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Fang S, Wang H, Qiu K, Pang Y, Li C, Liang X. The fungicide pyraclostrobin affects gene expression by altering the DNA methylation pattern in Magnaporthe oryzae. FRONTIERS IN PLANT SCIENCE 2024; 15:1391900. [PMID: 38745924 PMCID: PMC11091397 DOI: 10.3389/fpls.2024.1391900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 04/17/2024] [Indexed: 05/16/2024]
Abstract
Introduction Rice blast disease caused by Magnaporthe oryzae has long been the main cause of rice (Oryza sativa L.) yield reduction worldwide. The quinone external inhibitor pyraclostrobin is widely used as a fungicide to effectively control the spread of pathogenic fungi, including M. oryzae. However, M. oryzae can develop resistance through multiple levels of mutation, such as target protein cytb mutation G143A/S, leading to a decrease in the effectiveness of the biocide after a period of application. Therefore, uncovering the possible mutational mechanisms from multiple perspectives will further provide feasible targets for drug development. Methods In this work, we determined the gene expression changes in M. oryzae in response to pyraclostrobin stress and their relationship with DNA methylation by transcriptome and methylome. Results The results showed that under pyraclostrobin treatment, endoplasmic reticulum (ER)-associated and ubiquitin-mediated proteolysis were enhanced, suggesting that more aberrant proteins may be generated that need to be cleared. DNA replication and repair processes were inhibited. Glutathione metabolism was enhanced, while lipid metabolism was impaired. The number of alternative splicing events increased. These changes may be related to the elevated methylation levels of cytosine and adenine in gene bodies. Both hypermethylation and hypomethylation of differentially methylated genes (DMGs) mainly occurred in exons and promoters. Some DMGs and differentially expressed genes (DEGs) were annotated to the same pathways by GO and KEGG, including protein processing in the ER, ubiquitin-mediated proteolysis, RNA transport and glutathione metabolism, suggesting that pyraclostrobin may affect gene expression by altering the methylation patterns of cytosine and adenine. Discussion Our results revealed that 5mC and 6mA in the gene body are associated with gene expression and contribute to adversity adaptation in M. oryzae. This enriched the understanding for potential mechanism of quinone inhibitor resistance, which will facilitate the development of feasible strategies for maintaining the high efficacy of this kind of fungicide.
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Affiliation(s)
- Shumei Fang
- Heilongjiang Plant Growth Regulator Engineering Technology Research Center, College of Agriculture, Heilongjiang Bayi Agricultural University, Daqing, China
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Hanxin Wang
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Kaihua Qiu
- Heilongjiang Plant Growth Regulator Engineering Technology Research Center, College of Agriculture, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Yuanyuan Pang
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Chen Li
- Heilongjiang Plant Growth Regulator Engineering Technology Research Center, College of Agriculture, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Xilong Liang
- Heilongjiang Plant Growth Regulator Engineering Technology Research Center, College of Agriculture, Heilongjiang Bayi Agricultural University, Daqing, China
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Huang QR, Jiang Q, Tan JY, Nong RB, Yan J, Yang XW, Mo LG, Ling GY, Deng T, Gong YZ. The prognostic and immunological role of MCM3 in pan-cancer and validation of prognosis in a clinical lower-grade glioma cohort. Front Pharmacol 2024; 15:1390615. [PMID: 38698811 PMCID: PMC11063780 DOI: 10.3389/fphar.2024.1390615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 04/05/2024] [Indexed: 05/05/2024] Open
Abstract
Background: Previous studies have shown that MCM3 plays a key role in initiating DNA replication. However, the mechanism of MCM3 function in most cancers is still unknown. The aim of our study was to explore the expression, prognostic role, and immunological characteristics of MCM3 across cancers. Methods: We explored the expression pattern of MCM3 across cancers. We subsequently explored the prognostic value of MCM3 expression by using univariate Cox regression analysis. Spearman correlation analysis was performed to determine the correlations between MCM3 and immune-related characteristics, mismatching repair (MMR) signatures, RNA modulator genes, cancer stemness, programmed cell death (PCD) gene expression, tumour mutation burden (TMB), microsatellite instability (MSI), and neoantigen levels. The role of MCM3 in predicting the response to immune checkpoint blockade (ICB) therapy was further evaluated in four immunotherapy cohorts. Single-cell data from CancerSEA were analysed to assess the biological functions associated with MCM3 in 14 cancers. The clinical correlation and independent prognostic significance of MCM3 were further analysed in the TCGA and CGGA lower-grade glioma (LGG) cohorts, and a prognostic nomogram was constructed. Immunohistochemistry in a clinical cohort was utilized to validate the prognostic utility of MCM3 expression in LGG. Results: MCM3 expression was upregulated in most tumours and strongly associated with patient outcomes in many cancers. Correlation analyses demonstrated that MCM3 expression was closely linked to immune cell infiltration, immune checkpoints, MMR genes, RNA modulator genes, cancer stemness, PCD genes and the TMB in most tumours. There was an obvious difference in outcomes between patients with high MCM3 expression and those with low MCM3 expression in the 4 ICB treatment cohorts. Single-cell analysis indicated that MCM3 was mainly linked to the cell cycle, DNA damage and DNA repair. The expression of MCM3 was associated with the clinical features of LGG patients and was an independent prognostic indicator. Finally, the prognostic significance of MCM3 in LGG was validated in a clinical cohort. Conclusion: Our study suggested that MCM3 can be used as a potential prognostic marker for cancers and may be associated with tumour immunity. In addition, MCM3 is a promising predictor of immunotherapy responses.
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Affiliation(s)
- Qian-Rong Huang
- Department of Neurosurgery, Guangxi Medical University Cancer Hospital, Nanning, China
| | - Qian Jiang
- Department of Neurosurgery, Guangxi Medical University Cancer Hospital, Nanning, China
| | - Ju-Yuan Tan
- Department of Neurosurgery, Guangxi Medical University Cancer Hospital, Nanning, China
| | - Ren-Bao Nong
- Department of Neurosurgery, Guangxi Medical University Cancer Hospital, Nanning, China
| | - Jun Yan
- Department of Neurosurgery, Guangxi Medical University Cancer Hospital, Nanning, China
| | | | - Li-Gen Mo
- Department of Neurosurgery, Guangxi Medical University Cancer Hospital, Nanning, China
| | - Guo-Yuan Ling
- Department of Neurosurgery, Guangxi Medical University Cancer Hospital, Nanning, China
| | - Teng Deng
- Department of Neurosurgery, Guangxi Medical University Cancer Hospital, Nanning, China
| | - Yi-Zhen Gong
- Department of Clinical Research, Guangxi Medical University Cancer Hospital, Nanning, China
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Distinct roles of Arabidopsis ORC1 proteins in DNA replication and heterochromatic H3K27me1 deposition. Nat Commun 2023; 14:1270. [PMID: 36882445 PMCID: PMC9992703 DOI: 10.1038/s41467-023-37024-8] [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: 09/14/2021] [Accepted: 02/24/2023] [Indexed: 03/09/2023] Open
Abstract
Most cellular proteins involved in genome replication are conserved in all eukaryotic lineages including yeast, plants and animals. However, the mechanisms controlling their availability during the cell cycle are less well defined. Here we show that the Arabidopsis genome encodes for two ORC1 proteins highly similar in amino acid sequence and that have partially overlapping expression domains but with distinct functions. The ancestral ORC1b gene, present before the partial duplication of the Arabidopsis genome, has retained the canonical function in DNA replication. ORC1b is expressed in both proliferating and endoreplicating cells, accumulates during G1 and is rapidly degraded upon S-phase entry through the ubiquitin-proteasome pathway. In contrast, the duplicated ORC1a gene has acquired a specialized function in heterochromatin biology. ORC1a is required for efficient deposition of the heterochromatic H3K27me1 mark by the ATXR5/6 histone methyltransferases. The distinct roles of the two ORC1 proteins may be a feature common to other organisms with duplicated ORC1 genes and a major difference with animal cells.
