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Lichauco C, Foss EJ, Gatbonton-Schwager T, Athow NF, Lofts BR, Acob R, Taylor E, Lao U, Miles S, Bedalov A. Sir2 and Fun30 regulate ribosomal DNA replication timing via Mcm helicase positioning and nucleosome occupancy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.21.586113. [PMID: 38585982 PMCID: PMC10996493 DOI: 10.1101/2024.03.21.586113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
The association between late replication timing and low transcription rates in eukaryotic heterochromatin is well-known, yet the specific mechanisms underlying this link remain uncertain. In Saccharomyces cerevisiae, the histone deacetylase Sir2 is required for both transcriptional silencing and late replication at the repetitive ribosomal DNA arrays (rDNA). We have previously reported that in the absence of SIR2, a derepressed RNA PolII repositions MCM replicative helicases from their loading site at the ribosomal origin, where they abut well-positioned, high-occupancy nucleosomes, to an adjacent region with lower nucleosome occupancy. By developing a method that can distinguish activation of closely spaced MCM complexes, here we show that the displaced MCMs at rDNA origins have increased firing propensity compared to the non-displaced MCMs. Furthermore, we found that both, activation of the repositioned MCMs and low occupancy of the adjacent nucleosomes critically depend on the chromatin remodeling activity of FUN30. Our study elucidates the mechanism by which Sir2 delays replication timing, and it demonstrates, for the first time, that activation of a specific replication origin in vivo relies on the nucleosome context shaped by a single chromatin remodeler.
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Affiliation(s)
- Carmina Lichauco
- Translational Sciences and Therapeutics Division, Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA
| | - Eric J. Foss
- Translational Sciences and Therapeutics Division, Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA
| | - Tonibelle Gatbonton-Schwager
- Translational Sciences and Therapeutics Division, Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA
| | - Nelson F. Athow
- Translational Sciences and Therapeutics Division, Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA
| | - Brandon R. Lofts
- Translational Sciences and Therapeutics Division, Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA
| | - Robin Acob
- Translational Sciences and Therapeutics Division, Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA
| | - Erin Taylor
- Translational Sciences and Therapeutics Division, Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA
| | - Uyen Lao
- Translational Sciences and Therapeutics Division, Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA
| | - Shawna Miles
- Translational Sciences and Therapeutics Division, Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA
| | - Antonio Bedalov
- Translational Sciences and Therapeutics Division, Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA
- Department of Biochemistry and Department of Medicine, University of Washington, Seattle, WA
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2
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Wang M, Qiu ZH, Wang YZ, Lian B, Bai JK, Zhou YJ, Ji HJ. Analysis of the expression and prognostic significance of DDK complex in Hepatocarcinoma. BMC Cancer 2023; 23:19. [PMID: 36609254 PMCID: PMC9817372 DOI: 10.1186/s12885-022-10475-w] [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: 08/31/2022] [Accepted: 12/22/2022] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Hepatocellular carcinoma (HCC) remains one of the most common and lethal malignancies worldwide. Although DBF4-dependent kinase (DDK) complex composed of CDC7 kinase and its regulatory subunit DBF4 has been shown to be overexpressed in primary tumors and promotes tumor development, while its role and prognostic value in HCC remain largely unknown. In the present study, the expression of DBF4 and CDC7 and their relationship with clinical characteristics were comprehensively analyzed. METHODS The mRNA expression profiles of HCC and the corresponding clinical data of HCC patients were downloaded from TCGA and GEO databases, respectively. The differences in DBF4 and CDC7 expression in tumor tissues and adjacent normal tissues were analyzed. HCC-derived tissue microarray (TMA) was used to evaluate and score the expression of CDC7 by immunohistochemistry (IHC) staining. The Kaplan-Meier method and the Cox regression method were used to analyze the relationship between overall survival and clinical characteristics of the patients. Gene set enrichment analysis (GSEA) was used to analyze the pathway enrichment of DBF4 and CDC7. RESULTS DBF4 and CDC7 had similar expression patterns in HCC patients. Detailly, compared with adjacent tissues, both mRNA and protein of DBF4 and CDC7 were significantly higher in HCC, and their expression was positively correlated with AJCC_T stage, clinical stage and G stage (grade) of liver cancer patients, and higher DBF4 or CDC7 expression predicted a worse prognosis in HCC patients with shorter overall survival (OS), recurrence-free survival (RFS), disease-specific survival (DSS) and progress-free survival (PFS). Cox regression analysis suggested that both DBF4 and CDC7 were independent risk factors for the prognosis of HCC patients in TCGA dataset. GSEA suggested that both DBF4 and CDC7 were positively correlated with cell cycle and DNA replication. Finally, the prognostic value of CDC7 was furtherly confirmed by TMA-based IHC staining results. CONCLUSIONS Our study showed that DDK complex was significantly increased in HCC. Both DBF4 and CDC7 may be potential diagnostic and prognostic markers for HCC, and high expression of DDK members predicts a worse prognosis in patients with HCC, which may be associated with high tumor cell proliferation rate.
