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Guo M, Hundseth K, Ding H, Vidhyasagar V, Inoue A, Nguyen CH, Zain R, Lee JS, Wu Y. A distinct triplex DNA unwinding activity of ChlR1 helicase. J Biol Chem 2015; 290:5174-5189. [PMID: 25561740 DOI: 10.1074/jbc.m114.634923] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Mutations in the human ChlR1 (DDX11) gene are associated with a unique genetic disorder known as Warsaw breakage syndrome characterized by cellular defects in genome maintenance. The DNA triplex helix structures that form by Hoogsteen or reverse Hoogsteen hydrogen bonding are examples of alternate DNA structures that can be a source of genomic instability. In this study, we have examined the ability of human ChlR1 helicase to destabilize DNA triplexes. Biochemical studies demonstrated that ChlR1 efficiently melted both intermolecular and intramolecular DNA triplex substrates in an ATP-dependent manner. Compared with other substrates such as replication fork and G-quadruplex DNA, triplex DNA was a preferred substrate for ChlR1. Also, compared with FANCJ, a helicase of the same family, the triplex resolving activity of ChlR1 is unique. On the other hand, the mutant protein from a Warsaw breakage syndrome patient failed to unwind these triplexes. A previously characterized triplex DNA-specific antibody (Jel 466) bound triplex DNA structures and inhibited ChlR1 unwinding activity. Moreover, cellular assays demonstrated that there were increased triplex DNA content and double-stranded breaks in ChlR1-depleted cells, but not in FANCJ(-/-) cells, when cells were treated with a triplex stabilizing compound benzoquinoquinoxaline, suggesting that ChlR1 melting of triple-helix structures is distinctive and physiologically important to defend genome integrity. On the basis of our results, we conclude that the abundance of ChlR1 known to exist in vivo is likely to be a strong deterrent to the stability of triplexes that can potentially form in the human genome.
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Affiliation(s)
- Manhong Guo
- From the Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Kristian Hundseth
- From the Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Hao Ding
- From the Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | | | - Akira Inoue
- the Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | - Chi-Hung Nguyen
- UMR176 CNRS-Institut Curie, Laboratoire de Pharmacochimie, Centre Universitaire, 91405 Orsay, France, and
| | - Rula Zain
- the Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, 141 86 Huddinge, Stockholm, Sweden
| | - Jeremy S Lee
- From the Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Yuliang Wu
- From the Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada,.
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2
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Abstract
The maintenance of DNA methylation in nascent DNA is a critical event for numerous biological processes. Following DNA replication, DNMT1 is the key enzyme that strictly copies the methylation pattern from the parental strand to the nascent DNA. However, the mechanism underlying this highly specific event is not thoroughly understood. In this study, we identified topoisomerase IIα (TopoIIα) as a novel regulator of the maintenance DNA methylation. UHRF1, a protein important for global DNA methylation, interacts with TopoIIα and regulates its localization to hemimethylated DNA. TopoIIα decatenates the hemimethylated DNA following replication, which might facilitate the methylation of the nascent strand by DNMT1. Inhibiting this activity impairs DNA methylation at multiple genomic loci. We have uncovered a novel mechanism during the maintenance of DNA methylation.
