1
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Chappleboim M, Naveh-Tassa S, Carmi M, Levy Y, Barkai N. Ordered and disordered regions of the Origin Recognition Complex direct differential in vivo binding at distinct motif sequences. Nucleic Acids Res 2024; 52:5720-5731. [PMID: 38597680 PMCID: PMC11162778 DOI: 10.1093/nar/gkae249] [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: 01/10/2024] [Revised: 03/16/2024] [Accepted: 04/09/2024] [Indexed: 04/11/2024] Open
Abstract
The Origin Recognition Complex (ORC) seeds replication-fork formation by binding to DNA replication origins, which in budding yeast contain a 17bp DNA motif. High resolution structure of the ORC-DNA complex revealed two base-interacting elements: a disordered basic patch (Orc1-BP4) and an insertion helix (Orc4-IH). To define the ORC elements guiding its DNA binding in vivo, we mapped genomic locations of 38 designed ORC mutants, revealing that different ORC elements guide binding at different sites. At silencing-associated sites lacking the motif, ORC binding and activity were fully explained by a BAH domain. Within replication origins, we reveal two dominating motif variants showing differential binding modes and symmetry: a non-repetitive motif whose binding requires Orc1-BP4 and Orc4-IH, and a repetitive one where another basic patch, Orc1-BP3, can replace Orc4-IH. Disordered basic patches are therefore key for ORC-motif binding in vivo, and we discuss how these conserved, minor-groove interacting elements can guide specific ORC-DNA recognition.
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Affiliation(s)
- Michal Chappleboim
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Segev Naveh-Tassa
- Department of Chemical and structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Miri Carmi
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Yaakov Levy
- Department of Chemical and structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Naama Barkai
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
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2
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Inoue S, Ikeda Y, Fujiyama S, Ueda T, Abe Y. Oligomeric state of the N-terminal domain of DnaT for replication restart in Escherichia coli. BIOCHIMICA ET BIOPHYSICA ACTA. PROTEINS AND PROTEOMICS 2023:140929. [PMID: 37328019 DOI: 10.1016/j.bbapap.2023.140929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 06/09/2023] [Accepted: 06/12/2023] [Indexed: 06/18/2023]
Abstract
DNA replication stops when chemical or physical damage occurs to the DNA. Repairing genomic DNA and reloading the replication helicase are crucial steps for restarting DNA replication. The Escherichia coli primosome is a complex of proteins and DNA responsible for reloading the replication helicase DnaB. DnaT, a protein found in the primosome complex, contains two functional domains. The C-terminal domain (89-179) forms an oligomeric complex with single-stranded DNA. Although the N-terminal domain (1-88) forms an oligomer, the specific residues responsible for this oligomeric structure have not yet been identified. In this study, we proposed that the N-terminal domain of DnaT has a dimeric antitoxin structure based on its primary sequence. Based on the proposed model, we confirmed the site of oligomerization in the N-terminal domain of DnaT through site-directed mutagenesis. The molecular masses and thermodynamic stabilities of the site-directed mutants located at the dimer interface, namely Phe42, Tyr43, Leu50, Leu53, and Leu54, were found to be lower than those of the wild-type. Moreover, we observed a decrease in the molecular masses of the V10S and F35S mutants compared to the wild-type DnaT. NMR analysis of the V10S mutant revealed that the secondary structure of the N-terminal domain of DnaT was consistent with the proposed model. Additionally, we have demonstrated that the stability of the oligomer formed by the N-terminal domain of DnaT is crucial for its function. Based on these findings, we propose that the DnaT oligomer plays a role in replication restart in Escherichia coli.
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Affiliation(s)
- Shogo Inoue
- Department of Protein Structure, Function and Design, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Yohei Ikeda
- Department of Protein Structure, Function and Design, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Saki Fujiyama
- Department of Protein Structure, Function and Design, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Tadashi Ueda
- Department of Protein Structure, Function and Design, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Yoshito Abe
- Department of Protein Structure, Function and Design, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan; Department of Pharmaceutical Sciences, School of Pharmacy at Fukuoka, International University of Health and Welfare, Okawa 831-8501, Japan.
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3
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Borrelia burgdorferi DnaA and the Nucleoid-Associated Protein EbfC Coordinate Expression of the dnaX-ebfC Operon. J Bacteriol 2023; 205:e0039622. [PMID: 36533911 PMCID: PMC9879097 DOI: 10.1128/jb.00396-22] [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] [Indexed: 12/23/2022] Open
Abstract
Borrelia burgdorferi, the spirochete agent of Lyme disease, has evolved within a consistent infectious cycle between tick and vertebrate hosts. The transmission of the pathogen from tick to vertebrate is characterized by rapid replication and a change in the outer surface protein profile. EbfC, a highly conserved nucleoid-associated protein, binds throughout the borrelial genome, affecting expression of many genes, including the Erp outer surface proteins. In B. burgdorferi, like many other bacterial species, ebfC is cotranscribed with dnaX, an essential component of the DNA polymerase III holoenzyme, which facilitates chromosomal replication. The expression of the dnaX-ebfC operon is tied to the spirochete's replication rate, but the underlying mechanism for this connection was unknown. In this work, we provide evidence that the expression of dnaX-ebfC is controlled by direct interactions of DnaA, the chromosomal replication initiator, and EbfC at the unusually long dnaX-ebfC 5' untranslated region (UTR). Both proteins bind to the 5' UTR DNA, with EbfC also binding to the RNA. The DNA binding of DnaA to this region was similarly impacted by ATP and ADP. In vitro studies characterized DnaA as an activator of dnaX-ebfC and EbfC as an antiactivator. We further found evidence that DnaA may regulate other genes essential for replication. IMPORTANCE The dual life cycle of Borrelia burgdorferi, the causative agent of Lyme disease, is characterized by periods of rapid and slowed replication. The expression patterns of many of the spirochete's virulence factors are impacted by these changes in replication rates. The connection between replication and virulence can be understood at the dnaX-ebfC operon. DnaX is an essential component of the DNA polymerase III holoenzyme, which replicates the chromosome. EbfC is a nucleoid-associated protein that regulates the infection-associated outer surface Erp proteins, as well as other transcripts. The expression of dnaX-ebfC is tied to replication rate, which we demonstrate is mediated by DnaA, the master chromosomal initiator protein and transcription factor, and EbfC.
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4
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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: 1] [Impact Index Per Article: 0.5] [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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5
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Kothapalli R, Ghirlando R, Khan ZA, Chatterjee S, Kedei N, Chattoraj D. The dimerization interface of initiator RctB governs chaperone and enhancer dependence of Vibrio cholerae chromosome 2 replication. Nucleic Acids Res 2022; 50:4529-4544. [PMID: 35390166 PMCID: PMC9071482 DOI: 10.1093/nar/gkac210] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 03/01/2022] [Accepted: 03/20/2022] [Indexed: 11/13/2022] Open
Abstract
Protein function often requires remodeling of protein structure. In the well-studied iteron-containing plasmids, the initiator of replication has a dimerization interface that undergoes chaperone-mediated remodeling. This remodeling reduces dimerization and promotes DNA replication, since only monomers bind origin DNA. A structurally homologs interface exists in RctB, the replication initiator of Vibrio cholerae chromosome 2 (Chr2). Chaperones also promote Chr2 replication, although both monomers and dimers of RctB bind to origin, and chaperones increase the binding of both. Here we report how five changes in the dimerization interface of RctB affect the protein. The mutants are variously defective in dimerization, more active as initiator, and except in one case, unresponsive to chaperone (DnaJ). The results indicate that chaperones also reduce RctB dimerization and support the proposal that the paradoxical chaperone-promoted dimer binding likely represents sequential binding of monomers on DNA. RctB is also activated for replication initiation upon binding to a DNA site, crtS, and three of the mutants are also unresponsive to crtS. This suggests that crtS, like chaperones, reduces dimerization, but additional evidence suggests that the remodelling activities function independently. Involvement of two remodelers in reducing dimerization signifies the importance of dimerization in limiting Chr2 replication.