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Affiliation(s)
- Min Wang
- grid.268079.20000 0004 1790 6079School of Life Science and Technology, Weifang Medical University, No.7166, Baotongxi Street, Weifang, 261053 China
| | - Zu-Hua Qiu
- grid.268079.20000 0004 1790 6079School of Life Science and Technology, Weifang Medical University, No.7166, Baotongxi Street, Weifang, 261053 China
| | - Yu-Zhuo Wang
- grid.268079.20000 0004 1790 6079School of Life Science and Technology, Weifang Medical University, No.7166, Baotongxi Street, Weifang, 261053 China
| | - Bo Lian
- grid.268079.20000 0004 1790 6079School of Life Science and Technology, Weifang Medical University, No.7166, Baotongxi Street, Weifang, 261053 China
| | - Jing-Kun Bai
- grid.268079.20000 0004 1790 6079School of Life Science and Technology, Weifang Medical University, No.7166, Baotongxi Street, Weifang, 261053 China
| | - Yong-Jie Zhou
- grid.412901.f0000 0004 1770 1022Laboratory of Liver Transplantation, West China Hospital, Sichuan University, No.1, Keyuan 4 Road, Chengdu, 610041 China
| | - Hong-Jie Ji
- grid.268079.20000 0004 1790 6079School of Life Science and Technology, Weifang Medical University, No.7166, Baotongxi Street, Weifang, 261053 China
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3
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Pauzaite T, Tollitt J, Sopaci B, Caprani L, Iwanowytsch O, Thacker U, Hardy JG, Allinson SL, Copeland NA. Dbf4-Cdc7 (DDK) Inhibitor PHA-767491 Displays Potent Anti-Proliferative Effects via Crosstalk with the CDK2-RB-E2F Pathway. Biomedicines 2022; 10:biomedicines10082012. [PMID: 36009559 PMCID: PMC9405858 DOI: 10.3390/biomedicines10082012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 08/04/2022] [Accepted: 08/10/2022] [Indexed: 11/17/2022] Open
Abstract
Precise regulation of DNA replication complex assembly requires cyclin-dependent kinase (CDK) and Dbf4-dependent kinase (DDK) activities to activate the replicative helicase complex and initiate DNA replication. Chemical probes have been essential in the molecular analysis of DDK-mediated regulation of MCM2-7 activation and the initiation phase of DNA replication. Here, the inhibitory activity of two distinct DDK inhibitor chemotypes, PHA-767491 and XL-413, were assessed in cell-free and cell-based proliferation assays. PHA-767491 and XL-413 show distinct effects at the level of cellular proliferation, initiation of DNA replication and replisome activity. XL-413 and PHA-767491 both reduce DDK-specific phosphorylation of MCM2 but show differential potency in prevention of S-phase entry. DNA combing and DNA replication assays show that PHA-767491 is a potent inhibitor of the initiation phase of DNA replication but XL413 has weak activity. Importantly, PHA-767491 decreased E2F-mediated transcription of the G1/S regulators cyclin A2, cyclin E1 and cyclin E2, and this effect was independent of CDK9 inhibition. Significantly, the enhanced inhibitory profile of PHA-767491 is mediated by potent inhibition of both DDK and the CDK2-Rb-E2F transcriptional network, that provides the molecular basis for its increased anti-proliferative effects in RB+ cancer cell lines.
