1
|
Lin YC, Liu D, Chakraborty A, Macias V, Brister E, Sonalkar J, Shen L, Mitra J, Ha T, Kajdacsy-Balla A, Prasanth KV, Prasanth SG. DNA Damage-Induced, S-Phase Specific Phosphorylation of Orc6 is Critical for the Maintenance of Genome Stability. Mol Cell Biol 2023; 43:143-156. [PMID: 37096556 PMCID: PMC10153009 DOI: 10.1080/10985549.2023.2196204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 02/16/2023] [Accepted: 02/17/2023] [Indexed: 04/26/2023] Open
Abstract
The smallest subunit of the human Origin Recognition Complex, hOrc6, is required for DNA replication progression and plays an important role in mismatch repair (MMR) during S-phase. However, the molecular details of how hOrc6 regulates DNA replication and DNA damage response remain to be elucidated. Orc6 levels are elevated upon specific types of genotoxic stress, and it is phosphorylated at Thr229, predominantly during S-phase, in response to oxidative stress. Many repair pathways, including MMR, mediate oxidative DNA damage repair. Defects in MMR are linked to Lynch syndrome, predisposing patients to many cancers, including colorectal cancer. Orc6 levels are known to be elevated in colorectal cancers. Interestingly, tumor cells show reduced hOrc6-Thr229 phosphorylation compared to adjacent normal mucosa. Further, elevated expression of wild-type and the phospho-dead forms of Orc6 results in increased tumorigenicity, implying that in the absence of this "checkpoint" signal, cells proliferate unabated. Based on these results, we propose that DNA-damage-induced hOrc6-pThr229 phosphorylation during S-phase facilitates ATR signaling in the S-phase, halts fork progression, and enables assembly of repair factors to mediate efficient repair to prevent tumorigenesis. Our study provides novel insights into how hOrc6 regulates genome stability.
Collapse
Affiliation(s)
- Yo-Chuen Lin
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Dazhen Liu
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Arindam Chakraborty
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Virgilia Macias
- Research Tissue Imaging Core, Department of Pathology, University of Illinois, Chicago, Illinois, USA
| | - Eileen Brister
- Research Tissue Imaging Core, Department of Pathology, University of Illinois, Chicago, Illinois, USA
| | - Jay Sonalkar
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Linyuan Shen
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Jaba Mitra
- Biophysics and Biophysical Chemistry, Johns Hopkins University, Baltimore, Maryland, USA
| | - Taekjip Ha
- Biophysics and Biophysical Chemistry, Johns Hopkins University, Baltimore, Maryland, USA
- Howard Hughes Medical Institute, Johns Hopkins University, Baltimore, Maryland, USA
| | - Andre Kajdacsy-Balla
- Research Tissue Imaging Core, Department of Pathology, University of Illinois, Chicago, Illinois, USA
| | - Kannanganattu V. Prasanth
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Cancer Center at Illinois, UIUC, Urbana, Illinois, USA
| | - Supriya G. Prasanth
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Cancer Center at Illinois, UIUC, Urbana, Illinois, USA
| |
Collapse
|
2
|
Anachkova BB, Djeliova VL. Stability of proteins involved in initiation of DNA replication in UV damaged human cells. ACTA ACUST UNITED AC 2021; 77:113-123. [PMID: 34333892 DOI: 10.1515/znc-2020-0286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 07/17/2021] [Indexed: 11/15/2022]
Abstract
The protein stability of the initiation factors Orc2, Orc3, Orc4, and Cdc6 was analyzed after UV light exposure in two human cell lines. In the cell line with higher repair capacity, HEK 293, no changes in the cell cycle distribution or in the protein levels of the investigated factors were detected. In HeLa cells that are characterized by lower repair capacity, UV irradiation caused a reduction of the levels of Cdc6, Orc2 and Orc3, but not of Orc4 or triggered apoptosis. The appearance of the truncated 49 kDa form of Cdc6 suggested the involvement of the caspase pathway in the degradation of the proteins. Reduced protein levels of Cdc6 were detected in UV damaged HeLa cells in which the apoptotic process was blocked with the caspase inhibitor Z-VAD-fmk, indicating that the degradation of Cdc6 is mediated by the proteasome pathway instead. In the presence of caffeine, an inhibitor of the cell cycle checkpoint kinases, Cdc6 was stabilized, demonstrating that its degradation is controlled by the DNA damage cell cycle checkpoint. We conclude that in response to DNA damage, the activation of origins of replication can be prevented by the degradation of Cdc6, most likely through the proteasome pathway.
