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Herrick J, Norris V, Kohiyama M. 60 Years of Studies into the Initiation of Chromosome Replication in Bacteria. Biomolecules 2025; 15:203. [PMID: 40001506 PMCID: PMC11853086 DOI: 10.3390/biom15020203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2024] [Revised: 01/20/2025] [Accepted: 01/26/2025] [Indexed: 02/27/2025] Open
Abstract
The Replicon Theory has guided the way experiments into DNA replication have been designed and interpreted for 60 years. As part of the related, explanatory package guiding experiments, it is thought that the timing of the cell cycle depends in some way on a critical mass for initiation, Mi, as licensed by a variety of macromolecules and molecules reflecting the state of the cell. To help in the re-interpretation of this data, we focus mainly on the roles of DnaA, RNA polymerase, SeqA, and ribonucleotide reductase in the context of the "nucleotypic effect".
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Affiliation(s)
- John Herrick
- Independent Researcher, 3 rue des Jeûneurs, 75002 Paris, France;
| | - Vic Norris
- Laboratory of Bacterial Communication and Anti-Infection Strategies, EA 4312, University of Rouen, 76000 Rouen, France
| | - Masamichi Kohiyama
- Université Paris Cité, CNRS, Institut Jacques Monod, 75013 Paris, France;
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2
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Kasho K, Miyoshi K, Yoshida M, Sakai R, Nakagawa S, Katayama T. Negative DNA supercoiling enhances DARS2 binding of DNA-bending protein IHF in the activation of Fis-dependent ATP-DnaA production. Nucleic Acids Res 2025; 53:gkae1291. [PMID: 39797733 PMCID: PMC11724364 DOI: 10.1093/nar/gkae1291] [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: 08/09/2024] [Revised: 12/13/2024] [Accepted: 12/19/2024] [Indexed: 01/13/2025] Open
Abstract
Oscillation of the active form of the initiator protein DnaA (ATP-DnaA) allows for the timely regulation for chromosome replication. After initiation, DnaA-bound ATP is hydrolyzed, producing inactive ADP-DnaA. For the next round of initiation, ADP-DnaA interacts with the chromosomal locus DARS2 bearing binding sites for DnaA, a DNA-bending protein IHF, and a transcription activator Fis. The IHF binding site is about equidistant between the DnaA and Fis binding sites within DARS2. The DARS2-IHF-Fis complex promotes ADP dissociation from DnaA and furnishes ATP-DnaA at the pre-initiation stage, which dissociates Fis in a negative-feedback manner. However, regulation for IHF binding as well as mechanistic roles of Fis and specific DNA structure at DARS2 remain largely unknown. We have discovered that negative DNA supercoiling of DARS2 is required for stimulating IHF binding and ADP dissociation from DnaA in vitro. Consistent with these, novobiocin, a DNA gyrase inhibitor, inhibits DARS2 function in vivo. Fis Gln68, an RNA polymerase-interaction site, is suggested to be required for interaction with DnaA and full DARS2 activation. Based on these and other results, we propose that DNA supercoiling activates DARS2 function by stimulating stable IHF binding and DNA loop formation, thereby directing specific Fis-DnaA interaction.
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Affiliation(s)
- Kazutoshi Kasho
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Kenya Miyoshi
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Mizuki Yoshida
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Ryuji Sakai
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Sho Nakagawa
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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3
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Kasho K, Sakai R, Ito K, Nakagaki W, Satomura R, Jinnouchi T, Ozaki S, Katayama T. Read-through transcription of tRNA underlies the cell cycle-dependent dissociation of IHF from the DnaA-inactivating sequence datA. Front Microbiol 2024; 15:1360108. [PMID: 38505555 PMCID: PMC10950094 DOI: 10.3389/fmicb.2024.1360108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 02/05/2024] [Indexed: 03/21/2024] Open
Abstract
Timely initiation of chromosomal DNA replication in Escherichia coli is achieved by cell cycle-coordinated regulation of the replication origin, oriC, and the replication initiator, ATP-DnaA. Cellular levels of ATP-DnaA increase and peak at the time for initiation at oriC, after which hydrolysis of DnaA-bound ATP causes those to fall, yielding initiation-inactive ADP-DnaA. This hydrolysis is facilitated by the chromosomal locus datA located downstream of the tRNA-Gly (glyV-X-Y) operon, which possesses a cluster of DnaA-binding sequences and a single binding site (IBS) for the DNA bending protein IHF (integration host factor). While IHF binding activates the datA function and is regulated to occur specifically at post-initiation time, the underlying regulatory mechanisms remain obscure. Here, we demonstrate that datA-IHF binding at pre-initiation time is down-regulated depending on the read-through transcription of datA IBS initiated at the glyV-X-Y promoter. During the cell cycle, the level of read-through transcription, but not promoter activity, fluctuated in a manner inversely related to datA-IHF binding. Transcription from the glyV-X-Y promoter was predominantly interrupted at datA IBS by IHF binding. The terminator/attenuator sequence of the glyV-X-Y operon, as well as DnaA binding within datA overall, contributed to attenuation of transcription upstream of datA IBS, preserving the timely fluctuation of read-through transcription. These findings provide a mechanistic insight of tRNA transcription-dependent datA-IHF regulation, in which an unidentified factor is additionally required for the timely datA-IHF dissociation, and support the significance of datA for controlling the cell cycle progression as a connecting hub of tRNA production and replication initiation.
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Kasho K, Ozaki S, Katayama T. IHF and Fis as Escherichia coli Cell Cycle Regulators: Activation of the Replication Origin oriC and the Regulatory Cycle of the DnaA Initiator. Int J Mol Sci 2023; 24:11572. [PMID: 37511331 PMCID: PMC10380432 DOI: 10.3390/ijms241411572] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 07/14/2023] [Accepted: 07/16/2023] [Indexed: 07/30/2023] Open
Abstract
This review summarizes current knowledge about the mechanisms of timely binding and dissociation of two nucleoid proteins, IHF and Fis, which play fundamental roles in the initiation of chromosomal DNA replication in Escherichia coli. Replication is initiated from a unique replication origin called oriC and is tightly regulated so that it occurs only once per cell cycle. The timing of replication initiation at oriC is rigidly controlled by the timely binding of the initiator protein DnaA and IHF to oriC. The first part of this review presents up-to-date knowledge about the timely stabilization of oriC-IHF binding at oriC during replication initiation. Recent advances in our understanding of the genome-wide profile of cell cycle-coordinated IHF binding have revealed the oriC-specific stabilization of IHF binding by ATP-DnaA oligomers at oriC and by an initiation-specific IHF binding consensus sequence at oriC. The second part of this review summarizes the mechanism of the timely regulation of DnaA activity via the chromosomal loci DARS2 (DnaA-reactivating sequence 2) and datA. The timing of replication initiation at oriC is controlled predominantly by the phosphorylated form of the adenosine nucleotide bound to DnaA, i.e., ATP-DnaA, but not ADP-ADP, is competent for initiation. Before initiation, DARS2 increases the level of ATP-DnaA by stimulating the exchange of ADP for ATP on DnaA. This DARS2 function is activated by the site-specific and timely binding of both IHF and Fis within DARS2. After initiation, another chromosomal locus, datA, which inactivates ATP-DnaA by stimulating ATP hydrolysis, is activated by the timely binding of IHF. A recent study has shown that ATP-DnaA oligomers formed at DARS2-Fis binding sites competitively dissociate Fis via negative feedback, whereas IHF regulation at DARS2 and datA still remains to be investigated. This review summarizes the current knowledge about the specific role of IHF and Fis in the regulation of replication initiation and proposes a mechanism for the regulation of timely IHF binding and dissociation at DARS2 and datA.
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Affiliation(s)
- Kazutoshi Kasho
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Shogo Ozaki
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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5
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Yoshida R, Ozaki S, Kawakami H, Katayama T. Single-stranded DNA recruitment mechanism in replication origin unwinding by DnaA initiator protein and HU, an evolutionary ubiquitous nucleoid protein. Nucleic Acids Res 2023; 51:6286-6306. [PMID: 37178000 PMCID: PMC10325909 DOI: 10.1093/nar/gkad389] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 04/18/2023] [Accepted: 05/02/2023] [Indexed: 05/15/2023] Open
Abstract
The Escherichia coli replication origin oriC contains the initiator ATP-DnaA-Oligomerization Region (DOR) and its flanking duplex unwinding element (DUE). In the Left-DOR subregion, ATP-DnaA forms a pentamer by binding to R1, R5M and three other DnaA boxes. The DNA-bending protein IHF binds sequence-specifically to the interspace between R1 and R5M boxes, promoting DUE unwinding, which is sustained predominantly by binding of R1/R5M-bound DnaAs to the single-stranded DUE (ssDUE). The present study describes DUE unwinding mechanisms promoted by DnaA and IHF-structural homolog HU, a ubiquitous protein in eubacterial species that binds DNA sequence-non-specifically, preferring bent DNA. Similar to IHF, HU promoted DUE unwinding dependent on ssDUE binding of R1/R5M-bound DnaAs. Unlike IHF, HU strictly required R1/R5M-bound DnaAs and interactions between the two DnaAs. Notably, HU site-specifically bound the R1-R5M interspace in a manner stimulated by ATP-DnaA and ssDUE. These findings suggest a model that interactions between the two DnaAs trigger DNA bending within the R1/R5M-interspace and initial DUE unwinding, which promotes site-specific HU binding that stabilizes the overall complex and DUE unwinding. Moreover, HU site-specifically bound the replication origin of the ancestral bacterium Thermotoga maritima depending on the cognate ATP-DnaA. The ssDUE recruitment mechanism could be evolutionarily conserved in eubacteria.
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Affiliation(s)
- Ryusei Yoshida
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Shogo Ozaki
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Hironori Kawakami
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
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Lu C, Yoshida R, Katayama T, Ozaki S. Thermotoga maritima oriC involves a DNA unwinding element with distinct modules and a DnaA-oligomerizing region with a novel directional binding mode. J Biol Chem 2023:104888. [PMID: 37276959 PMCID: PMC10316083 DOI: 10.1016/j.jbc.2023.104888] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 05/23/2023] [Accepted: 05/30/2023] [Indexed: 06/07/2023] Open
Abstract
Initiation of chromosomal replication requires dynamic nucleoprotein complexes. In most eubacteria, the origin oriC contains multiple DnaA box sequences to which the ubiquitous DnaA initiators bind. In Escherichia coli oriC, DnaA boxes sustain construction of higher-order complexes via DnaA-DnaA interactions, promoting the unwinding of the DNA unwinding element (DUE) within oriC and concomitantly binding the single-stranded DUE to install replication machinery. Despite the significant sequence homologies among DnaA proteins, bacterial oriC sequences are highly diverse. The present study investigated the design of oriC (tma-oriC) from Thermotoga maritima, an evolutionarily ancient eubacterium. The minimal tma-oriC sequence includes a DUE and a flanking region containing five DnaA boxes recognized by the cognate DnaA initiator (tmaDnaA). This DUE was comprised of two distinct functional modules, an unwinding module and a tmaDnaA-binding module. Three direct repeats of the trinucleotide TAG within DUE were essential for both unwinding and single-stranded DUE binding by tmaDnaA complexes constructed on the DnaA boxes. Its surrounding AT-rich sequences stimulated only duplex unwinding. Moreover, head-to-tail oligomers of ATP-bound tmaDnaA were constructed within tma-oriC, irrespective of the directions of the DnaA boxes. This binding mode was considered to be induced by flexible swiveling of DnaA domains III and IV, which were responsible for DnaA-DnaA interactions and DnaA box binding, respectively. Phasing of specific tmaDnaA boxes in tma-oriC DNA was also responsible for unwinding. These findings indicate that a single-stranded DUE recruitment mechanism was responsible for unwinding, and would enhance understanding of the fundamental molecular nature of the origin sequences present in evolutionarily divergent bacteria.
