1
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You Z, Masai H. Assembly, Activation, and Helicase Actions of MCM2-7: Transition from Inactive MCM2-7 Double Hexamers to Active Replication Forks. BIOLOGY 2024; 13:629. [PMID: 39194567 DOI: 10.3390/biology13080629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2024] [Revised: 08/13/2024] [Accepted: 08/14/2024] [Indexed: 08/29/2024]
Abstract
In this review, we summarize the processes of the assembly of multi-protein replisomes at the origins of replication. Replication licensing, the loading of inactive minichromosome maintenance double hexamers (dhMCM2-7) during the G1 phase, is followed by origin firing triggered by two serine-threonine kinases, Cdc7 (DDK) and CDK, leading to the assembly and activation of Cdc45/MCM2-7/GINS (CMG) helicases at the entry into the S phase and the formation of replisomes for bidirectional DNA synthesis. Biochemical and structural analyses of the recruitment of initiation or firing factors to the dhMCM2-7 for the formation of an active helicase and those of origin melting and DNA unwinding support the steric exclusion unwinding model of the CMG helicase.
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Affiliation(s)
- Zhiying You
- Genome Dynamics Project, Department of Basic Medical Sciences, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo 156-8506, Japan
| | - Hisao Masai
- Genome Dynamics Project, Department of Basic Medical Sciences, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo 156-8506, Japan
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Chiba 277-8561, Japan
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2
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Göder A, Maric CA, Rainey MD, O’Connor A, Cazzaniga C, Shamavu D, Cadoret JC, Santocanale C. DBF4, not DRF1, is the crucial regulator of CDC7 kinase at replication forks. J Cell Biol 2024; 223:e202402144. [PMID: 38865090 PMCID: PMC11169917 DOI: 10.1083/jcb.202402144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 04/02/2024] [Accepted: 05/04/2024] [Indexed: 06/13/2024] Open
Abstract
CDC7 kinase is crucial for DNA replication initiation and is involved in fork processing and replication stress response. Human CDC7 requires the binding of either DBF4 or DRF1 for its activity. However, it is unclear whether the two regulatory subunits target CDC7 to a specific set of substrates, thus having different biological functions, or if they act redundantly. Using genome editing technology, we generated isogenic cell lines deficient in either DBF4 or DRF1: these cells are viable but present signs of genomic instability, indicating that both can independently support CDC7 for bulk DNA replication. Nonetheless, DBF4-deficient cells show altered replication efficiency, partial deficiency in MCM helicase phosphorylation, and alterations in the replication timing of discrete genomic regions. Notably, we find that CDC7 function at replication forks is entirely dependent on DBF4 and not on DRF1. Thus, DBF4 is the primary regulator of CDC7 activity, mediating most of its functions in unperturbed DNA replication and upon replication interference.
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Affiliation(s)
- Anja Göder
- Centre for Chromosome Biology, School of Biological and Chemical Sciences, University of Galway, Galway, Ireland
| | | | - Michael D. Rainey
- Centre for Chromosome Biology, School of Biological and Chemical Sciences, University of Galway, Galway, Ireland
| | - Aisling O’Connor
- Centre for Chromosome Biology, School of Biological and Chemical Sciences, University of Galway, Galway, Ireland
| | - Chiara Cazzaniga
- Centre for Chromosome Biology, School of Biological and Chemical Sciences, University of Galway, Galway, Ireland
| | - Daniel Shamavu
- Centre for Chromosome Biology, School of Biological and Chemical Sciences, University of Galway, Galway, Ireland
| | | | - Corrado Santocanale
- Centre for Chromosome Biology, School of Biological and Chemical Sciences, University of Galway, Galway, Ireland
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3
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Zhang Q, Lam WH, Zhai Y. Assembly and activation of replicative helicases at origin DNA for replication initiation. Curr Opin Struct Biol 2024; 88:102876. [PMID: 38986167 DOI: 10.1016/j.sbi.2024.102876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 06/01/2024] [Accepted: 06/14/2024] [Indexed: 07/12/2024]
Abstract
To initiate DNA replication, it is essential to properly assemble a pair of replicative helicases at each replication origin. While the general principle of this process applies universally from prokaryotes to eukaryotes, the specific mechanisms governing origin selection, helicase loading, and subsequent helicase activation vary significantly across different species. Recent advancements in cryo-electron microscopy (cryo-EM) have revolutionized our ability to visualize large protein or protein-DNA complexes involved in the initiation of DNA replication. Complemented by real-time single-molecule analysis, the available high-resolution cryo-EM structures have greatly enhanced our understanding of the dynamic regulation of this process at origin DNA. This review primarily focuses on the latest structural discoveries that shed light on the key molecular machineries responsible for driving replication initiation, with a particular emphasis on the assembly of pre-replication complex (pre-RC) in eukaryotes.
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Affiliation(s)
- Qiongdan Zhang
- School of Biological Sciences, The University of Hong Kong, Hong Kong
| | - Wai Hei Lam
- School of Biological Sciences, The University of Hong Kong, Hong Kong
| | - Yuanliang Zhai
- School of Biological Sciences, The University of Hong Kong, Hong Kong.