Collapse
Affiliation(s)
- Boyka Borisova Anachkova
- Department of the Molecular Biology of the Cell Cycle, Institute of Molecular Biology "RoumenTsanev", Bulgarian Academy of Sciences, Akad. G. Bonchev Street, Bl. 21, Sofia1113, Bulgaria
| | - Vera Lyubchova Djeliova
- Department of the Molecular Biology of the Cell Cycle, Institute of Molecular Biology "RoumenTsanev", Bulgarian Academy of Sciences, Akad. G. Bonchev Street, Bl. 21, Sofia1113, Bulgaria
| |
Collapse
|
3
|
Urrutia G, de Assuncao TM, Mathison AJ, Salmonson A, Kerketta R, Zeighami A, Stodola TJ, Adsay V, Pehlivanoglu B, Dwinell MB, Zimmermann MT, Iovanna JL, Urrutia R, Lomberk G. Inactivation of the Euchromatic Histone-Lysine N-Methyltransferase 2 Pathway in Pancreatic Epithelial Cells Antagonizes Cancer Initiation and Pancreatitis-Associated Promotion by Altering Growth and Immune Gene Expression Networks. Front Cell Dev Biol 2021; 9:681153. [PMID: 34249932 PMCID: PMC8261250 DOI: 10.3389/fcell.2021.681153] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 04/27/2021] [Indexed: 12/24/2022] Open
Abstract
Pancreatic ductal adenocarcinoma (PDAC) is an aggressive, painful disease with a 5-year survival rate of only 9%. Recent evidence indicates that distinct epigenomic landscapes underlie PDAC progression, identifying the H3K9me pathway as important to its pathobiology. Here, we delineate the role of Euchromatic Histone-lysine N-Methyltransferase 2 (EHMT2), the enzyme that generates H3K9me, as a downstream effector of oncogenic KRAS during PDAC initiation and pancreatitis-associated promotion. EHMT2 inactivation in pancreatic cells reduces H3K9me2 and antagonizes Kras G12D -mediated acinar-to-ductal metaplasia (ADM) and Pancreatic Intraepithelial Neoplasia (PanIN) formation in both the Pdx1-Cre and P48 Cre/+ Kras G12D mouse models. Ex vivo acinar explants also show impaired EGFR-KRAS-MAPK pathway-mediated ADM upon EHMT2 deletion. Notably, Kras G12D increases EHMT2 protein levels and EHMT2-EHMT1-WIZ complex formation. Transcriptome analysis reveals that EHMT2 inactivation upregulates a cell cycle inhibitory gene expression network that converges on the Cdkn1a/p21-Chek2 pathway. Congruently, pancreas tissue from Kras G12D animals with EHMT2 inactivation have increased P21 protein levels and enhanced senescence. Furthermore, loss of EHMT2 reduces inflammatory cell infiltration typically induced during Kras G12D -mediated initiation. The inhibitory effect on Kras G12D -induced growth is maintained in the pancreatitis-accelerated model, while simultaneously modifying immunoregulatory gene networks that also contribute to carcinogenesis. This study outlines the existence of a novel KRAS-EHMT2 pathway that is critical for mediating the growth-promoting and immunoregulatory effects of this oncogene in vivo, extending human observations to support a pathophysiological role for the H3K9me pathway in PDAC.