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Affiliation(s)
- Chuyuan Lu
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan
| | - Ryusei Yoshida
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan
| | - Shogo Ozaki
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan.
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Hou Y, Kumar P, Aggarwal M, Sarkari F, Wolcott KM, Chattoraj DK, Crooke E, Saxena R. The linker domain of the initiator DnaA contributes to its ATP binding and membrane association in E. coli chromosomal replication. SCIENCE ADVANCES 2022; 8:eabq6657. [PMID: 36197974 PMCID: PMC9534497 DOI: 10.1126/sciadv.abq6657] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 08/18/2022] [Indexed: 06/16/2023]
Abstract
DnaA, the initiator of Escherichia coli chromosomal replication, has in its adenosine triphosphatase (ATPase) domain residues required for adenosine 5'-triphosphate (ATP) binding and membrane attachment. Here, we show that D118Q substitution in the DnaA linker domain, a domain known to be without major regulatory functions, influences ATP binding of DnaA and replication initiation in vivo. Although initiation defective by itself, overexpression of DnaA(D118Q) caused overinitiation of replication in dnaA46ts cells and prevented cell growth. The growth defect was rescued by overexpressing the initiation inhibitor, SeqA, indicating that the growth inhibition resulted from overinitiation. Small deletions within the linker showed another unexpected phenotype: cellular growth without requiring normal levels of anionic membrane lipids, a property found in DnaA mutated in its ATPase domain. The deleted proteins were defective in association with anionic membrane vesicles. These results show that changes in the linker domain can alter DnaA functions similarly to the previously shown changes in the ATPase domain.
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Affiliation(s)
- Yanqi Hou
- Department of Biochemistry and Molecular and Cellular Biology, Georgetown University Medical Center, Washington, DC 20007, USA
| | - Pankaj Kumar
- Center for Tuberculosis Research, Department of Medicine, Johns Hopkins University, Baltimore, MD 21287, USA
| | - Monika Aggarwal
- Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20007, USA
| | - Farzad Sarkari
- Department of Biochemistry and Molecular and Cellular Biology, Georgetown University Medical Center, Washington, DC 20007, USA
| | - Karen M. Wolcott
- Laboratory of Genome Integrity, Flow Cytometry Core Facility, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Dhruba K. Chattoraj
- Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Elliott Crooke
- Department of Biochemistry and Molecular and Cellular Biology, Georgetown University Medical Center, Washington, DC 20007, USA
- Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20007, USA
| | - Rahul Saxena
- Department of Biochemistry and Molecular and Cellular Biology, Georgetown University Medical Center, Washington, DC 20007, USA
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Alonso-Fernández S, Arribas-Díez I, Fernández-García G, González-Quiñónez N, Jensen ON, Manteca A. Quantitative phosphoproteome analysis of Streptomyces coelicolor by immobilized zirconium (IV) affinity chromatography and mass spectrometry reveals novel regulated protein phosphorylation sites and sequence motifs. J Proteomics 2022; 269:104719. [PMID: 36089190 DOI: 10.1016/j.jprot.2022.104719] [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: 06/07/2022] [Revised: 08/25/2022] [Accepted: 09/03/2022] [Indexed: 11/12/2022]
Abstract
Streptomycetes are multicellular gram-positive bacteria that produce many bioactive compounds, including antibiotics, antitumorals and immunosuppressors. The Streptomyces phosphoproteome remains largely uncharted even though protein phosphorylation at Ser/Thr/Tyr is known to modulate morphological differentiation and specialized metabolic processes. We here expand the S. coelicolor phosphoproteome by optimised immobilized zirconium (IV) affinity chromatography and mass spectrometry to identify phosphoproteins at the vegetative and sporulating stages. We mapped 361 phosphorylation sites (41% pSer, 56.2% pThr, 2.8% pTyr) and discovered four novel Thr phosphorylation motifs ("Kxxxx(pT)xxxxK", "DxE(pT)", "D(pT)" and "Exxxxx(pT)") in 351 phosphopeptides derived from 187 phosphoproteins. We identified 154 novel phosphoproteins, thereby almost doubling the number of experimentally verified Streptomyces phosphoproteins. Novel phosphoproteins included cell division proteins (FtsK, CrgA) and specialized metabolism regulators (ArgR, AfsR, CutR and HrcA) that were differentially phosphorylated in the vegetative and in the antibiotic producing sporulating stages. Phosphoproteins involved in primary metabolism included 27 novel ribosomal proteins that were phosphorylated during the vegetative stage. Phosphorylation of these proteins likely participate in the intricate and incompletely understood regulation of Streptomyces development and secondary metabolism. We conclude that Zr(IV)-IMAC is an efficient and sensitive method to study protein phosphorylation and regulation in bacteria and enhance our understanding of bacterial signalling. SIGNIFICANCE: Two thirds of the secondary metabolites used in clinic, especially antibiotics, were discovered in Streptomyces strains. Antibiotic resistance became one of the major challenges in clinic, and new antibiotics are urgently required in clinic. Next-generation sequencing analyses revealed that streptomycetes harbour many cryptic secondary metabolite pathways, i.e. pathways not expressed in the laboratory. Secondary metabolism is tightly connected with hypha differentiation and sporulation, and understanding Streptomyces differentiation is one of the main challenges in industrial microbiology, in order to activate the expression of cryptic pathways in the laboratory. Protein phosphorylation at Ser/Thr/Tyr modulates development and secondary metabolism, but the Streptomyces phosphoproteome is still largely uncharted. Previous S. coelicolor phosphoproteomic studies used TiO2 affinity enrichment and LC-MS/MS identifying a total of 184 Streptomyces phosphoproteins. Here, we used by first time zirconium (IV) affinity chromatography and mass spectrometry, identifying 186 S. coelicolor phosphoproteins. Most of these phosphoproteins (154) were not identified in previous phosphoproteomic studies using TiO2 affinity enrichment. Thereby we almost doubling the number of experimentally verified Streptomyces phosphoproteins. Zr(IV)-IMAC affinity chromatography also worked in E. coli, allowing the identification of phosphoproteins that were not identified by TiO2 affinity chromatography. We conclude that Zr(IV)-IMAC is an efficient and sensitive method for studies of protein phosphorylation and regulation in bacteria to enhance our understanding of bacterial signalling networks. Moreover, the new Streptomyces phosphoproteins identified will contribute to design further works to understand and modulate Streptomyces secondary metabolism activation.
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Affiliation(s)
- Sergio Alonso-Fernández
- Área de Microbiología, Departamento de Biología Funcional, IUOPA, ISPA, Facultad de Medicina, Universidad de Oviedo, 33006 Oviedo, Spain
| | - Ignacio Arribas-Díez
- Department of Biochemistry and Molecular Biology and VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Gemma Fernández-García
- Área de Microbiología, Departamento de Biología Funcional, IUOPA, ISPA, Facultad de Medicina, Universidad de Oviedo, 33006 Oviedo, Spain
| | - Nathaly González-Quiñónez
- Área de Microbiología, Departamento de Biología Funcional, IUOPA, ISPA, Facultad de Medicina, Universidad de Oviedo, 33006 Oviedo, Spain
| | - Ole N Jensen
- Department of Biochemistry and Molecular Biology and VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
| | - Angel Manteca
- Área de Microbiología, Departamento de Biología Funcional, IUOPA, ISPA, Facultad de Medicina, Universidad de Oviedo, 33006 Oviedo, Spain.
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Sakiyama Y, Nagata M, Yoshida R, Kasho K, Ozaki S, Katayama T. Concerted actions of DnaA complexes with DNA-unwinding sequences within and flanking replication origin oriC promote DnaB helicase loading. J Biol Chem 2022; 298:102051. [PMID: 35598828 PMCID: PMC9198467 DOI: 10.1016/j.jbc.2022.102051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 05/11/2022] [Accepted: 05/13/2022] [Indexed: 12/01/2022] Open
Abstract
Unwinding of the replication origin and loading of DNA helicases underlie the initiation of chromosomal replication. In Escherichia coli, the minimal origin oriC contains a duplex unwinding element (DUE) region and three (Left, Middle, and Right) regions that bind the initiator protein DnaA. The Left/Right regions bear a set of DnaA-binding sequences, constituting the Left/Right-DnaA subcomplexes, while the Middle region has a single DnaA-binding site, which stimulates formation of the Left/Right-DnaA subcomplexes. In addition, a DUE-flanking AT-cluster element (TATTAAAAAGAA) is located just outside of the minimal oriC region. The Left-DnaA subcomplex promotes unwinding of the flanking DUE exposing TT[A/G]T(T) sequences that then bind to the Left-DnaA subcomplex, stabilizing the unwound state required for DnaB helicase loading. However, the role of the Right-DnaA subcomplex is largely unclear. Here, we show that DUE unwinding by both the Left/Right-DnaA subcomplexes, but not the Left-DnaA subcomplex only, was stimulated by a DUE-terminal subregion flanking the AT-cluster. Consistently, we found the Right-DnaA subcomplex–bound single-stranded DUE and AT-cluster regions. In addition, the Left/Right-DnaA subcomplexes bound DnaB helicase independently. For only the Left-DnaA subcomplex, we show the AT-cluster was crucial for DnaB loading. The role of unwound DNA binding of the Right-DnaA subcomplex was further supported by in vivo data. Taken together, we propose a model in which the Right-DnaA subcomplex dynamically interacts with the unwound DUE, assisting in DUE unwinding and efficient loading of DnaB helicases, while in the absence of the Right-DnaA subcomplex, the AT-cluster assists in those processes, supporting robustness of replication initiation.
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Affiliation(s)
- Yukari Sakiyama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Mariko Nagata
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Ryusei Yoshida
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Kazutoshi Kasho
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Shogo Ozaki
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.