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The Impact of [C16Pyr][Amp] on the Aggressiveness in Breast and Prostate Cancer Cell Lines. Int J Mol Sci 2020; 21:ijms21249584. [PMID: 33339207 PMCID: PMC7765672 DOI: 10.3390/ijms21249584] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 12/05/2020] [Accepted: 12/14/2020] [Indexed: 12/18/2022] Open
Abstract
Breast (BrCa) and prostate (PCa) cancers are the most common malignancies in women and men, respectively. The available therapeutic options for these tumors are still not curative and have severe side effects. Therefore, there is an urgent need for more effective antineoplastic agents. Herein, BrCa, PCa, and benign cell lines were treated with two ionic liquids and two quinoxalines and functional experiments were performed-namely cell viability, apoptosis, cytotoxicity, and colony formation assays. At the molecular level, an array of gene expressions encompassing several molecular pathways were used to explore the impact of treatment on gene expression. Although both quinoxalines and the ionic liquid [C2OHMIM][Amp] did not show any effect on the BrCa and PCa cell lines, [C16Pyr][Amp] significantly decreased cell viability and colony formation ability, while it increased the apoptosis levels of all cell lines. Importantly, [C16Pyr][Amp] was found to be more selective for cancer cells and less toxic than cisplatin. At the molecular level, this ionic liquid was also associated with reduced expression levels of CPT2, LDHA, MCM2, and SKP2, in both BrCa and PCa cell lines. Hence, [C16Pyr][Amp] was shown to be a promising anticancer therapeutic agent for BrCa and PCa cell lines.
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5
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Yuan Z, Li H. Molecular mechanisms of eukaryotic origin initiation, replication fork progression, and chromatin maintenance. Biochem J 2020; 477:3499-3525. [PMID: 32970141 PMCID: PMC7574821 DOI: 10.1042/bcj20200065] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/29/2020] [Accepted: 09/04/2020] [Indexed: 12/13/2022]
Abstract
Eukaryotic DNA replication is a highly dynamic and tightly regulated process. Replication involves several dozens of replication proteins, including the initiators ORC and Cdc6, replicative CMG helicase, DNA polymerase α-primase, leading-strand DNA polymerase ε, and lagging-strand DNA polymerase δ. These proteins work together in a spatially and temporally controlled manner to synthesize new DNA from the parental DNA templates. During DNA replication, epigenetic information imprinted on DNA and histone proteins is also copied to the daughter DNA to maintain the chromatin status. DNA methyltransferase 1 is primarily responsible for copying the parental DNA methylation pattern into the nascent DNA. Epigenetic information encoded in histones is transferred via a more complex and less well-understood process termed replication-couple nucleosome assembly. Here, we summarize the most recent structural and biochemical insights into DNA replication initiation, replication fork elongation, chromatin assembly and maintenance, and related regulatory mechanisms.
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Affiliation(s)
- Zuanning Yuan
- Structural Biology Program, Van Andel Institute, Grand Rapids, Michigan, U.S.A
| | - Huilin Li
- Structural Biology Program, Van Andel Institute, Grand Rapids, Michigan, U.S.A
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6
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Qian W, Li Z, Song W, Zhao T, Wang W, Peng J, Wei L, Xia Q, Cheng D. A novel transcriptional cascade is involved in Fzr-mediated endoreplication. Nucleic Acids Res 2020; 48:4214-4229. [PMID: 32182338 PMCID: PMC7192621 DOI: 10.1093/nar/gkaa158] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 02/29/2020] [Indexed: 01/08/2023] Open
Abstract
Endoreplication, known as endocycle, is a variant of the cell cycle that differs from mitosis and occurs in specific tissues of different organisms. Endoreplicating cells generally undergo multiple rounds of genome replication without chromosome segregation. Previous studies demonstrated that Drosophila fizzy-related protein (Fzr) and its mammalian homolog Cdh1 function as key regulators of endoreplication entrance by activating the anaphase-promoting complex/cyclosome to initiate the ubiquitination and subsequent degradation of cell cycle factors such as Cyclin B (CycB). However, the molecular mechanism underlying Fzr-mediated endoreplication is not completely understood. In this study, we demonstrated that the transcription factor Myc acts downstream of Fzr during endoreplication in Drosophila salivary gland. Mechanistically, Fzr interacts with chromatin-associated histone H2B to enhance H2B ubiquitination in the Myc promoter and promotes Myc transcription. In addition to negatively regulating CycB transcription, the Fzr-ubiquitinated H2B (H2Bub)-Myc signaling cascade also positively regulates the transcription of the MCM6 gene that is involved in DNA replication by directly binding to specific motifs within their promoters. We further found that the Fzr-H2Bub-Myc signaling cascade regulating endoreplication progression is conserved between insects and mammalian cells. Altogether, our work uncovers a novel transcriptional cascade that is involved in Fzr-mediated endoreplication.