Collapse
Affiliation(s)
- Guillermo Urrutia
- Division of Research, Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Thiago Milech de Assuncao
- Division of Research, Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, United States
- Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Angela J. Mathison
- Division of Research, Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, United States
- Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Ann Salmonson
- Division of Research, Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Romica Kerketta
- Division of Research, Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, United States
- Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Atefeh Zeighami
- Division of Research, Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, United States
- Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Timothy J. Stodola
- Division of Research, Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, United States
- Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Volkan Adsay
- Department of Pathology, Koç University Hospital, Istanbul, Turkey
| | - Burcin Pehlivanoglu
- Department of Pathology, Adiyaman University Training and Research Hospital, Adiyaman, Turkey
| | - Michael B. Dwinell
- Division of Research, Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, United States
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI, United States
- Center for Immunology, Medical College of Wisconsin, Milwaukee, WI, United States
- LaBahn Pancreatic Cancer Program, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Michael T. Zimmermann
- Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, WI, United States
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, United States
- Clinical and Translational Sciences Institute, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Juan L. Iovanna
- Centre de Recherche en Cancérologie de Marseille (CRCM), INSERM U1068, CNRS UMR 7258, Aix-Marseille Université and Institut Paoli-Calmettes, Parc Scientifique et Technologique de Luminy, Marseille, France
| | - Raul Urrutia
- Division of Research, Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, United States
- Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, WI, United States
- LaBahn Pancreatic Cancer Program, Medical College of Wisconsin, Milwaukee, WI, United States
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, United States
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Gwen Lomberk
- Division of Research, Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, United States
- Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, WI, United States
- LaBahn Pancreatic Cancer Program, Medical College of Wisconsin, Milwaukee, WI, United States
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, United States
| |
Collapse
|
4
|
Abstract
The DNA damage response (DDR) is a coordinated cellular response to a variety of insults to the genome. DDR initiates the activation of cell cycle checkpoints preventing the propagation of damaged DNA followed by DNA repair, which are both critical in maintaining genome integrity. Several model systems have been developed to study the mechanisms and complexity of checkpoint function. Here we describe the application of cell-free extracts derived from Xenopus eggs as a model system to investigate signaling from DNA damage, modulation of DNA replication, checkpoint activation, and ultimately DNA repair. We outline the preparation of cell-free extracts, DNA substrates, and their subsequent use in assays aimed at understanding the cellular response to DNA damage. Cell-free extracts derived from the eggs of Xenopus laevis remain a robust and versatile system to decipher the biochemical steps underlying this essential characteristic of all cells, critical for genome stability.
Collapse
|
5
|
Early Hereditary Diffuse Gastric Cancer (eHDGC) is Characterized by Subtle Genomic Instability and Active DNA Damage Response. Pathol Oncol Res 2018; 25:711-721. [PMID: 30547291 DOI: 10.1007/s12253-018-0547-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2017] [Accepted: 11/16/2018] [Indexed: 12/26/2022]
Abstract
Diffuse gastric cancer (DGC) is one of the two primary types of stomach cancer. Carriers of germline mutations in the gene encoding E-cadherin are predisposed to DGC. The primary aim of the present study was to determine if genomic instability is an early event in DGC and how it may lead to disease progression. Chromosomal aberrations in early intramucosal hereditary diffuse gastric cancer (eHDGC) were assessed using array comparative genomic hybridization (array CGH). Notably, no aneuploidy or other large-scale chromosomal rearrangements were detected. Instead, all aberrations affected small regions (< 4.8 Mb) and were predominantly deletions. Analysis of DNA sequence patterns revealed that essentially all aberrations possessed the characteristics of common fragile sites. These results and the results of subsequent immunohistochemical examinations demonstrated that unlike advanced DGC, eHDGCs is characterized by low levels of genomic instability at fragile sites. Furthermore, they express an active DNA damage response, providing a molecular basis for the observed indolence of eHDGC. This finding is an important step to understanding the pathology underlying natural history of DGC and supports a revision of the current definition of eHDGC as a malignant disease.
Collapse
|
6
|
Pozo PN, Matson JP, Cole Y, Kedziora KM, Grant GD, Temple B, Cook JG. Cdt1 variants reveal unanticipated aspects of interactions with cyclin/CDK and MCM important for normal genome replication. Mol Biol Cell 2018; 29:2989-3002. [PMID: 30281379 PMCID: PMC6333176 DOI: 10.1091/mbc.e18-04-0242] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The earliest step in DNA replication is origin licensing, which is the DNA loading of minichromosome maintenance (MCM) helicase complexes. The Cdc10-dependent transcript 1 (Cdt1) protein is essential for MCM loading during the G1 phase of the cell cycle, but the mechanism of Cdt1 function is still incompletely understood. We examined a collection of rare Cdt1 variants that cause a form of primordial dwarfism (the Meier-Gorlin syndrome) plus one hypomorphic Drosophila allele to shed light on Cdt1 function. Three hypomorphic variants load MCM less efficiently than wild-type (WT) Cdt1, and their lower activity correlates with impaired MCM binding. A structural homology model of the human Cdt1-MCM complex positions the altered Cdt1 residues at two distinct interfaces rather than the previously described single MCM interaction domain. Surprisingly, one dwarfism allele (Cdt1-A66T) is more active than WT Cdt1. This hypermorphic variant binds both cyclin A and SCFSkp2 poorly relative to WT Cdt1. Detailed quantitative live-cell imaging analysis demonstrated no change in the stability of this variant, however. Instead, we propose that cyclin A/CDK inhibits the Cdt1 licensing function independent of the creation of the SCFSkp2 phosphodegron. Together, these findings identify key Cdt1 interactions required for both efficient origin licensing and tight Cdt1 regulation to ensure normal cell proliferation and genome stability.
