1
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Bai G, Endres T, Kühbacher U, Mengoli V, Greer BH, Peacock EM, Newton MD, Stanage T, Dello Stritto MR, Lungu R, Crossley MP, Sathirachinda A, Cortez D, Boulton SJ, Cejka P, Eichman BF, Cimprich KA. HLTF resolves G4s and promotes G4-induced replication fork slowing to maintain genome stability. Mol Cell 2024; 84:3044-3060.e11. [PMID: 39142279 PMCID: PMC11366124 DOI: 10.1016/j.molcel.2024.07.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 05/29/2024] [Accepted: 07/18/2024] [Indexed: 08/16/2024]
Abstract
G-quadruplexes (G4s) form throughout the genome and influence important cellular processes. Their deregulation can challenge DNA replication fork progression and threaten genome stability. Here, we demonstrate an unexpected role for the double-stranded DNA (dsDNA) translocase helicase-like transcription factor (HLTF) in responding to G4s. We show that HLTF, which is enriched at G4s in the human genome, can directly unfold G4s in vitro and uses this ATP-dependent translocase function to suppress G4 accumulation throughout the cell cycle. Additionally, MSH2 (a component of MutS heterodimers that bind G4s) and HLTF act synergistically to suppress G4 accumulation, restrict alternative lengthening of telomeres, and promote resistance to G4-stabilizing drugs. In a discrete but complementary role, HLTF restrains DNA synthesis when G4s are stabilized by suppressing primase-polymerase (PrimPol)-dependent repriming. Together, the distinct roles of HLTF in the G4 response prevent DNA damage and potentially mutagenic replication to safeguard genome stability.
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Affiliation(s)
- Gongshi Bai
- Department of Chemical & Systems Biology, Stanford University, Stanford, CA 94305, USA
| | - Theresa Endres
- Department of Chemical & Systems Biology, Stanford University, Stanford, CA 94305, USA
| | - Ulrike Kühbacher
- Department of Chemical & Systems Biology, Stanford University, Stanford, CA 94305, USA
| | - Valentina Mengoli
- Institute for Research in Biomedicine, Università della Svizzera italiana, Bellinzona 6500, Switzerland
| | - Briana H Greer
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA
| | - Emma M Peacock
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA
| | - Matthew D Newton
- DSB Repair Metabolism Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Tyler Stanage
- DSB Repair Metabolism Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | | | - Roxana Lungu
- Department of Chemical & Systems Biology, Stanford University, Stanford, CA 94305, USA
| | - Magdalena P Crossley
- Department of Chemical & Systems Biology, Stanford University, Stanford, CA 94305, USA
| | - Ataya Sathirachinda
- Department of Chemical & Systems Biology, Stanford University, Stanford, CA 94305, USA
| | - David Cortez
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Simon J Boulton
- DSB Repair Metabolism Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Petr Cejka
- Institute for Research in Biomedicine, Università della Svizzera italiana, Bellinzona 6500, Switzerland
| | - Brandt F Eichman
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA; Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Karlene A Cimprich
- Department of Chemical & Systems Biology, Stanford University, Stanford, CA 94305, USA.
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2
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Zhao R, Xu M, Yu X, Wondisford AR, Lackner RM, Salsman J, Dellaire G, Chenoweth DM, O'Sullivan RJ, Zhao X, Zhang H. SUMO promotes DNA repair protein collaboration to support alternative telomere lengthening in the absence of PML. Genes Dev 2024; 38:614-630. [PMID: 39038850 PMCID: PMC11368244 DOI: 10.1101/gad.351667.124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Accepted: 07/08/2024] [Indexed: 07/24/2024]
Abstract
The alternative lengthening of telomeres (ALT) pathway maintains telomere length in a significant fraction of cancers that are associated with poor clinical outcomes. A better understanding of ALT mechanisms is therefore necessary for developing new treatment strategies for ALT cancers. SUMO modification of telomere proteins contributes to the formation of ALT telomere-associated PML bodies (APBs), in which telomeres are clustered and DNA repair proteins are enriched to promote homology-directed telomere DNA synthesis in ALT. However, it is still unknown whether-and if so, how-SUMO supports ALT beyond APB formation. Here, we show that SUMO condensates that contain DNA repair proteins enable telomere maintenance in the absence of APBs. In PML knockout ALT cell lines that lack APBs, we found that SUMOylation is required for manifesting ALT features independent of PML and APBs. Chemically induced telomere targeting of SUMO produces condensate formation and ALT features in PML-null cells. This effect requires both SUMOylation and interactions between SUMO and SUMO interaction motifs (SIMs). Mechanistically, SUMO-induced effects are associated with the accumulation of DNA repair proteins, including Rad52, Rad51AP1, RPA, and BLM, at telomeres. Furthermore, Rad52 can undergo phase separation, enrich SUMO at telomeres, and promote telomere DNA synthesis in collaboration with the BLM helicase in a SUMO-dependent manner. Collectively, our findings suggest that SUMO condensate formation promotes collaboration among DNA repair factors to support ALT telomere maintenance without PML. Given the promising effects of SUMOylation inhibitors in cancer treatment, our findings suggest their potential use in perturbing telomere maintenance in ALT cancer cells.