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Affiliation(s)
- Wenliang Qian
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400715, China.,Chongqing Key Laboratory of Sericultural Science, Chongqing engineering and technology research center for novel silk materials, Southwest University, Chongqing 400715, China
| | - Zheng Li
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400715, China.,Chongqing Key Laboratory of Sericultural Science, Chongqing engineering and technology research center for novel silk materials, Southwest University, Chongqing 400715, China
| | - Wei Song
- Medical Research Institute, Wuhan University, Wuhan 430071, China.,Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Tujing Zhao
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400715, China.,Chongqing Key Laboratory of Sericultural Science, Chongqing engineering and technology research center for novel silk materials, Southwest University, Chongqing 400715, China
| | - Weina Wang
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400715, China.,Chongqing Key Laboratory of Sericultural Science, Chongqing engineering and technology research center for novel silk materials, Southwest University, Chongqing 400715, China
| | - Jian Peng
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400715, China.,Chongqing Key Laboratory of Sericultural Science, Chongqing engineering and technology research center for novel silk materials, Southwest University, Chongqing 400715, China
| | - Ling Wei
- School of Life Science, Southwest University, Chongqing 400715, China
| | - Qingyou Xia
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400715, China.,Chongqing Key Laboratory of Sericultural Science, Chongqing engineering and technology research center for novel silk materials, Southwest University, Chongqing 400715, China
| | - Daojun Cheng
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400715, China.,Chongqing Key Laboratory of Sericultural Science, Chongqing engineering and technology research center for novel silk materials, Southwest University, Chongqing 400715, China
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7
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Bleichert F. Mechanisms of replication origin licensing: a structural perspective. Curr Opin Struct Biol 2019; 59:195-204. [PMID: 31630057 DOI: 10.1016/j.sbi.2019.08.007] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 08/26/2019] [Accepted: 08/29/2019] [Indexed: 12/24/2022]
Abstract
The duplication of chromosomal DNA is a key cell cycle event that involves the controlled, bidirectional assembly of the replicative machinery. In a tightly regulated, multi-step reaction, replicative helicases and other components of the DNA synthesis apparatus are recruited to replication start sites. Although the molecular approaches for assembling this machinery vary between the different domains of life, a common theme revolves around the use of ATP-dependent initiation factors to recognize and remodel origins and to load replicative helicases in a bidirectional manner onto DNA. This review summarizes recent advances in understanding the mechanisms of replication initiation in eukaryotes, focusing on how the replicative helicase is loaded in this system.
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8
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Wu R, Amin A, Wang Z, Huang Y, Man-Hei Cheung M, Yu Z, Yang W, Liang C. The interaction networks of the budding yeast and human DNA replication-initiation proteins. Cell Cycle 2019; 18:723-741. [PMID: 30890025 DOI: 10.1080/15384101.2019.1586509] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
DNA replication is a stringently regulated cellular process. In proliferating cells, DNA replication-initiation proteins (RIPs) are sequentially loaded onto replication origins during the M-to-G1 transition to form the pre-replicative complex (pre-RC), a process known as replication licensing. Subsequently, additional RIPs are recruited to form the pre-initiation complex (pre-IC). RIPs and their regulators ensure that chromosomal DNA is replicated exactly once per cell cycle. Origin recognition complex (ORC) binds to, and marks replication origins throughout the cell cycle and recruits other RIPs including Noc3p, Ipi1-3p, Cdt1p, Cdc6p and Mcm2-7p to form the pre-RC. The detailed mechanisms and regulation of the pre-RC and its exact architecture still remain unclear. In this study, pairwise protein-protein interactions among 23 budding yeast and 16 human RIPs were systematically and comprehensively examined by yeast two-hybrid analysis. This study tested 470 pairs of yeast and 196 pairs of human RIPs, from which 113 and 96 positive interactions, respectively, were identified. While many of these interactions were previously reported, some were novel, including various ORC and MCM subunit interactions, ORC self-interactions, and the interactions of IPI3 and NOC3 with several pre-RC and pre-IC proteins. Ten of the novel interactions were further confirmed by co-immunoprecipitation assays. Furthermore, we identified the conserved interaction networks between the yeast and human RIPs. This study provides a foundation and framework for further understanding the architectures, interactions and functions of the yeast and human pre-RC and pre-IC.
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Affiliation(s)
- Rentian Wu
- a Division of Life Science, Center for Cancer Research and State Key Lab for Molecular Neuroscience , Hong Kong University of Science and Technology , Hong Kong , China.,b Guangzhou HKUST Fok Ying Tung Research Institute , Guangzhou , China
| | - Aftab Amin
- a Division of Life Science, Center for Cancer Research and State Key Lab for Molecular Neuroscience , Hong Kong University of Science and Technology , Hong Kong , China.,b Guangzhou HKUST Fok Ying Tung Research Institute , Guangzhou , China.,c School of Chinese Medicine , Hong Kong Baptist University , Guangzhou , China
| | - Ziyi Wang
- a Division of Life Science, Center for Cancer Research and State Key Lab for Molecular Neuroscience , Hong Kong University of Science and Technology , Hong Kong , China
| | - Yining Huang
- a Division of Life Science, Center for Cancer Research and State Key Lab for Molecular Neuroscience , Hong Kong University of Science and Technology , Hong Kong , China
| | - Marco Man-Hei Cheung
- a Division of Life Science, Center for Cancer Research and State Key Lab for Molecular Neuroscience , Hong Kong University of Science and Technology , Hong Kong , China.,b Guangzhou HKUST Fok Ying Tung Research Institute , Guangzhou , China
| | - Zhiling Yu
- c School of Chinese Medicine , Hong Kong Baptist University , Guangzhou , China
| | - Wei Yang
- a Division of Life Science, Center for Cancer Research and State Key Lab for Molecular Neuroscience , Hong Kong University of Science and Technology , Hong Kong , China.,d Guangdong Lewwin Pharmaceutical Research Institute Co., Ltd , Hong Kong , China
| | - Chun Liang
- a Division of Life Science, Center for Cancer Research and State Key Lab for Molecular Neuroscience , Hong Kong University of Science and Technology , Hong Kong , China.,b Guangzhou HKUST Fok Ying Tung Research Institute , Guangzhou , China.,e ntelgen Limited , Hong Kong-Guangzhou-Foshan , China
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Shi X, Chen S, Zhang Y, Xie W, Hu Z, Li H, Li J, Zhou Z, Tan W. Norcantharidin inhibits the DDR of bladder cancer stem-like cells through cdc6 degradation. Onco Targets Ther 2019; 12:4403-4413. [PMID: 31239709 PMCID: PMC6560209 DOI: 10.2147/ott.s209907] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 05/14/2019] [Indexed: 01/16/2023] Open
Abstract
Introduction: Cancer stem cells (CSCs) are the main source of tumor resistance and recurrence. At present, the main treatment for patients with advanced or metastatic bladder cancer (BCa) is cisplatin-based combination chemotherapy. However, CSCs are not sensitive to DNA-damaging drugs due to their enhanced DNA damage response (DDR) activity. Materials and methods: Bladder cancer stem cell-like cells (BCSLCs) were obtained by treating UMUC3 cells with cisplatin. The characteristics of the BCSLCs were identified by qPCR, flow cytometry, scratch wound-healing assays, transwell assays, tumorigenic ability experiments, Edu assays and Western blot assays in vivo. After BCSLCs were treated with norcantharidin (NCTD), the expression of Cdc6 and activation of the ATR-Chk1 pathway were detected by Western blotting. A subcutaneous tumor model in nude mice was successfully established to assess the anti-tumor efficacy of NCTD and cisplatin either alone or in combination in vivo. The tumor tissues were detected by immunohistochemistry. Results: The derived BCSLCs showed higher expression of stemness markers, increased invasiveness, improved resistance to multiple chemotherapeutics, and higher tumorigenic capacity in vivo. The protein expression level of chromatin-binding Cdc6 was increased in BCSLCs; however, NCTD decreased the level of chromatin-binding Cdc6 and inhibited the activation of the ATR-Chk1 pathway, which ultimately led to reduction in DDR activity in BCSLCs. NCTD enhanced the killing effect of cisplatin on BCSLCs in vitro and vivo. NCTD combined with cisplatin enhanced cisplatin-induced DNA damage in BCSLCs. Conclusion: Long-term cisplatin treatment can enrich BCSLCs. However, NCTD enhanced the killing effect of cisplatin on BCSLCs in vitro and vivo. The mechanism is inhibiting the DDR activity by reducing the expression of chromatin-binding Cdc6.