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Affiliation(s)
- Roopa Kothapalli
- Basic Research Laboratory, Center for Cancer Research, NCI, NIH, Bethesda, MD 20892, USA
| | - Rodolfo Ghirlando
- Laboratory of Molecular Biology, NIDDK, NIH, Bethesda, MD 20892, USA
| | - Zaki Ali Khan
- Basic Research Laboratory, Center for Cancer Research, NCI, NIH, Bethesda, MD 20892, USA
| | - Soniya Chatterjee
- Basic Research Laboratory, Center for Cancer Research, NCI, NIH, Bethesda, MD 20892, USA
| | - Noemi Kedei
- Collaborative Protein Technology Resource, OSTP, Center for Cancer Research, NCI, NIH, Bethesda, MD 20892, USA
| | - Dhruba K Chattoraj
- Basic Research Laboratory, Center for Cancer Research, NCI, NIH, Bethesda, MD 20892, USA
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6
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Stępień K, Skoneczna A, Kula-Maximenko M, Jurczyk Ł, Mołoń M. Depletion of the Origin Recognition Complex Subunits Delays Aging in Budding Yeast. Cells 2022; 11:cells11081252. [PMID: 35455932 PMCID: PMC9032818 DOI: 10.3390/cells11081252] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 03/31/2022] [Accepted: 04/05/2022] [Indexed: 12/01/2022] Open
Abstract
Precise DNA replication is pivotal for ensuring the accurate inheritance of genetic information. To avoid genetic instability, each DNA fragment needs to be amplified only once per cell cycle. DNA replication in eukaryotes starts with the binding of the origin recognition complex (ORC) to the origins of DNA replication. The genes encoding ORC subunits have been conserved across eukaryotic evolution and are essential for the initiation of DNA replication. In this study, we conducted an extensive physiological and aging-dependent analysis of heterozygous cells lacking one copy of ORC genes in the BY4743 background. Cells with only one copy of the ORC genes showed a significant decrease in the level of ORC mRNA, a delay in the G1 phase of the cell cycle, and an extended doubling time. Here, we also show that the reducing the levels of Orc1-6 proteins significantly extends both the budding and average chronological lifespans. Heterozygous ORC/orcΔ and wild-type diploid cells easily undergo haploidization during chronological aging. This ploidy shift might be related to nutrient starvation or the inability to survive under stress conditions. A Raman spectroscopy analysis helped us to strengthen the hypothesis of the importance of lipid metabolism and homeostasis in aging.
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Affiliation(s)
- Karolina Stępień
- Department of Biology, Institute of Biology and Biotechnology, University of Rzeszów, 35-601 Rzeszów, Poland;
| | - Adrianna Skoneczna
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland
- Correspondence: (A.S.); (M.M.); Tel.: +48-22-659-70-72 (A.S.); +48-17-785-54-07 (M.M.)
| | - Monika Kula-Maximenko
- The Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, 30-239 Krakow, Poland;
| | - Łukasz Jurczyk
- Institute of Agricultural Sciences, Land Management and Environmental Protection, University of Rzeszow, 35-601 Rzeszów, Poland;
| | - Mateusz Mołoń
- Department of Biology, Institute of Biology and Biotechnology, University of Rzeszów, 35-601 Rzeszów, Poland;
- Correspondence: (A.S.); (M.M.); Tel.: +48-22-659-70-72 (A.S.); +48-17-785-54-07 (M.M.)
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7
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Padmanabhan S, Sanyal K, Dubey D. Identification and in silico analysis of the origin recognition complex in the human fungal pathogen Candida albicans. MICROPUBLICATION BIOLOGY 2021; 2021:10.17912/micropub.biology.000465. [PMID: 34568775 PMCID: PMC8456302 DOI: 10.17912/micropub.biology.000465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 09/08/2021] [Accepted: 09/08/2021] [Indexed: 11/06/2022]
Abstract
DNA replication in eukaryotes is initiated by the orchestrated assembly and association of initiator proteins (heterohexameric Origin Recognition Complex, ORC) on the replication origins. These functionally conserved proteins play significant roles in diverse cellular processes besides their central role in ignition of DNA replication at origins. Candida albicans, a major human fungal pathogen, is a diploid budding yeast that belongs to Ascomycota. However, C. albicans is significantly diverged from a well-studied model organism Saccharomyces cerevisiae, another ascomycete. The components of the DNA replication machinery in C. albicans remain largely uncharacterized. Identification of factors required for DNA replication is essential for understanding the evolution of the DNA replication machinery. We identified the putative ORC homologs in C. albicans and determined their relatedness with those of other eukaryotes including several yeast species. Our extensive in silico studies demonstrate that the domain architecture of CaORC proteins share similarities with the ORC proteins of S. cerevisiae. We dissect the domain organization of ORC (trans-acting factors) subunits that seem to associate with DNA replication origins in C. albicans. We present a model of the 3D structure of CaORC4 to gain further insights of this protein's function.
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Affiliation(s)
- Sreedevi Padmanabhan
- Molecular Biology Laboratory, Veer Bahadur Singh Purvanchal University, Jaunpur- 222003, Uttar Pradesh, India
| | - Kaustuv Sanyal
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, JNCASR, Bangalore - 560064, India.,
Correspondence to: Kaustuv Sanyal (); Dharanidhar Dubey ()
| | - Dharanidhar Dubey
- Molecular Biology Laboratory, Veer Bahadur Singh Purvanchal University, Jaunpur- 222003, Uttar Pradesh, India.,
Correspondence to: Kaustuv Sanyal (); Dharanidhar Dubey ()
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8
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Yuan Z, Li H. Molecular mechanisms of eukaryotic origin initiation, replication fork progression, and chromatin maintenance. Biochem J 2020; 477:3499-3525. [PMID: 32970141 PMCID: PMC7574821 DOI: 10.1042/bcj20200065] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/29/2020] [Accepted: 09/04/2020] [Indexed: 12/13/2022]
Abstract
Eukaryotic DNA replication is a highly dynamic and tightly regulated process. Replication involves several dozens of replication proteins, including the initiators ORC and Cdc6, replicative CMG helicase, DNA polymerase α-primase, leading-strand DNA polymerase ε, and lagging-strand DNA polymerase δ. These proteins work together in a spatially and temporally controlled manner to synthesize new DNA from the parental DNA templates. During DNA replication, epigenetic information imprinted on DNA and histone proteins is also copied to the daughter DNA to maintain the chromatin status. DNA methyltransferase 1 is primarily responsible for copying the parental DNA methylation pattern into the nascent DNA. Epigenetic information encoded in histones is transferred via a more complex and less well-understood process termed replication-couple nucleosome assembly. Here, we summarize the most recent structural and biochemical insights into DNA replication initiation, replication fork elongation, chromatin assembly and maintenance, and related regulatory mechanisms.
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Affiliation(s)
- Zuanning Yuan
- Structural Biology Program, Van Andel Institute, Grand Rapids, Michigan, U.S.A
| | - Huilin Li
- Structural Biology Program, Van Andel Institute, Grand Rapids, Michigan, U.S.A
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9
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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: 5] [Impact Index Per Article: 1.3] [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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10
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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: 0.5] [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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11
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Blocking the Trigger: Inhibition of the Initiation of Bacterial Chromosome Replication as an Antimicrobial Strategy. Antibiotics (Basel) 2019; 8:antibiotics8030111. [PMID: 31390740 PMCID: PMC6784150 DOI: 10.3390/antibiotics8030111] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 08/02/2019] [Accepted: 08/04/2019] [Indexed: 12/19/2022] Open
Abstract
All bacterial cells must duplicate their genomes prior to dividing into two identical daughter cells. Chromosome replication is triggered when a nucleoprotein complex, termed the orisome, assembles, unwinds the duplex DNA, and recruits the proteins required to establish new replication forks. Obviously, the initiation of chromosome replication is essential to bacterial reproduction, but this process is not inhibited by any of the currently-used antimicrobial agents. Given the urgent need for new antibiotics to combat drug-resistant bacteria, it is logical to evaluate whether or not unexploited bacterial processes, such as orisome assembly, should be more closely examined for sources of novel drug targets. This review will summarize current knowledge about the proteins required for bacterial chromosome initiation, as well as how orisomes assemble and are regulated. Based upon this information, we discuss current efforts and potential strategies and challenges for inhibiting this initiation pharmacologically.
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12
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Kawakami H, Muraoka R, Ohashi E, Kawabata K, Kanamoto S, Chichibu T, Tsurimoto T, Katayama T. Specific basic patch-dependent multimerization of Saccharomyces cerevisiae ORC on single-stranded DNA promotes ATP hydrolysis. Genes Cells 2019; 24:608-618. [PMID: 31233675 DOI: 10.1111/gtc.12710] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 06/12/2019] [Accepted: 06/18/2019] [Indexed: 11/26/2022]
Abstract
Replication initiation at specific genomic loci dictates precise duplication and inheritance of genetic information. In eukaryotic cells, ATP-bound origin recognition complexes (ORCs) stably bind to double-stranded (ds) DNA origins to recruit the replicative helicase onto the origin DNA. To achieve these processes, an essential region of the origin DNA must be recognized by the eukaryotic origin sensor (EOS) basic patch within the disordered domain of the largest ORC subunit, Orc1. Although ORC also binds single-stranded (ss) DNA in an EOS-independent manner, it is unknown whether EOS regulates ORC on ssDNA. We found that, in budding yeast, ORC multimerizes on ssDNA in vitro independently of adenine nucleotides. We also found that the ORC multimers form in an EOS-dependent manner and stimulate the ORC ATPase activity. An analysis of genomics data supported the idea that ORC-ssDNA binding occurs in vivo at specific genomic loci outside of replication origins. These results suggest that EOS function is differentiated by ORC-bound ssDNA, which promotes ORC self-assembly and ATP hydrolysis. These mechanisms could modulate ORC activity at specific genomic loci and could be conserved among eukaryotes.