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Affiliation(s)
- Lin-Yu Lu
- From the Women's Hospital, School of Medicine, and the Institute of Translational Medicine, Zhejiang University, Hangzhou, Zhejiang 310006, China and
| | - Henry Kuang
- the Division of Molecular Medicine and Genetics, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Gautam Korakavi
- the Division of Molecular Medicine and Genetics, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Xiaochun Yu
- the Division of Molecular Medicine and Genetics, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan 48109
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3
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Abstract
RNA and DNA ligases catalyze the formation of a phosphodiester bond between the 5'-phosphate and 3'-hydroxyl ends of nucleic acids. In this work, we describe the ability of the thermophilic RNA ligase MthRnl from Methanobacterium thermoautotrophicum to recognize and modify the 3'-terminal phosphate of RNA and single-stranded DNA (ssDNA). This ligase can use an RNA 3'p substrate to generate an RNA 2',3'-cyclic phosphate or convert DNA3'p to ssDNA(3')pp(5')A. An RNA ligase from the Thermus scotoductus bacteriophage TS2126 and a predicted T4 Rnl1-like protein from Thermovibrio ammonificans, TVa, were also able to adenylate ssDNA 3'p. These modifications of RNA and DNA 3'-phosphates are similar to the activities of RtcA, an RNA 3'-phosphate cyclase. The initial step involves adenylation of the enzyme by ATP, which is then transferred to either RNA 3'p or DNA 3'p to generate the adenylated intermediate. For RNA (3')pp(5')A, the third step involves attack of the adjacent 2' hydroxyl to generate the RNA 2',3'-cyclic phosphate. These steps are analogous to those in classical 5' phosphate ligation. MthRnl and TS2126 RNA ligases were not able to modify a 3'p in nicked double-stranded DNA. However, T4 DNA ligase and RtcA can use 3'-phosphorylated nicks in double-stranded DNA to produce a 3'-adenylated product. These 3'-terminal phosphate-adenylated intermediates are substrates for deadenylation by yeast 5'Deadenylase. Our findings that classic ligases can duplicate the adenylation and phosphate cyclization activity of RtcA suggests that they have an essential role in metabolism of nucleic acids with 3'-terminal phosphates.
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Affiliation(s)
- Alexander M Zhelkovsky
- From the Division of RNA Biology, New England Biolabs, Inc., Ipswich, Massachusetts 01938
| | - Larry A McReynolds
- From the Division of RNA Biology, New England Biolabs, Inc., Ipswich, Massachusetts 01938
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4
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Wang H, Wang X, Chen G, Zhang X, Tang X, Park D, Cucinotta FA, Yu DS, Deng X, Dynan WS, Doetsch PW, Wang Y. Distinct roles of Ape1 protein, an enzyme involved in DNA repair, in high or low linear energy transfer ionizing radiation-induced cell killing. J Biol Chem 2014; 289:30635-30644. [PMID: 25210033 DOI: 10.1074/jbc.m114.604959] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
High linear energy transfer (LET) radiation from space heavy charged particles or a heavier ion radiotherapy machine kills more cells than low LET radiation, mainly because high LET radiation-induced DNA damage is more difficult to repair. Relative biological effectiveness (RBE) is the ratio of the effects generated by high LET radiation to low LET radiation. Previously, our group and others demonstrated that the cell-killing RBE is involved in the interference of high LET radiation with non-homologous end joining but not homologous recombination repair. This effect is attributable, in part, to the small DNA fragments (≤40 bp) directly produced by high LET radiation, the size of which prevents Ku protein from efficiently binding to the two ends of one fragment at the same time, thereby reducing non-homologous end joining efficiency. Here we demonstrate that Ape1, an enzyme required for processing apurinic/apyrimidinic (known as abasic) sites, is also involved in the generation of small DNA fragments during the repair of high LET radiation-induced base damage, which contributes to the higher RBE of high LET radiation-induced cell killing. This discovery opens a new direction to develop approaches for either protecting astronauts from exposure to space radiation or benefiting cancer patients by sensitizing tumor cells to high LET radiotherapy.