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Affiliation(s)
- Rongwei Zhao
- Department of Biology, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Meng Xu
- Department of Biology, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Xiaoyang Yu
- Department of Biology, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Anne R Wondisford
- Department of Pharmacology and Chemical Biology, University of Pittsburgh Medical Center Hillman Cancer Center, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA
| | - Rachel M Lackner
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19014, USA
| | - Jayme Salsman
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Graham Dellaire
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - David M Chenoweth
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19014, USA
| | - Roderick J O'Sullivan
- Department of Pharmacology and Chemical Biology, University of Pittsburgh Medical Center Hillman Cancer Center, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA
| | - Xiaolan Zhao
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Huaiying Zhang
- Department of Biology, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA;
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3
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Bournaka S, Badra-Fajardo N, Arbi M, Taraviras S, Lygerou Z. The cell cycle revisited: DNA replication past S phase preserves genome integrity. Semin Cancer Biol 2024; 99:45-55. [PMID: 38346544 DOI: 10.1016/j.semcancer.2024.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 01/23/2024] [Accepted: 02/05/2024] [Indexed: 02/20/2024]
Abstract
Accurate and complete DNA duplication is critical for maintaining genome integrity. Multiple mechanisms regulate when and where DNA replication takes place, to ensure that the entire genome is duplicated once and only once per cell cycle. Although the bulk of the genome is copied during the S phase of the cell cycle, increasing evidence suggests that parts of the genome are replicated in G2 or mitosis, in a last attempt to secure that daughter cells inherit an accurate copy of parental DNA. Remaining unreplicated gaps may be passed down to progeny and replicated in the next G1 or S phase. These findings challenge the long-established view that genome duplication occurs strictly during the S phase, bridging DNA replication to DNA repair and providing novel therapeutic strategies for cancer treatment.
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Affiliation(s)
- Spyridoula Bournaka
- Department of General Biology, Medical School, University of Patras, Patras 26504, Greece
| | - Nibal Badra-Fajardo
- Department of General Biology, Medical School, University of Patras, Patras 26504, Greece
| | - Marina Arbi
- Department of General Biology, Medical School, University of Patras, Patras 26504, Greece
| | - Stavros Taraviras
- Department of Physiology, Medical School, University of Patras, Patras 26504, Greece
| | - Zoi Lygerou
- Department of General Biology, Medical School, University of Patras, Patras 26504, Greece.
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4
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Spegg V, Altmeyer M. Genome maintenance meets mechanobiology. Chromosoma 2024; 133:15-36. [PMID: 37581649 PMCID: PMC10904543 DOI: 10.1007/s00412-023-00807-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 06/20/2023] [Accepted: 07/26/2023] [Indexed: 08/16/2023]
Abstract
Genome stability is key for healthy cells in healthy organisms, and deregulated maintenance of genome integrity is a hallmark of aging and of age-associated diseases including cancer and neurodegeneration. To maintain a stable genome, genome surveillance and repair pathways are closely intertwined with cell cycle regulation and with DNA transactions that occur during transcription and DNA replication. Coordination of these processes across different time and length scales involves dynamic changes of chromatin topology, clustering of fragile genomic regions and repair factors into nuclear repair centers, mobilization of the nuclear cytoskeleton, and activation of cell cycle checkpoints. Here, we provide a general overview of cell cycle regulation and of the processes involved in genome duplication in human cells, followed by an introduction to replication stress and to the cellular responses elicited by perturbed DNA synthesis. We discuss fragile genomic regions that experience high levels of replication stress, with a particular focus on telomere fragility caused by replication stress at the ends of linear chromosomes. Using alternative lengthening of telomeres (ALT) in cancer cells and ALT-associated PML bodies (APBs) as examples of replication stress-associated clustered DNA damage, we discuss compartmentalization of DNA repair reactions and the role of protein properties implicated in phase separation. Finally, we highlight emerging connections between DNA repair and mechanobiology and discuss how biomolecular condensates, components of the nuclear cytoskeleton, and interfaces between membrane-bound organelles and membraneless macromolecular condensates may cooperate to coordinate genome maintenance in space and time.