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Affiliation(s)
- Hironori Kawakami
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Ryuya Muraoka
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Eiji Ohashi
- Department of Biology, Faculty of Science, Kyushu University, Fukuoka, Japan
| | - Kenta Kawabata
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Shota Kanamoto
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Takeaki Chichibu
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Toshiki Tsurimoto
- Department of Biology, Faculty of Science, Kyushu University, Fukuoka, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
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13
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Martin E, Williams HEL, Pitoulias M, Stevens D, Winterhalter C, Craggs TD, Murray H, Searle MS, Soultanas P. DNA replication initiation in Bacillus subtilis: structural and functional characterization of the essential DnaA-DnaD interaction. Nucleic Acids Res 2019; 47:2101-2112. [PMID: 30534966 PMCID: PMC6393240 DOI: 10.1093/nar/gky1220] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 11/15/2018] [Accepted: 11/22/2018] [Indexed: 02/06/2023] Open
Abstract
The homotetrameric DnaD protein is essential in low G+C content gram positive bacteria and is involved in replication initiation at oriC and re-start of collapsed replication forks. It interacts with the ubiquitously conserved bacterial master replication initiation protein DnaA at the oriC but structural and functional details of this interaction are lacking, thus contributing to our incomplete understanding of the molecular details that underpin replication initiation in bacteria. DnaD comprises N-terminal (DDBH1) and C-terminal (DDBH2) domains, with contradicting bacterial two-hybrid and yeast two-hybrid studies suggesting that either the former or the latter interact with DnaA, respectively. Using Nuclear Magnetic Resonance (NMR) we showed that both DDBH1 and DDBH2 interact with the N-terminal domain I of DnaA and studied the DDBH2 interaction in structural detail. We revealed two families of conformations for the DDBH2-DnaA domain I complex and showed that the DnaA-interaction patch of DnaD is distinct from the DNA-interaction patch, suggesting that DnaD can bind simultaneously DNA and DnaA. Using sensitive single-molecule FRET techniques we revealed that DnaD remodels DnaA-DNA filaments consistent with stretching and/or untwisting. Furthermore, the DNA binding activity of DnaD is redundant for this filament remodelling. This in turn suggests that DnaA and DnaD are working collaboratively in the oriC to locally melt the DNA duplex during replication initiation.
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Affiliation(s)
- Eleyna Martin
- Centre for Biomolecular Sciences, School of Chemistry, University of Nottingham, Nottingham NG7 2RD, UK
| | - Huw E L Williams
- Centre for Biomolecular Sciences, School of Chemistry, University of Nottingham, Nottingham NG7 2RD, UK
| | - Matthaios Pitoulias
- Centre for Biomolecular Sciences, School of Chemistry, University of Nottingham, Nottingham NG7 2RD, UK
| | - Daniel Stevens
- Centre for Bacterial Cell Biology, Medical School, Newcastle University, Newcastle NE2 4AX, UK
| | - Charles Winterhalter
- Centre for Bacterial Cell Biology, Medical School, Newcastle University, Newcastle NE2 4AX, UK
| | - Timothy D Craggs
- Sheffield Institute for Nucleic Acids, Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, UK
| | - Heath Murray
- Centre for Bacterial Cell Biology, Medical School, Newcastle University, Newcastle NE2 4AX, UK
| | - Mark S Searle
- Centre for Biomolecular Sciences, School of Chemistry, University of Nottingham, Nottingham NG7 2RD, UK
- Correspondence may also be addressed to Mark S. Searle. Tel: +44 115 9513567; Fax: +44 115 9513564;
| | - Panos Soultanas
- Centre for Biomolecular Sciences, School of Chemistry, University of Nottingham, Nottingham NG7 2RD, UK
- To whom correspondence should be addressed. Tel: +44 115 9513525; Fax: +44 115 9513564;
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14
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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: 2.7] [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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15
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Marques CA, McCulloch R. Conservation and Variation in Strategies for DNA Replication of Kinetoplastid Nuclear Genomes. Curr Genomics 2018; 19:98-109. [PMID: 29491738 PMCID: PMC5814967 DOI: 10.2174/1389202918666170815144627] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Revised: 03/19/2017] [Accepted: 04/11/2017] [Indexed: 12/21/2022] Open
Abstract
Introduction: Understanding how the nuclear genome of kinetoplastid parasites is replicated received experimental stimulus from sequencing of the Leishmania major, Trypanosoma brucei and Trypanosoma cruzi genomes around 10 years ago. Gene annotations suggested key players in DNA replication initiation could not be found in these organisms, despite considerable conservation amongst characterised eukaryotes. Initial studies that indicated trypanosomatids might possess an archaeal-like Origin Recognition Complex (ORC), composed of only a single factor termed ORC1/CDC6, have been supplanted by the more recent identification of an ORC in T. brucei. However, the constituent subunits of T. brucei ORC are highly diverged relative to other eukaryotic ORCs and the activity of the complex appears subject to novel, positive regulation. The availability of whole genome sequences has also allowed the deployment of genome-wide strategies to map DNA replication dynamics, to date in T. brucei and Leishmania. ORC1/CDC6 binding and function in T. brucei displays pronounced overlap with the unconventional organisation of gene expression in the genome. Moreover, mapping of sites of replication initiation suggests pronounced differences in replication dynamics in Leishmania relative to T. brucei. Conclusion: Here we discuss what implications these emerging data may have for parasite and eukaryotic biology of DNA replication.
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Affiliation(s)
- Catarina A Marques
- Division of Biological Chemistry and Drug Discovery, School of Life Sciences, Dow Street, University of Dundee, Dundee, DD1 5EH, UK
| | - Richard McCulloch
- The Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, Sir Graeme Davis Building, 120 University Place, University of Glasgow, Glasgow, G12 8TA, UK
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16
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Gehring AM, Astling DP, Matsumi R, Burkhart BW, Kelman Z, Reeve JN, Jones KL, Santangelo TJ. Genome Replication in Thermococcus kodakarensis Independent of Cdc6 and an Origin of Replication. Front Microbiol 2017; 8:2084. [PMID: 29163389 PMCID: PMC5663688 DOI: 10.3389/fmicb.2017.02084] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 10/11/2017] [Indexed: 11/22/2022] Open
Abstract
The initiation of DNA replication is typically tightly regulated by proteins that form initiation complexes at specific sequences known as replication origins. In Archaea and Eukaryotes, Cdc6, a near-universally conserved protein binds and facilitates the origin-dependent assembly of the replicative apparatus. TK1901 encodes Cdc6 in Thermococcus kodakarensis but, as we report here, TK1901 and the presumed origin of replication can be deleted from the genome of this hyperthermophilic Archaeon without any detectable effects on growth, genetic competence or the ability to support autonomous plasmid replication. All regions of the genome were equally represented in the sequences generated by whole genome sequencing of DNA isolated from T. kodakarensis strains with or without TK1901, inconsistent with DNA initiation occurring at one or few origins, and instead suggestive of replication initiating at many sites distributed throughout the genome. We were unable to generate strains lacking the recombination factors, RadA or RadB, consistent with T. kodakarensis cells, that are oligoploid (7–19 genomes per cell), employing a recombination-based mechanism of DNA replication. Deletion of the previously presumed origin region reduced the long-term viability of cultures supporting the possibility that retaining an origin-based mechanism of DNA initiation provides a survival mechanism for stationary phase cells with only one genome.
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Affiliation(s)
- Alexandra M Gehring
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, United States
| | - David P Astling
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO, United States
| | - Rie Matsumi
- Department of Microbiology, Ohio State University, Columbus, OH, United States
| | - Brett W Burkhart
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, United States
| | - Zvi Kelman
- Biomolecular Labeling Laboratory, Institute for Bioscience and Biotechnology Research, National Institute of Standards and Technology and the University of Maryland, Rockville, MD, United States
| | - John N Reeve
- Department of Microbiology, Ohio State University, Columbus, OH, United States
| | - Kenneth L Jones
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO, United States
| | - Thomas J Santangelo
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, United States
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17
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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: 24] [Impact Index Per Article: 3.4] [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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18
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Babu VMP, Itsko M, Baxter JC, Schaaper RM, Sutton MD. Insufficient levels of the nrdAB-encoded ribonucleotide reductase underlie the severe growth defect of the Δhda E. coli strain. Mol Microbiol 2017; 104:377-399. [PMID: 28130843 DOI: 10.1111/mmi.13632] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/23/2017] [Indexed: 11/28/2022]
Abstract
The ATP-bound form of the Escherichia coli DnaA replication initiator protein remodels the chromosomal origin of replication, oriC, to load the replicative helicase. The primary mechanism for regulating the activity of DnaA involves the Hda and β clamp proteins, which act together to dramatically stimulate the intrinsic DNA-dependent ATPase activity of DnaA via a process termed Regulatory Inactivation of DnaA. In addition to hyperinitiation, strains lacking hda function also exhibit cold sensitive growth at 30°C. Strains impaired for the other regulators of initiation (i.e., ΔseqA or ΔdatA) fail to exhibit cold sensitivity. The goal of this study was to gain insight into why loss of hda function impedes growth. We used a genetic approach to isolate 9 suppressors of Δhda cold sensitivity, and characterized the mechanistic basis by which these suppressors alleviated Δhda cold sensitivity. Taken together, our results provide strong support for the view that the fundamental defect associated with Δhda is diminished levels of DNA precursors, particularly dGTP and dATP. We discuss possible mechanisms by which the suppressors identified here may regulate dNTP pool size, as well as similarities in phenotypes between the Δhda strain and hda+ strains exposed to the ribonucleotide reductase inhibitor hydroxyurea.