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10
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Miyoshi K, Tatsumoto Y, Ozaki S, Katayama T. Negative feedback for DARS2-Fis complex by ATP-DnaA supports the cell cycle-coordinated regulation for chromosome replication. Nucleic Acids Res 2021; 49:12820-12835. [PMID: 34871419 PMCID: PMC8682772 DOI: 10.1093/nar/gkab1171] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 11/05/2021] [Accepted: 11/11/2021] [Indexed: 11/13/2022] Open
Abstract
In Escherichia coli, the replication initiator DnaA oscillates between an ATP- and an ADP-bound state in a cell cycle-dependent manner, supporting regulation for chromosome replication. ATP-DnaA cooperatively assembles on the replication origin using clusters of low-affinity DnaA-binding sites. After initiation, DnaA-bound ATP is hydrolyzed, producing initiation-inactive ADP-DnaA. For the next round of initiation, ADP-DnaA binds to the chromosomal locus DARS2, which promotes the release of ADP, yielding the apo-DnaA to regain the initiation activity through ATP binding. This DnaA reactivation by DARS2 depends on site-specific binding of IHF (integration host factor) and Fis proteins and IHF binding to DARS2 occurs specifically during pre-initiation. Here, we reveal that Fis binds to an essential region in DARS2 specifically during pre-initiation. Further analyses demonstrate that ATP-DnaA, but not ADP-DnaA, oligomerizes on a cluster of low-affinity DnaA-binding sites overlapping the Fis-binding region, which competitively inhibits Fis binding and hence the DARS2 activity. DiaA (DnaA initiator-associating protein) stimulating ATP-DnaA assembly enhances the dissociation of Fis. These observations lead to a negative feedback model where the activity of DARS2 is repressed around the time of initiation by the elevated ATP-DnaA level and is stimulated following initiation when the ATP-DnaA level is reduced.
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Affiliation(s)
- Kenya Miyoshi
- Department of Molecular Biology, Kyushu University Graduate School of Pharmaceutical Sciences, Fukuoka 812-8582, Japan
| | - Yuka Tatsumoto
- Department of Molecular Biology, Kyushu University Graduate School of Pharmaceutical Sciences, Fukuoka 812-8582, Japan
| | - Shogo Ozaki
- Department of Molecular Biology, Kyushu University Graduate School of Pharmaceutical Sciences, Fukuoka 812-8582, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Kyushu University Graduate School of Pharmaceutical Sciences, Fukuoka 812-8582, Japan
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11
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Oliveira Paiva AM, van Eijk E, Friggen AH, Weigel C, Smits WK. Identification of the Unwinding Region in the Clostridioides difficile Chromosomal Origin of Replication. Front Microbiol 2020; 11:581401. [PMID: 33133049 PMCID: PMC7561715 DOI: 10.3389/fmicb.2020.581401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 08/31/2020] [Indexed: 12/14/2022] Open
Abstract
Faithful DNA replication is crucial for viability of cells across all kingdoms. Targeting DNA replication is a viable strategy for inhibition of bacterial pathogens. Clostridioides difficile is an important enteropathogen that causes potentially fatal intestinal inflammation. Knowledge about DNA replication in this organism is limited and no data is available on the very first steps of DNA replication. Here, we use a combination of in silico predictions and in vitro experiments to demonstrate that C. difficile employs a bipartite origin of replication that shows DnaA-dependent melting at oriC2, located in the dnaA-dnaN intergenic region. Analysis of putative origins of replication in different clostridia suggests that the main features of the origin architecture are conserved. This study is the first to characterize aspects of the origin region of C. difficile and contributes to our understanding of the initiation of DNA replication in clostridia.
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Affiliation(s)
- Ana M Oliveira Paiva
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, Netherlands.,Centre for Microbial Cell Biology, Leiden, Netherlands
| | - Erika van Eijk
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, Netherlands
| | - Annemieke H Friggen
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, Netherlands
| | - Christoph Weigel
- Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
| | - Wiep Klaas Smits
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, Netherlands.,Centre for Microbial Cell Biology, Leiden, Netherlands
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12
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Hayashi C, Miyazaki E, Ozaki S, Abe Y, Katayama T. DnaB helicase is recruited to the replication initiation complex via binding of DnaA domain I to the lateral surface of the DnaB N-terminal domain. J Biol Chem 2020; 295:11131-11143. [PMID: 32540966 DOI: 10.1074/jbc.ra120.014235] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 06/10/2020] [Indexed: 01/09/2023] Open
Abstract
The DNA replication protein DnaA in Escherichia coli constructs higher-order complexes on the origin, oriC, to unwind this region. DnaB helicase is loaded onto unwound oriC via interactions with the DnaC loader and the DnaA complex. The DnaB-DnaC complex is recruited to the DnaA complex via stable binding of DnaB to DnaA domain I. The DnaB-DnaC complex is then directed to unwound oriC via a weak interaction between DnaB and DnaA domain III. Previously, we showed that Phe46 in DnaA domain I binds to DnaB. Here, we searched for the DnaA domain I-binding site in DnaB. The DnaB L160A variant was impaired in binding to DnaA complex on oriC but retained its DnaC-binding and helicase activities. DnaC binding moderately stimulated DnaA binding of DnaB L160A, and loading of DnaB L160A onto oriC was consistently and moderately inhibited. In a helicase assay with partly single-stranded DNA bearing a DnaA-binding site, DnaA stimulated DnaB loading, which was strongly inhibited in DnaB L160A even in the presence of DnaC. DnaB L160A was functionally impaired in vivo On the basis of these findings, we propose that DnaB Leu160 interacts with DnaA domain I Phe46 DnaB Leu160 is exposed on the lateral surface of the N-terminal domain, which can explain unobstructed interactions of DnaA domain I-bound DnaB with DnaC, DnaG primase, and DnaA domain III. We propose a probable structure for the DnaA-DnaB-DnaC complex, which could be relevant to the process of DnaB loading onto oriC.
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Affiliation(s)
- Chihiro Hayashi
- Department of Molecular Biology, Kyushu University Graduate School of Pharmaceutical Sciences, Fukuoka, Japan
| | - Erika Miyazaki
- Department of Molecular Biology, Kyushu University Graduate School of Pharmaceutical Sciences, Fukuoka, Japan
| | - Shogo Ozaki
- Department of Molecular Biology, Kyushu University Graduate School of Pharmaceutical Sciences, Fukuoka, Japan
| | - Yoshito Abe
- Department of Protein Structure, Function, and Design, Kyushu University Graduate School of Pharmaceutical Sciences, Fukuoka, Japan.,Department of Pharmaceutical Sciences, International University of Health and Welfare, Okawa, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Kyushu University Graduate School of Pharmaceutical Sciences, Fukuoka, Japan
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13
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Sugiyama R, Kasho K, Miyoshi K, Ozaki S, Kagawa W, Kurumizaka H, Katayama T. A novel mode of DnaA-DnaA interaction promotes ADP dissociation for reactivation of replication initiation activity. Nucleic Acids Res 2020; 47:11209-11224. [PMID: 31535134 PMCID: PMC6868365 DOI: 10.1093/nar/gkz795] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 09/03/2019] [Accepted: 09/07/2019] [Indexed: 01/01/2023] Open
Abstract
ATP-DnaA is temporally increased to initiate replication during the cell cycle. Two chromosomal loci, DARS (DnaA-reactivating sequences) 1 and 2, promote ATP-DnaA production by nucleotide exchange of ADP-DnaA for timely initiation. ADP-DnaA complexes are constructed on DARS1 and DARS2, bearing a cluster of three DnaA-binding sequences (DnaA boxes I−III), promoting ADP dissociation. Although DnaA has an AAA+ domain, which ordinarily directs construction of oligomers in a head-to-tail manner, DnaA boxes I and II are oriented oppositely. In this study, we constructed a structural model of a head-to-head dimer of DnaA AAA+ domains, and analyzed residues residing on the interface of the model dimer. Gln208 was specifically required for DARS-dependent ADP dissociation in vitro, and in vivo analysis yielded consistent results. Additionally, ADP release from DnaA protomers bound to DnaA boxes I and II was dependent on Gln208 of the DnaA protomers, and DnaA box III-bound DnaA did not release ADP nor require Gln208 for ADP dissociation by DARS–DnaA complexes. Based on these and other findings, we propose a model for DARS–DnaA complex dynamics during ADP dissociation, and provide novel insight into the regulatory mechanisms of DnaA and the interaction modes of AAA+ domains.
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Affiliation(s)
- Ryo Sugiyama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan
| | - Kazutoshi Kasho
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan
| | - Kenya Miyoshi
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan
| | - Shogo Ozaki
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan
| | - Wataru Kagawa
- Department of Chemistry, Graduate School of Science and Engineering, Meisei University, Hino, Tokyo 191-8506, Japan
| | - Hitoshi Kurumizaka
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan
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14
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Saxena R, Stanley CB, Kumar P, Cuneo MJ, Patil D, Jha J, Weiss KL, Chattoraj DK, Crooke E. A nucleotide-dependent oligomerization of the Escherichia coli replication initiator DnaA requires residue His136 for remodeling of the chromosomal origin. Nucleic Acids Res 2020; 48:200-211. [PMID: 31665475 PMCID: PMC7145717 DOI: 10.1093/nar/gkz939] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 09/30/2019] [Accepted: 10/08/2019] [Indexed: 12/03/2022] Open
Abstract
Escherichia coli replication initiator protein DnaA binds ATP with high affinity but the amount of ATP required to initiate replication greatly exceeds the amount required for binding. Previously, we showed that ATP-DnaA, not ADP-DnaA, undergoes a conformational change at the higher nucleotide concentration, which allows DnaA oligomerization at the replication origin but the association state remains unclear. Here, we used Small Angle X-ray Scattering (SAXS) to investigate oligomerization of DnaA in solution. Whereas ADP-DnaA was predominantly monomeric, AMP–PNP–DnaA (a non-hydrolysable ATP-analog bound-DnaA) was oligomeric, primarily dimeric. Functional studies using DnaA mutants revealed that DnaA(H136Q) is defective in initiating replication in vivo. The mutant retains high-affinity ATP binding, but was defective in producing replication-competent initiation complexes. Docking of ATP on a structure of E. coli DnaA, modeled upon the crystallographic structure of Aquifex aeolicus DnaA, predicts a hydrogen bond between ATP and imidazole ring of His136, which is disrupted when Gln is present at position 136. SAXS performed on AMP–PNP–DnaA (H136Q) indicates that the protein has lost its ability to form oligomers. These results show the importance of high ATP in DnaA oligomerization and its dependence on the His136 residue.