Collapse
Affiliation(s)
- Pedro N Pozo
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Jacob P Matson
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Yasemin Cole
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Katarzyna M Kedziora
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Gavin D Grant
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599.,Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Brenda Temple
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599.,R. L. Juliano Structural Bioinformatics Core Facility, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599.,Center for Structural Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Jeanette Gowen Cook
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599.,Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599.,Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| |
Collapse
|
7
|
Walter D, Hoffmann S, Komseli ES, Rappsilber J, Gorgoulis V, Sørensen CS. SCF(Cyclin F)-dependent degradation of CDC6 suppresses DNA re-replication. Nat Commun 2016; 7:10530. [PMID: 26818844 PMCID: PMC4738361 DOI: 10.1038/ncomms10530] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 12/22/2015] [Indexed: 02/06/2023] Open
Abstract
Maintenance of genome stability requires that DNA is replicated precisely once per cell cycle. This is believed to be achieved by limiting replication origin licensing and thereby restricting the firing of each replication origin to once per cell cycle. CDC6 is essential for eukaryotic replication origin licensing, however, it is poorly understood how CDC6 activity is constrained in higher eukaryotes. Here we report that the SCFCyclin F ubiquitin ligase complex prevents DNA re-replication by targeting CDC6 for proteasomal degradation late in the cell cycle. We show that CDC6 and Cyclin F interact through defined sequence motifs that promote CDC6 ubiquitylation and degradation. Absence of Cyclin F or expression of a stable mutant of CDC6 promotes re-replication and genome instability in cells lacking the CDT1 inhibitor Geminin. Together, our work reveals a novel SCFCyclin F-mediated mechanism required for precise once per cell cycle replication. To ensure genome stability, cells need to restrict DNA replication to once per cell cycle. Here the authors show that Cyclin F interacts with and targets the licensing factor CDC6 for degradation, preventing re-firing of replication origins.
Collapse
Affiliation(s)
- David Walter
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Ole Maaløes Vej 5, Copenhagen N 2200, Denmark
| | - Saskia Hoffmann
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Ole Maaløes Vej 5, Copenhagen N 2200, Denmark
| | - Eirini-Stavroula Komseli
- Department of Histology and Embryology, School of Medicine, University of Athens, Athens GR-11527, Greece
| | - Juri Rappsilber
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Kings Buildings, Max Born Crescent, Edinburgh EH9 3BF, Scotland.,Department of Bioanalytics, Institute of Biotechnology, Technische Universität Berlin, Berlin 13355, Germany
| | - Vassilis Gorgoulis
- Department of Histology and Embryology, School of Medicine, University of Athens, Athens GR-11527, Greece.,Faculty Institute of Cancer Sciences, University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Claus Storgaard Sørensen
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Ole Maaløes Vej 5, Copenhagen N 2200, Denmark
| |
Collapse
|
8
|
Dellino GI, Pelicci PG. Next-generation sequencing and DNA replication in human cells: the future has arrived. Future Oncol 2015; 10:683-93. [PMID: 24754597 DOI: 10.2217/fon.13.182] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Accurate regulation of DNA replication ensures faithful transmission of eukaryotic genomes and maintenance of genomic stability and chromatin organization. However, by itself the replication process is a threat for both DNA and chromatin integrity. This becomes particularly relevant in cancer cells, where activated oncogenes induce replication-stress, including unscheduled initiation, fork stalling and collapse and, ultimately, genomic instability. Studies addressing the relationship between (epi)genome integrity and disease have been hampered by our poor knowledge of the mechanisms regulating where and when eukaryotic replication initiates. Recently developed genome-scale methods for the analysis of DNA replication in mammals will contribute to the identification of missing links between replication, chromatin regulation and genome stability in normal and cancer cells.