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Affiliation(s)
- Hongyan Wang
- Department of Radiation Oncology, Emory University School of Medicine and Winship Cancer Institute of Emory University, Atlanta, Georgia 30322 and
| | - Xiang Wang
- Department of Radiation Oncology, Emory University School of Medicine and Winship Cancer Institute of Emory University, Atlanta, Georgia 30322 and
| | - Guangnan Chen
- Department of Radiation Oncology, Emory University School of Medicine and Winship Cancer Institute of Emory University, Atlanta, Georgia 30322 and
| | - Xiangming Zhang
- Department of Radiation Oncology, Emory University School of Medicine and Winship Cancer Institute of Emory University, Atlanta, Georgia 30322 and
| | - Xiaobing Tang
- Department of Radiation Oncology, Emory University School of Medicine and Winship Cancer Institute of Emory University, Atlanta, Georgia 30322 and
| | - Dongkyoo Park
- Department of Radiation Oncology, Emory University School of Medicine and Winship Cancer Institute of Emory University, Atlanta, Georgia 30322 and
| | - Francis A Cucinotta
- Department of Health Physics and Diagnostic Sciences, University of Nevada, Las Vegas, Nevada 89154
| | - David S Yu
- Department of Radiation Oncology, Emory University School of Medicine and Winship Cancer Institute of Emory University, Atlanta, Georgia 30322 and
| | - Xingming Deng
- Department of Radiation Oncology, Emory University School of Medicine and Winship Cancer Institute of Emory University, Atlanta, Georgia 30322 and
| | - William S Dynan
- Department of Radiation Oncology, Emory University School of Medicine and Winship Cancer Institute of Emory University, Atlanta, Georgia 30322 and
| | - Paul W Doetsch
- Department of Radiation Oncology, Emory University School of Medicine and Winship Cancer Institute of Emory University, Atlanta, Georgia 30322 and
| | - Ya Wang
- Department of Radiation Oncology, Emory University School of Medicine and Winship Cancer Institute of Emory University, Atlanta, Georgia 30322 and.
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Emperle M, Rajavelu A, Reinhardt R, Jurkowska RZ, Jeltsch A. Cooperative DNA binding and protein/DNA fiber formation increases the activity of the Dnmt3a DNA methyltransferase. J Biol Chem 2014; 289:29602-13. [PMID: 25147181 DOI: 10.1074/jbc.m114.572032] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Dnmt3a DNA methyltransferase has been shown to bind cooperatively to DNA and to form large multimeric protein/DNA fibers. However, it has also been reported to methylate DNA in a processive manner, a property that is incompatible with protein/DNA fiber formation. We show here that the DNA methylation rate of Dnmt3a increases more than linearly with increasing enzyme concentration on a long DNA substrate, but not on a short 30-mer oligonucleotide substrate. We also show that addition of a catalytically inactive Dnmt3a mutant, which carries an amino acid exchange in the catalytic center, increases the DNA methylation rate by wild type Dnmt3a on the long substrate but not on the short one. In agreement with this finding, preincubation experiments indicate that stable protein/DNA fibers are formed on the long, but not on the short substrate. In addition, methylation experiments with substrates containing one or two CpG sites did not provide evidence for a processive mechanism over a wide range of enzyme concentrations. These data clearly indicate that Dnmt3a binds to DNA in a cooperative reaction and that the formation of stable protein/DNA fibers increases the DNA methylation rate. Fiber formation occurs at low μm concentrations of Dnmt3a, which are in the range of Dnmt3a concentrations in the nucleus of embryonic stem cells. Understanding the mechanism of Dnmt3a is of vital importance because Dnmt3a is a hotspot of somatic cancer mutations one of which has been implicated in changing Dnmt3a processivity.
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Affiliation(s)
- Max Emperle
- From the Institute of Biochemistry, Stuttgart University, D-70569 Stuttgart, Germany and
| | - Arumugam Rajavelu
- From the Institute of Biochemistry, Stuttgart University, D-70569 Stuttgart, Germany and
| | | | - Renata Z Jurkowska
- From the Institute of Biochemistry, Stuttgart University, D-70569 Stuttgart, Germany and
| | - Albert Jeltsch
- From the Institute of Biochemistry, Stuttgart University, D-70569 Stuttgart, Germany and
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Gupta S, Yeeles JTP, Marians KJ. Regression of replication forks stalled by leading-strand template damage: I. Both RecG and RuvAB catalyze regression, but RuvC cleaves the holliday junctions formed by RecG preferentially. J Biol Chem 2014; 289:28376-87. [PMID: 25138216 DOI: 10.1074/jbc.m114.587881] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The orderly progression of replication forks formed at the origin of replication in Escherichia coli is challenged by encounters with template damage, slow moving RNA polymerases, and frozen DNA-protein complexes that stall the fork. These stalled forks are foci for genomic instability and must be reactivated. Many models of replication fork reactivation invoke nascent strand regression as an intermediate in the processing of the stalled fork. We have investigated the replication fork regression activity of RecG and RuvAB, two proteins commonly thought to be involved in the process, using a reconstituted DNA replication system where the replisome is stalled by collision with leading-strand template damage. We find that both RecG and RuvAB can regress the stalled fork in the presence of the replisome and SSB; however, RuvAB generates a completely unwound product consisting of the paired nascent leading and lagging strands, whereas RuvC cleaves the Holliday junction generated by RecG-catalyzed fork regression. We also find that RecG stimulates RuvAB-catalyzed regression, presumably because it is more efficient at generating the initial Holliday junction from the stalled fork.
