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MacDonald KM, Khan S, Lin B, Hurren R, Schimmer AD, Kislinger T, Harding SM. The proteomic landscape of genotoxic stress-induced micronuclei. Mol Cell 2024; 84:1377-1391.e6. [PMID: 38423013 DOI: 10.1016/j.molcel.2024.02.001] [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: 08/02/2023] [Revised: 12/20/2023] [Accepted: 02/05/2024] [Indexed: 03/02/2024]
Abstract
Micronuclei (MN) are induced by various genotoxic stressors and amass nuclear- and cytoplasmic-resident proteins, priming the cell for MN-driven signaling cascades. Here, we measured the proteome of micronuclear, cytoplasmic, and nuclear fractions from human cells exposed to a panel of six genotoxins, comprehensively profiling their MN protein landscape. We find that MN assemble a proteome distinct from both surrounding cytoplasm and parental nuclei, depleted of spliceosome and DNA damage repair components while enriched for a subset of the replisome. We show that the depletion of splicing machinery within transcriptionally active MN contributes to intra-MN DNA damage, a known precursor to chromothripsis. The presence of transcription machinery in MN is stress-dependent, causing a contextual induction of MN DNA damage through spliceosome deficiency. This dataset represents a unique resource detailing the global proteome of MN, guiding mechanistic studies of MN generation and MN-associated outcomes of genotoxic stress.
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Affiliation(s)
- Kate M MacDonald
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Shahbaz Khan
- Princess Margaret Cancer Center, University Health Network, Toronto, ON M5G 2C4, Canada
| | - Brian Lin
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Rose Hurren
- Princess Margaret Cancer Center, University Health Network, Toronto, ON M5G 2C4, Canada
| | - Aaron D Schimmer
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada; Princess Margaret Cancer Center, University Health Network, Toronto, ON M5G 2C4, Canada
| | - Thomas Kislinger
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada; Princess Margaret Cancer Center, University Health Network, Toronto, ON M5G 2C4, Canada
| | - Shane M Harding
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada; Princess Margaret Cancer Center, University Health Network, Toronto, ON M5G 2C4, Canada; Department of Radiation Oncology and Immunology, University of Toronto, Toronto, ON M5T 1P5, Canada.
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2
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Jiang H, Chan YW. Chromatin bridges: stochastic breakage or regulated resolution? Trends Genet 2024; 40:69-82. [PMID: 37891096 DOI: 10.1016/j.tig.2023.10.004] [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: 08/15/2023] [Revised: 09/25/2023] [Accepted: 10/03/2023] [Indexed: 10/29/2023]
Abstract
Genetic material is organized in the form of chromosomes, which need to be segregated accurately into two daughter cells in each cell cycle. However, chromosome fusion or the presence of unresolved interchromosomal linkages lead to the formation of chromatin bridges, which can induce DNA lesions and genome instability. Persistent chromatin bridges are trapped in the cleavage furrow and are broken at or after abscission, the final step of cytokinesis. In this review, we focus on recent progress in understanding the mechanism of bridge breakage and resolution. We discuss the molecular machinery and enzymes that have been implicated in the breakage and processing of bridge DNA. In addition, we outline both the immediate outcomes and genomic consequences induced by bridge breakage.
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Affiliation(s)
- Huadong Jiang
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region of China
| | - Ying Wai Chan
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region of China.
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Petroni M, La Monica V, Fabretti F, Augusto M, Battaglini D, Polonara F, Di Giulio S, Giannini G. The Multiple Faces of the MRN Complex: Roles in Medulloblastoma and Beyond. Cancers (Basel) 2023; 15:3599. [PMID: 37509263 PMCID: PMC10377613 DOI: 10.3390/cancers15143599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 07/09/2023] [Accepted: 07/10/2023] [Indexed: 07/30/2023] Open
Abstract
Hypomorphic mutations in MRN complex genes are frequently found in cancer, supporting their role as oncosuppressors. However, unlike canonical oncosuppressors, MRN proteins are often overexpressed in tumor tissues, where they actively work to counteract DSBs induced by both oncogene-dependent RS and radio-chemotherapy. Moreover, at the same time, MRN genes are also essential genes, since the constitutive KO of each component leads to embryonic lethality. Therefore, even though it is paradoxical, MRN genes may work as oncosuppressive, oncopromoting, and essential genes. In this review, we discussed how alterations in the MRN complex impact the physiopathology of cancer, in light of our recent discoveries on the gene-dosage-dependent effect of NBS1 in Medulloblastoma. These updates aim to understand whether MRN complex can be realistically used as a prognostic/predictive marker and/or as a therapeutic target for the treatment of cancer patients in the future.