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Affiliation(s)
- Vincent Spegg
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
| | - Matthias Altmeyer
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland.
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5
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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 : THE PREPRINT SERVER FOR BIOLOGY 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] [Abstract] [Grants] [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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6
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Bhowmick R, Hickson ID, Liu Y. Completing genome replication outside of S phase. Mol Cell 2023; 83:3596-3607. [PMID: 37716351 DOI: 10.1016/j.molcel.2023.08.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 08/03/2023] [Accepted: 08/17/2023] [Indexed: 09/18/2023]
Abstract
Mitotic DNA synthesis (MiDAS) is an unusual form of DNA replication that occurs during mitosis. Initially, MiDAS was characterized as a process associated with intrinsically unstable loci known as common fragile sites that occurs after cells experience DNA replication stress (RS). However, it is now believed to be a more widespread "salvage" mechanism that is called upon to complete the duplication of any under-replicated genomic region. Emerging data suggest that MiDAS is a DNA repair process potentially involving two or more pathways working in parallel or sequentially. In this review, we introduce the causes of RS, regions of the human genome known to be especially vulnerable to RS, and the strategies used to complete DNA replication outside of S phase. Additionally, because MiDAS is a prominent feature of aneuploid cancer cells, we will discuss how targeting MiDAS might potentially lead to improvements in cancer therapy.
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Affiliation(s)
- Rahul Bhowmick
- Center for Chromosome Stability and Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Panum Institute, Blegdamsvej 3B, 2200 Copenhagen N, Denmark; Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Ian D Hickson
- Center for Chromosome Stability and Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Panum Institute, Blegdamsvej 3B, 2200 Copenhagen N, Denmark.
| | - Ying Liu
- Center for Chromosome Stability and Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Panum Institute, Blegdamsvej 3B, 2200 Copenhagen N, Denmark.
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7
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Kim SM, Forsburg SL. Multiple DNA repair pathways contribute to MMS-induced post-replicative DNA synthesis in S. pombe . MICROPUBLICATION BIOLOGY 2023; 2023:10.17912/micropub.biology.000974. [PMID: 37854101 PMCID: PMC10580077 DOI: 10.17912/micropub.biology.000974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Revised: 09/22/2023] [Accepted: 09/29/2023] [Indexed: 10/20/2023]
Abstract
Replication stress can induce DNA synthesis outside of replicative S-phase. We have previously demonstrated that fission yeast cells stimulate DNA synthesis in G2-phase but not in M-phase in response to DNA alkylating agent MMS. In this study, we show that various DNA repair pathways, including translesion synthesis and break-induced replication contribute to post-replicative DNA synthesis. Checkpoint kinases, various repair and resection proteins, and multiple polymerases are also involved.
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Affiliation(s)
- Seong Min Kim
- Molecular and Computational Biology, University of Southern California, Los Angeles, California, United States
| | - Susan L. Forsburg
- University of Southern California, Los Angeles, California, United States
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8
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Besse L, Rumiac T, Reynaud-Angelin A, Messaoudi C, Soler MN, Lambert SAE, Pennaneach V. Protocol for automated multivariate quantitative-image-based cytometry analysis by fluorescence microscopy of asynchronous adherent cells. STAR Protoc 2023; 4:102446. [PMID: 37453067 PMCID: PMC10365954 DOI: 10.1016/j.xpro.2023.102446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 03/31/2023] [Accepted: 06/19/2023] [Indexed: 07/18/2023] Open
Abstract
Here, we present a protocol for multivariate quantitative-image-based cytometry (QIBC) analysis by fluorescence microscopy of asynchronous adherent cells. We describe steps for the preparation, treatment, and fixation of cells, sample staining, and imaging for QIBC. We then detail image analysis with our open source Fiji script developed for QIBC and present multiparametric data visualization. Our QIBC Fiji script integrates modern artificial-intelligence-based tools, applying deep learning, for robust automated nuclei segmentation with minimal user adjustments, a major asset for efficient QIBC analysis. For complete details on the use and execution of this protocol, please refer to Besse et al. (2023).1.