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Affiliation(s)
- Tekle Pauzaite
- Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster LA1 4YQ, UK
| | - James Tollitt
- Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster LA1 4YQ, UK
| | - Betul Sopaci
- Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster LA1 4YQ, UK
| | - Louise Caprani
- Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster LA1 4YQ, UK
| | - Olivia Iwanowytsch
- Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster LA1 4YQ, UK
| | - Urvi Thacker
- Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster LA1 4YQ, UK
| | - John G. Hardy
- Materials Science Institute, Lancaster University, Lancaster LA1 4YW, UK
- Department of Chemistry, Faculty of Science and Technology, Lancaster University, Lancaster LA1 4YB, UK
| | - Sarah L. Allinson
- Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster LA1 4YQ, UK
| | - Nikki A. Copeland
- Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster LA1 4YQ, UK
- Materials Science Institute, Lancaster University, Lancaster LA1 4YW, UK
- Correspondence:
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4
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Saleh A, Noguchi Y, Aramayo R, Ivanova ME, Stevens KM, Montoya A, Sunidhi S, Carranza NL, Skwark MJ, Speck C. The structural basis of Cdc7-Dbf4 kinase dependent targeting and phosphorylation of the MCM2-7 double hexamer. Nat Commun 2022; 13:2915. [PMID: 35614055 PMCID: PMC9133112 DOI: 10.1038/s41467-022-30576-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 05/06/2022] [Indexed: 12/12/2022] Open
Abstract
The controlled assembly of replication forks is critical for genome stability. The Dbf4-dependent Cdc7 kinase (DDK) initiates replisome assembly by phosphorylating the MCM2-7 replicative helicase at the N-terminal tails of Mcm2, Mcm4 and Mcm6. At present, it remains poorly understood how DDK docks onto the helicase and how the kinase targets distal Mcm subunits for phosphorylation. Using cryo-electron microscopy and biochemical analysis we discovered that an interaction between the HBRCT domain of Dbf4 with Mcm2 serves as an anchoring point, which supports binding of DDK across the MCM2-7 double-hexamer interface and phosphorylation of Mcm4 on the opposite hexamer. Moreover, a rotation of DDK along its anchoring point allows phosphorylation of Mcm2 and Mcm6. In summary, our work provides fundamental insights into DDK structure, control and selective activation of the MCM2-7 helicase during DNA replication. Importantly, these insights can be exploited for development of novel DDK inhibitors.
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Affiliation(s)
- Almutasem Saleh
- DNA Replication Group, Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Yasunori Noguchi
- DNA Replication Group, Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Ricardo Aramayo
- DNA Replication Group, Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Marina E Ivanova
- DNA Replication Group, Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Kathryn M Stevens
- DNA Replication Group, Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Du Cane Road, London, W12 0NN, UK
- MRC London Institute of Medical Sciences (LMS), Du Cane Road, London, W12 0NN, UK
| | - Alex Montoya
- Proteomics and Metabolomics Facility, MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK
| | - S Sunidhi
- InstaDeep Ltd, 5 Merchant Square, London, W2 1AY, UK
| | | | | | - Christian Speck
- DNA Replication Group, Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Du Cane Road, London, W12 0NN, UK.
- MRC London Institute of Medical Sciences (LMS), Du Cane Road, London, W12 0NN, UK.