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4
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Radhakrishnan A, Gangopadhyay R, Sharma C, Kapardar RK, Sharma NK, Srivastav R. Unwinding Helicase MCM Functionality for Diagnosis and Therapeutics of Replication Abnormalities Associated with Cancer: A Review. Mol Diagn Ther 2024; 28:249-264. [PMID: 38530633 DOI: 10.1007/s40291-024-00701-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/28/2024] [Indexed: 03/28/2024]
Abstract
The minichromosome maintenance (MCM) protein is a component of an active helicase that is essential for the initiation of DNA replication. Dysregulation of MCM functions contribute to abnormal cell proliferation and genomic instability. The interactions of MCM with cellular factors, including Cdc45 and GINS, determine the formation of active helicase and functioning of helicase. The functioning of MCM determines the fate of DNA replication and, thus, genomic integrity. This complex is upregulated in precancerous cells and can act as an important tool for diagnostic applications. The MCM protein complex can be an important broad-spectrum therapeutic target in various cancers. Investigations have supported the potential and applications of MCM in cancer diagnosis and its therapeutics. In this article, we discuss the physiological roles of MCM and its associated factors in DNA replication and cancer pathogenesis.
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Affiliation(s)
| | - Ritwik Gangopadhyay
- Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh, India
| | | | | | - Nilesh Kumar Sharma
- Cancer and Translational Research Lab, Dr. DY Patil Biotechnology and Bioinformatics Institute, Dr. DY Patil Vidyapeeth, Pune, Maharashtra, India
| | - Rajpal Srivastav
- Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh, India.
- Department of Science and Technology, Ministry of Science and Technology, New Delhi, India.
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5
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Day M, Tetik B, Parlak M, Almeida-Hernández Y, Räschle M, Kaschani F, Siegert H, Marko A, Sanchez-Garcia E, Kaiser M, Barker IA, Pearl LH, Oliver AW, Boos D. TopBP1 utilises a bipartite GINS binding mode to support genome replication. Nat Commun 2024; 15:1797. [PMID: 38413589 PMCID: PMC10899662 DOI: 10.1038/s41467-024-45946-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 02/07/2024] [Indexed: 02/29/2024] Open
Abstract
Activation of the replicative Mcm2-7 helicase by loading GINS and Cdc45 is crucial for replication origin firing, and as such for faithful genetic inheritance. Our biochemical and structural studies demonstrate that the helicase activator GINS interacts with TopBP1 through two separate binding surfaces, the first involving a stretch of highly conserved amino acids in the TopBP1-GINI region, the second a surface on TopBP1-BRCT4. The two surfaces bind to opposite ends of the A domain of the GINS subunit Psf1. Mutation analysis reveals that either surface is individually able to support TopBP1-GINS interaction, albeit with reduced affinity. Consistently, either surface is sufficient for replication origin firing in Xenopus egg extracts and becomes essential in the absence of the other. The TopBP1-GINS interaction appears sterically incompatible with simultaneous binding of DNA polymerase epsilon (Polε) to GINS when bound to Mcm2-7-Cdc45, although TopBP1-BRCT4 and the Polε subunit PolE2 show only partial competitivity in binding to Psf1. Our TopBP1-GINS model improves the understanding of the recently characterised metazoan pre-loading complex. It further predicts the coordination of three molecular origin firing processes, DNA polymerase epsilon arrival, TopBP1 ejection and GINS integration into Mcm2-7-Cdc45.
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Affiliation(s)
- Matthew Day
- School of Biological and Behavioural Sciences, Blizard Institute, Queen Mary University of London, London, E1 2AT, UK.
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9RQ, UK.
| | - Bilal Tetik
- Molecular Genetics II, Center of Medical Biotechnology, University of Duisburg-Essen, Universitätsstraße 2-5, 45141, Essen, Germany
| | - Milena Parlak
- Molecular Genetics II, Center of Medical Biotechnology, University of Duisburg-Essen, Universitätsstraße 2-5, 45141, Essen, Germany
| | - Yasser Almeida-Hernández
- Computational Bioengineering, Fakultät Bio- und Chemieingenieurwesen, Technical University Dortmund, Emil-Figge Str. 66, 44227, Dortmund, Germany
- Computational Biochemistry, Center of Medical Biotechnology, University of Duisburg-Essen, Universitätsstraße 2-5, 45141, Essen, Germany
| | - Markus Räschle
- Molecular Genetics, Technical University Kaiserslautern, Paul-Ehrlich Straße 24, 67663, Kaiserslautern, Germany
| | - Farnusch Kaschani
- Analytics Core Facility Essen, Center of Medical Biotechnology, University of Duisburg-Essen, Universitätsstraße 2-5, 45141, Essen, Germany
- Chemical Biology, Center of Medical Biotechnology, University Duisburg-Essen, Fakultät Biologie, Essen, Germany
| | - Heike Siegert
- Molecular Genetics II, Center of Medical Biotechnology, University of Duisburg-Essen, Universitätsstraße 2-5, 45141, Essen, Germany
| | - Anika Marko
- Molecular Genetics II, Center of Medical Biotechnology, University of Duisburg-Essen, Universitätsstraße 2-5, 45141, Essen, Germany
| | - Elsa Sanchez-Garcia
- Computational Bioengineering, Fakultät Bio- und Chemieingenieurwesen, Technical University Dortmund, Emil-Figge Str. 66, 44227, Dortmund, Germany
- Computational Biochemistry, Center of Medical Biotechnology, University of Duisburg-Essen, Universitätsstraße 2-5, 45141, Essen, Germany
| | - Markus Kaiser
- Analytics Core Facility Essen, Center of Medical Biotechnology, University of Duisburg-Essen, Universitätsstraße 2-5, 45141, Essen, Germany
- Chemical Biology, Center of Medical Biotechnology, University Duisburg-Essen, Fakultät Biologie, Essen, Germany
| | - Isabel A Barker
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9RQ, UK
| | - Laurence H Pearl
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9RQ, UK.