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Affiliation(s)
- Marialaura Petroni
- Department of Molecular Medicine, University La Sapienza, 00161 Rome, Italy
- Istituto Pasteur-Fondazione Cenci Bolognetti, 00161 Rome, Italy
| | - Veronica La Monica
- Department of Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - Francesca Fabretti
- Department of Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - Mariaconcetta Augusto
- Department of Molecular Medicine, University La Sapienza, 00161 Rome, Italy
- Center for Life Nano- & Neuro-Science, Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy
| | - Damiana Battaglini
- Department of Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - Francesca Polonara
- Department of Molecular Medicine, University La Sapienza, 00161 Rome, Italy
- Istituto Pasteur-Fondazione Cenci Bolognetti, 00161 Rome, Italy
| | - Stefano Di Giulio
- Department of Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - Giuseppe Giannini
- Department of Molecular Medicine, University La Sapienza, 00161 Rome, Italy
- Istituto Pasteur-Fondazione Cenci Bolognetti, 00161 Rome, Italy
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Mac M, DeVico BM, Raspanti SM, Moody CA. The SETD2 Methyltransferase Supports Productive HPV31 Replication through the LEDGF/CtIP/Rad51 Pathway. J Virol 2023; 97:e0020123. [PMID: 37154769 PMCID: PMC10231177 DOI: 10.1128/jvi.00201-23] [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: 02/07/2023] [Accepted: 04/17/2023] [Indexed: 05/10/2023] Open
Abstract
The human papillomavirus (HPV) life cycle takes place in the stratified epithelium, with the productive phase being activated by epithelial differentiation. The HPV genome is histone-associated, and the life cycle is epigenetically regulated, in part, by histone tail modifications that facilitate the recruitment of DNA repair factors that are required for viral replication. We previously showed that the SETD2 methyltransferase facilitates the productive replication of HPV31 through the trimethylation of H3K36 on viral chromatin. SETD2 regulates numerous cellular processes, including DNA repair via homologous recombination (HR) and alternative splicing, through the recruitment of various effectors to histone H3 lysine 36 trimethylation (H3K36me3). We previously demonstrated that the HR factor Rad51 is recruited to HPV31 genomes and is required for productive replication; however, the mechanism of Rad51 recruitment has not been defined. SET domain containing 2 (SETD2) promotes the HR repair of double-strand breaks (DSBs) in actively transcribed genes through the recruitment of carboxy-terminal binding protein (CtBP)-interacting protein (CtIP) to lens epithelium-derived growth factor (LEDGF)-bound H3K36me3, which promotes DNA end resection and thereby allows for the recruitment of Rad51 to damaged sites. In this study, we found that reducing H3K36me3 through the depletion of SETD2 or the overexpression of an H3.3K36M mutant leads to an increase in γH2AX, which is a marker of damage, on viral DNA upon epithelial differentiation. This is coincident with decreased Rad51 binding. Additionally, LEDGF and CtIP are bound to HPV DNA in a SETD2-dependent and H3K36me3-dependent manner, and they are required for productive replication. Furthermore, CtIP depletion increases DNA damage on viral DNA and blocks Rad51 recruitment upon differentiation. Overall, these studies indicate that H3K36me3 enrichment on transcriptionally active viral genes promotes the rapid repair of viral DNA upon differentiation through the LEDGF-CtIP-Rad51 axis. IMPORTANCE The productive phase of the HPV life cycle is restricted to the differentiating cells of the stratified epithelium. The HPV genome is histone-associated and subject to epigenetic regulation, though the manner in which epigenetic modifications contribute to productive replication is largely undefined. In this study, we demonstrate that SETD2-mediated H3K36me3 on HPV31 chromatin promotes productive replication through the repair of damaged DNA. We show that SETD2 facilitates the recruitment of the homologous recombination repair factors CtIP and Rad51 to viral DNA through LEDGF binding to H3K36me3. CtIP is recruited to damaged viral DNA upon differentiation, and, in turn, recruits Rad51. This likely occurs through the end resection of double-strand breaks. SETD2 trimethylates H3K36me3 during transcription, and active transcription is necessary for Rad51 recruitment to viral DNA. We propose that the enrichment of SETD2-mediated H3K36me3 on transcriptionally active viral genes upon differentiation facilitates the repair of damaged viral DNA during the productive phase of the viral life cycle.