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Affiliation(s)
- Rahul Saxena
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, Washington, DC 20007, USA
| | - Christopher B Stanley
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Pankaj Kumar
- Department of Biochemistry, Jamia Hamdard University, Delhi 110062, India
| | - Matthew J Cuneo
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
| | - Digvijay Patil
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, Washington, DC 20007, USA
| | - Jyoti Jha
- Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Kevin L Weiss
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Dhruba K Chattoraj
- Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Elliott Crooke
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, Washington, DC 20007, USA.,Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20007, USA
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15
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AfsK-Mediated Site-Specific Phosphorylation Regulates DnaA Initiator Protein Activity in Streptomyces coelicolor. J Bacteriol 2020; 202:JB.00597-19. [PMID: 31712280 DOI: 10.1128/jb.00597-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 11/05/2019] [Indexed: 11/20/2022] Open
Abstract
In all organisms, chromosome replication is regulated mainly at the initiation step. Most of the knowledge about the mechanisms that regulate replication initiation in bacteria has come from studies on rod-shaped bacteria, such as Escherichia coli and Bacillus subtilis Streptomyces is a bacterial genus that is characterized by distinctive features and a complex life cycle that shares some properties with the developmental cycle of filamentous fungi. The unusual lifestyle of streptomycetes suggests that these bacteria use various mechanisms to control key cellular processes. Here, we provide the first insights into the phosphorylation of the bacterial replication initiator protein, DnaA, from Streptomyces coelicolor We suggest that phosphorylation of DnaA triggers a conformational change that increases its ATPase activity and decreases its affinity for the replication origin, thereby blocking the formation of a functional orisome. We suggest that the phosphorylation of DnaA is catalyzed by Ser/Thr kinase AfsK, which was shown to regulate the polar growth of S. coelicolor Together, our results reveal that phosphorylation of the DnaA initiator protein functions as a negative regulatory mechanism to control the initiation of chromosome replication in a manner that presumably depends on the cellular localization of the protein.IMPORTANCE This work provides insights into the phosphorylation of the DnaA initiator protein in Streptomyces coelicolor and suggests a novel bacterial regulatory mechanism for initiation of chromosome replication. Although phosphorylation of DnaA has been reported earlier, its biological role was unknown. This work shows that upon phosphorylation, the cooperative binding of the replication origin by DnaA may be disturbed. We found that AfsK kinase is responsible for phosphorylation of DnaA. Upon upregulation of AfsK, chromosome replication occurred further from the hyphal tip. Orthologs of AfsK are exclusively found in mycelial actinomycetes that are related to Streptomyces and exhibit a complex life cycle. We propose that the AfsK-mediated regulatory pathway serves as a nonessential, energy-saving mechanism in S. coelicolor.
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16
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Leonard AC, Rao P, Kadam RP, Grimwade JE. Changing Perspectives on the Role of DnaA-ATP in Orisome Function and Timing Regulation. Front Microbiol 2019; 10:2009. [PMID: 31555240 PMCID: PMC6727663 DOI: 10.3389/fmicb.2019.02009] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Accepted: 08/16/2019] [Indexed: 01/20/2023] Open
Abstract
Bacteria, like all cells, must precisely duplicate their genomes before they divide. Regulation of this critical process focuses on forming a pre-replicative nucleoprotein complex, termed the orisome. Orisomes perform two essential mechanical tasks that configure the unique chromosomal replication origin, oriC to start a new round of chromosome replication: (1) unwinding origin DNA and (2) assisting with loading of the replicative DNA helicase on exposed single strands. In Escherichia coli, a necessary orisome component is the ATP-bound form of the bacterial initiator protein, DnaA. DnaA-ATP differs from DnaA-ADP in its ability to oligomerize into helical filaments, and in its ability to access a subset of low affinity recognition sites in the E. coli replication origin. The helical filaments have been proposed to play a role in both of the key mechanical tasks, but recent studies raise new questions about whether they are mandatory for orisome activity. It was recently shown that a version of E. coli oriC (oriCallADP), whose multiple low affinity DnaA recognition sites bind DnaA-ATP and DnaA-ADP similarly, was fully occupied and unwound by DnaA-ADP in vitro, and in vivo suppressed the lethality of DnaA mutants defective in ATP binding and ATP-specific oligomerization. However, despite their functional equivalency, orisomes assembled on oriCallADP were unable to trigger chromosome replication at the correct cell cycle time and displayed a hyper-initiation phenotype. Here we present a new perspective on DnaA-ATP, and suggest that in E. coli, DnaA-ATP is not required for mechanical functions, but rather is needed for site recognition and occupation, so that initiation timing is coupled to DnaA-ATP levels. We also discuss how other bacterial types may utilize DnaA-ATP and DnaA-ADP, and whether the high diversity of replication origins in the bacterial world reflects different regulatory strategies for how DnaA-ATP is used to control orisome assembly.
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Affiliation(s)
- Alan C Leonard
- Laboratory of Microbial Genetics, Department of Biomedical and Chemical Engineering and Science, Florida Institute of Technology, Melbourne, FL, United States
| | - Prassanna Rao
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Rohit P Kadam
- Laboratory of Microbial Genetics, Department of Biomedical and Chemical Engineering and Science, Florida Institute of Technology, Melbourne, FL, United States
| | - Julia E Grimwade
- Laboratory of Microbial Genetics, Department of Biomedical and Chemical Engineering and Science, Florida Institute of Technology, Melbourne, FL, United States
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17
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Sakiyama Y, Nishimura M, Hayashi C, Akama Y, Ozaki S, Katayama T. The DnaA AAA+ Domain His136 Residue Directs DnaB Replicative Helicase to the Unwound Region of the Replication Origin, oriC. Front Microbiol 2018; 9:2017. [PMID: 30233515 PMCID: PMC6127211 DOI: 10.3389/fmicb.2018.02017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 08/09/2018] [Indexed: 11/16/2022] Open
Abstract
Chromosomal replication initiation requires dynamic mechanisms in higher-order nucleoprotein complexes that are constructed at the origin of replication. In Escherichia coli, DnaA molecules construct functional oligomers at the origin oriC, enabling localized unwinding of oriC and stable binding of DnaB helicases via multiple domain I molecules of oriC-bound DnaA. DnaA-bound DnaB helicases are then loaded onto the unwound region of oriC for construction of a pair of replisomes for bidirectional replication. However, mechanisms of DnaB loading to the unwound oriC remain largely elusive. In this study, we determined that His136 of DnaA domain III has an important role in loading of DnaB helicases onto the unwound oriC. DnaA H136A mutant protein was impaired in replication initiation in vivo, and in DnaB loading to the unwound oriC in vitro, whereas the protein fully sustained activities for oriC unwinding and DnaA domain I-dependent stable binding between DnaA and DnaB. Functional and structural analyses supported the idea that transient weak interactions between DnaB helicase and DnaA His136 within specific protomers of DnaA oligomers direct DnaB to a region in close proximity to single stranded DNA at unwound oriC bound to DnaA domain III of the DnaA oligomer. The aromatic moiety of His136 is basically conserved at corresponding residues of eubacterial DnaA orthologs, implying that the guidance function of DnaB is common to all eubacterial species.
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Affiliation(s)
- Yukari Sakiyama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Masahiro Nishimura
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Chihiro Hayashi
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Yusuke Akama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Shogo Ozaki
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
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18
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Katayama T. Initiation of DNA Replication at the Chromosomal Origin of E. coli, oriC. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1042:79-98. [PMID: 29357054 DOI: 10.1007/978-981-10-6955-0_4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The Escherichia coli chromosomal origin consists of a duplex-unwinding region and a region bearing a DNA-bending protein, IHF-binding site, and clusters of binding sites for the initiator protein DnaA. ATP-DnaA molecules form highly organized oligomers in a process stimulated by DiaA, a DnaA-binding protein. The resultant ATP-DnaA complexes promote local unwinding of oriC with the aid of IHF, for which specific interaction of DnaA with the single-stranded DNA is crucial. DnaA complexes also interact with DnaB helicases bound to DnaC loaders, promoting loading of DnaB onto the unwound DNA strands for bidirectional replication. Initiation of replication is strictly regulated during the cell cycle by multiple regulatory systems for oriC and DnaA. The activity of oriC is regulated by its methylation state, whereas that of DnaA depends on the form of the bound nucleotide. ATP-DnaA can be yielded from initiation-inactive ADP-DnaA in a timely manner depending on specific chromosomal DNA elements termed DARS (DnaA-reactivating sequences). After initiation, DnaA-bound ATP is hydrolyzed by two systems, yielding ADP-DnaA. In this review, these and other mechanisms of initiation and its regulation in E. coli are described.
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Affiliation(s)
- Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Science, Kyushu University, Fukuoka, Japan.
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19
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Kaguni JM. The Macromolecular Machines that Duplicate the Escherichia coli Chromosome as Targets for Drug Discovery. Antibiotics (Basel) 2018. [PMID: 29538288 PMCID: PMC5872134 DOI: 10.3390/antibiotics7010023] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
DNA replication is an essential process. Although the fundamental strategies to duplicate chromosomes are similar in all free-living organisms, the enzymes of the three domains of life that perform similar functions in DNA replication differ in amino acid sequence and their three-dimensional structures. Moreover, the respective proteins generally utilize different enzymatic mechanisms. Hence, the replication proteins that are highly conserved among bacterial species are attractive targets to develop novel antibiotics as the compounds are unlikely to demonstrate off-target effects. For those proteins that differ among bacteria, compounds that are species-specific may be found. Escherichia coli has been developed as a model system to study DNA replication, serving as a benchmark for comparison. This review summarizes the functions of individual E. coli proteins, and the compounds that inhibit them.
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Affiliation(s)
- Jon M Kaguni
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824-1319, USA.
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20
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Abstract
More than 50 years have passed since the presentation of the Replicon Model which states that a positively acting initiator interacts with a specific site on a circular chromosome molecule to initiate DNA replication. Since then, the origin of chromosome replication, oriC, has been determined as a specific region that carries sequences required for binding of positively acting initiator proteins, DnaA-boxes and DnaA proteins, respectively. In this review we will give a historical overview of significant findings which have led to the very detailed knowledge we now possess about the initiation process in bacteria using Escherichia coli as the model organism, but emphasizing that virtually all bacteria have DnaA proteins that interacts with DnaA boxes to initiate chromosome replication. We will discuss the dnaA gene regulation, the special features of the dnaA gene expression, promoter strength, and translation efficiency, as well as, the DnaA protein, its concentration, its binding to DnaA-boxes, and its binding of ATP or ADP. Furthermore, we will discuss the different models for regulation of initiation which have been proposed over the years, with particular emphasis on the Initiator Titration Model.