- Division of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London, SW1E 6BT, UK.
| | - Antony W Oliver
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9RQ, UK.
| | - Dominik Boos
- Molecular Genetics II, Center of Medical Biotechnology, University of Duisburg-Essen, Universitätsstraße 2-5, 45141, Essen, Germany.
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6
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Tye BK, Zhai Y. The Origin Recognition Complex: From Origin Selection to Replication Licensing in Yeast and Humans. BIOLOGY 2023; 13:13. [PMID: 38248444 PMCID: PMC10813338 DOI: 10.3390/biology13010013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 12/15/2023] [Accepted: 12/20/2023] [Indexed: 01/23/2024]
Abstract
Understanding human DNA replication through the study of yeast has been an extremely fruitful journey. The minichromosome maintenance (MCM) 2-7 genes that encode the catalytic core of the eukaryotic replisome were initially identified through forward yeast genetics. The origin recognition complexes (ORC) that load the MCM hexamers at replication origins were purified from yeast extracts. We have reached an age where high-resolution cryoEM structures of yeast and human replication complexes can be compared side-by-side. Their similarities and differences are converging as alternative strategies that may deviate in detail but are shared by both species.
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Affiliation(s)
- Bik-Kwoon Tye
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Yuanliang Zhai
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China;
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7
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Lewis JS, van Oijen AM, Spenkelink LM. Embracing Heterogeneity: Challenging the Paradigm of Replisomes as Deterministic Machines. Chem Rev 2023; 123:13419-13440. [PMID: 37971892 PMCID: PMC10790245 DOI: 10.1021/acs.chemrev.3c00436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Revised: 10/15/2023] [Accepted: 10/20/2023] [Indexed: 11/19/2023]
Abstract
The paradigm of cellular systems as deterministic machines has long guided our understanding of biology. Advancements in technology and methodology, however, have revealed a world of stochasticity, challenging the notion of determinism. Here, we explore the stochastic behavior of multi-protein complexes, using the DNA replication system (replisome) as a prime example. The faithful and timely copying of DNA depends on the simultaneous action of a large set of enzymes and scaffolding factors. This fundamental cellular process is underpinned by dynamic protein-nucleic acid assemblies that must transition between distinct conformations and compositional states. Traditionally viewed as a well-orchestrated molecular machine, recent experimental evidence has unveiled significant variability and heterogeneity in the replication process. In this review, we discuss recent advances in single-molecule approaches and single-particle cryo-EM, which have provided insights into the dynamic processes of DNA replication. We comment on the new challenges faced by structural biologists and biophysicists as they attempt to describe the dynamic cascade of events leading to replisome assembly, activation, and progression. The fundamental principles uncovered and yet to be discovered through the study of DNA replication will inform on similar operating principles for other multi-protein complexes.
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Affiliation(s)
- Jacob S. Lewis
- Macromolecular
Machines Laboratory, The Francis Crick Institute, London NW1 1AT, United Kingdom
| | - Antoine M. van Oijen
- Molecular
Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Lisanne M. Spenkelink
- Molecular
Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
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8
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Cvetkovic MA, Passaretti P, Butryn A, Reynolds-Winczura A, Kingsley G, Skagia A, Fernandez-Cuesta C, Poovathumkadavil D, George R, Chauhan AS, Jhujh SS, Stewart GS, Gambus A, Costa A. The structural mechanism of dimeric DONSON in replicative helicase activation. Mol Cell 2023; 83:4017-4031.e9. [PMID: 37820732 DOI: 10.1016/j.molcel.2023.09.029] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 09/15/2023] [Accepted: 09/25/2023] [Indexed: 10/13/2023]
Abstract
The MCM motor of the replicative helicase is loaded onto origin DNA as an inactive double hexamer before replication initiation. Recruitment of activators GINS and Cdc45 upon S-phase transition promotes the assembly of two active CMG helicases. Although work with yeast established the mechanism for origin activation, how CMG is formed in higher eukaryotes is poorly understood. Metazoan Downstream neighbor of Son (DONSON) has recently been shown to deliver GINS to MCM during CMG assembly. What impact this has on the MCM double hexamer is unknown. Here, we used cryoelectron microscopy (cryo-EM) on proteins isolated from replicating Xenopus egg extracts to identify a double CMG complex bridged by a DONSON dimer. We find that tethering elements mediating complex formation are essential for replication. DONSON reconfigures the MCM motors in the double CMG, and primordial dwarfism patients' mutations disrupting DONSON dimerization affect GINS and MCM engagement in human cells and DNA synthesis in Xenopus egg extracts.