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Affiliation(s)
- Laetitia Besse
- Institut Curie, Université PSL, CNRS UAR2016, Inserm US43, Université Paris-Saclay, Multimodal Imaging Center, 91400 Orsay, France
| | - Typhaine Rumiac
- Institut Curie, Université PSL, CNRS UMR3348, Orsay, France; Université Paris-Saclay, CNRS UMR3348, Orsay, France; Equipe Labélisée Ligue Nationale Contre Le Cancer, 91400 Orsay, France; Inovarion, 75005 Paris, France
| | - Anne Reynaud-Angelin
- Institut Curie, Université PSL, CNRS UMR3348, Orsay, France; Université Paris-Saclay, CNRS UMR3348, Orsay, France; Equipe Labélisée Ligue Nationale Contre Le Cancer, 91400 Orsay, France
| | - Cédric Messaoudi
- Institut Curie, Université PSL, CNRS UAR2016, Inserm US43, Université Paris-Saclay, Multimodal Imaging Center, 91400 Orsay, France
| | - Marie-Noëlle Soler
- Institut Curie, Université PSL, CNRS UAR2016, Inserm US43, Université Paris-Saclay, Multimodal Imaging Center, 91400 Orsay, France
| | - Sarah A E Lambert
- Institut Curie, Université PSL, CNRS UMR3348, Orsay, France; Université Paris-Saclay, CNRS UMR3348, Orsay, France; Equipe Labélisée Ligue Nationale Contre Le Cancer, 91400 Orsay, France.
| | - Vincent Pennaneach
- Institut Curie, Université PSL, CNRS UMR3348, Orsay, France; Université Paris-Saclay, CNRS UMR3348, Orsay, France; Equipe Labélisée Ligue Nationale Contre Le Cancer, 91400 Orsay, France.
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9
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Ferrand J, Dabin J, Chevallier O, Kupai A, Rothbart SB, Polo SE. Mitotic chromatin marking governs asymmetric segregation of DNA damage. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.04.556166. [PMID: 37732208 PMCID: PMC10508772 DOI: 10.1101/2023.09.04.556166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
The faithful segregation of intact genetic material and the perpetuation of chromatin states through mitotic cell divisions are pivotal for maintaining cell function and identity across cell generations. However, most exogenous mutagens generate long-lasting DNA lesions that are segregated during mitosis. How this segregation is controlled is unknown. Here, we uncover a mitotic chromatin-marking pathway that governs the segregation of UV-induced damage in human cells. Our mechanistic analyses reveal two layers of control: histone ADP-ribosylation, and the incorporation of newly synthesized histones at UV damage sites, that both prevent local mitotic phosphorylations on histone H3 serines. Functionally, this chromatin-marking pathway drives the asymmetric segregation of UV damage in the cell progeny with potential consequences on daughter cell fate. We propose that this mechanism may help preserve the integrity of stem cell compartments during asymmetric cell divisions.