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Affiliation(s)
- Vignesh M P Babu
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY, USA
| | - Mark Itsko
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | - Jamie C Baxter
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY, USA
| | - Roel M Schaaper
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | - Mark D Sutton
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY, USA
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19
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Seid CA, Smith JL, Grossman AD. Genetic and biochemical interactions between the bacterial replication initiator DnaA and the nucleoid-associated protein Rok in Bacillus subtilis. Mol Microbiol 2017; 103:798-817. [PMID: 27902860 DOI: 10.1111/mmi.13590] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/25/2016] [Indexed: 12/16/2022]
Abstract
We identified interactions between the conserved bacterial replication initiator and transcription factor DnaA and the nucleoid-associated protein Rok of Bacillus subtilis. DnaA binds directly to clusters of DnaA boxes at the origin of replication and elsewhere, including the promoters of several DnaA-regulated genes. Rok, an analog of H-NS from gamma-proteobacteria that affects chromosome architecture and of Lsr2 from Mycobacteria, binds A+T-rich sequences throughout the genome and represses expression of many genes. Using crosslinking and immunoprecipitation followed by deep sequencing (ChIP-seq), we found that DnaA was associated with eight previously identified regions containing clusters of DnaA boxes, plus 36 additional regions that were also bound by Rok. Association of DnaA with these additional regions appeared to be indirect as it was dependent on Rok and independent of the DNA-binding domain of DnaA. Gene expression and mutant analyses support a model in which DnaA and Rok cooperate to repress transcription of yxaJ, the yybNM operon and the sunA-bdbB operon. Our results indicate that DnaA modulates the activity of Rok. We postulate that this interaction might affect nucleoid architecture. Furthermore, DnaA might interact similarly with Rok analogues in other organisms.
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Affiliation(s)
- Charlotte A Seid
- Department of Biology, Massachusetts Institute of Technology, Building 68-530, Cambridge, MA, 02139, USA
| | - Janet L Smith
- Department of Biology, Massachusetts Institute of Technology, Building 68-530, Cambridge, MA, 02139, USA
| | - Alan D Grossman
- Department of Biology, Massachusetts Institute of Technology, Building 68-530, Cambridge, MA, 02139, USA
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20
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Zhang Q, Zhou A, Li S, Ni J, Tao J, Lu J, Wan B, Li S, Zhang J, Zhao S, Zhao GP, Shao F, Yao YF. Reversible lysine acetylation is involved in DNA replication initiation by regulating activities of initiator DnaA in Escherichia coli. Sci Rep 2016; 6:30837. [PMID: 27484197 PMCID: PMC4971506 DOI: 10.1038/srep30837] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 07/11/2016] [Indexed: 11/09/2022] Open
Abstract
The regulation of chromosomal replication is critical and the activation of DnaA by ATP binding is a key step in replication initiation. However, it remains unclear whether and how the process of ATP-binding to DnaA is regulated. Here, we show that DnaA can be acetylated, and its acetylation level varies with cell growth and correlates with DNA replication initiation frequencies in E. coli. Specifically, the conserved K178 in Walker A motif of DnaA can be acetylated and its acetylation level reaches the summit at the stationary phase, which prevents DnaA from binding to ATP or oriC and leads to inhibition of DNA replication initiation. The deacetylation process of DnaA is catalyzed by deacetylase CobB. The acetylation process of DnaA is mediated by acetyltransferase YfiQ, and nonenzymatically by acetyl-phosphate. These findings suggest that the reversible acetylation of DnaA ensures cells to respond promptly to environmental changes. Since Walker A motif is universally distributed across organisms, acetylation of Walker A motif may present a novel regulatory mechanism conserved from bacteria to eukaryotes.
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Affiliation(s)
- Qiufen Zhang
- Laboratory of Bacterial Pathogenesis, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Aiping Zhou
- Laboratory of Bacterial Pathogenesis, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.,Department of Laboratory Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Shuxian Li
- Laboratory of Bacterial Pathogenesis, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Jinjing Ni
- Laboratory of Bacterial Pathogenesis, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Jing Tao
- Laboratory of Bacterial Pathogenesis, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Jie Lu
- Department of Infectious Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Baoshan Wan
- Laboratory of Bacterial Pathogenesis, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Shuai Li
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Jian Zhang
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Shimin Zhao
- State Key Lab of Genetic Engineering &Institutes of Biomedical Sciences, Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Guo-Ping Zhao
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Feng Shao
- National Institute of Biological Sciences, Beijing 102206, China
| | - Yu-Feng Yao
- Laboratory of Bacterial Pathogenesis, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.,Department of Laboratory Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
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21
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Bugala J, Cimová V, Grones P, Grones J. Characterization of newly identified DnaA and DnaB proteins from Acetobacter. Res Microbiol 2016; 167:655-668. [PMID: 27404460 DOI: 10.1016/j.resmic.2016.06.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 06/19/2016] [Accepted: 06/27/2016] [Indexed: 10/21/2022]
Abstract
Although chromosomal replication is an essential feature of the bacterial life cycle, the replication mechanism and involved molecular players have never been properly characterized in the Acetobacter genera. Thanks to whole-genome sequencing, the unknown replication proteins from Acetobacter pasteurianus and Acetobacter orleanensis, DnaA-like and DnaB-like, could be identified. Despite the low nucleotide or amino acid similarity to the respective orthologs from Escherichia coli, their involvement during replication regulation was corroborated by artificial microRNA. In the Acetobacter genome, a novel replication origin, oriAo, was detected with three 9-nucleotide-long DnaA boxes to which DnaA-like proteins bind actively. Bacterial two-hybrid systems and co-immunoprecipitation confirmed the homologous and heterologous interactions between DnaA-like and DnaB-like proteins with their E. coli orthologs. This communication is due to the conserved tryptophan at position 6 for E. coli or 25 for Acetobacter that unables DnaA-like proteins to form oligomeric protein structures after its substitution. Altogether, these results provide novel insights into the genome replication mechanism in Acetobacter.
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Affiliation(s)
- Juraj Bugala
- Department of Molecular Biology, Comenius University, Mlynská Dolina B2-122, 842 15 Bratislava, Slovak Republic.
| | - Viera Cimová
- Department of Molecular Biology, Comenius University, Mlynská Dolina B2-122, 842 15 Bratislava, Slovak Republic.
| | - Peter Grones
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Center, Swedish University of Agricultural Sciences, 901 83 Umeå, Sweden.
| | - Jozef Grones
- Department of Molecular Biology, Comenius University, Mlynská Dolina B2-122, 842 15 Bratislava, Slovak Republic.
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22
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Frage B, Döhlemann J, Robledo M, Lucena D, Sobetzko P, Graumann PL, Becker A. Spatiotemporal choreography of chromosome and megaplasmids in theSinorhizobium meliloticell cycle. Mol Microbiol 2016; 100:808-23. [DOI: 10.1111/mmi.13351] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/05/2016] [Indexed: 11/29/2022]
Affiliation(s)
- Benjamin Frage
- LOEWE Center for Synthetic Microbiology and Faculty of Biology; Philipps-Universität Marburg; 35032 Marburg Germany
| | - Johannes Döhlemann
- LOEWE Center for Synthetic Microbiology and Faculty of Biology; Philipps-Universität Marburg; 35032 Marburg Germany
| | - Marta Robledo
- LOEWE Center for Synthetic Microbiology and Faculty of Biology; Philipps-Universität Marburg; 35032 Marburg Germany
| | - Daniella Lucena
- LOEWE Center for Synthetic Microbiology and Faculty of Chemistry, Philipps-Universität Marburg, 35032; Marburg Germany
| | - Patrick Sobetzko
- LOEWE Center for Synthetic Microbiology and Faculty of Biology; Philipps-Universität Marburg; 35032 Marburg Germany
| | - Peter L. Graumann
- LOEWE Center for Synthetic Microbiology and Faculty of Chemistry, Philipps-Universität Marburg, 35032; Marburg Germany
| | - Anke Becker
- LOEWE Center for Synthetic Microbiology and Faculty of Biology; Philipps-Universität Marburg; 35032 Marburg Germany
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23
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Kawakami H, Ohashi E, Tsurimoto T, Katayama T. Rapid Purification and Characterization of Mutant Origin Recognition Complexes in Saccharomyces cerevisiae. Front Microbiol 2016; 7:521. [PMID: 27148210 PMCID: PMC4834435 DOI: 10.3389/fmicb.2016.00521] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 03/29/2016] [Indexed: 11/25/2022] Open
Abstract
Purification of the origin recognition complex (ORC) from wild-type budding yeast cells more than two decades ago opened up doors to analyze the initiation of eukaryotic chromosomal DNA replication biochemically. Although revised methods to purify ORC from overproducing cells were reported later, purification of mutant proteins using these systems still depends on time-consuming processes including genetic manipulation to construct and amplify mutant baculoviruses or yeast strains as well as several canonical protein fractionations. Here, we present a streamlined method to construct mutant overproducers, followed by purification of mutant ORCs. Use of mammalian cells co-transfected with conveniently mutagenized plasmids bearing a His tag excludes many of the construction and fractionation steps. Transfection is highly efficient. All the six subunits of ORC are overexpressed at a considerable level and isolated as a functional heterohexameric complex. Furthermore, use of mammalian cells prevents contamination of wild-type ORC from yeast cells. The method is applicable to wild-type and at least three mutant ORCs, and the resultant purified complexes show expected biochemical activities. The rapid acquisition of mutant ORCs using this system will boost systematic biochemical dissection of ORC and can be even applied to the purification of protein complexes other than ORC.