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5
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Cheng J, Li N, Huo Y, Dang S, Tye BK, Gao N, Zhai Y. Structural Insight into the MCM double hexamer activation by Dbf4-Cdc7 kinase. Nat Commun 2022; 13:1396. [PMID: 35296675 PMCID: PMC8927117 DOI: 10.1038/s41467-022-29070-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 02/24/2022] [Indexed: 12/27/2022] Open
Abstract
The Dbf4-dependent kinase Cdc7 (DDK) regulates DNA replication initiation by phosphorylation of the MCM double hexamer (MCM-DH) to promote helicase activation. Here, we determine a series of cryo electron microscopy (cryo-EM) structures of yeast DDK bound to the MCM-DH. These structures, occupied by one or two DDKs, differ primarily in the conformations of the kinase core. The interactions of DDK with the MCM-DH are mediated exclusively by subunit Dbf4 straddling across the hexamer interface on the three N-terminal domains (NTDs) of subunits Mcm2, Mcm6, and Mcm4. This arrangement brings Cdc7 close to its only essential substrate, the N-terminal serine/threonine-rich domain (NSD) of Mcm4. Dbf4 further displaces the NSD from its binding site on Mcm4-NTD, facilitating an immediate targeting of this motif by Cdc7. Moreover, the active center of Cdc7 is occupied by a unique Dbf4 inhibitory loop, which is disengaged when the kinase core assumes wobbling conformations. This study elucidates the versatility of Dbf4 in regulating the ordered multisite phosphorylation of the MCM-DH by Cdc7 kinase during helicase activation.
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Affiliation(s)
- Jiaxuan Cheng
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing, 100871, China.,Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Ningning Li
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing, 100871, China
| | - Yunjing Huo
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
| | - Shangyu Dang
- Division of Life Science, The Hong Kong University of Science & Technology, Hong Kong, China
| | - Bik-Kwoon Tye
- Institute for Advanced Study, The Hong Kong University of Science & Technology, Hong Kong, China. .,Department of Molecular Biology & Genetics, Cornell University, Ithaca, NY, 14853, USA.
| | - Ning Gao
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing, 100871, China. .,National Biomedical Imaging Center, Peking University, Beijing, 100871, China.
| | - Yuanliang Zhai
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China.
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6
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Dolson A, Sauty SM, Shaban K, Yankulov K. Dbf4-Dependent Kinase: DDK-ated to post-initiation events in DNA replication. Cell Cycle 2021; 20:2348-2360. [PMID: 34662256 DOI: 10.1080/15384101.2021.1986999] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Dbf4-Dependent Kinase (DDK) has a well-established essential role at origins of DNA replication, where it phosphorylates and activates the replicative MCM helicase. It also acts in the response to mutagens and in DNA repair as well as in key steps during meiosis. Recent studies have indicated that, in addition to the MCM helicase, DDK phosphorylates several substrates during the elongation stage of DNA replication or upon replication stress. However, these activities of DDK are not essential for viability. Dbf4-Dependent Kinase is also emerging as a key factor in the regulation of genome-wide origin firing and in replication-coupled chromatin assembly. In this review, we summarize recent progress in our understanding of the diverse roles of DDK.