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Affiliation(s)
- Juliette Ferrand
- Laboratory of Epigenome Integrity, Epigenetics & Cell Fate Centre, UMR7216 CNRS, Université Paris Cité, Paris, France
| | - Juliette Dabin
- Laboratory of Epigenome Integrity, Epigenetics & Cell Fate Centre, UMR7216 CNRS, Université Paris Cité, Paris, France
| | - Odile Chevallier
- Laboratory of Epigenome Integrity, Epigenetics & Cell Fate Centre, UMR7216 CNRS, Université Paris Cité, Paris, France
| | - Ariana Kupai
- Department of Epigenetics, Van Andel Institute, Grand Rapids, MI, USA
| | - Scott B. Rothbart
- Department of Epigenetics, Van Andel Institute, Grand Rapids, MI, USA
| | - Sophie E. Polo
- Laboratory of Epigenome Integrity, Epigenetics & Cell Fate Centre, UMR7216 CNRS, Université Paris Cité, Paris, France
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10
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Krishnan A, Spegg V, Dettwiler S, Schraml P, Moch H, Dedes K, Varga Z, Altmeyer M. Analysis of the PARP1, ADP-Ribosylation, and TRIP12 Triad With Markers of Patient Outcome in Human Breast Cancer. Mod Pathol 2023; 36:100167. [PMID: 36990278 DOI: 10.1016/j.modpat.2023.100167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 03/15/2023] [Accepted: 03/21/2023] [Indexed: 03/29/2023]
Abstract
PARP inhibitors (PARPi) are increasingly used in breast cancer therapy, including high-grade triple-negative breast cancer (TNBC) treatment. Varying treatment responses and PARPi resistance with relapse currently pose limitations to the efficacy of PARPi therapy. The pathobiological reasons why individual patients respond differently to PARPi are poorly understood. In this study, we analyzed expression of PARP1, the main target of PARPi, in normal breast tissue, breast cancer, and its precursor lesions using human breast cancer tissue microarrays covering a total of 824 patients, including more than 100 TNBC cases. In parallel, we analyzed nuclear adenosine diphosphate (ADP)-ribosylation as a marker of PARP1 activity and TRIP12, an antagonist of PARPi-induced PARP1 trapping. Although we found PARP1 expression to be generally increased in invasive breast cancer, PARP1 protein levels and nuclear ADP-ribosylation were lower in higher tumor grade and TNBC samples than non-TNBCs. Cancers with low levels of PARP1 and low levels of nuclear ADP-ribosylation were associated with significantly reduced overall survival. This effect was even more pronounced in cases with high levels of TRIP12. These results indicate that PARP1-dependent DNA repair capacity may be compromised in aggressive breast cancers, potentially fueling enhanced accumulation of mutations. Moreover, the results revealed a subset of breast cancers with low PARP1, low nuclear ADP-ribosylation, and high TRIP12 levels, which may compromise their response to PARPi, suggesting a combination of markers for PARP1 abundance, enzymatic activity, and trapping capabilities might aid patient stratification for PARPi therapy.
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Affiliation(s)
- Aswini Krishnan
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
| | - Vincent Spegg
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
| | - Susanne Dettwiler
- Department of Pathology and Molecular Pathology, University Hospital and University of Zurich, Zurich, Switzerland
| | - Peter Schraml
- Department of Pathology and Molecular Pathology, University Hospital and University of Zurich, Zurich, Switzerland
| | - Holger Moch
- Department of Pathology and Molecular Pathology, University Hospital and University of Zurich, Zurich, Switzerland
| | - Konstantin Dedes
- Department of Gynecology, University Hospital of Zurich, Zurich, Switzerland
| | - Zsuzsanna Varga
- Department of Pathology and Molecular Pathology, University Hospital and University of Zurich, Zurich, Switzerland
| | - Matthias Altmeyer
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland.
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11
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Schmolka N, Karemaker ID, Cardoso da Silva R, Recchia DC, Spegg V, Bhaskaran J, Teske M, de Wagenaar NP, Altmeyer M, Baubec T. Dissecting the roles of MBD2 isoforms and domains in regulating NuRD complex function during cellular differentiation. Nat Commun 2023; 14:3848. [PMID: 37385984 PMCID: PMC10310694 DOI: 10.1038/s41467-023-39551-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 06/19/2023] [Indexed: 07/01/2023] Open
Abstract
The Nucleosome Remodeling and Deacetylation (NuRD) complex is a crucial regulator of cellular differentiation. Two members of the Methyl-CpG-binding domain (MBD) protein family, MBD2 and MBD3, are known to be integral, but mutually exclusive subunits of the NuRD complex. Several MBD2 and MBD3 isoforms are present in mammalian cells, resulting in distinct MBD-NuRD complexes. Whether these different complexes serve distinct functional activities during differentiation is not fully explored. Based on the essential role of MBD3 in lineage commitment, we systematically investigated a diverse set of MBD2 and MBD3 variants for their potential to rescue the differentiation block observed for mouse embryonic stem cells (ESCs) lacking MBD3. While MBD3 is indeed crucial for ESC differentiation to neuronal cells, it functions independently of its MBD domain. We further identify that MBD2 isoforms can replace MBD3 during lineage commitment, however with different potential. Full-length MBD2a only partially rescues the differentiation block, while MBD2b, an isoform lacking an N-terminal GR-rich repeat, fully rescues the Mbd3 KO phenotype. In case of MBD2a, we further show that removing the methylated DNA binding capacity or the GR-rich repeat enables full redundancy to MBD3, highlighting the synergistic requirements for these domains in diversifying NuRD complex function.
