1
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Cornet F, Blanchais C, Dusfour-Castan R, Meunier A, Quebre V, Sekkouri Alaoui H, Boudsoq F, Campos M, Crozat E, Guynet C, Pasta F, Rousseau P, Ton Hoang B, Bouet JY. DNA Segregation in Enterobacteria. EcoSal Plus 2023; 11:eesp00382020. [PMID: 37220081 PMCID: PMC10729935 DOI: 10.1128/ecosalplus.esp-0038-2020] [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: 11/24/2022] [Accepted: 04/13/2023] [Indexed: 01/28/2024]
Abstract
DNA segregation ensures that cell offspring receive at least one copy of each DNA molecule, or replicon, after their replication. This important cellular process includes different phases leading to the physical separation of the replicons and their movement toward the future daughter cells. Here, we review these phases and processes in enterobacteria with emphasis on the molecular mechanisms at play and their controls.
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Affiliation(s)
- François Cornet
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - Corentin Blanchais
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - Romane Dusfour-Castan
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - Alix Meunier
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - Valentin Quebre
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - Hicham Sekkouri Alaoui
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - François Boudsoq
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - Manuel Campos
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - Estelle Crozat
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - Catherine Guynet
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - Franck Pasta
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - Philippe Rousseau
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - Bao Ton Hoang
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - Jean-Yves Bouet
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, Toulouse, France
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2
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Yáñez-Cuna FO, Koszul R. Insights in bacterial genome folding. Curr Opin Struct Biol 2023; 82:102679. [PMID: 37604045 DOI: 10.1016/j.sbi.2023.102679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 07/18/2023] [Accepted: 07/19/2023] [Indexed: 08/23/2023]
Abstract
Chromosomes in all domains of life are well-defined structural entities with complex hierarchical organization. The regulation of this hierarchical organization and its functional interplay with gene expression or other chromosome metabolic processes such as repair, replication, or segregation is actively investigated in a variety of species, including prokaryotes. Bacterial chromosomes are typically gene-dense with few non-coding sequences and are organized into the nucleoid, a membrane-less compartment composed of DNA, RNA, and proteins (nucleoid-associated proteins or NAPs). The continuous improvement of imaging and genomic methods has put the organization of these Mb-long molecules at reach, allowing to disambiguate some of their highly dynamic properties and intertwined structural features. Here we review and discuss some of the recent advances in the field of bacterial chromosome organization.
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Affiliation(s)
- Fares Osam Yáñez-Cuna
- Institut Pasteur, CNRS UMR 3525, Université Paris Cité, Unité Régulation Spatiale des Génomes, 75015, Paris, France
| | - Romain Koszul
- Institut Pasteur, CNRS UMR 3525, Université Paris Cité, Unité Régulation Spatiale des Génomes, 75015, Paris, France.
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3
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Cebrián J, Martínez V, Hernández P, Krimer DB, Fernández-Nestosa MJ, Schvartzman JB. Two-Dimensional Gel Electrophoresis to Study the Activity of Type IIA Topoisomerases on Plasmid Replication Intermediates. BIOLOGY 2021; 10:biology10111195. [PMID: 34827187 PMCID: PMC8615216 DOI: 10.3390/biology10111195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 11/11/2021] [Accepted: 11/13/2021] [Indexed: 11/28/2022]
Abstract
Simple Summary During replication, DNA molecules undergo topological changes that affect supercoiling, catenation and knotting. To better understand this process and the role of topoisomerases, the enzymes that control DNA topology in in vivo, two-dimensional agarose gel electrophoresis were used to investigate the efficiency of three type II DNA topoisomerases, the prokaryotic DNA gyrase, topoisomerase IV and the human topoisomerase 2α, on partially replicated bacterial plasmids containing replication forks stalled at specific sites. The results obtained revealed that despite the fact these DNA topoisomerases may have evolved to accomplish specific tasks, they share abilities. To our knowledge, this is the first time two-dimensional agarose gel electrophoresis have been used to examine the ability of these topoisomerases to relax supercoiling in the un-replicated region and unlink pre-catenanes in the replicated one of partially replicated molecules in vitro. The methodology described here can be used to study the role of different topoisomerases in partially replicated molecules. Abstract DNA topoisomerases are the enzymes that regulate DNA topology in all living cells. Since the discovery and purification of ω (omega), when the first were topoisomerase identified, the function of many topoisomerases has been examined. However, their ability to relax supercoiling and unlink the pre-catenanes of partially replicated molecules has received little attention. Here, we used two-dimensional agarose gel electrophoresis to test the function of three type II DNA topoisomerases in vitro: the prokaryotic DNA gyrase, topoisomerase IV and the human topoisomerase 2α. We examined the proficiency of these topoisomerases on a partially replicated bacterial plasmid: pBR-TerE@AatII, with an unidirectional replicating fork, stalled when approximately half of the plasmid had been replicated in vivo. DNA was isolated from two strains of Escherichia coli: DH5αF’ and parE10. These experiments allowed us to assess, for the first time, the efficiency of the topoisomerases examined to resolve supercoiling and pre-catenanes in partially replicated molecules and fully replicated catenanes formed in vivo. The results obtained revealed the preferential functions and also some redundancy in the abilities of these DNA topoisomerases in vitro.
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Affiliation(s)
- Jorge Cebrián
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas (CSIC), 28040 Madrid, Spain; (J.C.); (P.H.); (D.B.K.); (J.B.S.)
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón, CIBERCV, 28040 Madrid, Spain
| | - Victor Martínez
- Bioinformatics Laboratory, Polytechnic School, National University of Asunción, San Lorenzo P.O. Box 2111, Paraguay;
| | - Pablo Hernández
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas (CSIC), 28040 Madrid, Spain; (J.C.); (P.H.); (D.B.K.); (J.B.S.)
| | - Dora B. Krimer
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas (CSIC), 28040 Madrid, Spain; (J.C.); (P.H.); (D.B.K.); (J.B.S.)
| | - María-José Fernández-Nestosa
- Bioinformatics Laboratory, Polytechnic School, National University of Asunción, San Lorenzo P.O. Box 2111, Paraguay;
- Correspondence:
| | - Jorge B. Schvartzman
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas (CSIC), 28040 Madrid, Spain; (J.C.); (P.H.); (D.B.K.); (J.B.S.)