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Affiliation(s)
- Milos A Cvetkovic
- Macromolecular Machines Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Paolo Passaretti
- Institute of Cancer and Genomic Sciences, Birmingham Centre for Genome Biology, University of Birmingham, Birmingham B15 2TT, UK
| | - Agata Butryn
- Macromolecular Machines Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Alicja Reynolds-Winczura
- Institute of Cancer and Genomic Sciences, Birmingham Centre for Genome Biology, University of Birmingham, Birmingham B15 2TT, UK
| | - Georgia Kingsley
- Institute of Cancer and Genomic Sciences, Birmingham Centre for Genome Biology, University of Birmingham, Birmingham B15 2TT, UK
| | - Aggeliki Skagia
- Institute of Cancer and Genomic Sciences, Birmingham Centre for Genome Biology, University of Birmingham, Birmingham B15 2TT, UK
| | - Cyntia Fernandez-Cuesta
- Institute of Cancer and Genomic Sciences, Birmingham Centre for Genome Biology, University of Birmingham, Birmingham B15 2TT, UK
| | - Divyasree Poovathumkadavil
- Institute of Cancer and Genomic Sciences, Birmingham Centre for Genome Biology, University of Birmingham, Birmingham B15 2TT, UK
| | - Roger George
- Structural Biology Science Technology Platform, The Francis Crick Institute, London NW1 1AT, UK
| | - Anoop S Chauhan
- Institute of Cancer and Genomic Sciences, Birmingham Centre for Genome Biology, University of Birmingham, Birmingham B15 2TT, UK
| | - Satpal S Jhujh
- Institute of Cancer and Genomic Sciences, Birmingham Centre for Genome Biology, University of Birmingham, Birmingham B15 2TT, UK
| | - Grant S Stewart
- Institute of Cancer and Genomic Sciences, Birmingham Centre for Genome Biology, University of Birmingham, Birmingham B15 2TT, UK
| | - Agnieszka Gambus
- Institute of Cancer and Genomic Sciences, Birmingham Centre for Genome Biology, University of Birmingham, Birmingham B15 2TT, UK.
| | - Alessandro Costa
- Macromolecular Machines Laboratory, The Francis Crick Institute, London NW1 1AT, UK.
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9
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Xu Z, Feng J, Yu D, Huo Y, Ma X, Lam WH, Liu Z, Li XD, Ishibashi T, Dang S, Zhai Y. Synergism between CMG helicase and leading strand DNA polymerase at replication fork. Nat Commun 2023; 14:5849. [PMID: 37730685 PMCID: PMC10511561 DOI: 10.1038/s41467-023-41506-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 09/07/2023] [Indexed: 09/22/2023] Open
Abstract
The replisome that replicates the eukaryotic genome consists of at least three engines: the Cdc45-MCM-GINS (CMG) helicase that separates duplex DNA at the replication fork and two DNA polymerases, one on each strand, that replicate the unwound DNA. Here, we determined a series of cryo-electron microscopy structures of a yeast replisome comprising CMG, leading-strand polymerase Polε and three accessory factors on a forked DNA. In these structures, Polε engages or disengages with the motor domains of the CMG by occupying two alternative positions, which closely correlate with the rotational movement of the single-stranded DNA around the MCM pore. During this process, the polymerase remains stably coupled to the helicase using Psf1 as a hinge. This synergism is modulated by a concerted rearrangement of ATPase sites to drive DNA translocation. The Polε-MCM coupling is not only required for CMG formation to initiate DNA replication but also facilitates the leading-strand DNA synthesis mediated by Polε. Our study elucidates a mechanism intrinsic to the replisome that coordinates the activities of CMG and Polε to negotiate any roadblocks, DNA damage, and epigenetic marks encountered during translocation along replication forks.
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Affiliation(s)
- Zhichun Xu
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
| | - Jianrong Feng
- Division of Life Science, The Hong Kong University of Science & Technology, Hong Kong, China
| | - Daqi Yu
- Division of Life Science, The Hong Kong University of Science & Technology, Hong Kong, China
| | - Yunjing Huo
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
| | - Xiaohui Ma
- Division of Life Science, The Hong Kong University of Science & Technology, Hong Kong, China
| | - Wai Hei Lam
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
| | - Zheng Liu
- Department of Chemistry, The University of Hong Kong, Hong Kong, China
| | - Xiang David Li
- Department of Chemistry, The University of Hong Kong, Hong Kong, China
| | - Toyotaka Ishibashi
- Division of Life Science, The Hong Kong University of Science & Technology, Hong Kong, China
| | - Shangyu Dang
- Division of Life Science, The Hong Kong University of Science & Technology, Hong Kong, China.
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China.
- HKUST-Shenzhen Research Institute, 518057, Nanshan, Shenzhen, China.
| | - Yuanliang Zhai
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China.
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10
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Willemsen M, Barber JS, Nieuwenhove EV, Staels F, Gerbaux M, Neumann J, Prezzemolo T, Pasciuto E, Lagou V, Boeckx N, Filtjens J, De Visscher A, Matthys P, Schrijvers R, Tousseyn T, O'Driscoll M, Bucciol G, Schlenner S, Meyts I, Humblet-Baron S, Liston A. Homozygous DBF4 mutation as a cause of severe congenital neutropenia. J Allergy Clin Immunol 2023; 152:266-277. [PMID: 36841265 DOI: 10.1016/j.jaci.2023.02.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 01/23/2023] [Accepted: 02/16/2023] [Indexed: 02/26/2023]
Abstract
BACKGROUND Severe congenital neutropenia presents with recurrent infections early in life as a result of arrested granulopoiesis. Multiple genetic defects are known to block granulocyte differentiation; however, a genetic cause remains unknown in approximately 40% of cases. OBJECTIVE We aimed to characterize a patient with severe congenital neutropenia and syndromic features without a genetic diagnosis. METHODS Whole exome sequencing results were validated using flow cytometry, Western blotting, coimmunoprecipitation, quantitative PCR, cell cycle and proliferation analysis of lymphocytes and fibroblasts and granulocytic differentiation of primary CD34+ and HL-60 cells. RESULTS We identified a homozygous missense mutation in DBF4 in a patient with mild extra-uterine growth retardation, facial dysmorphism and severe congenital neutropenia. DBF4 is the regulatory subunit of the CDC7 kinase, together known as DBF4-dependent kinase (DDK), the complex essential for DNA replication initiation. The DBF4 variant demonstrated impaired ability to bind CDC7, resulting in decreased DDK-mediated phosphorylation, defective S-phase entry and progression and impaired differentiation of granulocytes associated with activation of the p53-p21 pathway. The introduction of wild-type DBF4 into patient CD34+ cells rescued the promyelocyte differentiation arrest. CONCLUSION Hypomorphic DBF4 mutation causes autosomal-recessive severe congenital neutropenia with syndromic features.
