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Cui K, Qin L, Tang X, Nong J, Chen J, Wu N, Gong X, Yi L, Yang C, Xia S. A Single Amino Acid Substitution in RFC4 Leads to Endoduplication and Compromised Resistance to DNA Damage in Arabidopsis thaliana. Genes (Basel) 2022; 13:genes13061037. [PMID: 35741798 PMCID: PMC9223238 DOI: 10.3390/genes13061037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 06/01/2022] [Accepted: 06/07/2022] [Indexed: 02/04/2023] Open
Abstract
Replication factor C (RFC) is a heteropentameric ATPase associated with the diverse cellular activities (AAA+ATPase) protein complex, which is composed of one large subunit, known as RFC1, and four small subunits, RFC2/3/4/5. Among them, RFC1 and RFC3 were previously reported to mediate genomic stability and resistance to pathogens in Arabidopsis. Here, we generated a viable rfc4e (rfc4-1/RFC4G54E) mutant with a single amino acid substitution by site-directed mutagenesis. Three of six positive T2 mutants with the same amino acid substitution, but different insertion loci, were sequenced to identify homozygotes, and the three homozygote mutants showed dwarfism, early flowering, and a partially sterile phenotype. RNA sequencing revealed that genes related to DNA repair and replication were highly upregulated. Moreover, the frequency of DNA lesions was found to be increased in rfc4e mutants. Consistent with this, the rfc4e mutants were very sensitive to DSB-inducing genotoxic agents. In addition, the G54E amino acid substitution in AtRFC4 delayed cell cycle progression and led to endoduplication. Overall, our study provides evidence supporting the notion that RFC4 plays an important role in resistance to genotoxicity and cell proliferation by regulating DNA damage repair in Arabidopsis thaliana.
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Affiliation(s)
- Kan Cui
- Hunan Provincial Key Laboratory of Phytohormones and Growth Development, College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China; (K.C.); (L.Q.); (X.T.); (J.N.); (N.W.); (X.G.); (C.Y.)
| | - Lei Qin
- Hunan Provincial Key Laboratory of Phytohormones and Growth Development, College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China; (K.C.); (L.Q.); (X.T.); (J.N.); (N.W.); (X.G.); (C.Y.)
| | - Xianyu Tang
- Hunan Provincial Key Laboratory of Phytohormones and Growth Development, College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China; (K.C.); (L.Q.); (X.T.); (J.N.); (N.W.); (X.G.); (C.Y.)
| | - Jieying Nong
- Hunan Provincial Key Laboratory of Phytohormones and Growth Development, College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China; (K.C.); (L.Q.); (X.T.); (J.N.); (N.W.); (X.G.); (C.Y.)
| | - Jin Chen
- Hunan Academy of Agricultural Sciences, Changsha 410125, China; (J.C.); (L.Y.)
- Changsha Technology Innovation Center for Phytoremediation of Heavy Metal Contaminated Soil, Hunan Academy of Agricultural Sciences, Changsha 410125, China
| | - Nan Wu
- Hunan Provincial Key Laboratory of Phytohormones and Growth Development, College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China; (K.C.); (L.Q.); (X.T.); (J.N.); (N.W.); (X.G.); (C.Y.)
| | - Xin Gong
- Hunan Provincial Key Laboratory of Phytohormones and Growth Development, College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China; (K.C.); (L.Q.); (X.T.); (J.N.); (N.W.); (X.G.); (C.Y.)
| | - Lixiong Yi
- Hunan Academy of Agricultural Sciences, Changsha 410125, China; (J.C.); (L.Y.)
| | - Chenghuizi Yang
- Hunan Provincial Key Laboratory of Phytohormones and Growth Development, College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China; (K.C.); (L.Q.); (X.T.); (J.N.); (N.W.); (X.G.); (C.Y.)
| | - Shitou Xia
- Hunan Provincial Key Laboratory of Phytohormones and Growth Development, College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China; (K.C.); (L.Q.); (X.T.); (J.N.); (N.W.); (X.G.); (C.Y.)