Collapse
Affiliation(s)
- Gaetano Ivan Dellino
- Department of Experimental Oncology, European Institute of Oncology, 20141 Milan, Italy
| | | |
Collapse
|
9
|
Iwakura T, Fujigaki Y, Fujikura T, Ohashi N, Kato A, Yasuda H. A high ratio of G1 to G0 phase cells and an accumulation of G1 phase cells before S phase progression after injurious stimuli in the proximal tubule. Physiol Rep 2014; 2:e12173. [PMID: 25293601 PMCID: PMC4254098 DOI: 10.14814/phy2.12173] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 09/09/2014] [Accepted: 09/10/2014] [Indexed: 12/25/2022] Open
Abstract
Proximal tubule (PT) cells can proliferate explosively after injurious stimuli. To investigate this proliferative capacity, we examined cell cycle status and the expression of cyclin-dependent kinase inhibitor p27, a G1 phase mediator, in PT cells after a proliferative or injurious stimulus. Rats were treated with lead acetate (proliferative stimulus) or uranyl acetate (UA; injurious stimulus). Isolated tubular cells were separated into PT and distal tubule (DT) cells by density-gradient centrifugation. Cell cycle status was analyzed with flow cytometry by using the Hoechst 33342/pyronin Y method. Most PT and DT cells from control rats were in G0/G1 phase, with a higher percentage of PT cells than DT cells in G1 phase. Lead acetate and UA administration promoted the G0-G1 transition and the accumulation of G1 phase cells before S phase progression. In PT cells from rats treated with lead acetate or a subnephrotoxic dose of UA, p27 levels increased or did not change, possibly reflecting G1 arrest. In contrast, p27 became undetectable before the appearance of apoptotic cells in rats treated with a nephrotoxic dose of UA. The decrease in p27 might facilitate rapid cell cycling. The decreased number of p27-positive cells was associated with PT cell proliferation in renal tissues after a proliferative or injurious stimulus. The findings suggest that a high ratio of G1 to G0 phase cells and a rapid accumulation of G1 phase cells before S phase progression in the PT is a biological strategy for safe, timely, and explosive cell proliferation in response to injurious stimuli.
Collapse
Affiliation(s)
- Takamasa Iwakura
- Internal Medicine I, Division of Nephrology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Yoshihide Fujigaki
- Internal Medicine I, Division of Nephrology, Hamamatsu University School of Medicine, Hamamatsu, Japan
- Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Tomoyuki Fujikura
- Internal Medicine I, Division of Nephrology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Naro Ohashi
- Internal Medicine I, Division of Nephrology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Akihiko Kato
- Blood Purification Unit, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Hideo Yasuda
- Internal Medicine I, Division of Nephrology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| |
Collapse
|
10
|
Kalhorzadeh P, Hu Z, Cools T, Amiard S, Willing EM, De Winne N, Gevaert K, De Jaeger G, Schneeberger K, White CI, De Veylder L. Arabidopsis thaliana RNase H2 deficiency counteracts the needs for the WEE1 checkpoint kinase but triggers genome instability. THE PLANT CELL 2014; 26:3680-92. [PMID: 25217508 PMCID: PMC4213155 DOI: 10.1105/tpc.114.128108] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The WEE1 kinase is an essential cell cycle checkpoint regulator in Arabidopsis thaliana plants experiencing replication defects. Whereas under non-stress conditions WEE1-deficient plants develop normally, they fail to adapt to replication inhibitory conditions, resulting in the accumulation of DNA damage and loss of cell division competence. We identified mutant alleles of the genes encoding subunits of the ribonuclease H2 (RNase H2) complex, known for its role in removing ribonucleotides from DNA-RNA duplexes, as suppressor mutants of WEE1 knockout plants. RNase H2 deficiency triggered an increase in homologous recombination (HR), correlated with the accumulation of γ-H2AX foci. However, as HR negatively impacts the growth of WEE1-deficient plants under replication stress, it cannot account for the rescue of the replication defects of the WEE1 knockout plants. Rather, the observed increase in ribonucleotide incorporation in DNA indicates that the substitution of deoxynucleotide with ribonucleotide abolishes the need for WEE1 under replication stress. Strikingly, increased ribonucleotide incorporation in DNA correlated with the occurrence of small base pair deletions, identifying the RNase H2 complex as an important suppressor of genome instability.