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4
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Kumar R, Bahng S, Marians KJ. The MukB-topoisomerase IV interaction mutually suppresses their catalytic activities. Nucleic Acids Res 2021; 50:2621-2634. [PMID: 34747485 PMCID: PMC8934648 DOI: 10.1093/nar/gkab1027] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 10/11/2021] [Accepted: 10/13/2021] [Indexed: 02/05/2023] Open
Abstract
The bacterial condensin MukB and the cellular chromosomal decatenase, topoisomerase IV interact and this interaction is required for proper condensation and topological ordering of the chromosome. Here, we show that Topo IV stimulates MukB DNA condensation by stabilizing loops in DNA: MukB alone can condense nicked plasmid DNA into a protein–DNA complex that has greater electrophoretic mobility than that of the DNA alone, but both MukB and Topo IV are required for a similar condensation of a linear DNA representing long stretches of the chromosome. Remarkably, we show that rather than MukB stimulating the decatenase activity of Topo IV, as has been argued previously, in stoichiometric complexes of the two enzymes each inhibits the activity of the other: the ParC subunit of Topo IV inhibits the MukF-stimulated ATPase activity of MukB and MukB inhibits both DNA crossover trapping and DNA cleavage by Topo IV. These observations suggest that when in complex on the DNA, Topo IV inhibits the motor function of MukB and the two proteins provide a stable scaffold for chromosomal DNA condensation.
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Affiliation(s)
- Rupesh Kumar
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Soon Bahng
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Kenneth J Marians
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
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5
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Fisher GL, Bolla JR, Rajasekar KV, Mäkelä J, Baker R, Zhou M, Prince JP, Stracy M, Robinson CV, Arciszewska LK, Sherratt DJ. Competitive binding of MatP and topoisomerase IV to the MukB hinge domain. eLife 2021; 10:70444. [PMID: 34585666 PMCID: PMC8523169 DOI: 10.7554/elife.70444] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 09/21/2021] [Indexed: 11/13/2022] Open
Abstract
Structural Maintenance of Chromosomes (SMC) complexes have ubiquitous roles in compacting DNA linearly, thereby promoting chromosome organization-segregation. Interaction between the Escherichia coli SMC complex, MukBEF, and matS-bound MatP in the chromosome replication termination region, ter, results in depletion of MukBEF from ter, a process essential for efficient daughter chromosome individualization and for preferential association of MukBEF with the replication origin region. Chromosome-associated MukBEF complexes also interact with topoisomerase IV (ParC2E2), so that their chromosome distribution mirrors that of MukBEF. We demonstrate that MatP and ParC have an overlapping binding interface on the MukB hinge, leading to their mutually exclusive binding, which occurs with the same dimer to dimer stoichiometry. Furthermore, we show that matS DNA competes with the MukB hinge for MatP binding. Cells expressing MukBEF complexes that are mutated at the ParC/MatP binding interface are impaired in ParC binding and have a mild defect in MukBEF function. These data highlight competitive binding as a means of globally regulating MukBEF-topoisomerase IV activity in space and time.
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Affiliation(s)
- Gemma Lm Fisher
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Jani R Bolla
- Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, United Kingdom.,The Kavli Institute for Nanoscience Discovery, Oxford, United Kingdom
| | | | - Jarno Mäkelä
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Rachel Baker
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Man Zhou
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Josh P Prince
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Mathew Stracy
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Carol V Robinson
- Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, United Kingdom.,The Kavli Institute for Nanoscience Discovery, Oxford, United Kingdom
| | | | - David J Sherratt
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
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6
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Gogou C, Japaridze A, Dekker C. Mechanisms for Chromosome Segregation in Bacteria. Front Microbiol 2021; 12:685687. [PMID: 34220773 PMCID: PMC8242196 DOI: 10.3389/fmicb.2021.685687] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 05/19/2021] [Indexed: 11/13/2022] Open
Abstract
The process of DNA segregation, the redistribution of newly replicated genomic material to daughter cells, is a crucial step in the life cycle of all living systems. Here, we review DNA segregation in bacteria which evolved a variety of mechanisms for partitioning newly replicated DNA. Bacterial species such as Caulobacter crescentus and Bacillus subtilis contain pushing and pulling mechanisms that exert forces and directionality to mediate the moving of newly synthesized chromosomes to the bacterial poles. Other bacteria such as Escherichia coli lack such active segregation systems, yet exhibit a spontaneous de-mixing of chromosomes due to entropic forces as DNA is being replicated under the confinement of the cell wall. Furthermore, we present a synopsis of the main players that contribute to prokaryotic genome segregation. We finish with emphasizing the importance of bottom-up approaches for the investigation of the various factors that contribute to genome segregation.
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Affiliation(s)
- Christos Gogou
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, Netherlands
| | - Aleksandre Japaridze
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, Netherlands
| | - Cees Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, Netherlands
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7
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Kim S, Darcy IK. A topological analysis of difference topology experiments of condensin with topoisomerase II. Biol Open 2020; 9:bio048603. [PMID: 32184229 PMCID: PMC7132813 DOI: 10.1242/bio.048603] [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: 10/07/2019] [Accepted: 03/03/2020] [Indexed: 11/20/2022] Open
Abstract
An experimental technique called difference topology combined with the mathematics of tangle analysis has been used to unveil the structure of DNA bound by the Mu transpososome. However, difference topology experiments can be difficult and time consuming. We discuss a modification that greatly simplifies this experimental technique. This simple experiment involves using a topoisomerase to trap DNA crossings bound by a protein complex and then running a gel to determine the crossing number of the knotted product(s). We develop the mathematics needed to analyze the results and apply these results to model the topology of DNA bound by 13S condensin and by the condensin MukB.