- Correspondence:
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2
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Haskins JS, Su C, Maeda J, Walsh KD, Haskins AH, Allum AJ, Froning CE, Kato TA. Evaluating the Genotoxic and Cytotoxic Effects of Thymidine Analogs, 5-Ethynyl-2'-Deoxyuridine and 5-Bromo-2'-Deoxyurdine to Mammalian Cells. Int J Mol Sci 2020; 21:E6631. [PMID: 32927807 PMCID: PMC7555307 DOI: 10.3390/ijms21186631] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 09/02/2020] [Accepted: 09/08/2020] [Indexed: 12/23/2022] Open
Abstract
BrdU (bromodeoxyuridine) and EdU (ethynyldeoxyuridine) have been largely utilized as the means of monitoring DNA replication and cellular division. Although BrdU induces gene and chromosomal mutations and induces sensitization to photons, EdU's effects have not been extensively studied yet. Therefore, we investigated EdU's potential cytotoxic and mutagenic effects and its related underlying mechanisms when administered to Chinese hamster ovary (CHO) wild type and DNA repair-deficient cells. EdU treatment displayed a higher cytotoxicity and genotoxicity than BrdU treatment. Cells with defective homologous recombination repair displayed a greater growth delay and severe inhibition of clonogenicity with EdU compared to wild type and other DNA repair-deficient cells. Inductions of sister chromatid exchange and hypoxanthine phosphorybosyl transferase (HPRT) mutation were observed in EdU-incorporated cells as well. Interestingly, on the other hand, EdU did not induce sensitization to photons to the same degree as BrdU. Our results demonstrate that elevated concentrations (similar to manufacturers suggested concentration; >5-10 μM) of EdU treatment were toxic to the cell cultures, particularly in cells with a defect in homologous recombination repair. Therefore, EdU should be administered with additional precautions.
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Affiliation(s)
| | | | | | | | | | | | | | - Takamitsu A. Kato
- Department of Environmental & Radiological Health Sciences, Colorado State University, Fort Collins, CO 80526, USA; (J.S.H.); (C.S.); (J.M.); (K.D.W.); (A.H.H.); (A.J.A.); (C.E.F.)
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3
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Woods DP, Dong Y, Bouché F, Mayer K, Varner L, Ream TS, Thrower N, Wilkerson C, Cartwright A, Sibout R, Laudencia-Chingcuanco D, Vogel J, Amasino RM. Mutations in the predicted DNA polymerase subunit POLD3 result in more rapid flowering of Brachypodium distachyon. THE NEW PHYTOLOGIST 2020; 227:1725-1735. [PMID: 32173866 DOI: 10.1111/nph.16546] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Accepted: 02/18/2020] [Indexed: 06/10/2023]
Abstract
The timing of reproduction is a critical developmental decision in the life cycle of many plant species. Fine mapping of a rapid-flowering mutant was done using whole-genome sequence data from bulked DNA from a segregating F2 mapping populations. The causative mutation maps to a gene orthologous with the third subunit of DNA polymerase δ (POLD3), a previously uncharacterized gene in plants. Expression analyses of POLD3 were conducted via real time qPCR to determine when and in what tissues the gene is expressed. To better understand the molecular basis of the rapid-flowering phenotype, transcriptomic analyses were conducted in the mutant vs wild-type. Consistent with the rapid-flowering mutant phenotype, a range of genes involved in floral induction and flower development are upregulated in the mutant. Our results provide the first characterization of the developmental and gene expression phenotypes that result from a lesion in POLD3 in plants.