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Affiliation(s)
- Mathijs Willemsen
- Department of Microbiology, Immunology, and Transplantation, Laboratory of Adaptive Immunity, KU Leuven, Leuven, Belgium; VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium
| | - John S Barber
- Department of Microbiology, Immunology, and Transplantation, Laboratory of Adaptive Immunity, KU Leuven, Leuven, Belgium; VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium
| | - Erika Van Nieuwenhove
- Department of Microbiology, Immunology, and Transplantation, Laboratory of Adaptive Immunity, KU Leuven, Leuven, Belgium; VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium; Department of Pediatrics, University Hospitals Leuven, Leuven, Belgium
| | - Frederik Staels
- Department of Microbiology, Immunology, and Transplantation, Laboratory of Adaptive Immunity, KU Leuven, Leuven, Belgium; Department of Microbiology, Immunology, and Transplantation, Allergy and Clinical Immunology Research Group, KU Leuven, Leuven, Belgium
| | - Margaux Gerbaux
- Department of Microbiology, Immunology, and Transplantation, Laboratory of Adaptive Immunity, KU Leuven, Leuven, Belgium; Pediatric Department, Academic Children Hospital Queen Fabiola, Université Libre de Bruxelles, Brussels, Belgium
| | - Julika Neumann
- Department of Microbiology, Immunology, and Transplantation, Laboratory of Adaptive Immunity, KU Leuven, Leuven, Belgium; VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium
| | - Teresa Prezzemolo
- Department of Microbiology, Immunology, and Transplantation, Laboratory of Adaptive Immunity, KU Leuven, Leuven, Belgium; VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium
| | - Emanuela Pasciuto
- Department of Microbiology, Immunology, and Transplantation, Laboratory of Adaptive Immunity, KU Leuven, Leuven, Belgium; VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium
| | - Vasiliki Lagou
- Department of Microbiology, Immunology, and Transplantation, Laboratory of Adaptive Immunity, KU Leuven, Leuven, Belgium; VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium
| | - Nancy Boeckx
- Department of Laboratory Medicine, University Hospitals Leuven, Leuven, Belgium
| | - Jessica Filtjens
- Department of Microbiology, Immunology, and Transplantation, Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven, Leuve, Belgium
| | - Amber De Visscher
- Department of Microbiology, Immunology, and Transplantation, Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven, Leuve, Belgium
| | - Patrick Matthys
- Department of Microbiology, Immunology, and Transplantation, Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven, Leuve, Belgium
| | - Rik Schrijvers
- Department of Microbiology, Immunology, and Transplantation, Allergy and Clinical Immunology Research Group, KU Leuven, Leuven, Belgium
| | - Thomas Tousseyn
- Department of Pathology, University Hospitals Leuven, Leuven, Belgium
| | - Mark O'Driscoll
- Human DNA Damage Response Disorders Group, Genome Damage and Stability Centre, University of Sussex, Brighton, United Kingdom
| | - Giorgia Bucciol
- Department of Microbiology, Immunology, and Transplantation, Laboratory for Inborn Errors of Immunity, KU Leuven, Leuven, Belgium; Department of Pediatrics, Division of Primary Immunodeficiencies, University Hospitals Leuven, Leuven
| | - Susan Schlenner
- Department of Microbiology, Immunology, and Transplantation, Laboratory of Adaptive Immunity, KU Leuven, Leuven, Belgium
| | - Isabelle Meyts
- Department of Microbiology, Immunology, and Transplantation, Laboratory for Inborn Errors of Immunity, KU Leuven, Leuven, Belgium; Department of Pediatrics, Division of Primary Immunodeficiencies, University Hospitals Leuven, Leuven.
| | - Stephanie Humblet-Baron
- Department of Microbiology, Immunology, and Transplantation, Laboratory of Adaptive Immunity, KU Leuven, Leuven, Belgium.
| | - Adrian Liston
- Department of Microbiology, Immunology, and Transplantation, Laboratory of Adaptive Immunity, KU Leuven, Leuven, Belgium; VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium; Immunology Programme, The Babraham Institute, Babraham Research Campus, Cambridge, United Kingdom.