Collapse
Affiliation(s)
- Pooneh Kalhorzadeh
- Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), B-9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium
| | - Zhubing Hu
- Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), B-9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium
| | - Toon Cools
- Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), B-9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium
| | - Simon Amiard
- Génétique, Reproduction et Développement, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 6293-Clermont Université-Institut National de la Santé et de la Recherche Médicale U1103, F-63177 Aubière, France
| | - Eva-Maria Willing
- Department for Plant Developmental Biology, Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany
| | - Nancy De Winne
- Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), B-9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium
| | - Kris Gevaert
- Department of Medical Protein Research, Flanders Institute for Biotechnology (VIB), B-9000 Ghent, Belgium Department of Biochemistry, Ghent University, B-9000 Ghent, Belgium
| | - Geert De Jaeger
- Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), B-9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium
| | - Korbinian Schneeberger
- Department for Plant Developmental Biology, Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany
| | - Charles I White
- Génétique, Reproduction et Développement, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 6293-Clermont Université-Institut National de la Santé et de la Recherche Médicale U1103, F-63177 Aubière, France
| | - Lieven De Veylder
- Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), B-9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium
| |
Collapse
|
11
|
CHEN SANSAN, WAN PEI, DING WEN, LI FEI, HE CHENGWU, CHEN PENGLIANG, LI HONGWEI, HU ZHIMING, TAN WANLONG, LI JINLONG. Norcantharidin inhibits DNA replication and induces mitotic catastrophe by degrading initiation protein Cdc6. Int J Mol Med 2013; 32:43-50. [DOI: 10.3892/ijmm.2013.1359] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Accepted: 04/08/2013] [Indexed: 11/06/2022] Open
|
12
|
Symeonidou IE, Taraviras S, Lygerou Z. Control over DNA replication in time and space. FEBS Lett 2012; 586:2803-12. [PMID: 22841721 DOI: 10.1016/j.febslet.2012.07.042] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 07/18/2012] [Accepted: 07/18/2012] [Indexed: 12/23/2022]
Abstract
DNA replication is precisely regulated in time and space, thereby safeguarding genomic integrity. In eukaryotes, replication initiates from multiple sites along the genome, termed origins of replication, and propagates bidirectionally. Dynamic origin bound complexes dictate where and when replication should initiate. During late mitosis and G1 phase, putative origins are recognized and become "licensed" through the assembly of pre-replicative complexes (pre-RCs) that include the MCM2-7 helicases. Subsequently, at the G1/S phase transition, a fraction of pre-RCs are activated giving rise to the establishment of replication forks. Origin location is influenced by chromatin and nuclear organization and origin selection exhibits stochastic features. The regulatory mechanisms that govern these cell cycle events rely on the periodic fluctuation of cyclin dependent kinase (CDK) activity through the cell cycle.
Collapse
|
13
|
Dynamic association of ORCA with prereplicative complex components regulates DNA replication initiation. Mol Cell Biol 2012; 32:3107-20. [PMID: 22645314 DOI: 10.1128/mcb.00362-12] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
In eukaryotes, initiation of DNA replication requires the assembly of a multiprotein prereplicative complex (pre-RC) at the origins. We recently reported that a WD repeat-containing protein, origin recognition complex (ORC)-associated (ORCA/LRWD1), plays a crucial role in stabilizing ORC to chromatin. Here, we find that ORCA is required for the G(1)-to-S-phase transition in human cells. In addition to binding to ORC, ORCA associates with Cdt1 and its inhibitor, geminin. Single-molecule pulldown experiments demonstrate that each molecule of ORCA can bind to one molecule of ORC, one molecule of Cdt1, and two molecules of geminin. Further, ORCA directly interacts with the N terminus of Orc2, and the stability of ORCA is dependent on its association with Orc2. ORCA associates with Orc2 throughout the cell cycle, with Cdt1 during mitosis and G(1), and with geminin in post-G(1) cells. Overexpression of geminin results in the loss of interaction between ORCA and Cdt1, suggesting that increased levels of geminin in post-G(1) cells titrate Cdt1 away from ORCA. We propose that the dynamic association of ORCA with pre-RC components modulates the assembly of its interacting partners on chromatin and facilitates DNA replication initiation.
Collapse
|
14
|
Sacco E, Hasan MM, Alberghina L, Vanoni M. Comparative analysis of the molecular mechanisms controlling the initiation of chromosomal DNA replication in yeast and in mammalian cells. Biotechnol Adv 2012; 30:73-98. [DOI: 10.1016/j.biotechadv.2011.09.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Accepted: 09/14/2011] [Indexed: 11/26/2022]
|
15
|
Su TT. Safeguarding genetic information in Drosophila. Chromosoma 2011; 120:547-55. [PMID: 21927823 DOI: 10.1007/s00412-011-0342-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 08/24/2011] [Accepted: 08/26/2011] [Indexed: 12/11/2022]
Abstract
Eukaryotic cells employ a plethora of conserved proteins and mechanisms to ensure genome integrity. In metazoa, these mechanisms must operate in the context of organism development. This mini-review highlights two emerging features of DNA damage responses in Drosophila: a crosstalk between DNA damage responses and components of the spindle assembly checkpoint, and increasing evidence for the effect of DNA damage on the developmental program at multiple points during the Drosophila life cycle.