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Affiliation(s)
- Soojeong Kim
- Yonsei University, University College, Incheon 21983, South Korea
| | - Isabel K Darcy
- Department of Mathematics, University of Iowa, Iowa City 52242, USA
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8
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Dewachter L, Verstraeten N, Fauvart M, Michiels J. An integrative view of cell cycle control in Escherichia coli. FEMS Microbiol Rev 2018; 42:116-136. [PMID: 29365084 DOI: 10.1093/femsre/fuy005] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 01/19/2018] [Indexed: 11/14/2022] Open
Abstract
Bacterial proliferation depends on the cells' capability to proceed through consecutive rounds of the cell cycle. The cell cycle consists of a series of events during which cells grow, copy their genome, partition the duplicated DNA into different cell halves and, ultimately, divide to produce two newly formed daughter cells. Cell cycle control is of the utmost importance to maintain the correct order of events and safeguard the integrity of the cell and its genomic information. This review covers insights into the regulation of individual key cell cycle events in Escherichia coli. The control of initiation of DNA replication, chromosome segregation and cell division is discussed. Furthermore, we highlight connections between these processes. Although detailed mechanistic insight into these connections is largely still emerging, it is clear that the different processes of the bacterial cell cycle are coordinated to one another. This careful coordination of events ensures that every daughter cell ends up with one complete and intact copy of the genome, which is vital for bacterial survival.
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Affiliation(s)
- Liselot Dewachter
- Centre of Microbial and Plant Genetics, KU Leuven-University of Leuven, B-3001 Leuven, Belgium.,VIB Center for Microbiology, B-3001 Leuven, Belgium
| | - Natalie Verstraeten
- Centre of Microbial and Plant Genetics, KU Leuven-University of Leuven, B-3001 Leuven, Belgium.,VIB Center for Microbiology, B-3001 Leuven, Belgium
| | - Maarten Fauvart
- Centre of Microbial and Plant Genetics, KU Leuven-University of Leuven, B-3001 Leuven, Belgium.,VIB Center for Microbiology, B-3001 Leuven, Belgium.,Department of Life Sciences and Imaging, Smart Electronics Unit, imec, B-3001 Leuven, Belgium
| | - Jan Michiels
- Centre of Microbial and Plant Genetics, KU Leuven-University of Leuven, B-3001 Leuven, Belgium.,VIB Center for Microbiology, B-3001 Leuven, Belgium
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9
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Zawadzka K, Zawadzki P, Baker R, Rajasekar KV, Wagner F, Sherratt DJ, Arciszewska LK. MukB ATPases are regulated independently by the N- and C-terminal domains of MukF kleisin. eLife 2018; 7:31522. [PMID: 29323635 PMCID: PMC5812716 DOI: 10.7554/elife.31522] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 01/10/2018] [Indexed: 12/21/2022] Open
Abstract
The Escherichia coli SMC complex, MukBEF, acts in chromosome segregation. MukBEF shares the distinctive architecture of other SMC complexes, with one prominent difference; unlike other kleisins, MukF forms dimers through its N-terminal domain. We show that a 4-helix bundle adjacent to the MukF dimerisation domain interacts functionally with the MukB coiled-coiled ‘neck’ adjacent to the ATPase head. We propose that this interaction leads to an asymmetric tripartite complex, as in other SMC complexes. Since MukF dimerisation is preserved during this interaction, MukF directs the formation of dimer of dimer MukBEF complexes, observed previously in vivo. The MukF N- and C-terminal domains stimulate MukB ATPase independently and additively. We demonstrate that impairment of the MukF interaction with MukB in vivo leads to ATP hydrolysis-dependent release of MukBEF complexes from chromosomes. Most DNA in a cell is arranged in structures called chromosomes. From bacteria to humans, chromosomes have to be compacted and highly organized to allow the cells to maintain and use their genetic information. In all organisms, large ring-shaped protein complexes play a crucial role in managing chromosomes. They transport and organize DNA thanks to reactions whose precise mechanism remains unknown. In bacteria, MukB and a type of kleisin called MukF are two examples of molecules involved in chromosome management. Two MukBs join at one end to form a hinge; at the other end, each MukB protein has a neck and a head. The two heads are linked by the kleisin to form a large protein ring, which can open to capture DNA. The MukB heads can trigger a biochemical reaction that creates the energy essential to trap and release DNA during DNA transport. Here, Zawadzka et al. study how the different components of the MukB-kleisin complex interact with each other to undergo the biochemical reactions that lead to DNA transport. The experiments show that the kleisin joins two MukB heads by attaching the base of one to the neck of the other, asymmetrically closing the ring. The separate interactions of different regions of the kleisin to the head and neck of MukB independently activate the two MukB heads, thereby controlling essential steps in the reactions with DNA. Two MukB-kleisin ring complexes are joined to each other because of a tight interaction between the two kleisin molecules. This leads Zawadzka et al. to suggest that DNA is sequentially grabbed and released from these two rings during DNA transport, similar to how a climbing rope is attached and released through carabiners. Cells cannot survive or be healthy without their chromosomes being accurately managed. It is still unclear how molecules such as MukBs and kleinsins drive this process. A better picture of their structure and interactions is an essential first step to understand these mechanisms.