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Affiliation(s)
- Flemming G. Hansen
- Department of Bioengineering, Technical University of Denmark, Lyngby, Denmark
| | - Tove Atlung
- Department of Science and Environment, Roskilde University, Roskilde, Denmark
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21
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Sakiyama Y, Kasho K, Noguchi Y, Kawakami H, Katayama T. Regulatory dynamics in the ternary DnaA complex for initiation of chromosomal replication in Escherichia coli. Nucleic Acids Res 2017; 45:12354-12373. [PMID: 29040689 PMCID: PMC5716108 DOI: 10.1093/nar/gkx914] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 09/29/2017] [Indexed: 12/17/2022] Open
Abstract
In Escherichia coli, the level of the ATP-DnaA initiator is increased temporarily at the time of replication initiation. The replication origin, oriC, contains a duplex-unwinding element (DUE) flanking a DnaA-oligomerization region (DOR), which includes twelve DnaA-binding sites (DnaA boxes) and the DNA-bending protein IHF-binding site (IBS). Although complexes of IHF and ATP-DnaA assembly on the DOR unwind the DUE, the configuration of the crucial nucleoprotein complexes remains elusive. To resolve this, we analyzed individual DnaA protomers in the complex and here demonstrate that the DUE-DnaA-box-R1-IBS-DnaA-box-R5M region is essential for DUE unwinding. R5M-bound ATP-DnaA predominantly promotes ATP-DnaA assembly on the DUE-proximal DOR, and R1-bound DnaA has a supporting role. This mechanism might support timely assembly of ATP-DnaA on oriC. DnaA protomers bound to R1 and R5M directly bind to the unwound DUE strand, which is crucial in replication initiation. Data from in vivo experiments support these results. We propose that the DnaA assembly on the IHF-bent DOR directly binds to the unwound DUE strand, and timely formation of this ternary complex regulates replication initiation. Structural features of oriC support the idea that these mechanisms for DUE unwinding are fundamentally conserved in various bacterial species including pathogens.
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Affiliation(s)
- Yukari Sakiyama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Kazutoshi Kasho
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Yasunori Noguchi
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Hironori Kawakami
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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22
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Katayama T, Kasho K, Kawakami H. The DnaA Cycle in Escherichia coli: Activation, Function and Inactivation of the Initiator Protein. Front Microbiol 2017; 8:2496. [PMID: 29312202 PMCID: PMC5742627 DOI: 10.3389/fmicb.2017.02496] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 11/30/2017] [Indexed: 01/30/2023] Open
Abstract
This review summarizes the mechanisms of the initiator protein DnaA in replication initiation and its regulation in Escherichia coli. The chromosomal origin (oriC) DNA is unwound by the replication initiation complex to allow loading of DnaB helicases and replisome formation. The initiation complex consists of the DnaA protein, DnaA-initiator-associating protein DiaA, integration host factor (IHF), and oriC, which contains a duplex-unwinding element (DUE) and a DnaA-oligomerization region (DOR) containing DnaA-binding sites (DnaA boxes) and a single IHF-binding site that induces sharp DNA bending. DiaA binds to DnaA and stimulates DnaA assembly at the DOR. DnaA binds tightly to ATP and ADP. ATP-DnaA constructs functionally different sub-complexes at DOR, and the DUE-proximal DnaA sub-complex contains IHF and promotes DUE unwinding. The first part of this review presents the structures and mechanisms of oriC-DnaA complexes involved in the regulation of replication initiation. During the cell cycle, the level of ATP-DnaA level, the active form for initiation, is strictly regulated by multiple systems, resulting in timely replication initiation. After initiation, regulatory inactivation of DnaA (RIDA) intervenes to reduce ATP-DnaA level by hydrolyzing the DnaA-bound ATP to ADP to yield ADP-DnaA, the inactive form. RIDA involves the binding of the DNA polymerase clamp on newly synthesized DNA to the DnaA-inactivator Hda protein. In datA-dependent DnaA-ATP hydrolysis (DDAH), binding of IHF at the chromosomal locus datA, which contains a cluster of DnaA boxes, results in further hydrolysis of DnaA-bound ATP. SeqA protein inhibits untimely initiation at oriC by binding to newly synthesized oriC DNA and represses dnaA transcription in a cell cycle dependent manner. To reinitiate DNA replication, ADP-DnaA forms oligomers at DnaA-reactivating sequences (DARS1 and DARS2), resulting in the dissociation of ADP and the release of nucleotide-free apo-DnaA, which then binds ATP to regenerate ATP-DnaA. In vivo, DARS2 plays an important role in this process and its activation is regulated by timely binding of IHF to DARS2 in the cell cycle. Chromosomal locations of DARS sites are optimized for the strict regulation for timely replication initiation. The last part of this review describes how DDAH and DARS regulate DnaA activity.
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Affiliation(s)
- Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Kazutoshi Kasho
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Hironori Kawakami
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
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Zawilak-Pawlik A, Nowaczyk M, Zakrzewska-Czerwińska J. The Role of the N-Terminal Domains of Bacterial Initiator DnaA in the Assembly and Regulation of the Bacterial Replication Initiation Complex. Genes (Basel) 2017; 8:genes8050136. [PMID: 28489024 PMCID: PMC5448010 DOI: 10.3390/genes8050136] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 04/28/2017] [Accepted: 05/04/2017] [Indexed: 12/22/2022] Open
Abstract
The primary role of the bacterial protein DnaA is to initiate chromosomal replication. The DnaA protein binds to DNA at the origin of chromosomal replication (oriC) and assembles into a filament that unwinds double-stranded DNA. Through interaction with various other proteins, DnaA also controls the frequency and/or timing of chromosomal replication at the initiation step. Escherichia coli DnaA also recruits DnaB helicase, which is present in unwound single-stranded DNA and in turn recruits other protein machinery for replication. Additionally, DnaA regulates the expression of certain genes in E. coli and a few other species. Acting as a multifunctional factor, DnaA is composed of four domains that have distinct, mutually dependent roles. For example, C-terminal domain IV interacts with double-stranded DnaA boxes. Domain III drives ATP-dependent oligomerization, allowing the protein to form a filament that unwinds DNA and subsequently binds to and stabilizes single-stranded DNA in the initial replication bubble; this domain also interacts with multiple proteins that control oligomerization. Domain II constitutes a flexible linker between C-terminal domains III–IV and N-terminal domain I, which mediates intermolecular interactions between DnaA and binds to other proteins that affect DnaA activity and/or formation of the initiation complex. Of these four domains, the role of the N-terminus (domains I–II) in the assembly of the initiation complex is the least understood and appears to be the most species-dependent region of the protein. Thus, in this review, we focus on the function of the N-terminus of DnaA in orisome formation and the regulation of its activity in the initiation complex in different bacteria.
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Affiliation(s)
- Anna Zawilak-Pawlik
- Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, Wroclaw 53-114, Poland.
| | - Małgorzata Nowaczyk
- Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, Wroclaw 53-114, Poland.
| | - Jolanta Zakrzewska-Czerwińska
- Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, Wroclaw 53-114, Poland.
- Department of Molecular Microbiology, Faculty of Biotechnology, University of Wrocław, ul. Joliot-Curie 14A, Wrocław 50-383, Poland.
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Jameson KH, Wilkinson AJ. Control of Initiation of DNA Replication in Bacillus subtilis and Escherichia coli. Genes (Basel) 2017; 8:E22. [PMID: 28075389 PMCID: PMC5295017 DOI: 10.3390/genes8010022] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Revised: 12/16/2016] [Accepted: 12/20/2016] [Indexed: 01/21/2023] Open
Abstract
Initiation of DNA Replication is tightly regulated in all cells since imbalances in chromosomal copy number are deleterious and often lethal. In bacteria such as Bacillus subtilis and Escherichia coli, at the point of cytokinesis, there must be two complete copies of the chromosome to partition into the daughter cells following division at mid-cell during vegetative growth. Under conditions of rapid growth, when the time taken to replicate the chromosome exceeds the doubling time of the cells, there will be multiple initiations per cell cycle and daughter cells will inherit chromosomes that are already undergoing replication. In contrast, cells entering the sporulation pathway in B. subtilis can do so only during a short interval in the cell cycle when there are two, and only two, chromosomes per cell, one destined for the spore and one for the mother cell. Here, we briefly describe the overall process of DNA replication in bacteria before reviewing initiation of DNA replication in detail. The review covers DnaA-directed assembly of the replisome at oriC and the multitude of mechanisms of regulation of initiation, with a focus on the similarities and differences between E. coli and B. subtilis.
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Affiliation(s)
- Katie H Jameson
- Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK.
| | - Anthony J Wilkinson
- Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5DD, UK.
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25
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Wegrzyn KE, Gross M, Uciechowska U, Konieczny I. Replisome Assembly at Bacterial Chromosomes and Iteron Plasmids. Front Mol Biosci 2016; 3:39. [PMID: 27563644 PMCID: PMC4980987 DOI: 10.3389/fmolb.2016.00039] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 07/25/2016] [Indexed: 11/13/2022] Open
Abstract
The proper initiation and occurrence of DNA synthesis depends on the formation and rearrangements of nucleoprotein complexes within the origin of DNA replication. In this review article, we present the current knowledge on the molecular mechanism of replication complex assembly at the origin of bacterial chromosome and plasmid replicon containing direct repeats (iterons) within the origin sequence. We describe recent findings on chromosomal and plasmid replication initiators, DnaA and Rep proteins, respectively, and their sequence-specific interactions with double- and single-stranded DNA. Also, we discuss the current understanding of the activities of DnaA and Rep proteins required for replisome assembly that is fundamental to the duplication and stability of genetic information in bacterial cells.