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Affiliation(s)
- Hironori Kawakami
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University Fukuoka, Japan
| | - Eiji Ohashi
- Department of Biology, Faculty of Science, Kyushu University Fukuoka, Japan
| | - Toshiki Tsurimoto
- Department of Biology, Faculty of Science, Kyushu University Fukuoka, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University Fukuoka, Japan
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24
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Marques CA, Tiengwe C, Lemgruber L, Damasceno JD, Scott A, Paape D, Marcello L, McCulloch R. Diverged composition and regulation of the Trypanosoma brucei origin recognition complex that mediates DNA replication initiation. Nucleic Acids Res 2016; 44:4763-84. [PMID: 26951375 PMCID: PMC4889932 DOI: 10.1093/nar/gkw147] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 03/01/2016] [Indexed: 01/14/2023] Open
Abstract
Initiation of DNA replication depends upon recognition of genomic sites, termed origins, by AAA+ ATPases. In prokaryotes a single factor binds each origin, whereas in eukaryotes this role is played by a six-protein origin recognition complex (ORC). Why eukaryotes evolved a multisubunit initiator, and the roles of each component, remains unclear. In Trypanosoma brucei, an ancient unicellular eukaryote, only one ORC-related initiator, TbORC1/CDC6, has been identified by sequence homology. Here we show that three TbORC1/CDC6-interacting factors also act in T. brucei nuclear DNA replication and demonstrate that TbORC1/CDC6 interacts in a high molecular complex in which a diverged Orc4 homologue and one replicative helicase subunit can also be found. Analysing the subcellular localization of four TbORC1/CDC6-interacting factors during the cell cycle reveals that one factor, TbORC1B, is not a static constituent of ORC but displays S-phase restricted nuclear localization and expression, suggesting it positively regulates replication. This work shows that ORC architecture and regulation are diverged features of DNA replication initiation in T. brucei, providing new insight into this key stage of eukaryotic genome copying.
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Affiliation(s)
- Catarina A Marques
- The Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Sir Graeme Davis Building, 120 University Place, Glasgow, G12 8TA, UK
| | - Calvin Tiengwe
- The Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Sir Graeme Davis Building, 120 University Place, Glasgow, G12 8TA, UK
| | - Leandro Lemgruber
- The Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Sir Graeme Davis Building, 120 University Place, Glasgow, G12 8TA, UK
| | - Jeziel D Damasceno
- The Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Sir Graeme Davis Building, 120 University Place, Glasgow, G12 8TA, UK
| | - Alan Scott
- The Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Sir Graeme Davis Building, 120 University Place, Glasgow, G12 8TA, UK
| | - Daniel Paape
- The Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Sir Graeme Davis Building, 120 University Place, Glasgow, G12 8TA, UK
| | - Lucio Marcello
- The Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Sir Graeme Davis Building, 120 University Place, Glasgow, G12 8TA, UK
| | - Richard McCulloch
- The Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Sir Graeme Davis Building, 120 University Place, Glasgow, G12 8TA, UK
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25
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Specific binding of eukaryotic ORC to DNA replication origins depends on highly conserved basic residues. Sci Rep 2015; 5:14929. [PMID: 26456755 PMCID: PMC4601075 DOI: 10.1038/srep14929] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 09/09/2015] [Indexed: 12/16/2022] Open
Abstract
In eukaryotes, the origin recognition complex (ORC) heterohexamer preferentially binds replication origins to trigger initiation of DNA replication. Crystallographic studies using eubacterial and archaeal ORC orthologs suggested that eukaryotic ORC may bind to origin DNA via putative winged-helix DNA-binding domains and AAA+ ATPase domains. However, the mechanisms how eukaryotic ORC recognizes origin DNA remain elusive. Here, we show in budding yeast that Lys-362 and Arg-367 residues of the largest subunit (Orc1), both outside the aforementioned domains, are crucial for specific binding of ORC to origin DNA. These basic residues, which reside in a putative disordered domain, were dispensable for interaction with ATP and non-specific DNA sequences, suggesting a specific role in recognition. Consistent with this, both residues were required for origin binding of Orc1 in vivo. A truncated Orc1 polypeptide containing these residues solely recognizes ARS sequence with low affinity and Arg-367 residue stimulates sequence specific binding mode of the polypeptide. Lys-362 and Arg-367 residues of Orc1 are highly conserved among eukaryotic ORCs, but not in eubacterial and archaeal orthologs, suggesting a eukaryote-specific mechanism underlying recognition of replication origins by ORC.
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26
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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: 1.4] [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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27
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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: 69] [Impact Index Per Article: 7.7] [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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28
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Smith JL, Grossman AD. In Vitro Whole Genome DNA Binding Analysis of the Bacterial Replication Initiator and Transcription Factor DnaA. PLoS Genet 2015; 11:e1005258. [PMID: 26020636 PMCID: PMC4447404 DOI: 10.1371/journal.pgen.1005258] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 05/01/2015] [Indexed: 11/18/2022] Open
Abstract
DnaA, the replication initiation protein in bacteria, is an AAA+ ATPase that binds and hydrolyzes ATP and exists in a heterogeneous population of ATP-DnaA and ADP-DnaA. DnaA binds cooperatively to the origin of replication and several other chromosomal regions, and functions as a transcription factor at some of these regions. We determined the binding properties of Bacillus subtilis DnaA to genomic DNA in vitro at single nucleotide resolution using in vitro DNA affinity purification and deep sequencing (IDAP-Seq). We used these data to identify 269 binding regions, refine the consensus sequence of the DnaA binding site, and compare the relative affinity of binding regions for ATP-DnaA and ADP-DnaA. Most sites had a slightly higher affinity for ATP-DnaA than ADP-DnaA, but a few had a strong preference for binding ATP-DnaA. Of the 269 sites, only the eight strongest binding ones have been observed to bind DnaA in vivo, suggesting that other cellular factors or the amount of available DnaA in vivo restricts DnaA binding to these additional sites. Conversely, we found several chromosomal regions that were bound by DnaA in vivo but not in vitro, and that the nucleoid-associated protein Rok was required for binding in vivo. Our in vitro characterization of the inherent ability of DnaA to bind the genome at single nucleotide resolution provides a backdrop for interpreting data on in vivo binding and regulation of DnaA, and is an approach that should be adaptable to many other DNA binding proteins.
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Affiliation(s)
- Janet L Smith
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Alan D Grossman
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
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29
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Kasho K, Fujimitsu K, Matoba T, Oshima T, Katayama T. Timely binding of IHF and Fis to DARS2 regulates ATP-DnaA production and replication initiation. Nucleic Acids Res 2014; 42:13134-49. [PMID: 25378325 PMCID: PMC4245941 DOI: 10.1093/nar/gku1051] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
In Escherichia coli, the ATP-bound form of DnaA (ATP-DnaA) promotes replication initiation. During replication, the bound ATP is hydrolyzed to ADP to yield the ADP-bound form (ADP-DnaA), which is inactive for initiation. The chromosomal site DARS2 facilitates the regeneration of ATP-DnaA by catalyzing nucleotide exchange between free ATP and ADP bound to DnaA. However, the regulatory mechanisms governing this exchange reaction are unclear. Here, using in vitro reconstituted experiments, we show that two nucleoid-associated proteins, IHF and Fis, bind site-specifically to DARS2 to activate coordinately the exchange reaction. The regenerated ATP-DnaA was fully active in replication initiation and underwent DnaA-ATP hydrolysis. ADP-DnaA formed heteromultimeric complexes with IHF and Fis on DARS2, and underwent nucleotide dissociation more efficiently than ATP-DnaA. Consistently, mutant analyses demonstrated that specific binding of IHF and Fis to DARS2 stimulates the formation of ATP-DnaA production, thereby promoting timely initiation. Moreover, we show that IHF-DARS2 binding is temporally regulated during the cell cycle, whereas Fis only binds to DARS2 in exponentially growing cells. These results elucidate the regulation of ATP-DnaA and replication initiation in coordination with the cell cycle and growth phase.
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Affiliation(s)
- Kazutoshi Kasho
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Kazuyuki Fujimitsu
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Toshihiro Matoba
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Taku Oshima
- Division of Genomics of Bacterial Cell Functions, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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30
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Donczew R, Mielke T, Jaworski P, Zakrzewska-Czerwińska J, Zawilak-Pawlik A. Assembly of Helicobacter pylori initiation complex is determined by sequence-specific and topology-sensitive DnaA-oriC interactions. J Mol Biol 2014; 426:2769-82. [PMID: 24862285 DOI: 10.1016/j.jmb.2014.05.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Revised: 05/15/2014] [Accepted: 05/16/2014] [Indexed: 10/25/2022]
Abstract
In bacteria, chromosome replication is initiated by binding of the DnaA initiator protein to DnaA boxes located in the origin of chromosomal replication (oriC). This leads to DNA helix opening within the DNA-unwinding element. Helicobacter pylori oriC, the first bipartite origin identified in Gram-negative bacteria, contains two subregions, oriC1 and oriC2, flanking the dnaA gene. The DNA-unwinding element region is localized in the oriC2 subregion downstream of dnaA. Surprisingly, oriC2-DnaA interactions were shown to depend on DNA topology, which is unusual in bacteria but is similar to initiator-origin interactions observed in higher organisms. In this work, we identified three DnaA boxes in the oriC2 subregion, two of which were bound only as supercoiled DNA. We found that all three DnaA boxes play important roles in orisome assembly and subsequent DNA unwinding, but different functions can be assigned to individual boxes. This suggests that the H. pylori oriC may be functionally divided, similar to what was described recently for Escherichia coli oriC. On the basis of these results, we propose a model of initiation complex formation in H. pylori.