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Affiliation(s)
- Andrew Dolson
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Safia Mahabub Sauty
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Kholoud Shaban
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Krassimir Yankulov
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
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7
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Le TT, Ainsworth J, Polo Rivera C, Macartney T, Labib KP. Reconstitution of human CMG helicase ubiquitylation by CUL2LRR1 and multiple E2 enzymes. Biochem J 2021; 478:2825-2842. [PMID: 34195792 PMCID: PMC8331092 DOI: 10.1042/bcj20210315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 06/25/2021] [Accepted: 06/29/2021] [Indexed: 11/17/2022]
Abstract
Cullin ubiquitin ligases drive replisome disassembly during DNA replication termination. In worm, frog and mouse cells, CUL2LRR1 is required to ubiquitylate the MCM7 subunit of the CMG helicase. Here, we show that cullin ligases also drive CMG-MCM7 ubiquitylation in human cells, thereby making the helicase into a substrate for the p97 unfoldase. Using purified human proteins, including a panel of E2 ubiquitin-conjugating enzymes, we have reconstituted CMG helicase ubiquitylation, dependent upon neddylated CUL2LRR1. The reaction is highly specific to CMG-MCM7 and requires the LRR1 substrate targeting subunit, since replacement of LRR1 with the alternative CUL2 adaptor VHL switches ubiquitylation from CMG-MCM7 to HIF1. CUL2LRR1 firstly drives monoubiquitylation of CMG-MCM7 by the UBE2D class of E2 enzymes. Subsequently, CUL2LRR1 activates UBE2R1/R2 or UBE2G1/G2 to extend a single K48-linked ubiquitin chain on CMG-MCM7. Thereby, CUL2LRR1 converts CMG into a substrate for p97, which disassembles the ubiquitylated helicase during DNA replication termination.
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Affiliation(s)
- Thanh Thi Le
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, U.K
| | - Johanna Ainsworth
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, U.K
| | - Cristian Polo Rivera
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, U.K
| | - Thomas Macartney
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, U.K
| | - Karim P.M. Labib
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, U.K
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8
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Schmit M, Bielinsky AK. Congenital Diseases of DNA Replication: Clinical Phenotypes and Molecular Mechanisms. Int J Mol Sci 2021; 22:E911. [PMID: 33477564 PMCID: PMC7831139 DOI: 10.3390/ijms22020911] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 01/13/2021] [Accepted: 01/14/2021] [Indexed: 12/19/2022] Open
Abstract
Deoxyribonucleic acid (DNA) replication can be divided into three major steps: initiation, elongation and termination. Each time a human cell divides, these steps must be reiteratively carried out. Disruption of DNA replication can lead to genomic instability, with the accumulation of point mutations or larger chromosomal anomalies such as rearrangements. While cancer is the most common class of disease associated with genomic instability, several congenital diseases with dysfunctional DNA replication give rise to similar DNA alterations. In this review, we discuss all congenital diseases that arise from pathogenic variants in essential replication genes across the spectrum of aberrant replisome assembly, origin activation and DNA synthesis. For each of these conditions, we describe their clinical phenotypes as well as molecular studies aimed at determining the functional mechanisms of disease, including the assessment of genomic stability. By comparing and contrasting these diseases, we hope to illuminate how the disruption of DNA replication at distinct steps affects human health in a surprisingly cell-type-specific manner.
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Affiliation(s)
| | - Anja-Katrin Bielinsky
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA;
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9
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Calafí C, López-Malo M, Velázquez D, Zhang C, Fernández-Fernández J, Rodríguez-Galán O, de la Cruz J, Ariño J, Casamayor A. Overexpression of budding yeast protein phosphatase Ppz1 impairs translation. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118727. [DOI: 10.1016/j.bbamcr.2020.118727] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 04/09/2020] [Accepted: 04/16/2020] [Indexed: 12/25/2022]
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10
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Jin Y, Liang Z, Lou H. The Emerging Roles of Fox Family Transcription Factors in Chromosome Replication, Organization, and Genome Stability. Cells 2020; 9:cells9010258. [PMID: 31968679 PMCID: PMC7016735 DOI: 10.3390/cells9010258] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 01/13/2020] [Accepted: 01/14/2020] [Indexed: 12/13/2022] Open
Abstract
The forkhead box (Fox) transcription factors (TFs) are widespread from yeast to humans. Their mutations and dysregulation have been linked to a broad spectrum of malignant neoplasias. They are known as critical players in DNA repair, metabolism, cell cycle control, differentiation, and aging. Recent studies, especially those from the simple model eukaryotes, revealed unexpected contributions of Fox TFs in chromosome replication and organization. More importantly, besides functioning as a canonical TF in cell signaling cascades and gene expression, Fox TFs can directly participate in DNA replication and determine the global replication timing program in a transcription-independent mechanism. Yeast Fox TFs preferentially recruit the limiting replication factors to a subset of early origins on chromosome arms. Attributed to their dimerization capability and distinct DNA binding modes, Fkh1 and Fkh2 also promote the origin clustering and assemblage of replication elements (replication factories). They can mediate long-range intrachromosomal and interchromosomal interactions and thus regulate the four-dimensional chromosome organization. The novel aspects of Fox TFs reviewed here expand their roles in maintaining genome integrity and coordinating the multiple essential chromosome events. These will inevitably be translated to our knowledge and new treatment strategies of Fox TF-associated human diseases including cancer.