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Affiliation(s)
- Xianghua Shi
- Department of Urology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, People’s Republic of China
- Department of Health Management, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, People’s Republic of China
| | - Sansan Chen
- Department of Urology, The First Affiliated Hospital of Guangdong Pharmaceutical University, Guangzhou, Guangdong, People’s Republic of China
| | - Yongjun Zhang
- Institute of Biotherapy, School of Biotechnology, Southern Medical University, Guangzhou, Guangdong, People’s Republic of China
| | - Weiwei Xie
- Department of Urology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, People’s Republic of China
| | - Zhiming Hu
- Institute of Biotherapy, School of Biotechnology, Southern Medical University, Guangzhou, Guangdong, People’s Republic of China
| | - Hongwei Li
- Institute of Biotherapy, School of Biotechnology, Southern Medical University, Guangzhou, Guangdong, People’s Republic of China
| | - Jinlong Li
- Institute of Biotherapy, School of Biotechnology, Southern Medical University, Guangzhou, Guangdong, People’s Republic of China
| | - Zhongxin Zhou
- Department of Vascular Surgery, The Third Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong, People’s Republic of China
- Zhongxin ZhouDepartment of Vascular Surgery, The Third Affiliated Hospital of Southern Medical University, No. 183, Zhongshan Avenue West, Guangzhou, Guangdong510630, People’s Republic of ChinaTel +861 852 037 6040Email
| | - Wanlong Tan
- Department of Urology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, People’s Republic of China
- Correspondence: Wanlong TanDepartment of Urology, Nanfang Hospital, Southern Medical University, No. 1838, Guangzhou Avenue North, Guangzhou, Guangdong510515, People’s Republic of ChinaTel +861 360 298 3938Email
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Fei L, Xu H. Role of MCM2-7 protein phosphorylation in human cancer cells. Cell Biosci 2018; 8:43. [PMID: 30062004 PMCID: PMC6056998 DOI: 10.1186/s13578-018-0242-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 07/17/2018] [Indexed: 01/12/2023] Open
Abstract
A heterohexameric complex composed of minichromosome maintenance protein 2–7 (MCM2–7), which acts as a key replicative enzyme in eukaryotes, is crucial for initiating DNA synthesis only once per cell cycle. The MCM complex remains inactive through the G1 phase, until the S phase, when it is activated to initiate replication. During the transition from the G1 to S phase, the MCM undergoes multisite phosphorylation, an important change that promotes subsequent assembly of other replisome members. Phosphorylation is crucial for the regulation of MCM activity and function. MCMs can be phosphorylated by multiple kinases and these phosphorylation events are involved not only in DNA replication but also cell cycle progression and checkpoint response. Dysfunctional phosphorylation of MCMs appears to correlate with the occurrence and development of cancers. In this review, we summarize the currently available data regarding the regulatory mechanisms and functional consequences of MCM phosphorylation and seek the probability that protein kinase inhibitor can be used therapeutically to target MCM phosphorylation in cancer.
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Affiliation(s)
- Liangru Fei
- Department of Pathology, College of Basic Medical Sciences and the First Affiliated Hospital, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122 Liaoning Province People's Republic of China
| | - Hongtao Xu
- Department of Pathology, College of Basic Medical Sciences and the First Affiliated Hospital, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122 Liaoning Province People's Republic of China
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Riera A, Barbon M, Noguchi Y, Reuter LM, Schneider S, Speck C. From structure to mechanism-understanding initiation of DNA replication. Genes Dev 2017; 31:1073-1088. [PMID: 28717046 PMCID: PMC5538431 DOI: 10.1101/gad.298232.117] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In this Review, Riera et al. review recent structural and biochemical insights that start to explain how specific proteins recognize DNA replication origins, load the replicative helicase on DNA, unwind DNA, synthesize new DNA strands, and reassemble chromatin. DNA replication results in the doubling of the genome prior to cell division. This process requires the assembly of 50 or more protein factors into a replication fork. Here, we review recent structural and biochemical insights that start to explain how specific proteins recognize DNA replication origins, load the replicative helicase on DNA, unwind DNA, synthesize new DNA strands, and reassemble chromatin. We focus on the minichromosome maintenance (MCM2–7) proteins, which form the core of the eukaryotic replication fork, as this complex undergoes major structural rearrangements in order to engage with DNA, regulate its DNA-unwinding activity, and maintain genome stability.
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Affiliation(s)
- Alberto Riera
- DNA Replication Group, Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Marta Barbon
- DNA Replication Group, Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London W12 0NN, United Kingdom.,Medical Research Council (MRC) London Institute of Medical Sciences (LMS), London W12 0NN, United Kingdom
| | - Yasunori Noguchi
- DNA Replication Group, Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - L Maximilian Reuter
- DNA Replication Group, Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Sarah Schneider
- DNA Replication Group, Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Christian Speck
- DNA Replication Group, Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London W12 0NN, United Kingdom.,Medical Research Council (MRC) London Institute of Medical Sciences (LMS), London W12 0NN, United Kingdom
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12
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Gardner NJ, Gillespie PJ, Carrington JT, Shanks EJ, McElroy SP, Haagensen EJ, Frearson JA, Woodland A, Blow JJ. The High-Affinity Interaction between ORC and DNA that Is Required for Replication Licensing Is Inhibited by 2-Arylquinolin-4-Amines. Cell Chem Biol 2017; 24:981-992.e4. [PMID: 28781123 PMCID: PMC5563080 DOI: 10.1016/j.chembiol.2017.06.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 06/13/2017] [Accepted: 06/30/2017] [Indexed: 01/10/2023]
Abstract
In late mitosis and G1, origins of DNA replication must be "licensed" for use in the upcoming S phase by being encircled by double hexamers of the minichromosome maintenance proteins MCM2-7. A "licensing checkpoint" delays cells in G1 until sufficient origins have been licensed, but this checkpoint is lost in cancer cells. Inhibition of licensing can therefore kill cancer cells while only delaying normal cells in G1. In a high-throughput cell-based screen for licensing inhibitors we identified a family of 2-arylquinolin-4-amines, the most potent of which we call RL5a. The binding of the origin recognition complex (ORC) to origin DNA is the first step of the licensing reaction. We show that RL5a prevents ORC forming a tight complex with DNA that is required for MCM2-7 loading. Formation of this ORC-DNA complex requires ATP, and we show that RL5a inhibits ORC allosterically to mimic a lack of ATP.