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11
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Ramírez Montero D, Sánchez H, van Veen E, van Laar T, Solano B, Diffley JFX, Dekker NH. Nucleotide binding halts diffusion of the eukaryotic replicative helicase during activation. Nat Commun 2023; 14:2082. [PMID: 37059705 PMCID: PMC10104875 DOI: 10.1038/s41467-023-37093-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 03/02/2023] [Indexed: 04/16/2023] Open
Abstract
The eukaryotic replicative helicase CMG centrally orchestrates the replisome and leads the way at the front of replication forks. Understanding the motion of CMG on the DNA is therefore key to our understanding of DNA replication. In vivo, CMG is assembled and activated through a cell-cycle-regulated mechanism involving 36 polypeptides that has been reconstituted from purified proteins in ensemble biochemical studies. Conversely, single-molecule studies of CMG motion have thus far relied on pre-formed CMG assembled through an unknown mechanism upon overexpression of individual constituents. Here, we report the activation of CMG fully reconstituted from purified yeast proteins and the quantification of its motion at the single-molecule level. We observe that CMG can move on DNA in two ways: by unidirectional translocation and by diffusion. We demonstrate that CMG preferentially exhibits unidirectional translocation in the presence of ATP, whereas it preferentially exhibits diffusive motion in the absence of ATP. We also demonstrate that nucleotide binding halts diffusive CMG independently of DNA melting. Taken together, our findings support a mechanism by which nucleotide binding allows newly assembled CMG to engage with the DNA within its central channel, halting its diffusion and facilitating the initial DNA melting required to initiate DNA replication.
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Affiliation(s)
- Daniel Ramírez Montero
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Humberto Sánchez
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Edo van Veen
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Theo van Laar
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Belén Solano
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - John F X Diffley
- Chromosome Replication Laboratory, Francis Crick Institute, London, UK.
| | - Nynke H Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands.
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12
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Identifying CDC7 as a synergistic target of chemotherapy in resistant small-cell lung cancer via CRISPR/Cas9 screening. Cell Death Dis 2023; 9:40. [PMID: 36725843 PMCID: PMC9892530 DOI: 10.1038/s41420-023-01315-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Revised: 01/05/2023] [Accepted: 01/09/2023] [Indexed: 02/03/2023]
Abstract
There is currently a lack of efficacious treatments for patients with chemo-resistant small-cell lung cancer (SCLC), leading to poor prognoses. We examined a chemo-resistant SCLC cell line using genome-wide CRISPR/Cas9 screening and identified serine/threonine kinase cell division cycle 7 (CDC7) as a potential synergistic target. Silencing CDC7 in chemo-resistant SCLC cells decreased the IC50 and improved the efficacy of chemotherapy. Based on the highest single agent model, the CDC7 inhibitor XL413 had a synergistic effect with both cisplatin and etoposide in chemo-resistant SCLC cells, but had no such effect in chemo-sensitive SCLC cells; the combination of XL413 and chemotherapy significantly inhibited cell growth. Western blot and flow cytometry showed that the combined treatments increased apoptosis, whereas XL413 alone had little effect on apoptosis. An analysis of cell cycle and cyclin protein levels indicated that the combination of XL413 and chemotherapy-induced G1/S phase arrest and DNA damage in chemo-resistant SCLC cells. Xenografted tumor and histoculture drug response assays using patient-derived xenografts showed that XL413 improved the efficacy of chemotherapy in vivo and with SCLC tissues. These results suggest that XL413 exerts a synergistic effect with chemotherapy on chemo-resistant SCLC.
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13
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Li N, Gao N, Zhai Y. DDK promotes DNA replication initiation: Mechanistic and structural insights. Curr Opin Struct Biol 2023; 78:102504. [PMID: 36525878 DOI: 10.1016/j.sbi.2022.102504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/25/2022] [Accepted: 11/15/2022] [Indexed: 12/15/2022]
Abstract
DNA replication initiation in eukaryotes is tightly regulated through two cell-cycle specific processes, replication licensing to install inactive minichromosome maintenance (MCM) double-hexamers (DH) on origins in early G1 phase and origin firing to assemble and activate Cdc45-Mcm2-7-GINS (CMG) helicases upon S phase entry. Two kinases, cyclin-dependent kinase (CDK) and Dbf4-dependent kinase (DDK), are responsible for driving the association of replication factors with the MCM-DH to form CMG helicases for origin melting and DNA unwinding and eventually replisomes for bi-directional DNA synthesis. In recent years, cryo-electron microscopy studies have generated a collection of structural snapshots for the stepwise assembly and remodeling of the replication initiation machineries, creating a framework for understanding the regulation of this fundamental process at a molecular level. Very recent progress is the structural characterization of the elusive MCM-DH-DDK complex, which provides insights into mechanisms of kinase activation, substrate recognition and selection, as well as molecular role of DDK-mediated MCM-DH phosphorylation in helicase activation.
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Affiliation(s)
- Ningning Li
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - Ning Gao
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China; National Biomedical Imaging Center, Peking University, Beijing, China.
| | - Yuanliang Zhai
- School of Biological Sciences, The University of Hong Kong, Hong Kong.