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Affiliation(s)
- Nina Schmolka
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
- Institute of Experimental Immunology, University of Zurich, Zurich, Switzerland
| | - Ino D Karemaker
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
| | - Richard Cardoso da Silva
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
- Genome Biology and Epigenetics, Institute of Biodynamics and Biocomplexity, Department of Biology, Utrecht University, Utrecht, The Netherlands
| | - Davide C Recchia
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
- Genome Biology and Epigenetics, Institute of Biodynamics and Biocomplexity, Department of Biology, Utrecht University, Utrecht, The Netherlands
- Molecular Life Science PhD Program of the Life Science Zurich Graduate School, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Vincent Spegg
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
- Molecular Life Science PhD Program of the Life Science Zurich Graduate School, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Jahnavi Bhaskaran
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
- MRC London Institute of Medical Sciences, London, UK
| | - Michael Teske
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
- Molecular Life Science PhD Program of the Life Science Zurich Graduate School, University of Zurich and ETH Zurich, Zurich, Switzerland
- Institute of Experimental Immunology, University of Zurich, Zurich, Switzerland
| | - Nathalie P de Wagenaar
- Genome Biology and Epigenetics, Institute of Biodynamics and Biocomplexity, Department of Biology, Utrecht University, Utrecht, The Netherlands
| | - Matthias Altmeyer
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
| | - Tuncay Baubec
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland.
- Genome Biology and Epigenetics, Institute of Biodynamics and Biocomplexity, Department of Biology, Utrecht University, Utrecht, The Netherlands.
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12
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Roshan P, Kuppa S, Mattice JR, Kaushik V, Chadda R, Pokhrel N, Tumala BR, Biswas A, Bothner B, Antony E, Origanti S. An Aurora B-RPA signaling axis secures chromosome segregation fidelity. Nat Commun 2023; 14:3008. [PMID: 37230964 PMCID: PMC10212944 DOI: 10.1038/s41467-023-38711-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 05/09/2023] [Indexed: 05/27/2023] Open
Abstract
Errors in chromosome segregation underlie genomic instability associated with cancers. Resolution of replication and recombination intermediates and protection of vulnerable single-stranded DNA (ssDNA) intermediates during mitotic progression requires the ssDNA binding protein Replication Protein A (RPA). However, the mechanisms that regulate RPA specifically during unperturbed mitotic progression are poorly resolved. RPA is a heterotrimer composed of RPA70, RPA32 and RPA14 subunits and is predominantly regulated through hyperphosphorylation of RPA32 in response to DNA damage. Here, we have uncovered a mitosis-specific regulation of RPA by Aurora B kinase. Aurora B phosphorylates Ser-384 in the DNA binding domain B of the large RPA70 subunit and highlights a mode of regulation distinct from RPA32. Disruption of Ser-384 phosphorylation in RPA70 leads to defects in chromosome segregation with loss of viability and a feedback modulation of Aurora B activity. Phosphorylation at Ser-384 remodels the protein interaction domains of RPA. Furthermore, phosphorylation impairs RPA binding to DSS1 that likely suppresses homologous recombination during mitosis by preventing recruitment of DSS1-BRCA2 to exposed ssDNA. We showcase a critical Aurora B-RPA signaling axis in mitosis that is essential for maintaining genomic integrity.