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Affiliation(s)
- Rafał Donczew
- Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Department of Microbiology, Weigla 12, 53-114 Wrocław, Poland.
| | - Thorsten Mielke
- Max Planck Institute for Molecular Genetics, Ihnestrasse 63-73, 14195 Berlin, Germany.
| | - Paweł Jaworski
- Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Department of Microbiology, Weigla 12, 53-114 Wrocław, Poland.
| | - Jolanta Zakrzewska-Czerwińska
- Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Department of Microbiology, Weigla 12, 53-114 Wrocław, Poland; University of Wrocław, Faculty of Biotechnology, Joliot-Curie 14a, 50-138 Wrocław, Poland.
| | - Anna Zawilak-Pawlik
- Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Department of Microbiology, Weigla 12, 53-114 Wrocław, Poland.
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31
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Donczew R, Zakrzewska-Czerwińska J, Zawilak-Pawlik A. Beyond DnaA: the role of DNA topology and DNA methylation in bacterial replication initiation. J Mol Biol 2014; 426:2269-82. [PMID: 24747048 DOI: 10.1016/j.jmb.2014.04.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 04/10/2014] [Accepted: 04/11/2014] [Indexed: 12/31/2022]
Abstract
The replication of chromosomal DNA is a fundamental event in the life cycle of every cell. The first step of replication, initiation, is controlled by multiple factors to ensure only one round of replication per cell cycle. The process of initiation has been described most thoroughly for bacteria, especially Escherichia coli, and involves many regulatory proteins that vary considerably between different species. These proteins control the activity of the two key players of initiation in bacteria: the initiator protein DnaA and the origin of chromosome replication (oriC). Factors involved in the control of the availability, activity, or oligomerization of DnaA during initiation are generally regarded as the most important and thus have been thoroughly characterized. Other aspects of the initiation process, such as origin accessibility and susceptibility to unwinding, have been less explored. However, recent findings indicate that these factors have a significant role. This review focuses on DNA topology, conformation, and methylation as important factors that regulate the initiation process in bacteria. We present a comprehensive summary of the factors involved in the modulation of DNA topology, both locally at oriC and more globally at the level of the entire chromosome. We show clearly that the conformation of oriC dynamically changes, and control of this conformation constitutes another, important factor in the regulation of bacterial replication initiation. Furthermore, the process of initiation appears to be associated with the dynamics of the entire chromosome and this association is an important but largely unexplored phenomenon.
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Affiliation(s)
- Rafał Donczew
- Institute of Immunology and Experimental Therapy, Department of Microbiology, Polish Academy of Sciences, Weigla 12, 53-114 Wrocław, Poland.
| | - Jolanta Zakrzewska-Czerwińska
- Institute of Immunology and Experimental Therapy, Department of Microbiology, Polish Academy of Sciences, Weigla 12, 53-114 Wrocław, Poland; Faculty of Biotechnology, University of Wrocław, Joliot-Curie 14a, 50-138 Wrocław, Poland.
| | - Anna Zawilak-Pawlik
- Institute of Immunology and Experimental Therapy, Department of Microbiology, Polish Academy of Sciences, Weigla 12, 53-114 Wrocław, Poland.
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32
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Affiliation(s)
- Bénédicte Michel
- Centre de Génétique Moléculaire; CNRS; Gif sur Yvette France
- Université Paris-Sud; Orsay France
| | - Rolf Bernander
- Department of Molecular Biosciences; The Wenner-Gren Institute; Stockholm University; Stockholm Sweden
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33
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Baek JH, Chattoraj DK. Chromosome I controls chromosome II replication in Vibrio cholerae. PLoS Genet 2014; 10:e1004184. [PMID: 24586205 PMCID: PMC3937223 DOI: 10.1371/journal.pgen.1004184] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Accepted: 01/02/2014] [Indexed: 11/19/2022] Open
Abstract
Control of chromosome replication involves a common set of regulators in eukaryotes, whereas bacteria with divided genomes use chromosome-specific regulators. How bacterial chromosomes might communicate for replication is not known. In Vibrio cholerae, which has two chromosomes (chrI and chrII), replication initiation is controlled by DnaA in chrI and by RctB in chrII. DnaA has binding sites at the chrI origin of replication as well as outside the origin. RctB likewise binds at the chrII origin and, as shown here, to external sites. The binding to the external sites in chrII inhibits chrII replication. A new kind of site was found in chrI that enhances chrII replication. Consistent with its enhancing activity, the chrI site increased RctB binding to those chrII origin sites that stimulate replication and decreased binding to other sites that inhibit replication. The differential effect on binding suggests that the new site remodels RctB. The chaperone-like activity of the site is supported by the finding that it could relieve the dependence of chrII replication on chaperone proteins DnaJ and DnaK. The presence of a site in chrI that specifically controls chrII replication suggests a mechanism for communication between the two chromosomes for replication. Genome maintenance in dividing cells requires that the chromosomes replicate reliably once per cell cycle, and that this replication be timed to allow for proper segregation of the daughter chromosomes before cell division. In organisms with divided genomes, eukaryotes and a significant class of bacteria, the chromosomes must avoid interference with one another. They exhibit disciplined chromosome choreography, involving several regulators and control circuits that, even in the simplest organisms, are poorly understood. Here we examine the regulatory processes involved in maintaining the two chromosomes of the well-studied and medically important pathogen Vibrio cholerae. We provide evidence that a site in chromosome I can control the frequency and timing of replication of chromosome II. The mechanism involves a DNA-mediated remodeling of the chromosome II-specific initiator of replication by the chromosome I site. The site enhances the activity of the protein by differentially affecting its affinity for inhibitory and stimulatory sites on chromosome II. Our results provide the groundwork for determining whether coordination of replication might be a conserved feature that maintains chromosomes in proliferating cells of higher organisms.
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Affiliation(s)
- Jong Hwan Baek
- Laboratory of Biochemistry and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Dhruba K. Chattoraj
- Laboratory of Biochemistry and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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34
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Branagan AM, Klein JA, Jordan CS, Morrical SW. Control of helicase loading in the coupled DNA replication and recombination systems of bacteriophage T4. J Biol Chem 2013; 289:3040-54. [PMID: 24338568 DOI: 10.1074/jbc.m113.505842] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Gp59 protein of bacteriophage T4 promotes DNA replication by loading the replicative helicase, Gp41, onto replication forks and recombination intermediates. Gp59 also blocks DNA synthesis by Gp43 polymerase until Gp41 is loaded, ensuring that synthesis is tightly coupled to unwinding. The distinct polymerase blocking and helicase loading activities of Gp59 likely involve different binding interactions with DNA and protein partners. Here, we investigate how interactions of Gp59 with DNA and Gp32, the T4 single-stranded DNA (ssDNA)-binding protein, are related to these activities. A previously characterized mutant, Gp59-I87A, exhibits markedly reduced affinity for ssDNA and pseudo-fork DNA substrates. We demonstrate that on Gp32-covered ssDNA, the DNA binding defect of Gp59-I87A is not detrimental to helicase loading and translocation. In contrast, on pseudo-fork DNA the I87A mutation is detrimental to helicase loading and unwinding in the presence or absence of Gp32. Other results indicate that Gp32 binding to lagging strand ssDNA relieves the blockage of Gp43 polymerase activity by Gp59, whereas the inhibition of Gp43 exonuclease activity is maintained. Our findings suggest that Gp59-Gp32 and Gp59-DNA interactions perform separate but complementary roles in T4 DNA metabolism; Gp59-Gp32 interactions are needed to load Gp41 onto D-loops, and other nucleoprotein structures containing clusters of Gp32. Gp59-DNA interactions are needed to load Gp41 onto nascent or collapsed replication forks lacking clusters of Gp32 and to coordinate bidirectional replication from T4 origins. The dual functionalities of Gp59 allow it to promote the initiation or re-start of DNA replication from a wide variety of recombination and replication intermediates.