Collapse
Affiliation(s)
- Tin Tin Su
- MCD Biology, University of Colorado, Boulder, USA.
| |
Collapse
|
16
|
Abstract
DNA replication is a highly regulated process involving a number of licensing and replication factors that function in a carefully orchestrated manner to faithfully replicate DNA during every cell cycle. Loss of proper licensing control leads to deregulated DNA replication including DNA re-replication, which can cause genome instability and tumorigenesis. Eukaryotic organisms have established several conserved mechanisms to prevent DNA re-replication and to counteract its potentially harmful effects. These mechanisms include tightly controlled regulation of licensing factors and activation of cell cycle and DNA damage checkpoints. Deregulated licensing control and its associated compromised checkpoints have both been observed in tumor cells, indicating that proper functioning of these pathways is essential for maintaining genome stability. In this review, we discuss the regulatory mechanisms of licensing control, the deleterious consequences when both licensing and checkpoints are compromised, and present possible mechanisms to prevent re-replication in order to maintain genome stability.
Collapse
Affiliation(s)
- Lan N Truong
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | | |
Collapse
|
17
|
Cools T, Iantcheva A, Weimer AK, Boens S, Takahashi N, Maes S, Van den Daele H, Van Isterdael G, Schnittger A, De Veylder L. The Arabidopsis thaliana checkpoint kinase WEE1 protects against premature vascular differentiation during replication stress. THE PLANT CELL 2011; 23:1435-48. [PMID: 21498679 PMCID: PMC3101530 DOI: 10.1105/tpc.110.082768] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2010] [Revised: 03/22/2011] [Accepted: 03/30/2011] [Indexed: 05/17/2023]
Abstract
A sessile lifestyle forces plants to respond promptly to factors that affect their genomic integrity. Therefore, plants have developed checkpoint mechanisms to arrest cell cycle progression upon the occurrence of DNA stress, allowing the DNA to be repaired before onset of division. Previously, the WEE1 kinase had been demonstrated to be essential for delaying progression through the cell cycle in the presence of replication-inhibitory drugs, such as hydroxyurea. To understand the severe growth arrest of WEE1-deficient plants treated with hydroxyurea, a transcriptomics analysis was performed, indicating prolonged S-phase duration. A role for WEE1 during S phase was substantiated by its specific accumulation in replicating nuclei that suffered from DNA stress. Besides an extended replication phase, WEE1 knockout plants accumulated dead cells that were associated with premature vascular differentiation. Correspondingly, plants without functional WEE1 ectopically expressed the vascular differentiation marker VND7, and their vascular development was aberrant. We conclude that the growth arrest of WEE1-deficient plants is due to an extended cell cycle duration in combination with a premature onset of vascular cell differentiation. The latter implies that the plant WEE1 kinase acquired an indirect developmental function that is important for meristem maintenance upon replication stress.
Collapse
Affiliation(s)
- Toon Cools
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium
- Department of Plant Biotechnology and Genetics, Ghent University, B-9052 Ghent, Belgium
| | - Anelia Iantcheva
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium
- Department of Plant Biotechnology and Genetics, Ghent University, B-9052 Ghent, Belgium
| | - Annika K. Weimer
- Department of Molecular Mechanisms of Phenotypic Plasticity, Institut de Biologie Moléculaire des Plantes–Centre National de Recherche Scientifique, Unité Propre de Recherche 2357, Université de Strasbourg, 67084 Strasbourg Cedex, France
| | - Shannah Boens
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium
- Department of Plant Biotechnology and Genetics, Ghent University, B-9052 Ghent, Belgium
| | - Naoki Takahashi
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium
- Department of Plant Biotechnology and Genetics, Ghent University, B-9052 Ghent, Belgium
| | - Sara Maes
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium
- Department of Plant Biotechnology and Genetics, Ghent University, B-9052 Ghent, Belgium
| | - Hilde Van den Daele
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium
- Department of Plant Biotechnology and Genetics, Ghent University, B-9052 Ghent, Belgium
| | - Gert Van Isterdael
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium
- Department of Plant Biotechnology and Genetics, Ghent University, B-9052 Ghent, Belgium
| | - Arp Schnittger
- Department of Molecular Mechanisms of Phenotypic Plasticity, Institut de Biologie Moléculaire des Plantes–Centre National de Recherche Scientifique, Unité Propre de Recherche 2357, Université de Strasbourg, 67084 Strasbourg Cedex, France
| | - Lieven De Veylder
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium
- Department of Plant Biotechnology and Genetics, Ghent University, B-9052 Ghent, Belgium