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Affiliation(s)
- Katarzyna E Wegrzyn
- Department of Molecular and Cellular Biology, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk Gdansk, Poland
| | - Marta Gross
- Department of Molecular and Cellular Biology, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk Gdansk, Poland
| | - Urszula Uciechowska
- Department of Molecular and Cellular Biology, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk Gdansk, Poland
| | - Igor Konieczny
- Department of Molecular and Cellular Biology, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk Gdansk, Poland
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26
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Noguchi Y, Katayama T. The Escherichia coli Cryptic Prophage Protein YfdR Binds to DnaA and Initiation of Chromosomal Replication Is Inhibited by Overexpression of the Gene Cluster yfdQ-yfdR-yfdS-yfdT. Front Microbiol 2016; 7:239. [PMID: 26973617 PMCID: PMC4776307 DOI: 10.3389/fmicb.2016.00239] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 02/15/2016] [Indexed: 01/09/2023] Open
Abstract
The initiation of bacterial chromosomal replication is regulated by multiple pathways. To explore novel regulators, we isolated multicopy suppressors for the cold-sensitive hda-185 ΔsfiA(sulA) mutant. Hda is crucial for the negative regulation of the initiator DnaA and the hda-185 mutation causes severe replication overinitiation at the replication origin oriC. The SOS-associated division inhibitor SfiA inhibits FtsZ ring formation, an essential step for cell division regulation during the SOS response, and ΔsfiA enhances the cold sensitivity of hda-185 cells in colony formation. One of the suppressors comprised the yfdQ-yfdR-yfdS-yfdT gene cluster carried on a cryptic prophage. Increased copy numbers of yfdQRT or yfdQRS inhibited not only hda-185-dependent overinitiation, but also replication overinitiation in a hyperactive dnaA mutant, and in a mutant lacking an oriC-binding initiation-inhibitor SeqA. In addition, increasing the copy number of the gene set inhibited the growth of cells bearing specific, initiation-impairing dnaA mutations. In wild-type cells, multicopy supply of yfdQRT or yfdQRS also inhibited replication initiation and increased hydroxyurea (HU)-resistance, as seen in cells lacking DiaA, a stimulator of DnaA assembly on oriC. Deletion of the yfdQ-yfdR-yfdS-yfdT genes did not affect either HU resistance or initiation regulation. Furthermore, we found that DnaA bound specifically to YfdR in soluble protein extracts oversupplied with YfdQRST. Purified YfdR also bound to DnaA, and DnaA Phe46, an amino acid residue crucial for DnaA interactions with DiaA and DnaB replicative helicase was important for this interaction. Consistently, YfdR moderately inhibited DiaA-DnaA and DnaB-DnaA interactions. In addition, protein extracts oversupplied with YfdQRST inhibited replication initiation in vitro. Given the roles of yfdQ and yfdS in cell tolerance to specific environmental stresses, the yfdQ-yfdR-yfdS-yfdT genes might downregulate the initiator DnaA-oriC complex under specific growth conditions.
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Affiliation(s)
- Yasunori Noguchi
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University Fukuoka, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University Fukuoka, Japan
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27
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Huang H, Song CC, Yang ZL, Dong Y, Hu YZ, Gao F. Identification of the Replication Origins from Cyanothece ATCC 51142 and Their Interactions with the DnaA Protein: From In Silico to In Vitro Studies. Front Microbiol 2015; 6:1370. [PMID: 26696980 PMCID: PMC4674748 DOI: 10.3389/fmicb.2015.01370] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 11/17/2015] [Indexed: 11/30/2022] Open
Abstract
Based on the complete genome of Cyanothece ATCC 51142, the oriCs of both the circular and linear chromosomes in Cyanothece ATCC 51142 have been predicted by utilizing a web-based system Ori-Finder. Here, we provide experimental support for the results of Ori-Finder to identify the replication origins of Cyanothece ATCC 51142 and their interactions with the initiator protein, DnaA. The two replication origins are composed of three characteristically arranged DnaA boxes and an AT-rich stretch, and the oriC in the circular chromosome is followed by the dnaN gene. The dnaA gene is located downstream of the origin of the circular chromosome and it expresses a typical DnaA protein that is divided into four domains (I, II, III, IV), as with other members of the DnaA protein family. We purify DnaA (IV) and characterize the interaction of the purified protein with the replication origins, so as to offer experimental support for the prediction. The results of the electrophoretic mobility shift assay and DNase I footprint assay demonstrate that the C-terminal domain of the DnaA protein from Cyanothece ATCC 51142 specifically binds the oriCs of both the circular and linear chromosomes, and the DNase I footprint assay demonstrates that DnaA (IV) exhibits hypersensitive affinity with DnaA boxes in both oriCs.
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Affiliation(s)
- He Huang
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University Tianjin, China ; Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University Tianjin, China ; Collaborative Innovation Center of Chemical Science and Engineering Tianjin, China
| | - Cheng-Cheng Song
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University Tianjin, China ; Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University Tianjin, China ; Collaborative Innovation Center of Chemical Science and Engineering Tianjin, China
| | - Zhi-Liang Yang
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University Tianjin, China ; Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University Tianjin, China ; Collaborative Innovation Center of Chemical Science and Engineering Tianjin, China
| | - Yan Dong
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University Tianjin, China ; Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University Tianjin, China ; Collaborative Innovation Center of Chemical Science and Engineering Tianjin, China
| | - Yao-Zhong Hu
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University Tianjin, China ; Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University Tianjin, China ; Collaborative Innovation Center of Chemical Science and Engineering Tianjin, China
| | - Feng Gao
- Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University Tianjin, China ; Collaborative Innovation Center of Chemical Science and Engineering Tianjin, China ; Department of Physics, Tianjin University Tianjin, China
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28
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Nucleotide-Induced Conformational Changes in Escherichia coli DnaA Protein Are Required for Bacterial ORC to Pre-RC Conversion at the Chromosomal Origin. Int J Mol Sci 2015; 16:27897-911. [PMID: 26610483 PMCID: PMC4661922 DOI: 10.3390/ijms161126064] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 10/21/2015] [Accepted: 11/16/2015] [Indexed: 12/05/2022] Open
Abstract
DnaA oligomerizes when bound to origins of chromosomal replication. Structural analysis of a truncated form of DnaA from Aquifex aeolicus has provided insight into crucial conformational differences within the AAA+ domain that are specific to the ATP- versus ADP- bound form of DnaA. In this study molecular docking of ATP and ADP onto Escherichia coli DnaA, modeled on the crystal structure of Aquifex aeolicus DnaA, reveals changes in the orientation of amino acid residues within or near the vicinity of the nucleotide-binding pocket. Upon limited proteolysis with trypsin or chymotrypsin ADP-DnaA, but not ATP-DnaA generated relatively stable proteolytic fragments of various sizes. Examined sites of limited protease susceptibility that differ between ATP-DnaA and ADP-DnaA largely reside in the amino terminal half of DnaA. The concentration of adenine nucleotide needed to induce conformational changes, as detected by these protease susceptibilities of DnaA, coincides with the conversion of an inactive bacterial origin recognition complex (bORC) to a replication efficient pre-replication complex (pre-RC) at the E. coli chromosomal origin of replication (oriC).
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29
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Abstract
In recent years it has become clear that complex regulatory circuits control the initiation step of DNA replication by directing the assembly of a multicomponent molecular machine (the orisome) that separates DNA strands and loads replicative helicase at oriC, the unique chromosomal origin of replication. This chapter discusses recent efforts to understand the regulated protein-DNA interactions that are responsible for properly timed initiation of chromosome replication. It reviews information about newly identified nucleotide sequence features within Escherichia coli oriC and the new structural and biochemical attributes of the bacterial initiator protein DnaA. It also discusses the coordinated mechanisms that prevent improperly timed DNA replication. Identification of the genes that encoded the initiators came from studies on temperature-sensitive, conditional-lethal mutants of E. coli, in which two DNA replication-defective phenotypes, "immediate stop" mutants and "delayed stop" mutants, were identified. The kinetics of the delayed stop mutants suggested that the defective gene products were required specifically for the initiation step of DNA synthesis, and subsequently, two genes, dnaA and dnaC, were identified. The DnaA protein is the bacterial initiator, and in E. coli, the DnaC protein is required to load replicative helicase. Regulation of DnaA accessibility to oriC, the ordered assembly and disassembly of a multi-DnaA complex at oriC, and the means by which DnaA unwinds oriC remain important questions to be answered and the chapter discusses the current state of knowledge on these topics.
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30
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Song C, Zhang S, Huang H. Choosing a suitable method for the identification of replication origins in microbial genomes. Front Microbiol 2015; 6:1049. [PMID: 26483774 PMCID: PMC4588119 DOI: 10.3389/fmicb.2015.01049] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 09/14/2015] [Indexed: 12/19/2022] Open
Abstract
As the replication of genomic DNA is arguably the most important task performed by a cell and given that it is controlled at the initiation stage, the events that occur at the replication origin play a central role in the cell cycle. Making sense of DNA replication origins is important for improving our capacity to study cellular processes and functions in the regulation of gene expression, genome integrity in much finer detail. Thus, clearly comprehending the positions and sequences of replication origins which are fundamental to chromosome organization and duplication is the first priority of all. In view of such important roles of replication origins, tremendous work has been aimed at identifying and testing the specificity of replication origins. A number of computational tools based on various skew types have been developed to predict replication origins. Using various in silico approaches such as Ori-Finder, and databases such as DoriC, researchers have predicted the locations of replication origins sites for thousands of bacterial chromosomes and archaeal genomes. Based on the predicted results, we should choose an effective method for identifying and confirming the interactions at origins of replication. Here we describe the main existing experimental methods that aimed to determine the replication origin regions and list some of the many the practical applications of these methods.
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Affiliation(s)
- Chengcheng Song
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin UniversityTianjin, China
- Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin UniversityTianjin, China
- Collaborative Innovation Center of Chemical Science and EngineeringTianjin, China
| | - Shaocun Zhang
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin UniversityTianjin, China
- Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin UniversityTianjin, China
- Collaborative Innovation Center of Chemical Science and EngineeringTianjin, China
| | - He Huang
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin UniversityTianjin, China
- Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin UniversityTianjin, China
- Collaborative Innovation Center of Chemical Science and EngineeringTianjin, China
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31
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Noguchi Y, Sakiyama Y, Kawakami H, Katayama T. The Arg Fingers of Key DnaA Protomers Are Oriented Inward within the Replication Origin oriC and Stimulate DnaA Subcomplexes in the Initiation Complex. J Biol Chem 2015; 290:20295-312. [PMID: 26126826 DOI: 10.1074/jbc.m115.662601] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Indexed: 01/01/2023] Open
Abstract
ATP-DnaA binds to multiple DnaA boxes in the Escherichia coli replication origin (oriC) and forms left-half and right-half subcomplexes that promote DNA unwinding and DnaB helicase loading. DnaA forms homo-oligomers in a head-to-tail manner via interactions between the bound ATP and Arg-285 of the adjacent protomer. DnaA boxes R1 and R4 reside at the outer edges of the DnaA-binding region and have opposite orientations. In this study, roles for the protomers bound at R1 and R4 were elucidated using chimeric DnaA molecules that had alternative DNA binding sequence specificity and chimeric oriC molecules bearing the alternative DnaA binding sequence at R1 or R4. In vitro, protomers at R1 and R4 promoted initiation regardless of whether the bound nucleotide was ADP or ATP. Arg-285 was shown to play an important role in the formation of subcomplexes that were active in oriC unwinding and DnaB loading. The results of in vivo analysis using the chimeric molecules were consistent with the in vitro data. Taken together, the data suggest a model in which DnaA subcomplexes form in symmetrically opposed orientations and in which the Arg-285 fingers face inward to mediate interactions with adjacent protomers. This mode is consistent with initiation regulation by ATP-DnaA and bidirectional loading of DnaB helicases.