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Affiliation(s)
- Katarzyna Zawadzka
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Pawel Zawadzki
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Rachel Baker
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | | | - Florence Wagner
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - David J Sherratt
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
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10
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Piskadlo E, Oliveira RA. A Topology-Centric View on Mitotic Chromosome Architecture. Int J Mol Sci 2017; 18:E2751. [PMID: 29258269 PMCID: PMC5751350 DOI: 10.3390/ijms18122751] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 12/14/2017] [Accepted: 12/15/2017] [Indexed: 02/04/2023] Open
Abstract
Mitotic chromosomes are long-known structures, but their internal organization and the exact process by which they are assembled are still a great mystery in biology. Topoisomerase II is crucial for various aspects of mitotic chromosome organization. The unique ability of this enzyme to untangle topologically intertwined DNA molecules (catenations) is of utmost importance for the resolution of sister chromatid intertwines. Although still controversial, topoisomerase II has also been proposed to directly contribute to chromosome compaction, possibly by promoting chromosome self-entanglements. These two functions raise a strong directionality issue towards topoisomerase II reactions that are able to disentangle sister DNA molecules (in trans) while compacting the same DNA molecule (in cis). Here, we review the current knowledge on topoisomerase II role specifically during mitosis, and the mechanisms that directly or indirectly regulate its activity to ensure faithful chromosome segregation. In particular, we discuss how the activity or directionality of this enzyme could be regulated by the SMC (structural maintenance of chromosomes) complexes, predominantly cohesin and condensin, throughout mitosis.
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Affiliation(s)
- Ewa Piskadlo
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal.
| | - Raquel A Oliveira
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal.
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11
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Kumar R, Grosbart M, Nurse P, Bahng S, Wyman CL, Marians KJ. The bacterial condensin MukB compacts DNA by sequestering supercoils and stabilizing topologically isolated loops. J Biol Chem 2017; 292:16904-16920. [PMID: 28842486 PMCID: PMC5641887 DOI: 10.1074/jbc.m117.803312] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 08/14/2017] [Indexed: 11/06/2022] Open
Abstract
MukB is a structural maintenance of chromosome-like protein required for DNA condensation. The complete condensin is a large tripartite complex of MukB, the kleisin, MukF, and an accessory protein, MukE. As found previously, MukB DNA condensation is a stepwise process. We have defined these steps topologically. They proceed first via the formation of negative supercoils that are sequestered by the protein followed by hinge-hinge interactions between MukB dimers that stabilize topologically isolated loops in the DNA. MukB itself is sufficient to mediate both of these topological alterations; neither ATP nor MukEF is required. We show that the MukB hinge region binds DNA and that this region of the protein is involved in sequestration of supercoils. Cells carrying mutations in the MukB hinge that reduce DNA condensation in vitro exhibit nucleoid decondensation in vivo.
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Affiliation(s)
- Rupesh Kumar
- From the Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065 and
| | | | - Pearl Nurse
- From the Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065 and
| | - Soon Bahng
- From the Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065 and
| | - Claire L Wyman
- the Departments of Molecular Genetics and
- Radiation Oncology, Erasmus University Medical Center, P. O. Box 2040, 3000CA Rotterdam, The Netherlands
| | - Kenneth J Marians
- From the Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065 and
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12
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Kumar R, Nurse P, Bahng S, Lee CM, Marians KJ. The MukB-topoisomerase IV interaction is required for proper chromosome compaction. J Biol Chem 2017; 292:16921-16932. [PMID: 28842485 DOI: 10.1074/jbc.m117.803346] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 08/14/2017] [Indexed: 11/06/2022] Open
Abstract
The bacterial condensin MukB and the cellular decatenating enzyme topoisomerase IV interact. This interaction stimulates intramolecular reactions catalyzed by topoisomerase IV, supercoiled DNA relaxation, and DNA knotting but not intermolecular reactions such as decatenation of linked DNAs. We have demonstrated previously that MukB condenses DNA by sequestering negative supercoils and stabilizing topologically isolated loops in the DNA. We show here that the MukB-topoisomerase IV interaction stabilizes MukB on DNA, increasing the extent of DNA condensation without increasing the amount of MukB bound to the DNA. This effect does not require the catalytic activity of topoisomerase IV. Cells carrying a mukB mutant allele that encodes a protein that does not interact with topoisomerase IV exhibit severe nucleoid decompaction leading to chromosome segregation defects. These findings suggest that the MukB-topoisomerase IV complex may provide a scaffold for DNA condensation.
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Affiliation(s)
- Rupesh Kumar
- From the Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065
| | - Pearl Nurse
- From the Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065
| | - Soon Bahng
- From the Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065
| | - Chong M Lee
- From the Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065
| | - Kenneth J Marians
- From the Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065
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13
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Bahng S, Hayama R, Marians KJ. MukB-mediated Catenation of DNA Is ATP and MukEF Independent. J Biol Chem 2016; 291:23999-24008. [PMID: 27697840 DOI: 10.1074/jbc.m116.749994] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 09/21/2016] [Indexed: 01/07/2023] Open
Abstract
Properly condensed chromosomes are necessary for accurate segregation of the sisters after DNA replication. The Escherichia coli condesin is MukB, a structural maintenance of chromosomes (SMC)-like protein, which forms a complex with MukE and the kleisin MukF. MukB is known to be able to mediate knotting of a DNA ring, an intramolecular reaction. In our investigations of how MukB condenses DNA we discovered that it can also mediate catenation of two DNA rings, an intermolecular reaction. This activity of MukB requires DNA binding by the head domains of the protein but does not require either ATP or its partner proteins MukE or MukF. The ability of MukB to mediate DNA catenation underscores its potential for bringing distal regions of a chromosome together.
