123] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2005] [Accepted: 04/07/2006] [Indexed: 11/08/2022] Open
Abstract
An essential component of the ATR (ataxia telangiectasia-mutated and Rad3-related)-activating structure is single-stranded DNA. It has been suggested that nucleotide excision repair (NER) can lead to activation of ATR by generating such a signal, and in yeast, DNA damage processing through the NER pathway is necessary for checkpoint activation during G1. We show here that ultraviolet (UV) radiation-induced ATR signaling is compromised in XPA-deficient human cells during S phase, as shown by defects in ATRIP (ATR-interacting protein) translocation to sites of UV damage, UV-induced phosphorylation of Chk1 and UV-induced replication protein A phosphorylation and chromatin binding. However, ATR signaling was not compromised in XPC-, CSB-, XPF- and XPG-deficient cells. These results indicate that damage processing is not necessary for ATR-mediated S-phase checkpoint activation and that the lesion recognition function of XPA may be sufficient. In contrast, XP-V cells deficient in the UV bypass polymerase eta exhibited enhanced ATR signaling. Taken together, these results suggest that lesion bypass and not lesion repair may raise the level of UV damage that can be tolerated before checkpoint activation, and that XPA plays a critical role in this activation.
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Affiliation(s)
- Ryan D Bomgarden
- Department of Molecular Pharmacology, Stanford University, Stanford, CA, USA
| | - Patrick J Lupardus
- Department of Molecular Pharmacology, Stanford University, Stanford, CA, USA
| | - Deena V Soni
- Department of Molecular Pharmacology, Stanford University, Stanford, CA, USA
| | - Muh-Ching Yee
- Department of Molecular Pharmacology, Stanford University, Stanford, CA, USA
| | - James M Ford
- Departments of Medicine and Genetics, Division of Oncology, Stanford University, Stanford, CA, USA
| | - Karlene A Cimprich
- Department of Molecular Pharmacology, Stanford University, Stanford, CA, USA
- Department of Molecular Pharmacology, CCSR, Stanford University School of Medicine, 269 Campus Drive, Rm 3215a Stanford, CA 94305-5174, USA. Tel.: +1 650 498 4720; Fax: +1 650 725 4665; E-mail:
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49
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Lupardus PJ, Cimprich KA. Phosphorylation of Xenopus Rad1 and Hus1 defines a readout for ATR activation that is independent of Claspin and the Rad9 carboxy terminus. Mol Biol Cell 2006; 17:1559-69. [PMID: 16436514 PMCID: PMC1415302 DOI: 10.1091/mbc.e05-09-0865] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The DNA damage checkpoint pathways sense and respond to DNA damage to ensure genomic stability. The ATR kinase is a central regulator of one such pathway and phosphorylates a number of proteins that have roles in cell cycle progression and DNA repair. Using the Xenopus egg extract system, we have investigated regulation of the Rad1/Hus1/Rad9 complex. We show here that phosphorylation of Rad1 and Hus1 occurs in an ATR- and TopBP1-dependent manner on T5 of Rad1 and S219 and T223 of Hus1. Mutation of these sites has no effect on the phosphorylation of Chk1 by ATR. Interestingly, phosphorylation of Rad1 is independent of Claspin and the Rad9 carboxy terminus, both of which are required for Chk1 phosphorylation. These data suggest that an active ATR signaling complex exists in the absence of the carboxy terminus of Rad9 and that this carboxy-terminal domain may be a specific requirement for Chk1 phosphorylation and not necessary for all ATR-mediated signaling events. Thus, Rad1 phosphorylation provides an alternate and early readout for the study of ATR activation.
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Affiliation(s)
- Patrick J Lupardus
- Department of Molecular Pharmacology, Stanford University, Stanford, CA 94305-5441, USA
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50
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Sobeck A, Stone S, Costanzo V, de Graaf B, Reuter T, de Winter J, Wallisch M, Akkari Y, Olson S, Wang W, Joenje H, Christian JL, Lupardus PJ, Cimprich KA, Gautier J, Hoatlin ME. Fanconi anemia proteins are required to prevent accumulation of replication-associated DNA double-strand breaks. Mol Cell Biol 2006; 26:425-37. [PMID: 16382135 PMCID: PMC1346898 DOI: 10.1128/mcb.26.2.425-437.2006] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2005] [Revised: 07/20/2005] [Accepted: 10/13/2005] [Indexed: 12/19/2022] Open
Abstract
Fanconi anemia (FA) is a multigene cancer susceptibility disorder characterized by cellular hypersensitivity to DNA interstrand cross-linking agents such as mitomycin C (MMC). FA proteins are suspected to function at the interface between cell cycle checkpoints, DNA repair, and DNA replication. Using replicating extracts from Xenopus eggs, we developed cell-free assays for FA proteins (xFA). Recruitment of the xFA core complex and xFANCD2 to chromatin is strictly dependent on replication initiation, even in the presence of MMC indicating specific recruitment to DNA lesions encountered by the replication machinery. The increase in xFA chromatin binding following treatment with MMC is part of a caffeine-sensitive S-phase checkpoint that is controlled by xATR. Recruitment of xFANCD2, but not xFANCA, is dependent on the xATR-xATR-interacting protein (xATRIP) complex. Immunodepletion of either xFANCA or xFANCD2 from egg extracts results in accumulation of chromosomal DNA breaks during replicative synthesis. Our results suggest coordinated chromatin recruitment of xFA proteins in response to replication-associated DNA lesions and indicate that xFA proteins function to prevent the accumulation of DNA breaks that arise during unperturbed replication.
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Affiliation(s)
- Alexandra Sobeck
- Division of Biochemistry and Molecular Biology, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., Portland, Oregon 97239, USA
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