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Affiliation(s)
- Poonam Roshan
- Department of Biology, St. Louis University, St. Louis, MO, 63103, USA
| | - Sahiti Kuppa
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO, 63104, USA
| | - Jenna R Mattice
- Department of Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Vikas Kaushik
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO, 63104, USA
| | - Rahul Chadda
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO, 63104, USA
| | - Nilisha Pokhrel
- Department of Biological Sciences, Marquette University, Milwaukee, WI, 53217, USA
| | - Brunda R Tumala
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO, 63104, USA
| | - Aparna Biswas
- Department of Biology, St. Louis University, St. Louis, MO, 63103, USA
| | - Brian Bothner
- Department of Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Edwin Antony
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO, 63104, USA.
| | - Sofia Origanti
- Department of Biology, St. Louis University, St. Louis, MO, 63103, USA.
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13
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Sohn EJ, Goralsky JA, Shay JW, Min J. The Molecular Mechanisms and Therapeutic Prospects of Alternative Lengthening of Telomeres (ALT). Cancers (Basel) 2023; 15:cancers15071945. [PMID: 37046606 PMCID: PMC10093677 DOI: 10.3390/cancers15071945] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 03/14/2023] [Accepted: 03/15/2023] [Indexed: 04/14/2023] Open
Abstract
As detailed by the end replication problem, the linear ends of a cell's chromosomes, known as telomeres, shorten with each successive round of replication until a cell enters into a state of growth arrest referred to as senescence. To maintain their immortal proliferation capacity, cancer cells must employ a telomere maintenance mechanism, such as telomerase activation or the Alternative Lengthening of Telomeres pathway (ALT). With only 10-15% of cancers utilizing the ALT mechanism, progress towards understanding its molecular components and associated hallmarks has only recently been made. This review analyzes the advances towards understanding the ALT pathway by: (1) detailing the mechanisms associated with engaging the ALT pathway as well as (2) identifying potential therapeutic targets of ALT that may lead to novel cancer therapeutic treatments. Collectively, these studies indicate that the ALT molecular mechanisms involve at least two distinct pathways induced by replication stress and damage at telomeres. We suggest exploiting tumor dependency on ALT is a promising field of study because it suggests new approaches to ALT-specific therapies for cancers with poorer prognosis. While substantial progress has been made in the ALT research field, additional progress will be required to realize these advances into clinical practices to treat ALT cancers and improve patient prognoses.
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Affiliation(s)
- Eric J Sohn
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Julia A Goralsky
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Jerry W Shay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039, USA
| | - Jaewon Min
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY 10032, USA
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY 10032, USA
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14
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Phase separation properties of RPA combine high-affinity ssDNA binding with dynamic condensate functions at telomeres. Nat Struct Mol Biol 2023; 30:451-462. [PMID: 36894693 PMCID: PMC10113159 DOI: 10.1038/s41594-023-00932-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 01/27/2023] [Indexed: 03/11/2023]
Abstract
RPA has been shown to protect single-stranded DNA (ssDNA) intermediates from instability and breakage. RPA binds ssDNA with sub-nanomolar affinity, yet dynamic turnover is required for downstream ssDNA transactions. How ultrahigh-affinity binding and dynamic turnover are achieved simultaneously is not well understood. Here we reveal that RPA has a strong propensity to assemble into dynamic condensates. In solution, purified RPA phase separates into liquid droplets with fusion and surface wetting behavior. Phase separation is stimulated by sub-stoichiometric amounts of ssDNA, but not RNA or double-stranded DNA, and ssDNA gets selectively enriched in RPA condensates. We find the RPA2 subunit required for condensation and multi-site phosphorylation of the RPA2 N-terminal intrinsically disordered region to regulate RPA self-interaction. Functionally, quantitative proximity proteomics links RPA condensation to telomere clustering and integrity in cancer cells. Collectively, our results suggest that RPA-coated ssDNA is contained in dynamic RPA condensates whose properties are important for genome organization and stability.
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15
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Safeguarding DNA Replication: A Golden Touch of MiDAS and Other Mechanisms. Int J Mol Sci 2022; 23:ijms231911331. [PMID: 36232633 PMCID: PMC9570362 DOI: 10.3390/ijms231911331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 09/19/2022] [Accepted: 09/20/2022] [Indexed: 11/21/2022] Open
Abstract
DNA replication is a tightly regulated fundamental process allowing the correct duplication and transfer of the genetic information from the parental cell to the progeny. It involves the coordinated assembly of several proteins and protein complexes resulting in replication fork licensing, firing and progression. However, the DNA replication pathway is strewn with hurdles that affect replication fork progression during S phase. As a result, cells have adapted several mechanisms ensuring replication completion before entry into mitosis and segregating chromosomes with minimal, if any, abnormalities. In this review, we describe the possible obstacles that a replication fork might encounter and how the cell manages to protect DNA replication from S to the next G1.