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Affiliation(s)
- Soon Bahng
- From the Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065
| | - Ryo Hayama
- From the Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065
| | - Kenneth J Marians
- From the Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065
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14
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El Sayyed H, Le Chat L, Lebailly E, Vickridge E, Pages C, Cornet F, Cosentino Lagomarsino M, Espéli O. Mapping Topoisomerase IV Binding and Activity Sites on the E. coli Genome. PLoS Genet 2016; 12:e1006025. [PMID: 27171414 PMCID: PMC4865107 DOI: 10.1371/journal.pgen.1006025] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 04/11/2016] [Indexed: 11/27/2022] Open
Abstract
Catenation links between sister chromatids are formed progressively during DNA replication and are involved in the establishment of sister chromatid cohesion. Topo IV is a bacterial type II topoisomerase involved in the removal of catenation links both behind replication forks and after replication during the final separation of sister chromosomes. We have investigated the global DNA-binding and catalytic activity of Topo IV in E. coli using genomic and molecular biology approaches. ChIP-seq revealed that Topo IV interaction with the E. coli chromosome is controlled by DNA replication. During replication, Topo IV has access to most of the genome but only selects a few hundred specific sites for its activity. Local chromatin and gene expression context influence site selection. Moreover strong DNA-binding and catalytic activities are found at the chromosome dimer resolution site, dif, located opposite the origin of replication. We reveal a physical and functional interaction between Topo IV and the XerCD recombinases acting at the dif site. This interaction is modulated by MatP, a protein involved in the organization of the Ter macrodomain. These results show that Topo IV, XerCD/dif and MatP are part of a network dedicated to the final step of chromosome management during the cell cycle. DNA topoisomerases are ubiquitous enzymes that solve the topological problems associated with replication, transcription and recombination. Type II Topoisomerases play a major role in the management of newly replicated DNA. They contribute to the condensation and segregation of chromosomes to the future daughter cells and are essential for the optimal transmission of genetic information. In most bacteria, including the model organism Escherichia coli, these tasks are performed by two enzymes, DNA gyrase and DNA Topoisomerase IV (Topo IV). The distribution of the roles between these enzymes during the cell cycle is not yet completely understood. In the present study we use genomic and molecular biology methods to decipher the regulation of Topo IV during the cell cycle. Here we present data that strongly suggest the interaction of Topo IV with the chromosome is controlled by DNA replication and chromatin factors responsible for its loading to specific regions of the chromosome. In addition, our observations reveal, that by sharing several key factors, the DNA management processes ensuring accuracy of the late steps of chromosome segregation are all interconnected.
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Affiliation(s)
- Hafez El Sayyed
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, UMR-CNRS 7241, Paris, France
- Université Paris–Saclay, Gif-sur-Yvette, France
| | - Ludovic Le Chat
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, UMR-CNRS 7241, Paris, France
| | - Elise Lebailly
- Laboratoire de Microbiologie et de Génétique Moléculaires (LMGM), CNRS-Université Toulouse III, Toulouse, France
| | - Elise Vickridge
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, UMR-CNRS 7241, Paris, France
- Université Paris–Saclay, Gif-sur-Yvette, France
| | - Carine Pages
- Laboratoire de Microbiologie et de Génétique Moléculaires (LMGM), CNRS-Université Toulouse III, Toulouse, France
| | - Francois Cornet
- Laboratoire de Microbiologie et de Génétique Moléculaires (LMGM), CNRS-Université Toulouse III, Toulouse, France
| | | | - Olivier Espéli
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, UMR-CNRS 7241, Paris, France
- * E-mail:
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15
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Abstract
SMC (structural maintenance of chromosomes) complexes - which include condensin, cohesin and the SMC5-SMC6 complex - are major components of chromosomes in all living organisms, from bacteria to humans. These ring-shaped protein machines, which are powered by ATP hydrolysis, topologically encircle DNA. With their ability to hold more than one strand of DNA together, SMC complexes control a plethora of chromosomal activities. Notable among these are chromosome condensation and sister chromatid cohesion. Moreover, SMC complexes have an important role in DNA repair. Recent mechanistic insight into the function and regulation of these universal chromosomal machines enables us to propose molecular models of chromosome structure, dynamics and function, illuminating one of the fundamental entities in biology.
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16
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MatP regulates the coordinated action of topoisomerase IV and MukBEF in chromosome segregation. Nat Commun 2016; 7:10466. [PMID: 26818444 PMCID: PMC4738335 DOI: 10.1038/ncomms10466] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 12/11/2015] [Indexed: 01/08/2023] Open
Abstract
The Escherichia coli SMC complex, MukBEF, forms clusters of molecules that interact with the decatenase topisomerase IV and which are normally associated with the chromosome replication origin region (ori). Here we demonstrate an additional ATP-hydrolysis-dependent association of MukBEF with the replication termination region (ter). Consistent with this, MukBEF interacts with MatP, which binds matS sites in ter. MatP displaces wild-type MukBEF complexes from ter, thereby facilitating their association with ori, and limiting the availability of topoisomerase IV (TopoIV) at ter. Displacement of MukBEF is impaired when MukB ATP hydrolysis is compromised and when MatP is absent, leading to a stable association of ter and MukBEF. Impairing the TopoIV-MukBEF interaction delays sister ter segregation in cells lacking MatP. We propose that the interplay between MukBEF and MatP directs chromosome organization in relation to MukBEF clusters and associated topisomerase IV, thereby ensuring timely chromosome unlinking and segregation. MukBEF, the bacterial structural maintenance of chromosomes complex, is known to associate with origins of replication and topoisomerase IV. Here the authors show an association of MukBEF with MatP and replication termination regions, important for proper sister chromatid decatenation and segregation.