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14
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The CMG helicase and cancer: a tumor "engine" and weakness with missing mutations. Oncogene 2023; 42:473-490. [PMID: 36522488 PMCID: PMC9948756 DOI: 10.1038/s41388-022-02572-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 12/01/2022] [Accepted: 12/07/2022] [Indexed: 12/23/2022]
Abstract
The replicative Cdc45-MCM-GINS (CMG) helicase is a large protein complex that functions in the DNA melting and unwinding steps as a component of replisomes during DNA replication in mammalian cells. Although the CMG performs this important role in cell growth, the CMG is not a simple bystander in cell cycle events. Components of the CMG, specifically the MCM precursors, are also involved in maintaining genomic stability by regulating DNA replication fork speeds, facilitating recovery from replicative stresses, and preventing consequential DNA damage. Given these important functions, MCM/CMG complexes are highly regulated by growth factors such as TGF-ß1 and by signaling factors such as Myc, Cyclin E, and the retinoblastoma protein. Mismanagement of MCM/CMG complexes when these signaling mediators are deregulated, and in the absence of the tumor suppressor protein p53, leads to increased genomic instability and is a contributor to tumorigenic transformation and tumor heterogeneity. The goal of this review is to provide insight into the mechanisms and dynamics by which the CMG is regulated during its assembly and activation in mammalian genomes, and how errors in CMG regulation due to oncogenic changes promote tumorigenesis. Finally, and most importantly, we highlight the emerging understanding of the CMG helicase as an exploitable vulnerability and novel target for therapeutic intervention in cancer.
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15
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Song HY, Shen R, Mahasin H, Guo YN, Wang DG. DNA replication: Mechanisms and therapeutic interventions for diseases. MedComm (Beijing) 2023; 4:e210. [PMID: 36776764 PMCID: PMC9899494 DOI: 10.1002/mco2.210] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 01/08/2023] [Accepted: 01/09/2023] [Indexed: 02/09/2023] Open
Abstract
Accurate and integral cellular DNA replication is modulated by multiple replication-associated proteins, which is fundamental to preserve genome stability. Furthermore, replication proteins cooperate with multiple DNA damage factors to deal with replication stress through mechanisms beyond their role in replication. Cancer cells with chronic replication stress exhibit aberrant DNA replication and DNA damage response, providing an exploitable therapeutic target in tumors. Numerous evidence has indicated that posttranslational modifications (PTMs) of replication proteins present distinct functions in DNA replication and respond to replication stress. In addition, abundant replication proteins are involved in tumorigenesis and development, which act as diagnostic and prognostic biomarkers in some tumors, implying these proteins act as therapeutic targets in clinical. Replication-target cancer therapy emerges as the times require. In this context, we outline the current investigation of the DNA replication mechanism, and simultaneously enumerate the aberrant expression of replication proteins as hallmark for various diseases, revealing their therapeutic potential for target therapy. Meanwhile, we also discuss current observations that the novel PTM of replication proteins in response to replication stress, which seems to be a promising strategy to eliminate diseases.
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Affiliation(s)
- Hao-Yun Song
- School of Basic Medical Sciences Lanzhou University Lanzhou Gansu China
| | - Rong Shen
- School of Basic Medical Sciences Lanzhou University Lanzhou Gansu China
| | - Hamid Mahasin
- School of Basic Medical Sciences Lanzhou University Lanzhou Gansu China
| | - Ya-Nan Guo
- School of Basic Medical Sciences Lanzhou University Lanzhou Gansu China
| | - De-Gui Wang
- School of Basic Medical Sciences Lanzhou University Lanzhou Gansu China
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16
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The human pre-replication complex is an open complex. Cell 2023; 186:98-111.e21. [PMID: 36608662 DOI: 10.1016/j.cell.2022.12.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Revised: 10/13/2022] [Accepted: 12/05/2022] [Indexed: 01/07/2023]
Abstract
In eukaryotes, DNA replication initiation requires assembly and activation of the minichromosome maintenance (MCM) 2-7 double hexamer (DH) to melt origin DNA strands. However, the mechanism for this initial melting is unknown. Here, we report a 2.59-Å cryo-electron microscopy structure of the human MCM-DH (hMCM-DH), also known as the pre-replication complex. In this structure, the hMCM-DH with a constricted central channel untwists and stretches the DNA strands such that almost a half turn of the bound duplex DNA is distorted with 1 base pair completely separated, generating an initial open structure (IOS) at the hexamer junction. Disturbing the IOS inhibits DH formation and replication initiation. Mapping of hMCM-DH footprints indicates that IOSs are distributed across the genome in large clusters aligning well with initiation zones designed for stochastic origin firing. This work unravels an intrinsic mechanism that couples DH formation with initial DNA melting to license replication initiation in human cells.
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17
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A DNA Replication Fork-centric View of the Budding Yeast DNA Damage Response. DNA Repair (Amst) 2022; 119:103393. [DOI: 10.1016/j.dnarep.2022.103393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 08/25/2022] [Accepted: 08/26/2022] [Indexed: 11/23/2022]
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18
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Tanaka S, Ogawa S. Dimerization of Firing Factors for Replication Origin Activation in Eukaryotes: A Crucial Process for Simultaneous Assembly of Bidirectional Replication Forks? BIOLOGY 2022; 11:928. [PMID: 35741449 PMCID: PMC9219616 DOI: 10.3390/biology11060928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/13/2022] [Accepted: 06/15/2022] [Indexed: 11/17/2022]
Abstract
Controlling the activity of the heterohexameric Mcm2-7 replicative helicase is crucial for regulation of replication origin activity in eukaryotes. Because bidirectional replication forks are generated from every replication origin, when origins are licensed for replication in the first step of DNA replication, two inactive Mcm2-7 heterohexiameric complexes are loaded around double stranded DNA as a head-to-head double hexamer. The helicases are subsequently activated via a 'firing' reaction, in which the Mcm2-7 double hexamer is converted into two active helicase units, the CMG complex, by firing factors. Dimerization of firing factors may contribute to this process by allowing simultaneous activation of two sets of helicases and thus efficient assembly of bidirectional replication forks. An example of this is dimerization of the firing factor Sld3/Treslin/Ticrr via its binding partner, Sld7/MTBP. In organisms in which no Sld7 ortholog has been identified, such as the fission yeast Schizosaccharomyces pombe, Sld3 itself has a dimerization domain, and it has been suggested that this self-interaction is crucial for the firing reaction in this organism. Dimerization induces a conformational change in Sdl3 that appears to be critical for the firing reaction. Moreover, Mcm10 also seems to be regulated by self-interaction in yeasts. Although it is not yet clear to what extent dimerization of firing factors contributes to the firing reaction in eukaryotes, we discuss the possible roles of firing factor dimerization in simultaneous helicase activation.