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Affiliation(s)
- Nicola J Gardner
- Centre for Gene Regulation & Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Peter J Gillespie
- Centre for Gene Regulation & Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Jamie T Carrington
- Centre for Gene Regulation & Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Emma J Shanks
- Drug Discovery Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Stuart P McElroy
- Drug Discovery Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Emma J Haagensen
- Centre for Gene Regulation & Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Julie A Frearson
- Drug Discovery Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Andrew Woodland
- Drug Discovery Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.
| | - J Julian Blow
- Centre for Gene Regulation & Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.
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13
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Abstract
The accurate and complete replication of genomic DNA is essential for all life. In eukaryotic cells, the assembly of the multi-enzyme replisomes that perform replication is divided into stages that occur at distinct phases of the cell cycle. Replicative DNA helicases are loaded around origins of DNA replication exclusively during G1 phase. The loaded helicases are then activated during S phase and associate with the replicative DNA polymerases and other accessory proteins. The function of the resulting replisomes is monitored by checkpoint proteins that protect arrested replisomes and inhibit new initiation when replication is inhibited. The replisome also coordinates nucleosome disassembly, assembly, and the establishment of sister chromatid cohesion. Finally, when two replisomes converge they are disassembled. Studies in Saccharomyces cerevisiae have led the way in our understanding of these processes. Here, we review our increasingly molecular understanding of these events and their regulation.
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14
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Abstract
Cellular DNA replication factories depend on ring-shaped hexameric helicases to aid DNA synthesis by processively unzipping the parental DNA helix. Replicative helicases are loaded onto DNA by dedicated initiator, loader, and accessory proteins during the initiation of DNA replication in a tightly regulated, multistep process. We discuss here the molecular choreography of DNA replication initiation across the three domains of life, highlighting similarities and differences in the strategies used to deposit replicative helicases onto DNA and to melt the DNA helix in preparation for replisome assembly. Although initiators and loaders are phylogenetically related, the mechanisms they use for accomplishing similar tasks have diverged considerably and in an unpredictable manner.
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Affiliation(s)
- Franziska Bleichert
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Michael R Botchan
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA 94720, USA.
| | - James M Berger
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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15
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Yuan Z, Riera A, Bai L, Sun J, Nandi S, Spanos C, Chen ZA, Barbon M, Rappsilber J, Stillman B, Speck C, Li H. Structural basis of Mcm2-7 replicative helicase loading by ORC-Cdc6 and Cdt1. Nat Struct Mol Biol 2017; 24:316-324. [PMID: 28191893 PMCID: PMC5503505 DOI: 10.1038/nsmb.3372] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 01/09/2017] [Indexed: 12/19/2022]
Abstract
To start DNA replication, the Origin Recognition Complex (ORC) and Cdc6 load a Mcm2-7 double hexamer onto DNA. Without ATP hydrolysis, ORC-Cdc6 recruits one Cdt1-bound Mcm2-7 hexamer, forming an ORC-Cdc6-Cdt1-Mcm2-7 (OCCM) helicase loading intermediate. Here we report a 3.9Å structure of the OCCM on DNA. Flexible Mcm2-7 winged-helix domains (WHD) engage ORC-Cdc6. A three-domain Cdt1 configuration embraces Mcm2, Mcm4, and Mcm6, nearly half of the hexamer. The Cdt1 C-terminal domain extends to the Mcm6 WHD, which binds Orc4 WHD. DNA passes through the ORC-Cdc6 and Mcm2-7 rings. Origin DNA interaction is mediated by an α-helix in Orc4 and positively charged loops in Orc2 and Cdc6. The Mcm2-7 C-tier AAA+ ring is topologically closed by a Mcm5 loop that embraces Mcm2, but the N-tier ring Mcm2-Mcm5 interface remains open. This structure suggests loading mechanics of the first Cdt1-bound Mcm2-7 hexamer by ORC-Cdc6.
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Affiliation(s)
- Zuanning Yuan
- Cryo-EM Structural Biology Laboratory, Van Andel Research Institute, Grand Rapids, Michigan, USA
| | - Alberto Riera
- MRC London Institute of Medical Sciences (LMS), London, UK.,DNA Replication Group, Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London, UK
| | - Lin Bai
- Cryo-EM Structural Biology Laboratory, Van Andel Research Institute, Grand Rapids, Michigan, USA
| | - Jingchuan Sun
- Cryo-EM Structural Biology Laboratory, Van Andel Research Institute, Grand Rapids, Michigan, USA
| | - Saikat Nandi
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, USA
| | - Christos Spanos
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Zhuo Angel Chen
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Marta Barbon
- MRC London Institute of Medical Sciences (LMS), London, UK.,DNA Replication Group, Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London, UK
| | - Juri Rappsilber
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, UK.,Chair of Bioanalytics, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
| | - Bruce Stillman
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, USA
| | - Christian Speck
- MRC London Institute of Medical Sciences (LMS), London, UK.,DNA Replication Group, Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London, UK
| | - Huilin Li
- Cryo-EM Structural Biology Laboratory, Van Andel Research Institute, Grand Rapids, Michigan, USA
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16
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Zhai Y, Cheng E, Wu H, Li N, Yung PYK, Gao N, Tye BK. Open-ringed structure of the Cdt1-Mcm2-7 complex as a precursor of the MCM double hexamer. Nat Struct Mol Biol 2017; 24:300-308. [PMID: 28191894 DOI: 10.1038/nsmb.3374] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 01/09/2017] [Indexed: 12/17/2022]
Abstract
The minichromosome maintenance complex (MCM) hexameric complex (Mcm2-7) forms the core of the eukaryotic replicative helicase. During G1 phase, two Cdt1-Mcm2-7 heptamers are loaded onto each replication origin by the origin-recognition complex (ORC) and Cdc6 to form an inactive MCM double hexamer (DH), but the detailed loading mechanism remains unclear. Here we examine the structures of the yeast MCM hexamer and Cdt1-MCM heptamer from Saccharomyces cerevisiae. Both complexes form left-handed coil structures with a 10-15-Å gap between Mcm5 and Mcm2, and a central channel that is occluded by the C-terminal domain winged-helix motif of Mcm5. Cdt1 wraps around the N-terminal regions of Mcm2, Mcm6 and Mcm4 to stabilize the whole complex. The intrinsic coiled structures of the precursors provide insights into the DH formation, and suggest a spring-action model for the MCM during the initial origin melting and the subsequent DNA unwinding.