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17
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The Localization and Action of Topoisomerase IV in Escherichia coli Chromosome Segregation Is Coordinated by the SMC Complex, MukBEF. Cell Rep 2015; 13:2587-2596. [PMID: 26686641 PMCID: PMC5061553 DOI: 10.1016/j.celrep.2015.11.034] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 10/23/2015] [Accepted: 11/10/2015] [Indexed: 01/15/2023] Open
Abstract
The type II topoisomerase TopoIV, which has an essential role in Escherichia coli chromosome decatenation, interacts with MukBEF, an SMC (structural maintenance of chromosomes) complex that acts in chromosome segregation. We have characterized the intracellular dynamics of individual TopoIV molecules and the consequences of their interaction with MukBEF clusters by using photoactivated-localization microscopy. We show that ∼15 TopoIV molecules per cell are associated with MukBEF clusters that are preferentially localized to the replication origin region (ori), close to the long axis of the cell. A replication-dependent increase in the fraction of immobile molecules, together with a proposed catalytic cycle of ∼1.8 s, is consistent with the majority of active TopoIV molecules catalyzing decatenation, with a minority maintaining steady-state DNA supercoiling. Finally, we show that the MukB-ParC interaction is crucial for timely decatenation and segregation of newly replicated ori DNA. Individual molecules of topoisomerase IV (TopoIV) were tracked in live E. coli cells TopoIV was monitored in cellular space and in time throughout the cell cycle The interaction of TopoIV and MukBEF directs TopoIV to its sites of action The TopoIV-MukBEF interaction promotes timely segregation of newly replicated DNA
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18
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Narayanan S, Janakiraman B, Kumar L, Radhakrishnan SK. A cell cycle-controlled redox switch regulates the topoisomerase IV activity. Genes Dev 2015; 29:1175-87. [PMID: 26063575 PMCID: PMC4470285 DOI: 10.1101/gad.257030.114] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Narayanan et al. show in C. crescentus that NstA acts by binding to the ParC DNA-binding subunit of topoisomerase IV and inhibits its decatenation activity. They also uncover a dynamic oscillation of the intracellular redox state during the cell cycle, which correlates with and controls NstA activity. Topoisomerase IV (topo IV), an essential factor during chromosome segregation, resolves the catenated chromosomes at the end of each replication cycle. How the decatenating activity of the topo IV is regulated during the early stages of the chromosome cycle despite being in continuous association with the chromosome remains poorly understood. Here we report a novel cell cycle-regulated protein in Caulobacter crescentus, NstA (negative switch for topo IV decatenation activity), that inhibits the decatenation activity of the topo IV during early stages of the cell cycle. We demonstrate that in C. crescentus, NstA acts by binding to the ParC DNA-binding subunit of topo IV. Most importantly, we uncover a dynamic oscillation of the intracellular redox state during the cell cycle, which correlates with and controls NstA activity. Thus, we propose that predetermined dynamic intracellular redox fluctuations may act as a global regulatory switch to control cellular development and cell cycle progression and may help retain pathogens in a suitable cell cycle state when encountering redox stress from the host immune response.
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Affiliation(s)
- Sharath Narayanan
- School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram 695016, Kerala, India
| | - Balaganesh Janakiraman
- School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram 695016, Kerala, India
| | - Lokesh Kumar
- School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram 695016, Kerala, India
| | - Sunish Kumar Radhakrishnan
- School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram 695016, Kerala, India
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19
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Rybenkov VV, Herrera V, Petrushenko ZM, Zhao H. MukBEF, a chromosomal organizer. J Mol Microbiol Biotechnol 2015; 24:371-83. [PMID: 25732339 DOI: 10.1159/000369099] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Global folding of bacterial chromosome requires the activity of condensins. These highly conserved proteins are involved in various aspects of higher-order chromatin dynamics in a diverse range of organisms. Two distinct superfamilies of condensins have been identified in bacteria. The SMC-ScpAB proteins bear significant homology to eukaryotic condensins and cohesins and are found in most of the presently sequenced bacteria. This review focuses on the MukBEF/MksBEF superfamily, which is broadly distributed across diverse bacteria and is characterized by low sequence conservation. The prototypical member of this superfamily, the Escherichia coli condensin MukBEF, continues to provide critical insights into the mechanism of the proteins. MukBEF acts as a complex molecular machine that assists in chromosome segregation and global organization. The review focuses on the mechanistic analysis of DNA organization by MukBEF with emphasis on its involvement in the formation of chromatin scaffold and plausible other roles in chromosome segregation.
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Affiliation(s)
- Valentin V Rybenkov
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Okla., USA
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20
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Adachi S, Murakawa Y, Hiraga S. Dynamic nature of SecA and its associated proteins in Escherichia coli. Front Microbiol 2015; 6:75. [PMID: 25713567 PMCID: PMC4322705 DOI: 10.3389/fmicb.2015.00075] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 01/21/2015] [Indexed: 11/13/2022] Open
Abstract
Mechanical properties such as physical constraint and pushing of chromosomes are thought to be important for chromosome segregation in Escherichia coli and it could be mediated by a hypothetical molecular "tether." However, the actual tether that mediates these features is not known. We previously described that SecA (Secretory A) and Secretory Y (SecY), components of the membrane protein translocation machinery, and AcpP (Acyl carrier protein P) were involved in chromosome segregation and homeostasis of DNA topology. In the present work, we performed three-dimensional deconvolution of microscopic images and time-lapse experiments of these proteins together with MukB and DNA topoisomerases, and found that these proteins embraced the structures of tortuous nucleoids with condensed regions. Notably, SecA, SecY, and AcpP dynamically localized in cells, which was interdependent on each other requiring the ATPase activity of SecA. Our findings imply that the membrane protein translocation machinery plays a role in the maintenance of proper chromosome partitioning, possibly through "tethering" of MukB [a functional homolog of structural maintenance of chromosomes (SMC) proteins], DNA gyrase, DNA topoisomerase IV, and SeqA (Sequestration A).
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Affiliation(s)
- Shun Adachi
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University Kyoto, Japan
| | - Yasuhiro Murakawa
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University Kyoto, Japan
| | - Sota Hiraga
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University Kyoto, Japan
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21
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Abstract
A cell can be thought of as a highly sophisticated micro factory: in a pool of billions of molecules - metabolites, structural proteins, enzymes, oligonucleotides - multi-subunit complexes assemble to perform a large number of basic cellular tasks, such as DNA replication, RNA/protein synthesis or intracellular transport. By purifying single components and using them to reconstitute molecular processes in a test tube, researchers have gathered crucial knowledge about mechanistic, dynamic and structural properties of biochemical pathways. However, to sort this information into an accurate cellular road map, we need to understand reactions in their relevant context within the cellular hierarchy, which is at the individual molecule level within a crowded, cellular environment. Reactions occur in a stochastic fashion, have short-lived and not necessarily well-defined intermediates, and dynamically form functional entities. With the use of single-molecule techniques these steps can be followed and detailed kinetic information that otherwise would be hidden in ensemble averaging can be obtained. One of the first complex cellular tasks that have been studied at the single-molecule level is the replication of DNA. The replisome, the multi-protein machinery responsible for copying DNA, is built from a large number of proteins that function together in an intricate and efficient fashion allowing the complex to tolerate DNA damage, roadblocks or fluctuations in subunit concentration. In this review, we summarize advances in single-molecule studies, both in vitro and in vivo, that have contributed to our current knowledge of the mechanistic principles underlying DNA replication.