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Affiliation(s)
- Sankalp Gupta
- From the Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065
| | - Joseph T P Yeeles
- From the Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065
| | - Kenneth J Marians
- From the Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065
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7
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Gupta S, Yeeles JTP, Marians KJ. Regression of replication forks stalled by leading-strand template damage: II. Regression by RecA is inhibited by SSB. J Biol Chem 2014; 289:28388-98. [PMID: 25138217 DOI: 10.1074/jbc.m114.587907] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Stalled replication forks are sites of chromosome breakage and the formation of toxic recombination intermediates that undermine genomic stability. Thus, replication fork repair and reactivation are essential processes. Among the many models of replication fork reactivation is one that invokes fork regression catalyzed by the strand exchange protein RecA as an intermediate in the processing of the stalled fork. We have investigated the replication fork regression activity of RecA using a reconstituted DNA replication system where the replisome is stalled by collision with leading-strand template damage. We find that RecA is unable to regress the stalled fork in the presence of the replisome and SSB. If the replication proteins are removed from the stalled fork, RecA will catalyze net regression as long as the Okazaki fragments are sealed. RecA-generated Holliday junctions can be detected by RuvC cleavage, although this is not a robust reaction. On the other hand, extensive branch migration by RecA, where a completely unwound product consisting of the paired nascent leading and lagging strands is produced, is observed under conditions where RuvC activity is suppressed. This branch migration reaction is inhibited by SSB, possibly accounting for the failure of RecA to generate products in the presence of the replication proteins. Interestingly, we find that the RecA-RuvC reaction is supported to differing extents, depending on the template damage; templates carrying a cyclopyrimidine dimer elicit more RecA-RuvC product than those carrying a synthetic abasic site. This difference could be ascribed to a higher affinity of RecA binding to DNAs carrying a thymidine dimer than to those with an abasic site.
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Affiliation(s)
- Sankalp Gupta
- From the Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065
| | - Joseph T P Yeeles
- From the Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065
| | - Kenneth J Marians
- From the Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065
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8
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Bullard W, Lopes da Rosa-Spiegler J, Liu S, Wang Y, Sabatini R. Identification of the glucosyltransferase that converts hydroxymethyluracil to base J in the trypanosomatid genome. J Biol Chem 2014; 289:20273-82. [PMID: 24891501 DOI: 10.1074/jbc.m114.579821] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
O-linked glucosylation of thymine in DNA (base J) is an important regulatory epigenetic mark in trypanosomatids. β-d-glucopyranosyloxymethyluracil (base J) synthesis is initiated by the JBP1/2 enzymes that hydroxylate thymine, forming 5-hydroxymethyluracil (hmU). hmU is then glucosylated by a previously unknown glucosyltransferase. A recent computational screen identified a possible candidate for the base J-associated glucosyltransferase (JGT) in trypanosomatid genomes. We demonstrate that recombinant JGT utilizes uridine diphosphoglucose to transfer glucose to hmU in the context of dsDNA. Mutation of conserved residues typically involved in glucosyltransferase catalysis impairs DNA glucosylation in vitro. The deletion of both alleles of JGT from the genome of Trypanosoma brucei generates a cell line that completely lacks base J. Reintroduction of JGT in the JGT KO restores J synthesis. Ablation of JGT mRNA levels by RNAi leads to the sequential reduction in base J and increased levels of hmU that dissipate rapidly. The analysis of JGT function confirms the two-step J synthesis model and demonstrates that JGT is the only glucosyltransferase enzyme required for the second step of the pathway. Similar to the activity of the related Ten-Eleven Translocation (TET) family of dioxygenases on 5mC, our studies also suggest the ability of the base J-binding protein enzymes to catalyze iterative oxidation of thymine in trypanosome DNA. Here we discuss the regulation of hmU and base J formation in the trypanosome genome by JGT and base J-binding protein.