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Affiliation(s)
- Yuanliang Zhai
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.,Institute for Advanced Study, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - Erchao Cheng
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Hao Wu
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Ningning Li
- Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - Philip Yuk Kwong Yung
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - Ning Gao
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Bik-Kwoon Tye
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.,Department of Molecular Biology and Genetics, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York, USA
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17
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Parker MW, Botchan MR, Berger JM. Mechanisms and regulation of DNA replication initiation in eukaryotes. Crit Rev Biochem Mol Biol 2017; 52:107-144. [PMID: 28094588 DOI: 10.1080/10409238.2016.1274717] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cellular DNA replication is initiated through the action of multiprotein complexes that recognize replication start sites in the chromosome (termed origins) and facilitate duplex DNA melting within these regions. In a typical cell cycle, initiation occurs only once per origin and each round of replication is tightly coupled to cell division. To avoid aberrant origin firing and re-replication, eukaryotes tightly regulate two events in the initiation process: loading of the replicative helicase, MCM2-7, onto chromatin by the origin recognition complex (ORC), and subsequent activation of the helicase by its incorporation into a complex known as the CMG. Recent work has begun to reveal the details of an orchestrated and sequential exchange of initiation factors on DNA that give rise to a replication-competent complex, the replisome. Here, we review the molecular mechanisms that underpin eukaryotic DNA replication initiation - from selecting replication start sites to replicative helicase loading and activation - and describe how these events are often distinctly regulated across different eukaryotic model organisms.
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Affiliation(s)
- Matthew W Parker
- a Department of Biophysics and Biophysical Chemistry , Johns Hopkins University School of Medicine , Baltimore , MD , USA
| | - Michael R Botchan
- b Department of Molecular and Cell Biology , University of California Berkeley , Berkeley , CA , USA
| | - James M Berger
- a Department of Biophysics and Biophysical Chemistry , Johns Hopkins University School of Medicine , Baltimore , MD , USA
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18
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Emerging Roles for Ciz1 in Cell Cycle Regulation and as a Driver of Tumorigenesis. Biomolecules 2016; 7:biom7010001. [PMID: 28036012 PMCID: PMC5372713 DOI: 10.3390/biom7010001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 12/12/2016] [Accepted: 12/14/2016] [Indexed: 12/19/2022] Open
Abstract
Precise duplication of the genome is a prerequisite for the health and longevity of multicellular organisms. The temporal regulation of origin specification, replication licensing, and firing at replication origins is mediated by the cyclin-dependent kinases. Here the role of Cip1 interacting Zinc finger protein 1 (Ciz1) in regulation of cell cycle progression is discussed. Ciz1 contributes to regulation of the G1/S transition in mammalian cells. Ciz1 contacts the pre-replication complex (pre-RC) through cell division cycle 6 (Cdc6) interactions and aids localization of cyclin A- cyclin-dependent kinase 2 (CDK2) activity to chromatin and the nuclear matrix during initiation of DNA replication. We discuss evidence that Ciz1 serves as a kinase sensor that regulates both initiation of DNA replication and prevention of re-replication. Finally, the emerging role for Ciz1 in cancer biology is discussed. Ciz1 is overexpressed in common tumors and tumor growth is dependent on Ciz1 expression, suggesting that Ciz1 is a driver of tumor growth. We present evidence that Ciz1 may contribute to deregulation of the cell cycle due to its ability to alter the CDK activity thresholds that are permissive for initiation of DNA replication. We propose that Ciz1 may contribute to oncogenesis by induction of DNA replication stress and that Ciz1 may be a multifaceted target in cancer therapy.
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19
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Sun J, Yuan Z, Bai L, Li H. Cryo-EM of dynamic protein complexes in eukaryotic DNA replication. Protein Sci 2016; 26:40-51. [PMID: 27589669 DOI: 10.1002/pro.3033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 08/27/2016] [Accepted: 08/29/2016] [Indexed: 12/21/2022]
Abstract
DNA replication in Eukaryotes is a highly dynamic process that involves several dozens of proteins. Some of these proteins form stable complexes that are amenable to high-resolution structure determination by cryo-EM, thanks to the recent advent of the direct electron detector and powerful image analysis algorithm. But many of these proteins associate only transiently and flexibly, precluding traditional biochemical purification. We found that direct mixing of the component proteins followed by 2D and 3D image sorting can capture some very weakly interacting complexes. Even at 2D average level and at low resolution, EM images of these flexible complexes can provide important biological insights. It is often necessary to positively identify the feature-of-interest in a low resolution EM structure. We found that systematically fusing or inserting maltose binding protein (MBP) to selected proteins is highly effective in these situations. In this chapter, we describe the EM studies of several protein complexes involved in the eukaryotic DNA replication over the past decade or so. We suggest that some of the approaches used in these studies may be applicable to structural analysis of other biological systems.
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Affiliation(s)
- Jingchuan Sun
- Cryo-EM Structural Biology Laboratory, Van Andel Research Institute, Grand Rapids, Michigan, 49503
| | - Zuanning Yuan
- Cryo-EM Structural Biology Laboratory, Van Andel Research Institute, Grand Rapids, Michigan, 49503.,The Biochemistry and Structural Biology Program, Stony Brook University, Stony Brook, New York, 11794
| | - Lin Bai
- Cryo-EM Structural Biology Laboratory, Van Andel Research Institute, Grand Rapids, Michigan, 49503
| | - Huilin Li
- Cryo-EM Structural Biology Laboratory, Van Andel Research Institute, Grand Rapids, Michigan, 49503
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20
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Wu Z, Guo W, Xie Y, Zhou S. Juvenile Hormone Activates the Transcription of Cell-division-cycle 6 (Cdc6) for Polyploidy-dependent Insect Vitellogenesis and Oogenesis. J Biol Chem 2016; 291:5418-27. [PMID: 26728459 DOI: 10.1074/jbc.m115.698936] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Indexed: 11/06/2022] Open
Abstract
Although juvenile hormone (JH) is known to prevent insect larval metamorphosis and stimulate adult reproduction, the molecular mechanisms of JH action in insect reproduction remain largely unknown. Earlier, we reported that the JH-receptor complex, composed of methoprene-tolerant and steroid receptor co-activator, acts on mini-chromosome maintenance (Mcm) genes Mcm4 and Mcm7 to promote DNA replication and polyploidy for the massive vitellogenin (Vg) synthesis required for egg production in the migratory locust (Guo, W., Wu, Z., Song, J., Jiang, F., Wang, Z., Deng, S., Walker, V. K., and Zhou, S. (2014) PLoS Genet. 10, e1004702). In this study we have investigated the involvement of cell-division-cycle 6 (Cdc6) in JH-dependent vitellogenesis and oogenesis, as Cdc6 is essential for the formation of prereplication complex. We demonstrate here that Cdc6 is expressed in response to JH and methoprene-tolerant, and Cdc6 transcription is directly regulated by the JH-receptor complex. Knockdown of Cdc6 inhibits polyploidization of fat body and follicle cells, resulting in the substantial reduction of Vg expression in the fat body as well as severely impaired oocyte maturation and ovarian growth. Our data indicate the involvement of Cdc6 in JH pathway and a pivotal role of Cdc6 in JH-mediated polyploidization, vitellogenesis, and oogenesis.