- Address correspondence to
| |
Collapse
|
18
|
Fragel-Madeira L, Meletti T, Mariante RM, Monteiro RQ, Einicker-Lamas M, Bernardo RR, Lopes AH, Linden R. Platelet activating factor blocks interkinetic nuclear migration in retinal progenitors through an arrest of the cell cycle at the S/G2 transition. PLoS One 2011; 6:e16058. [PMID: 21298035 PMCID: PMC3029264 DOI: 10.1371/journal.pone.0016058] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Accepted: 12/06/2010] [Indexed: 02/06/2023] Open
Abstract
Nuclear migration is regulated by the LIS1 protein, which is the regulatory subunit of platelet activating factor (PAF) acetyl-hydrolase, an enzyme complex that inactivates the lipid mediator PAF. Among other functions, PAF modulates cell proliferation, but its effects upon mechanisms of the cell cycle are unknown. Here we show that PAF inhibited interkinetic nuclear migration (IKNM) in retinal proliferating progenitors. The lipid did not, however, affect the velocity of nuclear migration in cells that escaped IKNM blockade. The effect depended on the PAF receptor, Erk and p38 pathways and Chk1. PAF induced no cell death, nor a reduction in nucleotide incorporation, which rules out an intra-S checkpoint. Notwithstanding, the expected increase in cyclin B1 content during G2-phase was prevented in the proliferating cells. We conclude that PAF blocks interkinetic nuclear migration in retinal progenitor cells through an unusual arrest of the cell cycle at the transition from S to G2 phases. These data suggest the operation, in the developing retina, of a checkpoint that monitors the transition from S to G2 phases of the cell cycle.
Collapse
Affiliation(s)
| | - Tamara Meletti
- Institute of Biophysics, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Rafael M. Mariante
- Institute of Biophysics, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Robson Q. Monteiro
- Institute of Medical Biochemistry, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | | | - Robson R. Bernardo
- Institute of Chemistry, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Angela H. Lopes
- Institute of Microbiology, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Rafael Linden
- Institute of Biophysics, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
- * E-mail:
| |
Collapse
|
19
|
Abstract
Cell cycle checkpoints are involved in the coordinated response to DNA damage and thus play a key role in maintaining genome integrity. Several model systems have been developed to study the mechanisms and complexity of checkpoint function. Here we describe the application of cell-free extracts derived from Xenopus eggs as a model system to investigate DNA replication, damage, and checkpoint activation. We outline the preparation of cell-free extracts, DNA substrates and their subsequent use in assays aimed at understanding cell cycle checkpoints, and related processes. Several advances made over the years have enabled the continued use of the Xenopus system to answer a variety of questions in DNA replication, repair and checkpoint signaling. It is anticipated that the versatile Xenopus system is amenable to future modification as well to continue studies attempting to understand these important physiological processes.
Collapse
|
20
|
Abstract
In this issue, a study by Groehler and Lannigan (2010. J. Cell Biol. doi:10.1083/jcb.201002124) sheds light on the regulation of proliferating cell nuclear antigen (PCNA) turnover and how it is counteracted by the small chromatin-bound kinase ERK8 (extracellular signal-regulated kinase 8). Importantly, inactivation of ERK8 results in genome instability and is associated with cell transformation.
Collapse
Affiliation(s)
- Hai Dang Nguyen
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | | |
Collapse
|
21
|
A deneddylase encoded by Epstein-Barr virus promotes viral DNA replication by regulating the activity of cullin-RING ligases. Nat Cell Biol 2010; 12:351-61. [PMID: 20190741 DOI: 10.1038/ncb2035] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2009] [Accepted: 02/03/2010] [Indexed: 12/30/2022]
Abstract
The large tegument proteins of herpesviruses encode conserved cysteine proteases of unknown function. Here we show that BPLF1, the Epstein-Barr-virus-encoded member of this protease family, is a deneddylase that regulates virus production by modulating the activity of cullin-RING ligases (CRLs). BPLF1 hydrolyses NEDD8 conjugates in vitro, acts as a deneddylase in vivo, binds to cullins and stabilizes CRL substrates. Expression of BPLF1 alone or in the context of the productive virus cycle induces accumulation of the licensing factor CDT1 and deregulates S-phase DNA synthesis. Inhibition of BPLF1 during the productive virus cycle prevents cellular DNA re-replication and inhibits virus replication. Viral DNA synthesis is restored by overexpression of CDT1. Homologues encoded by other herpesviruses share the deneddylase activity. Thus, these enzymes are likely to have a key function in the virus life cycle by inducing a replication-permissive S-phase-like cellular environment.
Collapse
|