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Affiliation(s)
- Daniel P Woods
- Laboratory of Genetics, University of Wisconsin, 425-G Henry Mall, Madison, WI, 53706, USA
- United States Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin, Madison, WI, 53706, USA
- Department of Biochemistry, University of Wisconsin, 433 Babcock Dr., Madison, WI, 53706, USA
| | - Yinxin Dong
- Department of Biochemistry, University of Wisconsin, 433 Babcock Dr., Madison, WI, 53706, USA
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Frédéric Bouché
- Department of Biochemistry, University of Wisconsin, 433 Babcock Dr., Madison, WI, 53706, USA
| | - Kevin Mayer
- Laboratory of Genetics, University of Wisconsin, 425-G Henry Mall, Madison, WI, 53706, USA
| | - Leah Varner
- Department of Biochemistry, University of Wisconsin, 433 Babcock Dr., Madison, WI, 53706, USA
| | - Thomas S Ream
- United States Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin, Madison, WI, 53706, USA
- Department of Biochemistry, University of Wisconsin, 433 Babcock Dr., Madison, WI, 53706, USA
| | - Nicholas Thrower
- United States Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin, Madison, WI, 53706, USA
- Department of Plant Biology and Department of Molecular Biology and Biochemistry, Michigan State University, East Lansing, MI, 48824, USA
| | - Curtis Wilkerson
- United States Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin, Madison, WI, 53706, USA
- Department of Plant Biology and Department of Molecular Biology and Biochemistry, Michigan State University, East Lansing, MI, 48824, USA
| | - Amy Cartwright
- United States Department of Energy Joint Genome Institute, Berkeley, CA, 94720, USA
| | - Richard Sibout
- INRAE, UR BIA, F-44316, Nantes, France
- Institut Jean-Pierre Bourgin, UMR 1318, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France
| | | | - John Vogel
- United States Department of Energy Joint Genome Institute, Berkeley, CA, 94720, USA
- Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- University of California Berkeley, Berkeley, CA, 94704, USA
| | - Richard M Amasino
- Laboratory of Genetics, University of Wisconsin, 425-G Henry Mall, Madison, WI, 53706, USA
- United States Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin, Madison, WI, 53706, USA
- Department of Biochemistry, University of Wisconsin, 433 Babcock Dr., Madison, WI, 53706, USA
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Wolter F, Puchta H. In planta gene targeting can be enhanced by the use of CRISPR/Cas12a. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 100:1083-1094. [PMID: 31381206 DOI: 10.1111/tpj.14488] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Revised: 07/08/2019] [Accepted: 07/29/2019] [Indexed: 05/20/2023]
Abstract
The controlled change of plant genomes by homologous recombination (HR) is still difficult to achieve. We previously developed the in planta gene targeting (ipGT) technology which depends on the simultaneous activation of the target locus by a double-strand break and the excision of the target vector. Whereas the use of SpCas9 resulted in low ipGT frequencies in Arabidopsis, we were recently able to improve the efficiency by using egg cell-specific expression of the potent but less broadly applicable SaCas9 nuclease. In this study, we now tested whether we could improve ipGT further, by either performing it in cells with enhanced intrachromosomal HR efficiencies or by the use of Cas12a, a different kind of CRISPR/Cas nuclease with an alternative cutting mechanism. We could show before that plants possess three kinds of DNA ATPase complexes, which all lead to instabilities of homologous genomic repeats if lost by mutation. As these proteins act in independent pathways, we tested ipGT in double mutants in which intrachromosomal HR is enhanced 20-80-fold. However, we were not able to obtain higher ipGT frequencies, indicating that mechanisms for gene targeting (GT) and chromosomal repeat-induced HR differ. However, using LbCas12a, the GT frequencies were higher than with SaCas9, despite a lower non-homologous end-joining (NHEJ) induction efficiency, demonstrating the particular suitability of Cas12a to induce HR. As SaCas9 has substantial restrictions due to its longer GC rich PAM sequence, the use of LbCas12a with its AT-rich PAM broadens the range of ipGT drastically, particularly when targeting in CG-deserts like promoters and introns.
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Affiliation(s)
- Felix Wolter
- Botanical Institute, Karlsruhe Institute of Technology, POB 6980, 76049, Karlsruhe, Germany
| | - Holger Puchta
- Botanical Institute, Karlsruhe Institute of Technology, POB 6980, 76049, Karlsruhe, Germany
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5
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Hirakawa T, Kuwata K, Gallego ME, White CI, Nomoto M, Tada Y, Matsunaga S. LSD1-LIKE1-Mediated H3K4me2 Demethylation Is Required for Homologous Recombination Repair. PLANT PHYSIOLOGY 2019; 181:499-509. [PMID: 31366719 PMCID: PMC6776857 DOI: 10.1104/pp.19.00530] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 07/22/2019] [Indexed: 05/18/2023]
Abstract
Homologous recombination is a key process for maintaining genome integrity and diversity. In eukaryotes, the nucleosome structure of chromatin inhibits the progression of homologous recombination. The DNA repair and recombination protein RAD54 alters the chromatin structure via nucleosome sliding to enable homology searches. For homologous recombination to progress, appropriate recruitment and dissociation of RAD54 is required at the site of homologous recombination; however, little is known about the mechanism regulating RAD54 dynamics in chromatin. Here, we reveal that the histone demethylase LYSINE-SPECIFIC DEMETHYLASE1-LIKE 1 (LDL1) regulates the dissociation of RAD54 at damaged sites during homologous recombination repair in the somatic cells of Arabidopsis (Arabidopsis thaliana). Depletion of LDL1 leads to an overaccumulation of RAD54 at damaged sites with DNA double-strand breaks. Moreover, RAD54 accumulates at damaged sites by recognizing histone H3 Lys 4 di-methylation (H3K4me2); the frequency of the interaction between RAD54 and H3K4me2 increased in the ldl1 mutant with DNA double-strand breaks. We propose that LDL1 removes RAD54 at damaged sites by demethylating H3K4me2 during homologous recombination repair and thereby maintains genome stability in Arabidopsis.