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Affiliation(s)
- Yasunori Noguchi
- From the Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Yukari Sakiyama
- From the Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Hironori Kawakami
- From the Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Tsutomu Katayama
- From the Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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32
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Leonard AC, Grimwade JE. The orisome: structure and function. Front Microbiol 2015; 6:545. [PMID: 26082765 PMCID: PMC4451416 DOI: 10.3389/fmicb.2015.00545] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 05/18/2015] [Indexed: 11/15/2022] Open
Abstract
During the cell division cycle of all bacteria, DNA-protein complexes termed orisomes trigger the onset of chromosome duplication. Orisome assembly is both staged and stringently regulated to ensure that DNA synthesis begins at a precise time and only once at each origin per cycle. Orisomes comprise multiple copies of the initiator protein DnaA, which oligomerizes after interacting with specifically positioned recognition sites in the unique chromosomal replication origin, oriC. Since DnaA is highly conserved, it is logical to expect that all bacterial orisomes will share fundamental attributes. Indeed, although mechanistic details remain to be determined, all bacterial orisomes are capable of unwinding oriC DNA and assisting with loading of DNA helicase onto the single-strands. However, comparative analysis of oriCs reveals that the arrangement and number of DnaA recognition sites is surprisingly variable among bacterial types, suggesting there are many paths to produce functional orisome complexes. Fundamental questions exist about why these different paths exist and which features of orisomes must be shared among diverse bacterial types. In this review we present the current understanding of orisome assembly and function in Escherichia coli and compare the replication origins among the related members of the Gammaproteobacteria. From this information we propose that the diversity in orisome assembly reflects both the requirement to regulate the conformation of origin DNA as well as to provide an appropriate cell cycle timing mechanism that reflects the lifestyle of the bacteria. We suggest that identification of shared steps in orisome assembly may reveal particularly good targets for new antibiotics.
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Affiliation(s)
- Alan C Leonard
- Department of Biological Sciences, Florida Institute of Technology, Melbourne FL, USA
| | - Julia E Grimwade
- Department of Biological Sciences, Florida Institute of Technology, Melbourne FL, USA
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33
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Chodavarapu S, Felczak MM, Simmons LA, Murillo A, Kaguni JM. Mutant DnaAs of Escherichia coli that are refractory to negative control. Nucleic Acids Res 2013; 41:10254-67. [PMID: 23990329 PMCID: PMC3905854 DOI: 10.1093/nar/gkt774] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
DnaA is the initiator of DNA replication in bacteria. A mutant DnaA named DnaAcos is unusual because it is refractory to negative regulation. We developed a genetic method to isolate other mutant DnaAs that circumvent regulation to extend our understanding of mechanisms that control replication initiation. Like DnaAcos, one mutant bearing a tyrosine substitution for histidine 202 (H202Y) withstands the regulation exerted by datA, hda and dnaN (β clamp), and both DnaAcos and H202Y resist inhibition by the Hda-β clamp complex in vitro. Other mutant DnaAs carrying G79D, E244K, V303M or E445K substitutions are either only partially sensitive or refractory to inhibition by the Hda-β clamp complex in vitro but are responsive to hda expression in vivo. All mutant DnaAs remain able to interact directly with Hda. Of interest, both DnaAcos and DnaAE244K bind more avidly to Hda. These mutants, by sequestrating Hda, may limit its availability to regulate other DnaA molecules, which remain active to induce extra rounds of DNA replication. Other evidence suggests that a mutant bearing a V292M substitution hyperinitiates by escaping the effect of an unknown regulatory factor. Together, our results provide new insight into the mechanisms that regulate replication initiation in Escherichia coli.
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Affiliation(s)
- Sundari Chodavarapu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824-1319, USA and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048, USA
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34
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Bell SP, Kaguni JM. Helicase loading at chromosomal origins of replication. Cold Spring Harb Perspect Biol 2013; 5:cshperspect.a010124. [PMID: 23613349 DOI: 10.1101/cshperspect.a010124] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Loading of the replicative DNA helicase at origins of replication is of central importance in DNA replication. As the first of the replication fork proteins assemble at chromosomal origins of replication, the loaded helicase is required for the recruitment of the rest of the replication machinery. In this work, we review the current knowledge of helicase loading at Escherichia coli and eukaryotic origins of replication. In each case, this process requires both an origin recognition protein as well as one or more additional proteins. Comparison of these events shows intriguing similarities that suggest a similar underlying mechanism, as well as critical differences that likely reflect the distinct processes that regulate helicase loading in bacterial and eukaryotic cells.
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Affiliation(s)
- Stephen P Bell
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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35
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Su'etsugu M, Harada Y, Keyamura K, Matsunaga C, Kasho K, Abe Y, Ueda T, Katayama T. The DnaA N-terminal domain interacts with Hda to facilitate replicase clamp-mediated inactivation of DnaA. Environ Microbiol 2013; 15:3183-95. [PMID: 23679057 DOI: 10.1111/1462-2920.12147] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 03/17/2013] [Indexed: 11/28/2022]
Abstract
DnaA activity for replication initiation of the Escherichia coli chromosome is negatively regulated by feedback from the DNA-loaded form of the replicase clamp. In this process, called RIDA (regulatory inactivation of DnaA), ATP-bound DnaA transiently assembles into a complex consisting of Hda and the DNA-clamp, which promotes inter-AAA+ domain association between Hda and DnaA and stimulates hydrolysis of DnaA-bound ATP, producing inactive ADP-DnaA. Using a truncated DnaA mutant, we previously demonstrated that the DnaA N-terminal domain is involved in RIDA. However, the precise role of the N-terminal domain in RIDA has remained largely unclear. Here, we used an in vitro reconstituted system to demonstrate that the Asn-44 residue in the N-terminal domain of DnaA is crucial for RIDA but not for replication initiation. Moreover, an assay termed PDAX (pull-down after cross-linking) revealed an unstable interaction between a DnaA-N44A mutant and Hda. In vivo, this mutant exhibited an increase in the cellular level of ATP-bound DnaA. These results establish a model in which interaction between DnaA Asn-44 and Hda stabilizes the association between the AAA+ domains of DnaA and Hda to facilitate DnaA-ATP hydrolysis during RIDA.
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Affiliation(s)
- Masayuki Su'etsugu
- Department of Molecular Biology, Kyushu University Graduate School of Pharmaceutical Sciences, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
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36
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Ozaki S, Noguchi Y, Hayashi Y, Miyazaki E, Katayama T. Differentiation of the DnaA-oriC subcomplex for DNA unwinding in a replication initiation complex. J Biol Chem 2012; 287:37458-71. [PMID: 22942281 DOI: 10.1074/jbc.m112.372052] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In Escherichia coli, ATP-DnaA multimers formed on the replication origin oriC promote duplex unwinding, which leads to helicase loading. Based on a detailed functional analysis of the oriC sequence motifs, we previously proposed that the left half of oriC forms an ATP-DnaA subcomplex competent for oriC unwinding, whereas the right half of oriC forms a distinct ATP-DnaA subcomplex that facilitates helicase loading. However, the molecular basis for the functional difference between these ATP-DnaA subcomplexes remains unclear. By analyzing a series of novel DnaA mutants, we found that structurally distinct DnaA multimers form on each half of oriC. DnaA AAA+ domain residues Arg-227 and Leu-290 are specifically required for oriC unwinding. Notably, these residues are required for the ATP-DnaA-specific structure of DnaA multimers in complex with the left half of oriC but not for that with the right half. These results support the idea that the ATP-DnaA multimers formed on oriC are not uniform and that they can adopt different conformations. Based on a structural model, we propose that Arg-227 and Leu-290 play a crucial role in inter-ATP-DnaA interaction and are a prerequisite for the formation of unwinding-competent DnaA subcomplexes on the left half of oriC. These residues are not required for the interaction with DnaB, nucleotide binding, or regulatory DnaA-ATP hydrolysis, which further supports their important role in inter-DnaA interaction. The corresponding residues are evolutionarily conserved and are required for unwinding in the initial complexes of Thermotoga maritima, an ancient hyperthermophile. Therefore, our findings suggest a novel and common mechanism for ATP-DnaA-dependent activation of initial complexes.
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Affiliation(s)
- Shogo Ozaki
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
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Ozaki S, Noguchi Y, Nishimura M, Katayama T. Stable nucleotide binding to DnaA requires a specific glutamic acid residue within the AAA+ box II motif. J Struct Biol 2012; 179:242-50. [PMID: 22579783 DOI: 10.1016/j.jsb.2012.05.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Revised: 04/28/2012] [Accepted: 05/01/2012] [Indexed: 11/28/2022]
Abstract
In complex with ATP, but not ADP, DnaA protein multimers unwind a specific region of duplex DNA within the chromosomal replication origin, oriC, triggering a series of reactions that result in initiation of DNA replication. Following replication initiation, ATP hydrolysis, which is coupled to DNA replication, results in the generation of initiation-incompetent ADP-DnaA. Suppression of overinitiation of replication requires that ADP-DnaA complexes be stably maintained until the next round of replication. Thus, the functional and structural requirements that ensure stable nucleotide binding to DnaA are crucial for proper regulation of replication. Here, we demonstrate that Glu143 of DnaA, located within the AAA+ box II N-linker motif, is a key residue involved in stable nucleotide binding. A Glu143 substitution variant of DnaA (DnaA E143A) bound to ADP on ice with an affinity similar to wild-type DnaA, but the resultant ADP-DnaA E143A complex was more labile at 37 °C than wild-type ADP-DnaA complexes. Consistent with this, conversion of ADP-DnaA E143A to ATP-DnaA E143A was stimulated at 37°C in the presence of ATP, which also stimulated replication of a minichromosome in an in vitro reconstitution reaction. Expression of DnaA E143A in vivo inhibited cell growth in an oriC-dependent manner, suggesting that DnaA E143A caused over-initiation of replication, consistent with the in vitro results. Glu is a highly conserved residue at the corresponding position of γ-proteobacterial DnaA orthologs. Our finding of the novel role for the DnaA N-linker region may represent a conserved function of this motif among those DnaA orthologs.
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Affiliation(s)
- Shogo Ozaki
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
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Ozaki S, Katayama T. Highly organized DnaA-oriC complexes recruit the single-stranded DNA for replication initiation. Nucleic Acids Res 2011; 40:1648-65. [PMID: 22053082 PMCID: PMC3287180 DOI: 10.1093/nar/gkr832] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In Escherichia coli, the replication origin oriC consists of two functional regions: the duplex unwinding element (DUE) and its flanking DnaA-assembly region (DAR). ATP-DnaA molecules multimerize on DAR, unwinding DUE for DnaB helicase loading. However, DUE-unwinding mechanisms and functional structures in DnaA–oriC complexes supporting those remain unclear. Here, using various in vitro reconstituted systems, we identify functionally distinct DnaA sub-complexes formed on DAR and reveal novel mechanisms in DUE unwinding. The DUE-flanking left-half DAR carrying high-affinity DnaA box R1 and the ATP-DnaA-preferential DnaA box R5, τ1-2 and I1-2 sites formed a DnaA sub-complex competent in DUE unwinding and ssDUE binding, thereby supporting basal DnaB loading activity. This sub-complex is further subdivided into two; the DUE-distal DnaA sub-complex formed on the ATP–DnaA-preferential sites binds ssDUE. Notably, the DUE-flanking, DnaA box R1–DnaA sub-complex recruits DUE to the DUE-distal DnaA sub-complex in concert with a DNA-bending nucleoid protein IHF, thereby promoting DUE unwinding and binding of ssDUE. The right-half DAR–DnaA sub-complex stimulated DnaB loading, consistent with in vivo analyses. Similar features are seen in DUE unwinding of the hyperthermophile, Thermotoga maritima, indicating evolutional conservation of those mechanisms.