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Affiliation(s)
- Seiji Tanaka
- School of Environmental Science and Engineering, Kochi University of Technology, Kami 782-8502, Japan;
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19
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Gillespie PJ, Blow JJ. DDK: The Outsourced Kinase of Chromosome Maintenance. BIOLOGY 2022; 11:biology11060877. [PMID: 35741398 PMCID: PMC9220011 DOI: 10.3390/biology11060877] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 05/31/2022] [Accepted: 06/02/2022] [Indexed: 11/16/2022]
Abstract
The maintenance of genomic stability during the mitotic cell-cycle not only demands that the DNA is duplicated and repaired with high fidelity, but that following DNA replication the chromatin composition is perpetuated and that the duplicated chromatids remain tethered until their anaphase segregation. The coordination of these processes during S phase is achieved by both cyclin-dependent kinase, CDK, and Dbf4-dependent kinase, DDK. CDK orchestrates the activation of DDK at the G1-to-S transition, acting as the ‘global’ regulator of S phase and cell-cycle progression, whilst ‘local’ control of the initiation of DNA replication and repair and their coordination with the re-formation of local chromatin environments and the establishment of chromatid cohesion are delegated to DDK. Here, we discuss the regulation and the multiple roles of DDK in ensuring chromosome maintenance. Regulation of replication initiation by DDK has long been known to involve phosphorylation of MCM2-7 subunits, but more recent results have indicated that Treslin:MTBP might also be important substrates. Molecular mechanisms by which DDK regulates replisome stability and replicated chromatid cohesion are less well understood, though important new insights have been reported recently. We discuss how the ‘outsourcing’ of activities required for chromosome maintenance to DDK allows CDK to maintain outright control of S phase progression and the cell-cycle phase transitions whilst permitting ongoing chromatin replication and cohesion establishment to be completed and achieved faithfully.
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20
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Lewis JS, Gross MH, Sousa J, Henrikus SS, Greiwe JF, Nans A, Diffley JFX, Costa A. Mechanism of replication origin melting nucleated by CMG helicase assembly. Nature 2022; 606:1007-1014. [PMID: 35705812 PMCID: PMC9242855 DOI: 10.1038/s41586-022-04829-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 05/03/2022] [Indexed: 12/04/2022]
Abstract
The activation of eukaryotic origins of replication occurs in temporally separated steps to ensure that chromosomes are copied only once per cell cycle. First, the MCM helicase is loaded onto duplex DNA as an inactive double hexamer. Activation occurs after the recruitment of a set of firing factors that assemble two Cdc45-MCM-GINS (CMG) holo-helicases. CMG formation leads to the underwinding of DNA on the path to the establishment of the replication fork, but whether DNA becomes melted at this stage is unknown1. Here we use cryo-electron microscopy to image ATP-dependent CMG assembly on a chromatinized origin, reconstituted in vitro with purified yeast proteins. We find that CMG formation disrupts the double hexamer interface and thereby exposes duplex DNA in between the two CMGs. The two helicases remain tethered, which gives rise to a splayed dimer, with implications for origin activation and replisome integrity. Inside each MCM ring, the double helix becomes untwisted and base pairing is broken. This comes as the result of ATP-triggered conformational changes in MCM that involve DNA stretching and protein-mediated stabilization of three orphan bases. Mcm2 pore-loop residues that engage DNA in our structure are dispensable for double hexamer loading and CMG formation, but are essential to untwist the DNA and promote replication. Our results explain how ATP binding nucleates origin DNA melting by the CMG and maintains replisome stability at initiation.
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Affiliation(s)
- Jacob S Lewis
- Macromolecular Machines Laboratory, The Francis Crick Institute, London, UK
| | - Marta H Gross
- Chromosome Replication Laboratory, The Francis Crick Institute, London, UK
| | - Joana Sousa
- Macromolecular Machines Laboratory, The Francis Crick Institute, London, UK
- UCB Pharma, Slough, UK
| | - Sarah S Henrikus
- Macromolecular Machines Laboratory, The Francis Crick Institute, London, UK
| | - Julia F Greiwe
- Macromolecular Machines Laboratory, The Francis Crick Institute, London, UK
| | - Andrea Nans
- Structural Biology Science Technology Platform, The Francis Crick Institute, London, UK
| | - John F X Diffley
- Chromosome Replication Laboratory, The Francis Crick Institute, London, UK
| | - Alessandro Costa
- Macromolecular Machines Laboratory, The Francis Crick Institute, London, UK.
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