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Affiliation(s)
- Takeshi Hirakawa
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Keiko Kuwata
- Institute of Transformative Bio-Molecules, Nagoya University, Nagoya 464-8601, Japan
| | - Maria E Gallego
- Génétique, Reproduction et Développement, Unité de Mixte de Recherche, Centre National de la Recherche Scientifique 6293, Clermont Université, Institut National de la Santé et de la Recherche Médicale U1103, Université Clermont Auvergne, F-63000 Clermont-Ferrand, France
| | - Charles I White
- Génétique, Reproduction et Développement, Unité de Mixte de Recherche, Centre National de la Recherche Scientifique 6293, Clermont Université, Institut National de la Santé et de la Recherche Médicale U1103, Université Clermont Auvergne, F-63000 Clermont-Ferrand, France
| | - Mika Nomoto
- Center for Gene Research, Nagoya University, Nagoya 464-8602, Japan
| | - Yasuomi Tada
- Center for Gene Research, Nagoya University, Nagoya 464-8602, Japan
| | - Sachihiro Matsunaga
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
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6
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Abstract
Maintenance of genome integrity is a key process in all organisms. DNA polymerases (Pols) are central players in this process as they are in charge of the faithful reproduction of the genetic information, as well as of DNA repair. Interestingly, all eukaryotes possess a large repertoire of polymerases. Three protein complexes, DNA Pol α, δ, and ε, are in charge of nuclear DNA replication. These enzymes have the fidelity and processivity required to replicate long DNA sequences, but DNA lesions can block their progression. Consequently, eukaryotic genomes also encode a variable number of specialized polymerases (between five and 16 depending on the organism) that are involved in the replication of damaged DNA, DNA repair, and organellar DNA replication. This diversity of enzymes likely stems from their ability to bypass specific types of lesions. In the past 10–15 years, our knowledge regarding plant DNA polymerases dramatically increased. In this review, we discuss these recent findings and compare acquired knowledge in plants to data obtained in other eukaryotes. We also discuss the emerging links between genome and epigenome replication.
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7
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Abstract
When first asked to write a review of my life as a scientist, I doubted anyone would be interested in reading it. In addition, I did not really want to compose my own memorial. However, after discussing the idea with other scientists who have written autobiographies, I realized that it might be fun to dig into my past and to reflect on what has been important for me, my life, my family, my friends and colleagues, and my career. My life and research has taken me from bacteriophage to Agrobacterium tumefaciens-mediated DNA transfer to plants to the plant genome and its environmentally induced changes. I went from being a naïve, young student to a postdoc and married mother of two to the leader of an ever-changing group of fantastic coworkers-a journey made rich by many interesting scientific milestones, fascinating exploration of all corners of the world, and marvelous friendships.
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Affiliation(s)
- Barbara Hohn
- Friedrich Miescher Institute for Biomedical Research, CH-4058 Basel, Switzerland;
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8
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Wang C, Huang J, Zhang J, Wang H, Han Y, Copenhaver GP, Ma H, Wang Y. The Largest Subunit of DNA Polymerase Delta Is Required for Normal Formation of Meiotic Type I Crossovers. PLANT PHYSIOLOGY 2019; 179:446-459. [PMID: 30459265 PMCID: PMC6426404 DOI: 10.1104/pp.18.00861] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 11/15/2018] [Indexed: 05/12/2023]
Abstract
Meiotic recombination contributes to the maintenance of the association between homologous chromosomes (homologs) and ensures the accurate segregation of homologs during anaphase I, thus facilitating the redistribution of alleles among progeny. Meiotic recombination is initiated by the programmed formation of DNA double strand breaks, the repair of which requires DNA synthesis, but the role of DNA synthesis proteins during meiosis is largely unknown. Here, we hypothesized that the lagging strand-specific DNA Polymerase δ (POL δ) might be required for meiotic recombination, based on a previous analysis of DNA Replication Factor1 that suggested a role for lagging strand synthesis in meiotic recombination. In Arabidopsis (Arabidopsis thaliana), complete mutation of the catalytic subunit of POL δ, encoded by AtPOLD1, leads to embryo lethality. Therefore, we used a meiocyte-specific knockdown strategy to test this hypothesis. Reduced expression of AtPOLD1 in meiocytes caused decreased fertility and meiotic defects, including incomplete synapsis, the formation of multivalents, chromosome fragmentation, and improper segregation. Analysis of meiotic crossover (CO) frequencies showed that AtPOLD1RNAi plants had significantly fewer interference-sensitive COs than the wild type, indicating that AtPOL δ participates in type I CO formation. AtPOLD1RNAi atpol2a double mutant meiocytes displayed more severe meiotic phenotypes than those of either single mutant, suggesting that the function of AtPOLD1 and AtPOL2A is not identical in meiotic recombination. Given that POL δ is highly conserved among eukaryotes, we hypothesize that the described role of POL δ here in meiotic recombination likely exists widely in eukaryotes.