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Affiliation(s)
- Whitney Bullard
- From the Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602 and
| | | | - Shuo Liu
- the Environmental Toxicology Graduate Program and
| | - Yinsheng Wang
- the Environmental Toxicology Graduate Program and Department of Chemistry, University of California, Riverside, California 92521
| | - Robert Sabatini
- From the Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602 and
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9
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Cannan WJ, Tsang BP, Wallace SS, Pederson DS. Nucleosomes suppress the formation of double-strand DNA breaks during attempted base excision repair of clustered oxidative damages. J Biol Chem 2014; 289:19881-93. [PMID: 24891506 DOI: 10.1074/jbc.m114.571588] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Exposure to ionizing radiation can produce multiple, clustered oxidative lesions in DNA. The near simultaneous excision of nearby lesions in opposing DNA strands by the base excision repair (BER) enzymes can produce double-strand DNA breaks (DSBs). This attempted BER accounts for many of the potentially lethal or mutagenic DSBs that occur in vivo. To assess the impact of nucleosomes on the frequency and pattern of BER-dependent DSB formation, we incubated nucleosomes containing oxidative damages in opposing DNA strands with selected DNA glycosylases and human apurinic/apyrimidinic endonuclease 1. Overall, nucleosomes substantially suppressed DSB formation. However, the degree of suppression varied as a function of (i) the lesion type and DNA glycosylase tested, (ii) local sequence context and the stagger between opposing strand lesions, (iii) the helical orientation of oxidative lesions relative to the underlying histone octamer, and (iv) the distance between the lesion cluster and the nucleosome edge. In some instances the binding of a BER factor to one nucleosomal lesion appeared to facilitate binding to the opposing strand lesion. DSB formation did not invariably lead to nucleosome dissolution, and in some cases, free DNA ends resulting from DSB formation remained associated with the histone octamer. These observations explain how specific structural and dynamic properties of nucleosomes contribute to the suppression of BER-generated DSBs. These studies also suggest that most BER-generated DSBs will occur in linker DNA and in genomic regions associated with elevated rates of nucleosome turnover or remodeling.
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Affiliation(s)
- Wendy J Cannan
- From the Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont 05405
| | - Betty P Tsang
- From the Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont 05405
| | - Susan S Wallace
- From the Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont 05405
| | - David S Pederson
- From the Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont 05405
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Miazzi C, Ferraro P, Pontarin G, Rampazzo C, Reichard P, Bianchi V. Allosteric regulation of the human and mouse deoxyribonucleotide triphosphohydrolase sterile α-motif/histidine-aspartate domain-containing protein 1 (SAMHD1). J Biol Chem 2014; 289:18339-46. [PMID: 24828500 PMCID: PMC4140260 DOI: 10.1074/jbc.m114.571091] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The deoxyribonucleotide triphosphohydrolase SAMHD1 restricts lentiviral infection by depleting the dNTPs required for viral DNA synthesis. In cultured human fibroblasts SAMHD1 is expressed maximally during quiescence preventing accumulation of dNTPs outside S phase. siRNA silencing of SAMHD1 increases dNTP pools, stops cycling human cells in G1, and blocks DNA replication. Surprisingly, knock-out of the mouse gene does not affect the well being of the animals. dNTPs are both substrates and allosteric effectors for SAMHD1. In the crystal structure each subunit of the homotetrameric protein contains one substrate-binding site and two nonidentical effector-binding sites, site 1 binding dGTP, site 2 dGTP or dATP. Here we compare allosteric properties of pure recombinant human and mouse SAMHD1. Both enzymes are activated 3–4-fold by allosteric effectors. We propose that in quiescent cells where SAMHD1 is maximally expressed GTP binds to site 1 with very high affinity, stabilizing site 2 of the tetrameric structure. Any canonical dNTP can bind to site 2 and activate SAMHD1, but in cells only dATP or dTTP are present at sufficient concentrations. The apparent Km for dATP at site 2 is ∼10 μm for mouse and 1 μm for human SAMHD1, for dTTP the corresponding values are 50 and 2 μm. Tetrameric SAMHD1 is activated for the hydrolysis of any dNTP only after binding of a dNTP to site 2. The lower Km constants for human SAMHD1 induce activation at lower cellular concentrations of dNTPs thereby limiting the size of dNTP pools more efficiently in quiescent human cells.