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11
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Deshpande I, Keusch JJ, Challa K, Iesmantavicius V, Gasser SM, Gut H. The Sir4 H-BRCT domain interacts with phospho-proteins to sequester and repress yeast heterochromatin. EMBO J 2019; 38:e101744. [PMID: 31515872 PMCID: PMC6792019 DOI: 10.15252/embj.2019101744] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 07/24/2019] [Accepted: 08/11/2019] [Indexed: 12/22/2022] Open
Abstract
In Saccharomyces cerevisiae, the silent information regulator (SIR) proteins Sir2/3/4 form a complex that suppresses transcription in subtelomeric regions and at the homothallic mating-type (HM) loci. Here, we identify a non-canonical BRCA1 C-terminal domain (H-BRCT) in Sir4, which is responsible for tethering telomeres to the nuclear periphery. We show that Sir4 H-BRCT and the closely related Dbf4 H-BRCT serve as selective phospho-epitope recognition domains that bind to a variety of phosphorylated target peptides. We present detailed structural information about the binding mode of established Sir4 interactors (Esc1, Ty5, Ubp10) and identify several novel interactors of Sir4 H-BRCT, including the E3 ubiquitin ligase Tom1. Based on these findings, we propose a phospho-peptide consensus motif for interaction with Sir4 H-BRCT and Dbf4 H-BRCT. Ablation of the Sir4 H-BRCT phospho-peptide interaction disrupts SIR-mediated repression and perinuclear localization. In conclusion, the Sir4 H-BRCT domain serves as a hub for recruitment of phosphorylated target proteins to heterochromatin to properly regulate silencing and nuclear order.
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Affiliation(s)
- Ishan Deshpande
- Friedrich Miescher Institute for Biomedical ResearchBaselSwitzerland
- Faculty of Natural SciencesUniversity of BaselBaselSwitzerland
- Present address:
Department of Pharmaceutical ChemistryUniversity of California San FranciscoSan FranciscoCAUSA
| | - Jeremy J Keusch
- Friedrich Miescher Institute for Biomedical ResearchBaselSwitzerland
| | - Kiran Challa
- Friedrich Miescher Institute for Biomedical ResearchBaselSwitzerland
| | | | - Susan M Gasser
- Friedrich Miescher Institute for Biomedical ResearchBaselSwitzerland
- Faculty of Natural SciencesUniversity of BaselBaselSwitzerland
| | - Heinz Gut
- Friedrich Miescher Institute for Biomedical ResearchBaselSwitzerland
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12
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Shin G, Jeong D, Kim H, Im JS, Lee JK. RecQL4 tethering on the pre-replicative complex induces unscheduled origin activation and replication stress in human cells. J Biol Chem 2019; 294:16255-16265. [PMID: 31519754 DOI: 10.1074/jbc.ra119.009996] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 09/09/2019] [Indexed: 12/15/2022] Open
Abstract
Sequential activation of DNA replication origins is precisely programmed and critical to maintaining genome stability. RecQL4, a member of the conserved RecQ family of helicases, plays an essential role in the initiation of DNA replication in mammalian cells. Here, we showed that RecQL4 protein tethered on the pre-replicative complex (pre-RC) induces early activation of late replicating origins during S phase. Tethering of RecQL4 or its N terminus on pre-RCs via fusion with Orc4 protein resulted in the recruitment of essential initiation factors, such as Mcm10, And-1, Cdc45, and GINS, increasing nascent DNA synthesis in late replicating origins during early S phase. In this origin activation process, tethered RecQL4 was able to recruit Cdc45 even in the absence of cyclin-dependent kinase (CDK) activity, whereas CDK phosphorylation of RecQL4 N terminus was required for interaction with and origin recruitment of And-1 and GINS. In addition, forced activation of replication origins by RecQL4 tethering resulted in increased replication stress and the accumulation of ssDNAs, which can be recovered by transcription inhibition. Collectively, these results suggest that recruitment of RecQL4 to replication origins is an important step for temporal activation of replication origins during S phase. Further, perturbation of replication timing control by unscheduled origin activation significantly induces replication stress, which is mostly caused by transcription-replication conflicts.