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Affiliation(s)
- Amy M Branagan
- From the Department of Biochemistry, University of Vermont College of Medicine, Burlington, Vermont 05405
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35
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Jonas K, Liu J, Chien P, Laub MT. Proteotoxic stress induces a cell-cycle arrest by stimulating Lon to degrade the replication initiator DnaA. Cell 2013; 154:623-36. [PMID: 23911325 DOI: 10.1016/j.cell.2013.06.034] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 05/15/2013] [Accepted: 06/20/2013] [Indexed: 10/26/2022]
Abstract
The decision to initiate DNA replication is a critical step in the cell cycle of all organisms. Cells often delay replication in the face of stressful conditions, but the underlying mechanisms remain incompletely defined. Here, we demonstrate in Caulobacter crescentus that proteotoxic stress induces a cell-cycle arrest by triggering the degradation of DnaA, the conserved replication initiator. A depletion of available Hsp70 chaperone, DnaK, either through genetic manipulation or heat shock, induces synthesis of the Lon protease, which can directly degrade DnaA. Unexpectedly, we find that unfolded proteins, which accumulate following a loss of DnaK, also allosterically activate Lon to degrade DnaA, thereby ensuring a cell-cycle arrest. Our work reveals a mechanism for regulating DNA replication under adverse growth conditions. Additionally, our data indicate that unfolded proteins can actively and directly alter substrate recognition by cellular proteases.
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Affiliation(s)
- Kristina Jonas
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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36
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Abstract
The onset of genomic DNA synthesis requires precise interactions of specialized initiator proteins with DNA at sites where the replication machinery can be loaded. These sites, defined as replication origins, are found at a few unique locations in all of the prokaryotic chromosomes examined so far. However, replication origins are dispersed among tens of thousands of loci in metazoan chromosomes, thereby raising questions regarding the role of specific nucleotide sequences and chromatin environment in origin selection and the mechanisms used by initiators to recognize replication origins. Close examination of bacterial and archaeal replication origins reveals an array of DNA sequence motifs that position individual initiator protein molecules and promote initiator oligomerization on origin DNA. Conversely, the need for specific recognition sequences in eukaryotic replication origins is relaxed. In fact, the primary rule for origin selection appears to be flexibility, a feature that is modulated either by structural elements or by epigenetic mechanisms at least partly linked to the organization of the genome for gene expression.
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Affiliation(s)
- Alan C Leonard
- Department of Biological Sciences, Florida Institute of Technology, Melbourne, Florida 32901
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37
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Scholefield G, Murray H. YabA and DnaD inhibit helix assembly of the DNA replication initiation protein DnaA. Mol Microbiol 2013; 90:147-59. [PMID: 23909787 DOI: 10.1111/mmi.12353] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/31/2013] [Indexed: 12/12/2022]
Abstract
Control of DNA replication initiation is essential for cell growth. A unifying characteristic of DNA replication initiator proteins is their distinctive AAA+ nucleotide-binding domains. The bacterial initiator DnaA assembles into a right-handed helical oligomer built upon interactions between neighbouring AAA+ domains to form an active initiation complex. Recently we developed a unique cross-linking assay that specifically detects ATP-dependent DnaA helix assembly. Here we have utilized this assay to show that two DnaA regulatory proteins in Bacillus subtilis, YabA and DnaD, inhibit DnaA helix formation. These results, in combination with our previous finding that the regulatory factor Soj/ParA also targets DnaA filament formation, highlight the critical importance of regulating DnaA helix formation during the initiation reaction. Moreover, these observations lead us to suggest that DnaA oligomerization may be the main regulatory step of the initiator assembly pathway in B. subtilis, in contrast to the prevailing model of bacterial DNA replication based on Escherichia coli DnaA where ATP binding appears to be the targeted activity.
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Affiliation(s)
- Graham Scholefield
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle Upon Tyne, NE2 4AX, UK
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38
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Barańska S, Glinkowska M, Herman-Antosiewicz A, Maciąg-Dorszyńska M, Nowicki D, Szalewska-Pałasz A, Węgrzyn A, Węgrzyn G. Replicating DNA by cell factories: roles of central carbon metabolism and transcription in the control of DNA replication in microbes, and implications for understanding this process in human cells. Microb Cell Fact 2013; 12:55. [PMID: 23714207 PMCID: PMC3698200 DOI: 10.1186/1475-2859-12-55] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Accepted: 05/26/2013] [Indexed: 12/29/2022] Open
Abstract
Precise regulation of DNA replication is necessary to ensure the inheritance of genetic features by daughter cells after each cell division. Therefore, determining how the regulatory processes operate to control DNA replication is crucial to our understanding and application to biotechnological processes. Contrary to early concepts of DNA replication, it appears that this process is operated by large, stationary nucleoprotein complexes, called replication factories, rather than by single enzymes trafficking along template molecules. Recent discoveries indicated that in bacterial cells two processes, central carbon metabolism (CCM) and transcription, significantly and specifically influence the control of DNA replication of various replicons. The impact of these discoveries on our understanding of the regulation of DNA synthesis is discussed in this review. It appears that CCM may influence DNA replication by either action of specific metabolites or moonlighting activities of some enzymes involved in this metabolic pathway. The role of transcription in the control of DNA replication may arise from either topological changes in nucleic acids which accompany RNA synthesis or direct interactions between replication and transcription machineries. Due to intriguing similarities between some prokaryotic and eukaryotic regulatory systems, possible implications of studies on regulation of microbial DNA replication on understanding such a process occurring in human cells are discussed.
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Affiliation(s)
- Sylwia Barańska
- Department of Molecular Biology, University of Gdańsk, Wita Stwosza 59, Gdańsk 80-308, Poland
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39
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Abstract
The replication origin and the initiator protein DnaA are the main targets for regulation of chromosome replication in bacteria. The origin bears multiple DnaA binding sites, while DnaA contains ATP/ADP-binding and DNA-binding domains. When enough ATP-DnaA has accumulated in the cell, an active initiation complex can be formed at the origin resulting in strand opening and recruitment of the replicative helicase. In Escherichia coli, oriC activity is directly regulated by DNA methylation and specific oriC-binding proteins. DnaA activity is regulated by proteins that stimulate ATP-DnaA hydrolysis, yielding inactive ADP-DnaA in a replication-coupled negative-feedback manner, and by DnaA-binding DNA elements that control the subcellular localization of DnaA or stimulate the ADP-to-ATP exchange of the DnaA-bound nucleotide. Regulation of dnaA gene expression is also important for initiation. The principle of replication-coupled negative regulation of DnaA found in E. coli is conserved in eukaryotes as well as in bacteria. Regulations by oriC-binding proteins and dnaA gene expression are also conserved in bacteria.
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Affiliation(s)
- Kirsten Skarstad
- Department of Cell Biology, Institute for Cancer Research, The Radium Hospital, Oslo University Hospital, 0310 Oslo, Norway
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40
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Li Y, Araki H. Loading and activation of DNA replicative helicases: the key step of initiation of DNA replication. Genes Cells 2013; 18:266-77. [PMID: 23461534 PMCID: PMC3657122 DOI: 10.1111/gtc.12040] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 01/11/2013] [Indexed: 11/27/2022]
Abstract
Evolution has led to diversification of all living organisms from a common ancestor. Consequently, all living organisms use a common method to duplicate their genetic information and thus pass on their inherited traits to their offspring. To duplicate chromosomal DNA, double-stranded DNA must first be unwound by helicase, which is loaded to replication origins and activated during the DNA replication initiation step. In this review, we discuss the common features of, and differences in, replicative helicases between prokaryotes and eukaryotes.
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Affiliation(s)
- Yan Li
- Division of Microbial Genetics, National Institute of Genetics, Yata 1111, Mishima City, Shizuoka, 411-8540, Japan
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41
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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: 3.9] [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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42
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Donczew R, Weigel C, Lurz R, Zakrzewska-Czerwinska J, Zawilak-Pawlik A. Helicobacter pylori oriC--the first bipartite origin of chromosome replication in Gram-negative bacteria. Nucleic Acids Res 2012; 40:9647-60. [PMID: 22904070 PMCID: PMC3479198 DOI: 10.1093/nar/gks742] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Binding of the DnaA protein to oriC leads to DNA melting within the DNA unwinding element (DUE) and initiates replication of the bacterial chromosome. Helicobacter pylori oriC was previously identified as a region localized upstream of dnaA and containing a cluster of DnaA boxes bound by DnaA protein with a high affinity. However, no unwinding within the oriC sequence has been detected. Comprehensive in silico analysis presented in this work allowed us to identify an additional region (oriC2), separated from the original one (oriC1) by the dnaA gene. DnaA specifically binds both regions, but DnaA-dependent DNA unwinding occurs only within oriC2. Surprisingly, oriC2 is bound exclusively as supercoiled DNA, which directly shows the importance of the DNA topology in DnaA-oriC interactions, similarly as previously presented only for initiator-origin interactions in Archaea and some Eukaryota. We conclude that H. pylori oriC exhibits bipartite structure, being the first such origin discovered in a Gram-negative bacterium. The H. pylori mode of initiator-oriC interactions, with the loop formation between the subcomplexes of the discontinuous origin, resembles those discovered in Bacillus subtilis chromosome and in many plasmids, which might suggest a similar way of controlling initiation of replication.