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Affiliation(s)
- Cristina Miazzi
- From the Department of Biology, University of Padova, 35131 Padova, Italy
| | - Paola Ferraro
- From the Department of Biology, University of Padova, 35131 Padova, Italy
| | - Giovanna Pontarin
- From the Department of Biology, University of Padova, 35131 Padova, Italy
| | - Chiara Rampazzo
- From the Department of Biology, University of Padova, 35131 Padova, Italy
| | - Peter Reichard
- From the Department of Biology, University of Padova, 35131 Padova, Italy
| | - Vera Bianchi
- From the Department of Biology, University of Padova, 35131 Padova, Italy
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11
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Cañas C, Suzuki Y, Marchisone C, Carrasco B, Freire-Benéitez V, Takeyasu K, Alonso JC, Ayora S. Interaction of branch migration translocases with the Holliday junction-resolving enzyme and their implications in Holliday junction resolution. J Biol Chem 2014; 289:17634-46. [PMID: 24770420 DOI: 10.1074/jbc.m114.552794] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Double-strand break repair involves the formation of Holliday junction (HJ) structures that need to be resolved to promote correct replication and chromosomal segregation. The molecular mechanisms of HJ branch migration and/or resolution are poorly characterized in Firmicutes. Genetic evidence suggested that the absence of the RuvAB branch migration translocase and the RecU HJ resolvase is synthetically lethal in Bacillus subtilis, whereas a recU recG mutant was viable. In vitro RecU, which is restricted to bacteria of the Firmicutes phylum, binds HJs with high affinity. In this work we found that RecU does not bind simultaneously with RecG to a HJ. RuvB by interacting with RecU bound to the central region of HJ DNA, loses its nonspecific association with DNA, and re-localizes with RecU to form a ternary complex. RecU cannot stimulate the ATPase or branch migration activity of RuvB. The presence of RuvB·ATPγS greatly stimulates RecU-mediated HJ resolution, but the addition of ATP or RuvA abolishes this stimulatory effect. A RecU·HJ·RuvAB complex might be formed. RecU does not increase the RuvAB activities but slightly inhibits them.
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Affiliation(s)
- Cristina Cañas
- From the Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Departamento de Biotecnología Microbiana, 28049 Madrid, Spain and
| | - Yuki Suzuki
- Graduate School of Biostudies, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Chiara Marchisone
- From the Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Departamento de Biotecnología Microbiana, 28049 Madrid, Spain and
| | - Begoña Carrasco
- From the Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Departamento de Biotecnología Microbiana, 28049 Madrid, Spain and
| | - Verónica Freire-Benéitez
- From the Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Departamento de Biotecnología Microbiana, 28049 Madrid, Spain and
| | - Kunio Takeyasu
- Graduate School of Biostudies, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Juan C Alonso
- From the Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Departamento de Biotecnología Microbiana, 28049 Madrid, Spain and
| | - Silvia Ayora
- From the Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Departamento de Biotecnología Microbiana, 28049 Madrid, Spain and
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