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Affiliation(s)
- Gwangsu Shin
- Interdisciplinary Graduate Program in Genetic Engineering, Seoul National University, Seoul, 08826, Republic of Korea
| | - Dongsoo Jeong
- Interdisciplinary Graduate Program in Genetic Engineering, Seoul National University, Seoul, 08826, Republic of Korea
| | - Hyunsup Kim
- Interdisciplinary Graduate Program in Genetic Engineering, Seoul National University, Seoul, 08826, Republic of Korea
| | - Jun-Sub Im
- Department of Biology Education, Seoul National University, Seoul, 08826, Republic of Korea
| | - Joon-Kyu Lee
- Interdisciplinary Graduate Program in Genetic Engineering, Seoul National University, Seoul, 08826, Republic of Korea .,Department of Biology Education, Seoul National University, Seoul, 08826, Republic of Korea
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13
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Kim HS. Genome-wide function of MCM-BP in Trypanosoma brucei DNA replication and transcription. Nucleic Acids Res 2019; 47:634-647. [PMID: 30407533 PMCID: PMC6344857 DOI: 10.1093/nar/gky1088] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 10/21/2018] [Indexed: 12/13/2022] Open
Abstract
In Trypanosoma brucei, genes are arranged in Polycistronic Transcription Units (PTUs), which are demarcated by transcription start and stop sites. Transcription start sites are also binding sites of Origin Recognition Complex 1 (ORC1). This spatial coincidence implies that transcription and replication in trypanosomes must occur in a highly ordered and cooperative manner. Interestingly, a previously published genetic screen identified the T. brucei MCM-BP, which interacts with subunits of MCM helicase, as a protein whose downregulation results in the loss of transcriptional silencing at subtelomeric loci. Here, I show that TbMCM-BP is required for DNA replication and transcription. TbMCM-BP depletion causes a significant reduction of replicating cells in S phase and genome-wide impairments of replication origin activation. Moreover, levels of sense and antisense transcripts increase at boundaries of PTUs in the absence of TbMCM-BP. TbMCM-BP is also important for transcriptional repression of the specialized subtelomeric PTUs, the Bloodstream-form Expression-Sites (BESs), which house the major antigenic determinant (the Variant Surface Glycoprotein, VSG gene) as well as TbORC1 binding sites. Overall, this study reveals that TbMCM-BP, a replication initiation protein, also guides the initiation, termination and directionality of transcription.