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Affiliation(s)
- S A Stratmann
- Zernike Institute for Advanced Materials, Centre for Synthetic Biology, University of Groningen, The Netherlands.
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22
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Adachi S, Murakawa Y, Hiraga S. SecA defects are accompanied by dysregulation of MukB, DNA gyrase, chromosome partitioning and DNA superhelicity in Escherichia coli. MICROBIOLOGY-SGM 2014; 160:1648-1658. [PMID: 24858081 DOI: 10.1099/mic.0.077685-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Spatial regulation of nucleoids and chromosome-partitioning proteins is important for proper chromosome partitioning in Escherichia coli. However, the underlying molecular mechanisms are unknown. In the present work, we showed that mutation or chemical perturbation of secretory A (SecA), an ATPase component of the membrane protein translocation machinery, SecY, a component of the membrane protein translocation channel and acyl carrier protein P (AcpP), which binds to SecA and MukB, a functional homologue of structural maintenance of chromosomes protein (SMC), resulted in a defect in chromosome partitioning. We further showed that SecA is essential for proper positioning of the oriC DNA region, decatenation and maintenance of superhelicity of DNA. Genetic interaction studies revealed that the topological abnormality observed in the secA mutant was due to combined inhibitory effects of defects in MukB, DNA gyrase and Topo IV, suggesting a role for the membrane protein translocation machinery in chromosome partitioning and/or structural maintenance of chromosomes.
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Affiliation(s)
- Shun Adachi
- Medical Research Project, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima 770-8503, Japan.,Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Konoe-cho, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yasuhiro Murakawa
- Max Delbrück Center for Molecular Medicine Berlin-Buch, Robert-Rössle-Str. 10, 13125 Berlin, Germany.,Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Konoe-cho, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan
| | - Sota Hiraga
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Konoe-cho, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan
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23
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The SMC complex MukBEF recruits topoisomerase IV to the origin of replication region in live Escherichia coli. mBio 2014; 5:e01001-13. [PMID: 24520061 PMCID: PMC3950513 DOI: 10.1128/mbio.01001-13] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The Escherichia coli structural maintenance of chromosome (SMC) complex, MukBEF, and topoisomerase IV (TopoIV) interact in vitro through a direct contact between the MukB dimerization hinge and the C-terminal domain of ParC, the catalytic subunit of TopoIV. The interaction stimulates catalysis by TopoIV in vitro. Using live-cell quantitative imaging, we show that MukBEF directs TopoIV to ori, with fluorescent fusions of ParC and ParE both forming cellular foci that colocalize with those formed by MukBEF throughout the cell cycle and in cells unable to initiate DNA replication. Removal of MukBEF leads to loss of fluorescent ParC/ParE foci. In the absence of functional TopoIV, MukBEF forms multiple foci that are distributed uniformly throughout the nucleoid, whereas multiple catenated oris cluster at midcell. Once functional TopoIV is restored, the decatenated oris segregate to positions that are largely coincident with the MukBEF foci, thereby providing support for a mechanism by which MukBEF acts in chromosome segregation by positioning newly replicated and decatenated oris. Additional evidence for such a mechanism comes from the observation that in TopoIV-positive (TopoIV(+)) cells, newly replicated oris segregate rapidly to the positions of MukBEF foci. Taken together, the data implicate MukBEF as a key component of the DNA segregation process by acting in concert with TopoIV to promote decatenation and positioning of newly replicated oris. IMPORTANCE Mechanistic understanding of how newly replicated bacterial chromosomes are segregated prior to cell division is incomplete. In this work, we provide in vivo experimental support for the view that topoisomerase IV (TopoIV), which decatenates newly replicated sister duplexes as a prelude to successful segregation, is directed to the replication origin region of the Escherichia coli chromosome by the SMC (structural maintenance of chromosome) complex, MukBEF. We provide in vivo data that support the demonstration in vitro that the MukB interaction with TopoIV stimulates catalysis by TopoIV. Finally, we show that MukBEF directs the normal positioning of sister origins after their replication and during their segregation. Overall, the data support models in which the coordinate and sequential action of TopoIV and MukBEF plays an important role during bacterial chromosome segregation.
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24
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Wang X, Tang OW, Riley EP, Rudner DZ. The SMC condensin complex is required for origin segregation in Bacillus subtilis. Curr Biol 2014; 24:287-92. [PMID: 24440393 DOI: 10.1016/j.cub.2013.11.050] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 11/11/2013] [Accepted: 11/26/2013] [Indexed: 01/21/2023]
Abstract
SMC condensin complexes play a central role in organizing and compacting chromosomes in all domains of life [1, 2]. In the bacterium Bacillus subtilis, cells lacking SMC are viable only during slow growth and display decondensed chromosomes, suggesting that SMC complexes function throughout the genome [3, 4]. Here, we show that rapid inactivation of SMC or its partner protein ScpB during fast growth leads to a failure to resolve newly replicated origins and a complete block to chromosome segregation. Importantly, the loss of origin segregation is not due to an inability to unlink precatenated sister chromosomes by Topoisomerase IV. In support of the idea that ParB-mediated recruitment of SMC complexes to the origin is important for their segregation, cells with reduced levels of SMC that lack ParB are severely impaired in origin resolution. Finally, we demonstrate that origin segregation is a task shared by the condensin complex and the parABS partitioning system. We propose that origin-localized SMC constrains adjacent DNA segments along their lengths, drawing replicated origins in on themselves and away from each other. This SMC-mediated lengthwise condensation, bolstered by the parABS system, drives origin segregation.