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Affiliation(s)
- Shogo Ozaki
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
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Rozgaja TA, Grimwade JE, Iqbal M, Czerwonka C, Vora M, Leonard AC. Two oppositely oriented arrays of low-affinity recognition sites in oriC guide progressive binding of DnaA during Escherichia coli pre-RC assembly. Mol Microbiol 2011; 82:475-88. [PMID: 21895796 DOI: 10.1111/j.1365-2958.2011.07827.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The onset of chromosomal DNA replication requires highly precise and reproducible interactions between initiator proteins and replication origins to assemble a pre-replicative complex (pre-RC) that unwinds the DNA duplex. In bacteria, initiator protein DnaA, bound to specific high- and low-affinity recognition sites within the unique oriC locus, comprises the pre-RC, but how complex assembly is choreographed to ensure precise initiation timing during the cell cycle is not well understood. In this study, we present evidence that higher-order DnaA structures are formed at oriC when DnaA monomers are closely positioned on the same face of the DNA helix by interaction with two oppositely oriented essential arrays of closely spaced low-affinity DnaA binding sites. As DnaA levels increase, peripheral high-affinity anchor sites begin cooperative loading of the arrays, which is extended by sequential binding of additional DnaA monomers resulting in growth of the complexes towards the centre of oriC. We suggest that this polarized assembly of unique DnaA oligomers within oriC plays an important role in mediating pre-RC activity and may be a feature found in all bacterial replication origins.
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Affiliation(s)
- Tania A Rozgaja
- Department of Biological Sciences, Florida Institute of Technology, 150 W. University Blvd., Melbourne, FL 32901, USA
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40
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Replication initiation at the Escherichia coli chromosomal origin. Curr Opin Chem Biol 2011; 15:606-13. [PMID: 21856207 DOI: 10.1016/j.cbpa.2011.07.016] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Revised: 07/20/2011] [Accepted: 07/22/2011] [Indexed: 11/24/2022]
Abstract
To initiate DNA replication, DnaA recognizes and binds to specific sequences within the Escherichia coli chromosomal origin (oriC), and then unwinds a region within oriC. Next, DnaA interacts with DnaB helicase in loading the DnaB-DnaC complex on each separated strand. Primer formation by primase (DnaG) induces the dissociation of DnaC from DnaB, which involves the hydrolysis of ATP bound to DnaC. Recent evidence indicates that DnaC acts as a checkpoint in the transition from initiation to the elongation stage of DNA replication. Freed from DnaC, DnaB helicase unwinds the parental duplex DNA while interacting the cellular replicase, DNA polymerase III holoenzyme, and primase as it intermittently forms primers that are extended by the replicase in duplicating the chromosome.
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Leonard AC, Grimwade JE. Regulating DnaA complex assembly: it is time to fill the gaps. Curr Opin Microbiol 2010; 13:766-72. [PMID: 21035377 PMCID: PMC3005629 DOI: 10.1016/j.mib.2010.10.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Revised: 09/27/2010] [Accepted: 10/02/2010] [Indexed: 11/25/2022]
Abstract
New rounds of bacterial chromosome replication are triggered during each cell division cycle by the initiator protein, DnaA. For precise timing, interactions of DnaA-ATP monomers with the replication origin, oriC, must be carefully regulated during formation of complexes that unwind origin DNA and load replicative helicase. Recent studies in Escherichia coli suggest that high and low affinity DnaA recognition sites are positioned within oriC to direct staged assembly of bacterial pre-replication complexes, with DnaA contacting low affinity sites as it oligomerizes to 'fill the gaps' between high affinity sites. The wide variability of oriC DnaA recognition site patterns seen in nature may reflect myriad gap-filling strategies needed to couple oriC function to the lifestyle of different bacterial types.
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Affiliation(s)
- Alan C. Leonard
- Department of Biological Sciences, 234 Olin Life Sciences, Florida Institute of Technology, 150 W. University Blvd., Melbourne, FL 32901, USA
| | - Julia E. Grimwade
- Department of Biological Sciences, 235 Olin Life Sciences, Florida Institute of Technology, 150 W. University Blvd., Melbourne, FL 32901, USA
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Kawakami H, Katayama T. DnaA, ORC, and Cdc6: similarity beyond the domains of life and diversity. Biochem Cell Biol 2010; 88:49-62. [PMID: 20130679 DOI: 10.1139/o09-154] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
To initiate chromosomal DNA replication, specific proteins bind to the replication origin region and form multimeric and dynamic complexes. Bacterial DnaA, the eukaryotic origin recognition complex (ORC), and Cdc6 proteins, most of which include an AAA+(-like) motif, play crucial roles in replication initiation. The importance of ATP binding and hydrolysis in these proteins has recently become recognized. ATP binding of Escherichia coli DnaA is required for the formation of the activated form of a DnaA multimer on the replication origin. The ATP-DnaA multimer can unwind duplex DNA in an origin-dependent manner, which is supported by various specific functions of several AAA+ motifs. DnaA-ATP hydrolysis is stimulated after initiation, repressing extra initiations, and sustaining once-per-cell cycle replication. ATP binding of ORC and Cdc6 in Saccharomyces cerevisiae is required for heteromultimeric complex formation and specific DNA binding. ATP hydrolysis of these proteins is important for the efficient loading of the minichromosome maintenance protein complex, a component of the putative replicative helicase. In this review, we discuss the roles of DnaA, ORC, and Cdc6 in replication initiation and its regulation. We also summarize the functional features of the AAA+ domains of these proteins, and the functional divergence of ORC in chromosomal dynamics.
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Affiliation(s)
- Hironori Kawakami
- Cold Spring Harbor Laboratory, 1 Bungtown Rd., Cold Spring Harbor, NY 11724, USA.
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Keyamura K, Abe Y, Higashi M, Ueda T, Katayama T. DiaA dynamics are coupled with changes in initial origin complexes leading to helicase loading. J Biol Chem 2009; 284:25038-50. [PMID: 19632993 DOI: 10.1074/jbc.m109.002717] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Chromosomal replication initiation requires the regulated formation of dynamic higher order complexes. Escherichia coli ATP-DnaA forms a specific multimer on oriC, resulting in DNA unwinding and DnaB helicase loading. DiaA, a DnaA-binding protein, directly stimulates the formation of ATP-DnaA multimers on oriC and ensures timely replication initiation. In this study, DnaA Phe-46 was identified as the crucial DiaA-binding site required for DiaA-stimulated ATP-DnaA assembly on oriC. Moreover, we show that DiaA stimulation requires only a subgroup of DnaA molecules binding to oriC, that DnaA Phe-46 is also important in the loading of DnaB helicase onto the oriC-DnaA complexes, and that this process also requires only a subgroup of DnaA molecules. Despite the use of only a DnaA subgroup, DiaA inhibited DnaB loading on oriC-DnaA complexes, suggesting that DiaA and DnaB bind to a common DnaA subgroup. A cellular factor can relieve the DiaA inhibition, allowing DnaB loading. Consistently, DnaA F46A caused retarded initiations in vivo in a DiaA-independent manner. It is therefore likely that DiaA dynamics are crucial in the regulated sequential progress of DnaA assembly and DnaB loading. We accordingly propose a model for dynamic structural changes of initial oriC complexes loading DiaA or DnaB helicase.
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Affiliation(s)
- Kenji Keyamura
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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Ozaki S, Katayama T. DnaA structure, function, and dynamics in the initiation at the chromosomal origin. Plasmid 2009; 62:71-82. [PMID: 19527752 DOI: 10.1016/j.plasmid.2009.06.003] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2009] [Revised: 06/06/2009] [Accepted: 06/08/2009] [Indexed: 01/13/2023]
Abstract
Escherichia coli DnaA is the initiator of chromosomal replication. Multiple ATP-DnaA molecules assemble at the oriC replication origin in a highly regulated manner, and the resultant initiation complexes promote local duplex unwinding within oriC, resulting in open complexes. DnaB helicase is loaded onto the unwound single-stranded region within oriC via interaction with the DnaA multimers. The tertiary structure of the functional domains of DnaA has been determined and several crucial residues in the initiation process, as well as their unique functions, have been identified. These include specific DNA binding, inter-DnaA interaction, specific and regulatory interactions with ATP and with the unwound single-stranded oriC DNA, and functional interaction with DnaB helicase. An overall structure of the initiation complex is also proposed. These are important for deepening our understanding of the molecular mechanisms that underlie DnaA assembly, oriC duplex unwinding, regulation of the initiation reaction, and DnaB helicase loading. In this review, we summarize recent progress on the molecular mechanisms of the functions of DnaA on oriC. In addition, some members of the AAA+ protein family related to the initiation of replication and its regulation (e.g., DnaA) are briefly discussed.
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Affiliation(s)
- Shogo Ozaki
- Department of Molecular Biology, Kyushu University, Fukuoka, Japan
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45
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Replication initiator DnaA of Escherichia coli changes its assembly form on the replication origin during the cell cycle. J Bacteriol 2009; 191:4807-14. [PMID: 19502409 DOI: 10.1128/jb.00435-09] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
DnaA is a replication initiator protein that is conserved among bacteria. It plays a central role in the initiation of DNA replication. In order to monitor its behavior in living Escherichia coli cells, a nonessential portion of the protein was replaced by a fluorescent protein. Such a strain grew normally, and flow cytometry data suggested that the chimeric protein has no substantial loss of the initiator activity. The initiator was distributed all over the nucleoid. Furthermore, a majority of the cells exhibited certain distinct foci that emitted bright fluorescence. These foci colocalized with the replication origin (oriC) region and were brightest during the period spanning the initiation event. In cells that had undergone the initiation, the foci were enriched in less intense ones. In addition, a significant portion of the oriC regions at this cell cycle stage had no colocalized DnaA-enhanced yellow fluorescent protein (EYFP) focus point. It was difficult to distinguish the initiator titration locus (datA) from the oriC region. However, involvement of datA in the initiation control was suggested from the observation that, in DeltadatA cells, DnaA-EYFP maximally colocalized with the oriC region earlier in the cell cycle than it did in wild-type cells and oriC concentration was increased.
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