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Affiliation(s)
- Hee-Sook Kim
- Laboratory of Lymphocyte Biology, Rockefeller University, 1275 York Avenue, New York, NY 10065, USA.,Department of Biological, Geological, and Environmental Sciences, Center for Gene Regulation in Health and Disease, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA
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14
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Shen KF, Forsburg SL. Overlapping Roles in Chromosome Segregation for Heterochromatin Protein 1 (Swi6) and DDK in Schizosaccharomyces pombe. Genetics 2019; 212:417-430. [PMID: 31000521 PMCID: PMC6553818 DOI: 10.1534/genetics.119.302125] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 04/10/2019] [Indexed: 12/23/2022] Open
Abstract
Fission yeast Swi6 is a human HP1 homolog that plays important roles in multiple cellular processes. In addition to its role in maintaining heterochromatin silencing, Swi6 is required for cohesin enrichment at the pericentromere. Loss of Swi6 leads to abnormal mitosis, including defects in the establishment of bioriented sister kinetochores and microtubule attachment. Swi6 interacts with Dfp1, a regulatory subunit of DBF4-dependent kinase (DDK), and failure to recruit Dfp1 to the pericentromere results in late DNA replication. Using the dfp1-3A mutant allele, which specifically disrupts Swi6-Dfp1 association, we investigated how interaction between Swi6 and Dfp1 affects chromosome dynamics. We find that disrupting the interaction between Swi6 and Dfp1 delays mitotic progression in a spindle assembly checkpoint-dependent manner. Artificially tethering Dfp1 back to the pericentromere is sufficient to restore normal spindle length and rescue segregation defects in swi6-deleted cells. However, Swi6 is necessary for centromeric localization of Rad21-GFP independent of DDK. Our data indicate that DDK contributes to mitotic chromosome segregation in pathways that partly overlap with, but can be separated from both, Swi6 and the other HP1 homolog, Chp2.
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Affiliation(s)
- Kuo-Fang Shen
- Program in Molecular and Computational Biology, University of Southern California, Los Angeles, California 90089-2910
| | - Susan L Forsburg
- Program in Molecular and Computational Biology, University of Southern California, Los Angeles, California 90089-2910
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15
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Roles of CDK and DDK in Genome Duplication and Maintenance: Meiotic Singularities. Genes (Basel) 2017; 8:genes8030105. [PMID: 28335524 PMCID: PMC5368709 DOI: 10.3390/genes8030105] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 03/13/2017] [Accepted: 03/14/2017] [Indexed: 12/16/2022] Open
Abstract
Cells reproduce using two types of divisions: mitosis, which generates two daughter cells each with the same genomic content as the mother cell, and meiosis, which reduces the number of chromosomes of the parent cell by half and gives rise to four gametes. The mechanisms that promote the proper progression of the mitotic and meiotic cycles are highly conserved and controlled. They require the activities of two types of serine-threonine kinases, the cyclin-dependent kinases (CDKs) and the Dbf4-dependent kinase (DDK). CDK and DDK are essential for genome duplication and maintenance in both mitotic and meiotic divisions. In this review, we aim to highlight how these kinases cooperate to orchestrate diverse processes during cellular reproduction, focusing on meiosis-specific adaptions of their regulation and functions in DNA metabolism.
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16
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Herlihy AE, de Bruin RAM. The Role of the Transcriptional Response to DNA Replication Stress. Genes (Basel) 2017; 8:E92. [PMID: 28257104 PMCID: PMC5368696 DOI: 10.3390/genes8030092] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 02/20/2017] [Accepted: 02/23/2017] [Indexed: 01/14/2023] Open
Abstract
During DNA replication many factors can result in DNA replication stress. The DNA replication stress checkpoint prevents the accumulation of replication stress-induced DNA damage and the potential ensuing genome instability. A critical role for post-translational modifications, such as phosphorylation, in the replication stress checkpoint response has been well established. However, recent work has revealed an important role for transcription in the cellular response to DNA replication stress. In this review, we will provide an overview of current knowledge of the cellular response to DNA replication stress with a specific focus on the DNA replication stress checkpoint transcriptional response and its role in the prevention of replication stress-induced DNA damage.
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Affiliation(s)
- Anna E Herlihy
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK.
| | - Robertus A M de Bruin
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK.
- The UCL Cancer Institute, University College London, London WC1E 6BT, UK.
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