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Affiliation(s)
- Rafał Donczew
- Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Department of Microbiology, Weigla 12, 53-114 Wrocław, Poland
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43
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The primosomal protein DnaD inhibits cooperative DNA binding by the replication initiator DnaA in Bacillus subtilis. J Bacteriol 2012; 194:5110-7. [PMID: 22821970 DOI: 10.1128/jb.00958-12] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
DnaA is an AAA+ ATPase and the conserved replication initiator in bacteria. Bacteria control the timing of replication initiation by regulating the activity of DnaA. DnaA binds to multiple sites in the origin of replication (oriC) and is required for recruitment of proteins needed to load the replicative helicase. DnaA also binds to other chromosomal regions and functions as a transcription factor at some of these sites. Bacillus subtilis DnaD is needed during replication initiation for assembly of the replicative helicase at oriC and during replication restart at stalled replication forks. DnaD associates with DnaA at oriC and at other chromosomal regions bound by DnaA. Using purified proteins, we found that DnaD inhibited the ability of DnaA to bind cooperatively to DNA and caused a decrease in the apparent dissociation constant. These effects of DnaD were independent of the ability of DnaA to bind or hydrolyze ATP. Other proteins known to regulate B. subtilis DnaA also affect DNA binding, whereas much of the regulation of Escherichia coli DnaA affects nucleotide hydrolysis or exchange. We found that the rate of nucleotide exchange for B. subtilis DnaA was high and not affected by DnaD. The rapid exchange is similar to that of Staphylococcus aureus DnaA and in contrast to the low exchange rate of Escherichia coli DnaA. We suggest that organisms in which DnaA has a high rate of nucleotide exchange predominantly regulate the DNA binding activity of DnaA and that those with low rates of exchange regulate hydrolysis and exchange.
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44
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Sun J, Kawakami H, Zech J, Speck C, Stillman B, Li H. Cdc6-induced conformational changes in ORC bound to origin DNA revealed by cryo-electron microscopy. Structure 2012; 20:534-44. [PMID: 22405012 DOI: 10.1016/j.str.2012.01.011] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 01/16/2012] [Accepted: 01/17/2012] [Indexed: 01/21/2023]
Abstract
The eukaryotic origin recognition complex (ORC) interacts with and remodels origins of DNA replication prior to initiation in S phase. Here, we report a single-particle cryo-EM-derived structure of the supramolecular assembly comprising Saccharomyces cerevisiae ORC, the replication initiation factor Cdc6, and double-stranded ARS1 origin DNA in the presence of ATPγS. The six subunits of ORC are arranged as Orc1:Orc4:Orc5:Orc2:Orc3, with Orc6 binding to Orc2. Cdc6 binding changes the conformation of ORC, in particular reorienting the Orc1 N-terminal BAH domain. Segmentation of the 3D map of ORC-Cdc6 on DNA and docking with the crystal structure of the homologous archaeal Orc1/Cdc6 protein suggest an origin DNA binding model in which the DNA tracks along the interior surface of the crescent-like ORC. Thus, ORC bends and wraps the DNA. This model is consistent with the observation that binding of a single Cdc6 extends the ORC footprint on origin DNA from both ends.
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Affiliation(s)
- Jingchuan Sun
- Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA
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45
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Zorman S, Seitz H, Sclavi B, Strick TR. Topological characterization of the DnaA-oriC complex using single-molecule nanomanipuation. Nucleic Acids Res 2012; 40:7375-83. [PMID: 22581769 PMCID: PMC3424547 DOI: 10.1093/nar/gks371] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
In most bacteria, the timing and synchrony of initiation of chromosomal replication are determined by the binding of the AAA+ protein DnaA to a set of high- and low-affinity sites found within the origin of chromosomal replication (oriC). Despite the large amount of information on the role and regulation of DnaA, the actual structure of the DnaA–oriC complex and the mechanism by which it primes the origin for the initiation of replication remain unclear. In this study, we have performed magnetic tweezers experiments to investigate the structural properties of the DnaA–oriC complex. We show that the DnaA-ATP–oriC complex adopts a right-handed helical conformation involving a variable amount of DNA and protein whose features fit qualitatively as well as quantitatively with an existing model based on the crystal structure of a truncated DnaA tetramer obtained in the absence of DNA. We also investigate the topological effect of oriC’s DNA unwinding element.
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Affiliation(s)
- Sylvain Zorman
- Institut Jacques Monod, CN RS UMR 7592, Univ Paris Diderot, Sorbonne Paris Cité, F-75205 Paris, France
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46
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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: 0.7] [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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47
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Abstract
Threading of DNA through the central channel of a replicative ring helicase is known as helicase loading, and is a pivotal event during replication initiation at replication origins. Once loaded, the helicase recruits the primase through a direct protein-protein interaction to complete the initial 'priming step' of DNA replication. Subsequent assembly of the polymerases and processivity factors completes the structure of the replisome. Two replisomes are assembled, one on each strand, and move in opposite directions to replicate the parental DNA during the 'elongation step' of DNA replication. Replicative helicases are the motor engines of replisomes powered by the conversion of chemical energy to mechanical energy through ATP binding and hydrolysis. Bidirectional loading of two ring helicases at a replication origin is achieved by strictly regulated and intricately choreographed mechanisms, often through the action of replication initiation and helicase-loader proteins. Current structural and biochemical data reveal a wide range of different helicase-loading mechanisms. Here we review advances in this area and discuss their implications.
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Affiliation(s)
- Panos Soultanas
- School of Chemistry, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK.
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48
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Diffley JFX. Quality control in the initiation of eukaryotic DNA replication. Philos Trans R Soc Lond B Biol Sci 2012; 366:3545-53. [PMID: 22084381 PMCID: PMC3203456 DOI: 10.1098/rstb.2011.0073] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Origins of DNA replication must be regulated to ensure that the entire genome is replicated precisely once in each cell cycle. In human cells, this requires that tens of thousands of replication origins are activated exactly once per cell cycle. Failure to do so can lead to cell death or genome rearrangements such as those associated with cancer. Systems ensuring efficient initiation of replication, while also providing a robust block to re-initiation, play a crucial role in genome stability. In this review, I will discuss some of the strategies used by cells to ensure once per cell cycle replication and provide a quantitative framework to evaluate the relative importance and efficiency of individual pathways involved in this regulation.
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Affiliation(s)
- John F X Diffley
- Cancer Research UK London Research Institute, Clare Hall Laboratories, South Mimms, Herts EN6 3LD, UK
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49
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Jha JK, Baek JH, Venkova-Canova T, Chattoraj DK. Chromosome dynamics in multichromosome bacteria. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012; 1819:826-9. [PMID: 22306663 DOI: 10.1016/j.bbagrm.2012.01.012] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Revised: 01/10/2012] [Accepted: 01/17/2012] [Indexed: 12/23/2022]
Abstract
On the basis of limited information, bacteria were once assumed to have no more than one chromosome. In the era of genomics, it has become clear that some, like eukaryotes, have more than one chromosome. Multichromosome bacteria provide opportunities to investigate how split genomes emerged, whether the individual chromosomes communicate to coordinate their replication and segregation, and what selective advantages split genomes might provide. Our current knowledge of these topics comes mostly from studies in Vibrio cholerae, which has two chromosomes, chr1 and chr2. Chr1 carries out most of the house-keeping functions and is considered the main chromosome, whereas chr2 appears to have originated from a plasmid and has acquired genes of mostly unknown origin and function. Nevertheless, unlike plasmids, chr2 replicates once and only once per cell cycle, like a bona fide chromosome. The two chromosomes replicate and segregate using separate programs, unlike eukaryotic chromosomes. They terminate replication synchronously, suggesting that there might be communication between them. Replication of the chromosomes is affected by segregation genes but in a chromosome specific fashion, a new development in the field of DNA replication control. The split genome allows genome duplication to complete in less time and with fewer replication forks, which could be beneficial for genome maintenance during rapid growth, which is the norm for V. cholerae in broth cultures and in the human host. In the latter, the expression of chr2 genes increases preferentially. Studies of chromosome maintenance in multichromosomal bacteria, although in their infancy, are already broadening our view of chromosome biology. This article is part of a Special Issue entitled: Chromatin in time and space.
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Affiliation(s)
- Jyoti K Jha
- Laboratory of Molecular Biology and Biochemistry, Center for Cancer Research, NCI, NIH, Bethesda, MD, USA
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50
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Scholefield G, Errington J, Murray H. Soj/ParA stalls DNA replication by inhibiting helix formation of the initiator protein DnaA. EMBO J 2012; 31:1542-55. [PMID: 22286949 DOI: 10.1038/emboj.2012.6] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Accepted: 12/22/2011] [Indexed: 12/19/2022] Open
Abstract
Control of DNA replication initiation is essential for normal cell growth. A unifying characteristic of DNA replication initiator proteins across the kingdoms of life is their distinctive AAA+ nucleotide-binding domains. The bacterial initiator DnaA assembles into a right-handed helical oligomer built upon interactions between neighbouring AAA+ domains, that in vitro stretches DNA to promote replication origin opening. The Bacillus subtilis protein Soj/ParA has previously been shown to regulate DnaA-dependent DNA replication initiation; however, the mechanism underlying this control was unknown. Here, we report that Soj directly interacts with the AAA+ domain of DnaA and specifically regulates DnaA helix assembly. We also provide critical biochemical evidence indicating that DnaA assembles into a helical oligomer in vivo and that the frequency of replication initiation correlates with the extent of DnaA oligomer formation. This work defines a significant new regulatory mechanism for the control of DNA replication initiation in bacteria.
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Affiliation(s)
- Graham Scholefield
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle Upon Tyne, UK
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