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Affiliation(s)
- Zhongxia Wu
- From the School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Wei Guo
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yingtian Xie
- College of Life Sciences, Jilin University, Changchun, Jilin 30012, China, and
| | - Shutang Zhou
- State Key laboratory of Cotton Biology, Institute of Plant Stress Biology, School of Life Sciences, Henan University, Kaifeng, Henan 475004, China
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21
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Herrera MC, Tognetti S, Riera A, Zech J, Clarke P, Fernández-Cid A, Speck C. A reconstituted system reveals how activating and inhibitory interactions control DDK dependent assembly of the eukaryotic replicative helicase. Nucleic Acids Res 2015; 43:10238-50. [PMID: 26338774 PMCID: PMC4666391 DOI: 10.1093/nar/gkv881] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 08/22/2015] [Indexed: 11/17/2022] Open
Abstract
During G1-phase of the cell-cycle the replicative MCM2–7 helicase becomes loaded onto DNA into pre-replicative complexes (pre-RCs), resulting in MCM2–7 double-hexamers on DNA. In S-phase, Dbf4-dependent kinase (DDK) and cyclin-dependent-kinase (CDK) direct with the help of a large number of helicase-activation factors the assembly of a Cdc45–MCM2–7–GINS (CMG) complex. However, in the absence of S-phase kinases complex assembly is inhibited, which is unexpected, as the MCM2–7 double-hexamer represents a very large interaction surface. Currently it is unclear what mechanisms restricts complex assembly and how DDK can overcome this inhibition to promote CMG-assembly. We developed an advanced reconstituted-system to study helicase activation in-solution and discovered that individual factors like Sld3 and Sld2 can bind directly to the pre-RC, while Cdc45 cannot. When Sld3 and Sld2 were incubated together with the pre-RC, we observed that competitive interactions restrict complex assembly. DDK stabilizes the Sld3/Sld2–pre-RC complex, but the complex is only short-lived, indicating an anti-cooperative mechanism. Yet, a Sld3/Cdc45–pre-RC can form in the presence of DDK and the addition of Sld2 enhances complex stability. Our results indicate that helicase activation is regulated by competitive and cooperative interactions, which restrict illegitimate complex formation and direct limiting helicase-activation factors into pre-initiation complexes.
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Affiliation(s)
- M Carmen Herrera
- DNA Replication Group, Institute of Clinical Sciences, Imperial College London, London W12 0NN, UK
| | - Silvia Tognetti
- DNA Replication Group, Institute of Clinical Sciences, Imperial College London, London W12 0NN, UK
| | - Alberto Riera
- DNA Replication Group, Institute of Clinical Sciences, Imperial College London, London W12 0NN, UK
| | - Juergen Zech
- DNA Replication Group, Institute of Clinical Sciences, Imperial College London, London W12 0NN, UK
| | - Pippa Clarke
- DNA Replication Group, Institute of Clinical Sciences, Imperial College London, London W12 0NN, UK
| | - Alejandra Fernández-Cid
- DNA Replication Group, Institute of Clinical Sciences, Imperial College London, London W12 0NN, UK
| | - Christian Speck
- DNA Replication Group, Institute of Clinical Sciences, Imperial College London, London W12 0NN, UK
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22
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Abstract
DNA replication in eukaryotes is strictly regulated by several mechanisms. A central step in this replication is the assembly of the heterohexameric minichromosome maintenance (MCM2-7) helicase complex at replication origins during G1 phase as an inactive double hexamer. Here, using cryo-electron microscopy, we report a near-atomic structure of the MCM2-7 double hexamer purified from yeast G1 chromatin. Our structure shows that two single hexamers, arranged in a tilted and twisted fashion through interdigitated amino-terminal domain interactions, form a kinked central channel. Four constricted rings consisting of conserved interior β-hairpins from the two single hexamers create a narrow passageway that tightly fits duplex DNA. This narrow passageway, reinforced by the offset of the two single hexamers at the double hexamer interface, is flanked by two pairs of gate-forming subunits, MCM2 and MCM5. These unusual features of the twisted and tilted single hexamers suggest a concerted mechanism for the melting of origin DNA that requires structural deformation of the intervening DNA.
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23
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Sun J, Fernandez-Cid A, Riera A, Tognetti S, Yuan Z, Stillman B, Speck C, Li H. Structural and mechanistic insights into Mcm2-7 double-hexamer assembly and function. Genes Dev 2014; 28:2291-303. [PMID: 25319829 PMCID: PMC4201289 DOI: 10.1101/gad.242313.114] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Eukaryotic cells license each DNA replication origin during G1 phase by assembling a prereplication complex (pre-RC) that contains a Mcm2–7 double hexamer. In this study, Sun et al. examined the helicase loading reaction in the presence of ATP, revealing the basic architecture of a number of pre-RC assembly reaction intermediates, including a newly identified ORC–Cdc6–Mcm2–7–Mcm2–7 complex. The detailed architecture of the Mcm2–7 double hexamer was also established. Eukaryotic cells license each DNA replication origin during G1 phase by assembling a prereplication complex that contains a Mcm2–7 (minichromosome maintenance proteins 2–7) double hexamer. During S phase, each Mcm2–7 hexamer forms the core of a replicative DNA helicase. However, the mechanisms of origin licensing and helicase activation are poorly understood. The helicase loaders ORC–Cdc6 function to recruit a single Cdt1–Mcm2–7 heptamer to replication origins prior to Cdt1 release and ORC–Cdc6–Mcm2–7 complex formation, but how the second Mcm2–7 hexamer is recruited to promote double-hexamer formation is not well understood. Here, structural evidence for intermediates consisting of an ORC–Cdc6–Mcm2–7 complex and an ORC–Cdc6–Mcm2–7–Mcm2–7 complex are reported, which together provide new insights into DNA licensing. Detailed structural analysis of the loaded Mcm2–7 double-hexamer complex demonstrates that the two hexamers are interlocked and misaligned along the DNA axis and lack ATP hydrolysis activity that is essential for DNA helicase activity. Moreover, we show that the head-to-head juxtaposition of the Mcm2–7 double hexamer generates a new protein interaction surface that creates a multisubunit-binding site for an S-phase protein kinase that is known to activate DNA replication. The data suggest how the double hexamer is assembled and how helicase activity is regulated during DNA licensing, with implications for cell cycle control of DNA replication and genome stability.