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16
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Liddiard K, Aston-Evans AN, Cleal K, Hendrickson E, Baird D. POLQ suppresses genome instability and alterations in DNA repeat tract lengths. NAR Cancer 2022; 4:zcac020. [PMID: 35774233 PMCID: PMC9241439 DOI: 10.1093/narcan/zcac020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 05/19/2022] [Accepted: 06/10/2022] [Indexed: 11/26/2022] Open
Abstract
DNA polymerase theta (POLQ) is a principal component of the alternative non-homologous end-joining (ANHEJ) DNA repair pathway that ligates DNA double-strand breaks. Utilizing independent models of POLQ insufficiency during telomere-driven crisis, we found that POLQ - /- cells are resistant to crisis-induced growth deceleration despite sustaining inter-chromosomal telomere fusion frequencies equivalent to wild-type (WT) cells. We recorded longer telomeres in POLQ - / - than WT cells pre- and post-crisis, notwithstanding elevated total telomere erosion and fusion rates. POLQ - /- cells emerging from crisis exhibited reduced incidence of clonal gross chromosomal abnormalities in accordance with increased genetic heterogeneity. High-throughput sequencing of telomere fusion amplicons from POLQ-deficient cells revealed significantly raised frequencies of inter-chromosomal fusions with correspondingly depreciated intra-chromosomal recombinations. Long-range interactions culminating in telomere fusions with centromere alpha-satellite repeats, as well as expansions in HSAT2 and HSAT3 satellite and contractions in ribosomal DNA repeats, were detected in POLQ - / - cells. In conjunction with the expanded telomere lengths of POLQ - /- cells, these results indicate a hitherto unrealized capacity of POLQ for regulation of repeat arrays within the genome. Our findings uncover novel considerations for the efficacy of POLQ inhibitors in clinical cancer interventions, where potential genome destabilizing consequences could drive clonal evolution and resistant disease.
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Affiliation(s)
- Kate Liddiard
- Division of Cancer and Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, UK
| | - Alys N Aston-Evans
- Dementia Research Institute, School of Medicine, Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff CF24 4HQ, UK
| | - Kez Cleal
- Division of Cancer and Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, UK
| | - Eric A Hendrickson
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Duncan M Baird
- Division of Cancer and Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, UK
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17
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Chukrallah LG, Badrinath A, Vittor GG, Snyder EM. ADAD2 regulates heterochromatin in meiotic and post-meiotic male germ cells via translation of MDC1. J Cell Sci 2022; 135:jcs259196. [PMID: 35191498 PMCID: PMC8919335 DOI: 10.1242/jcs.259196] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 01/09/2022] [Indexed: 11/20/2022] Open
Abstract
Male germ cells establish a unique heterochromatin domain, the XY-body, early in meiosis. How this domain is maintained through the end of meiosis and into post-meiotic germ cell differentiation is poorly understood. ADAD2 is a late meiotic male germ cell-specific RNA-binding protein, loss of which leads to post-meiotic germ cell defects. Analysis of ribosome association in Adad2 mouse mutants revealed defective translation of Mdc1, a key regulator of XY-body formation, late in meiosis. As a result, Adad2 mutants show normal establishment but failed maintenance of the XY-body. Observed XY-body defects are concurrent with abnormal autosomal heterochromatin and ultimately lead to severely perturbed post-meiotic germ cell heterochromatin and cell death. These findings highlight the requirement of ADAD2 for Mdc1 translation, the role of MDC1 in maintaining meiotic male germ cell heterochromatin and the importance of late meiotic heterochromatin for normal post-meiotic germ cell differentiation.
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Affiliation(s)
| | - Aditi Badrinath
- Department of Animal Science, Rutgers University, New Brunswick, NJ 08901, USA
| | - Gabrielle G. Vittor
- Department of Animal Science, Rutgers University, New Brunswick, NJ 08901, USA
| | - Elizabeth M. Snyder
- Department of Animal Science, Rutgers University, New Brunswick, NJ 08901, USA
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