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Affiliation(s)
- Michelle Mac
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Brianna M. DeVico
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Sophia M. Raspanti
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Cary A. Moody
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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MacDonald KM, Nicholson-Puthenveedu S, Tageldein MM, Khasnis S, Arrowsmith CH, Harding SM. Antecedent chromatin organization determines cGAS recruitment to ruptured micronuclei. Nat Commun 2023; 14:556. [PMID: 36732527 PMCID: PMC9894866 DOI: 10.1038/s41467-023-36195-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 01/17/2023] [Indexed: 02/04/2023] Open
Abstract
Micronuclei (MN) are cytosolic bodies that sequester acentric fragments or mis-segregated chromosomes from the primary nucleus. Spontaneous rupture of the MN envelope allows recognition by the viral receptor cyclic GMP-AMP synthase (cGAS), initiating interferon signaling downstream of DNA damage. Here, we demonstrate that MN rupture is permissive but not sufficient for cGAS localization. Chromatin characteristics such as histone 3, lysine 79 dimethylation (H3K79me2) are present in the nucleus before DNA damage, retained in ruptured MN, and regulate cGAS recruitment. cGAS is further responsive to dynamic intra-MN processes occurring prior to rupture, including transcription. MN chromatin tethering via the nucleosome acidic patch is necessary for cGAS-dependent interferon signaling. Our data suggest that both damage-antecedent nuclear chromatin status and MN-contained chromatin organizational changes dictate cGAS recruitment and the magnitude of the cGAS-driven interferon cascade. Our work defines MN as integrative signaling hubs for the cellular response to genotoxic stress.
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Affiliation(s)
- Kate M MacDonald
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | | | - Maha M Tageldein
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Sarika Khasnis
- Princess Margaret Cancer Center, University Health Network, Toronto, ON, Canada
| | - Cheryl H Arrowsmith
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
- Princess Margaret Cancer Center, University Health Network, Toronto, ON, Canada
- Structural Genomics Consortium, University of Toronto, Toronto, ON, Canada
| | - Shane M Harding
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.
- Princess Margaret Cancer Center, University Health Network, Toronto, ON, Canada.
- Departments of Radiation Oncology and Immunology, University of Toronto, Toronto, ON, Canada.
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Asaithamby A, Shay JW, Minna JD. Cellular senescence and lung cancer prognosis. Transl Lung Cancer Res 2022; 11:1982-1987. [PMID: 36386455 PMCID: PMC9641047 DOI: 10.21037/tlcr-22-678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 10/17/2022] [Indexed: 01/25/2023]
Affiliation(s)
- Aroumougame Asaithamby
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, USA;,Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jerry W. Shay
- Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX, USA;,Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - John D. Minna
- Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX, USA;,Hamon Center for Therapeutic Oncology Research and the Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
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Guo X, Hintzsche H, Xu W, Ni J, Xue J, Wang X. Interplay of cGAS with micronuclei: Regulation and diseases. MUTATION RESEARCH. REVIEWS IN MUTATION RESEARCH 2022; 790:108440. [PMID: 35970331 DOI: 10.1016/j.mrrev.2022.108440] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 08/02/2022] [Accepted: 08/09/2022] [Indexed: 01/01/2023]
Abstract
In higher eukaryotes, sophisticate regulation of genome function requires all chromosomes to be packed into a single nucleus. Micronucleus (MN), the dissociative nucleus-like structure frequently observed in aging and multiple disease settings, has critical, yet under-recognized, pathophysiological functions. Micronuclei (MNi) have recently emerged as major sources of cytosolic DNA that can activate the cGAS-STING axis in a cell-intrinsic manner. However, MNi induced from different genotoxic stressors display great heterogeneity in binding or activating cGAS and the signaling responses downstream of the MN-induced cGAS-STING axis have divergent outcomes including autoimmunity, autoinflammation, metastasis, or cell death. Thus, full characterization of molecular network underpinning the interplay of cGAS and MN is important to elucidate the pathophysiological roles of immunogenic MN and design improved drugs that selectively target cancer via boosting the MN-derived cGAS-STING axis. Here, we summarize our current understanding of the mechanisms for self-DNA discrimination by cGAS. We focus on discussing how MN immunogencity is dictated by multiple mechanisms including integrity of micronuclear envelope, state of nucleosome and DNA, competitive factors, damaged mitochondrial DNA and micronucleophagy. We also describe emerging links between immunogenic MN and human diseases including cancer, neurodegenerative diseases and COVID-19. Particularly, we explore the exciting concept of inducing immunogenic MN as a therapeutic approach in treating cancer. We propose a new theoretical framework to describe immunogenic MN as a biological sensor to modulate cellular processes in response to genotoxic stress and provide perspectives on developing novel experimental approaches to unravel the complexity of MN immunogenicity regulation and immunogenic MN pathophysiology.
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Affiliation(s)
- Xihan Guo
- School of Life Sciences, The Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Yunnan Normal University, Kunming, Yunnan 650500, China.
| | - Henning Hintzsche
- Department of Food Safety, Institute of Nutrition and Food Sciences, University of Bonn, Germany.
| | - Weijiang Xu
- School of Life Sciences, The Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Yunnan Normal University, Kunming, Yunnan 650500, China
| | - Juan Ni
- School of Life Sciences, The Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Yunnan Normal University, Kunming, Yunnan 650500, China
| | - Jinglun Xue
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai 200433, China
| | - Xu Wang
- School of Life Sciences, The Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Yunnan Normal University, Kunming, Yunnan 650500, China.
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