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Affiliation(s)
- Jingchuan Sun
- Biosciences Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Alejandra Fernandez-Cid
- DNA Replication Group, MRC Clinical Sciences Centre, Imperial College Faculty of Medicine, London W12 0NN, United Kingdom
| | - Alberto Riera
- DNA Replication Group, MRC Clinical Sciences Centre, Imperial College Faculty of Medicine, London W12 0NN, United Kingdom
| | - Silvia Tognetti
- DNA Replication Group, MRC Clinical Sciences Centre, Imperial College Faculty of Medicine, London W12 0NN, United Kingdom
| | - Zuanning Yuan
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York 11794, USA
| | - Bruce Stillman
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Christian Speck
- DNA Replication Group, MRC Clinical Sciences Centre, Imperial College Faculty of Medicine, London W12 0NN, United Kingdom;
| | - Huilin Li
- Biosciences Department, Brookhaven National Laboratory, Upton, New York 11973, USA; Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York 11794, USA
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24
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Tognetti S, Riera A, Speck C. Switch on the engine: how the eukaryotic replicative helicase MCM2-7 becomes activated. Chromosoma 2014; 124:13-26. [PMID: 25308420 DOI: 10.1007/s00412-014-0489-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2014] [Revised: 09/24/2014] [Accepted: 09/25/2014] [Indexed: 12/17/2022]
Abstract
A crucial step during eukaryotic initiation of DNA replication is the correct loading and activation of the replicative DNA helicase, which ensures that each replication origin fires only once. Unregulated DNA helicase loading and activation, as it occurs in cancer, can cause severe DNA damage and genomic instability. The essential mini-chromosome maintenance proteins 2-7 (MCM2-7) represent the core of the eukaryotic replicative helicase that is loaded at DNA replication origins during G1-phase of the cell cycle. The MCM2-7 helicase activity, however, is only triggered during S-phase once the holo-helicase Cdc45-MCM2-7-GINS (CMG) has been formed. A large number of factors and several kinases interact and contribute to CMG formation and helicase activation, though the exact mechanisms remain unclear. Crucially, upon DNA damage, this reaction is temporarily halted to ensure genome integrity. Here, we review the current understanding of helicase activation; we focus on protein interactions during CMG formation, discuss structural changes during helicase activation, and outline similarities and differences of the prokaryotic and eukaryotic helicase activation process.
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Affiliation(s)
- Silvia Tognetti
- DNA Replication Group, Institute of Clinical Science, Imperial College, London, W12 0NN, UK
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25
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Samel SA, Fernández-Cid A, Sun J, Riera A, Tognetti S, Herrera MC, Li H, Speck C. A unique DNA entry gate serves for regulated loading of the eukaryotic replicative helicase MCM2-7 onto DNA. Genes Dev 2014; 28:1653-66. [PMID: 25085418 PMCID: PMC4117941 DOI: 10.1101/gad.242404.114] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 06/25/2014] [Indexed: 01/24/2023]
Abstract
The regulated loading of the replicative helicase minichromosome maintenance proteins 2-7 (MCM2-7) onto replication origins is a prerequisite for replication fork establishment and genomic stability. Origin recognition complex (ORC), Cdc6, and Cdt1 assemble two MCM2-7 hexamers into one double hexamer around dsDNA. Although the MCM2-7 hexamer can adopt a ring shape with a gap between Mcm2 and Mcm5, it is unknown which Mcm interface functions as the DNA entry gate during regulated helicase loading. Here, we establish that the Saccharomyces cerevisiae MCM2-7 hexamer assumes a closed ring structure, suggesting that helicase loading requires active ring opening. Using a chemical biology approach, we show that ORC-Cdc6-Cdt1-dependent helicase loading occurs through a unique DNA entry gate comprised of the Mcm2 and Mcm5 subunits. Controlled inhibition of DNA insertion triggers ATPase-driven complex disassembly in vitro, while in vivo analysis establishes that Mcm2/Mcm5 gate opening is essential for both helicase loading onto chromatin and cell cycle progression. Importantly, we demonstrate that the MCM2-7 helicase becomes loaded onto DNA as a single hexamer during ORC/Cdc6/Cdt1/MCM2-7 complex formation prior to MCM2-7 double hexamer formation. Our study establishes the existence of a unique DNA entry gate for regulated helicase loading, revealing key mechanisms in helicase loading, which has important implications for helicase activation.
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Affiliation(s)
- Stefan A Samel
- DNA Replication Group, Institute of Clinical Science, Imperial College, London W12 0NN, United Kingdom
| | - Alejandra Fernández-Cid
- DNA Replication Group, Institute of Clinical Science, Imperial College, London W12 0NN, United Kingdom
| | - Jingchuan Sun
- Biosciences Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Alberto Riera
- DNA Replication Group, Institute of Clinical Science, Imperial College, London W12 0NN, United Kingdom
| | - Silvia Tognetti
- DNA Replication Group, Institute of Clinical Science, Imperial College, London W12 0NN, United Kingdom
| | - M Carmen Herrera
- DNA Replication Group, Institute of Clinical Science, Imperial College, London W12 0NN, United Kingdom
| | - Huilin Li
- Biosciences Department, Brookhaven National Laboratory, Upton, New York 11973, USA; Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York 11794, USA
| | - Christian Speck
- DNA Replication Group, Institute of Clinical Science, Imperial College, London W12 0NN, United Kingdom;
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Riera A, Tognetti S, Speck C. Helicase loading: how to build a MCM2-7 double-hexamer. Semin Cell Dev Biol 2014; 30:104-9. [PMID: 24637008 DOI: 10.1016/j.semcdb.2014.03.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 03/06/2014] [Indexed: 12/27/2022]
Abstract
A central step in eukaryotic initiation of DNA replication is the loading of the helicase at replication origins, misregulation of this reaction leads to DNA damage and genome instability. Here we discuss how the helicase becomes recruited to origins and loaded into a double-hexamer around double-stranded DNA. We specifically describe the individual steps in complex assembly and explain how this process is regulated to maintain genome stability. Structural analysis of the helicase loader and the helicase has provided key insights into the process of double-hexamer formation. A structural comparison of the bacterial and eukaryotic system suggests a mechanism of helicase loading.
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Affiliation(s)
- Alberto Riera
- DNA Replication Group, Faculty of Medicine, Institute of Clinical Sciences, Imperial College, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Silvia Tognetti
- DNA Replication Group, Faculty of Medicine, Institute of Clinical Sciences, Imperial College, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Christian Speck
- DNA Replication Group, Faculty of Medicine, Institute of Clinical Sciences, Imperial College, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK.
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