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Affiliation(s)
- Xindan Wang
- Department of Microbiology and Immunobiology, Harvard Medical School, 77 Avenue Louis Pasteur, Boston MA 02115, USA
| | - Olive W Tang
- Department of Microbiology and Immunobiology, Harvard Medical School, 77 Avenue Louis Pasteur, Boston MA 02115, USA
| | - Eammon P Riley
- Department of Microbiology and Immunobiology, Harvard Medical School, 77 Avenue Louis Pasteur, Boston MA 02115, USA
| | - David Z Rudner
- Department of Microbiology and Immunobiology, Harvard Medical School, 77 Avenue Louis Pasteur, Boston MA 02115, USA.
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25
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Charbin A, Bouchoux C, Uhlmann F. Condensin aids sister chromatid decatenation by topoisomerase II. Nucleic Acids Res 2014; 42:340-8. [PMID: 24062159 PMCID: PMC3874195 DOI: 10.1093/nar/gkt882] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 09/06/2013] [Accepted: 09/09/2013] [Indexed: 11/14/2022] Open
Abstract
The condensin complex is a key determinant of mitotic chromosome architecture. In addition, condensin promotes resolution of sister chromatids during anaphase, a function that is conserved from prokaryotes to human. Anaphase bridges observed in cells lacking condensin are reminiscent of chromosome segregation failure after inactivation of topoisomerase II (topo II), the enzyme that removes catenanes persisting between sister chromatids following DNA replication. Circumstantial evidence has linked condensin to sister chromatid decatenation but, because of the difficulty of observing chromosome catenation, this link has remained indirect. Alternative models for how condensin facilitates chromosome resolution have been put forward. Here, we follow the catenation status of circular minichromosomes of three sizes during the Saccharomyeces cerevisiae cell cycle. Catenanes are produced during DNA replication and are for the most part swiftly resolved during and following S-phase, aided by sister chromatid separation. Complete resolution, however, requires the condensin complex, a dependency that becomes more pronounced with increasing chromosome size. Our results provide evidence that condensin prevents deleterious anaphase bridges during chromosome segregation by promoting sister chromatid decatenation.
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Affiliation(s)
- Adrian Charbin
- Chromosome Segregation Laboratory, Cancer Research UK London Research Institute, London WC2A 3LY, UK
| | - Céline Bouchoux
- Chromosome Segregation Laboratory, Cancer Research UK London Research Institute, London WC2A 3LY, UK
| | - Frank Uhlmann
- Chromosome Segregation Laboratory, Cancer Research UK London Research Institute, London WC2A 3LY, UK
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26
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Vos SM, Stewart NK, Oakley MG, Berger JM. Structural basis for the MukB-topoisomerase IV interaction and its functional implications in vivo. EMBO J 2013; 32:2950-62. [PMID: 24097060 PMCID: PMC3832749 DOI: 10.1038/emboj.2013.218] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Accepted: 09/11/2013] [Indexed: 01/07/2023] Open
Abstract
Chromosome partitioning in Escherichia coli is assisted by two interacting proteins, topoisomerase (topo) IV and MukB. MukB stimulates the relaxation of negative supercoils by topo IV; to understand the mechanism of their action and to define this functional interplay, we determined the crystal structure of a minimal MukB-topo IV complex to 2.3 Å resolution. The structure shows that the so-called 'hinge' region of MukB forms a heterotetrameric assembly with a C-terminal DNA binding domain (CTD) on topo IV's ParC subunit. Biochemical studies show that the hinge stimulates topo IV by competing for a site on the CTD that normally represses activity on negatively supercoiled DNA, while complementation tests using mutants implicated in the interaction reveal that the cellular dependency on topo IV derives from a joint need for both strand passage and MukB binding. Interestingly, the configuration of the MukB·topo IV complex sterically disfavours intradimeric interactions, indicating that the proteins may form oligomeric arrays with one another, and suggesting a framework by which MukB and topo IV may collaborate during daughter chromosome disentanglement.
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Affiliation(s)
- Seychelle M Vos
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | | | - Martha G Oakley
- Department of Chemistry, Indiana University, Bloomington, IN, USA
| | - James M Berger
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA,Department of Molecular and Cell Biology, California Institute of Quantitative Biosciences, University of California at Berkeley, 374D Stanley Hall, Berkeley, CA 94720, USA. Tel.:+1 510 643 9483; Fax:+1 510 666 2768; E-mail:
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27
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Vos SM, Lee I, Berger JM. Distinct regions of the Escherichia coli ParC C-terminal domain are required for substrate discrimination by topoisomerase IV. J Mol Biol 2013; 425:3029-45. [PMID: 23867279 DOI: 10.1016/j.jmb.2013.04.033] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 04/14/2013] [Accepted: 04/16/2013] [Indexed: 11/16/2022]
Abstract
Type IIA DNA topoisomerases are essential enzymes that use ATP to maintain chromosome supercoiling and remove links between sister chromosomes. In Escherichia coli, the type IIA topoisomerase topo IV rapidly removes positive supercoils and catenanes from DNA but is significantly slower when confronted with negatively supercoiled substrates. The ability of topo IV to discriminate between positively and negatively supercoiled DNA requires the C-terminal domain (CTD) of one of its two subunits, ParC. To determine how the ParC CTD might assist with substrate discrimination, we identified potential DNA interacting residues on the surface of the CTD, mutated these residues, and tested their effect on both topo IV enzymatic activity and DNA binding by the isolated domain. Surprisingly, different regions of the ParC CTD do not bind DNA equivalently, nor contribute equally to the action of topo IV on different types of DNA substrates. Moreover, we find that the CTD contains an autorepressive element that inhibits activity on negatively supercoiled and catenated substrates, as well as a distinct region that aids in bending the DNA duplex that tracks through the enzyme's nucleolytic center. Our data demonstrate that the CTD is essential for proper engagement of both gate and transfer segment DNAs, reconciling different models to explain how topo IV discriminates between distinct DNAs topologies.
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Affiliation(s)
- Seychelle M Vos
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
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