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Affiliation(s)
- Cong Wang
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory of Biodiversity Sciences and Ecological Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Jiyue Huang
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory of Biodiversity Sciences and Ecological Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200438, China
- Department of Biology and Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, North Carolina 27599-3280
| | - Jun Zhang
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory of Biodiversity Sciences and Ecological Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Hongkuan Wang
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory of Biodiversity Sciences and Ecological Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Yapeng Han
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory of Biodiversity Sciences and Ecological Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200438, China
- College of Life Sciences, Xinyang Normal University, Xinyang, Henan 464000, China
| | - Gregory P Copenhaver
- Department of Biology and Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, North Carolina 27599-3280
- Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-3280
| | - Hong Ma
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory of Biodiversity Sciences and Ecological Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200438, China
- Department of Biology, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania 16802
| | - Yingxiang Wang
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory of Biodiversity Sciences and Ecological Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200438, China
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9
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Jupe F, Rivkin AC, Michael TP, Zander M, Motley ST, Sandoval JP, Slotkin RK, Chen H, Castanon R, Nery JR, Ecker JR. The complex architecture and epigenomic impact of plant T-DNA insertions. PLoS Genet 2019; 15:e1007819. [PMID: 30657772 PMCID: PMC6338467 DOI: 10.1371/journal.pgen.1007819] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 11/07/2018] [Indexed: 12/17/2022] Open
Abstract
The bacterium Agrobacterium tumefaciens has been the workhorse in plant genome engineering. Customized replacement of native tumor-inducing (Ti) plasmid elements enabled insertion of a sequence of interest called Transfer-DNA (T-DNA) into any plant genome. Although these transfer mechanisms are well understood, detailed understanding of structure and epigenomic status of insertion events was limited by current technologies. Here we applied two single-molecule technologies and analyzed Arabidopsis thaliana lines from three widely used T-DNA insertion collections (SALK, SAIL and WISC). Optical maps for four randomly selected T-DNA lines revealed between one and seven insertions/rearrangements, and the length of individual insertions from 27 to 236 kilobases. De novo nanopore sequencing-based assemblies for two segregating lines partially resolved T-DNA structures and revealed multiple translocations and exchange of chromosome arm ends. For the current TAIR10 reference genome, nanopore contigs corrected 83% of non-centromeric misassemblies. The unprecedented contiguous nucleotide-level resolution enabled an in-depth study of the epigenome at T-DNA insertion sites. SALK_059379 line T-DNA insertions were enriched for 24nt small interfering RNAs (siRNA) and dense cytosine DNA methylation, resulting in transgene silencing via the RNA-directed DNA methylation pathway. In contrast, SAIL_232 line T-DNA insertions are predominantly targeted by 21/22nt siRNAs, with DNA methylation and silencing limited to a reporter, but not the resistance gene. Additionally, we profiled the H3K4me3, H3K27me3 and H2A.Z chromatin environments around T-DNA insertions using ChIP-seq in SALK_059379, SAIL_232 and five additional T-DNA lines. We discovered various effect s ranging from complete loss of chromatin marks to the de novo incorporation of H2A.Z and trimethylation of H3K4 and H3K27 around the T-DNA integration sites. This study provides new insights into the structural impact of inserting foreign fragments into plant genomes and demonstrates the utility of state-of-the-art long-range sequencing technologies to rapidly identify unanticipated genomic changes. Our routine ability to add or alter genes in plant genomes using transgenesis has proven to be a game changer to plant sciences. Transgenics not only enables the study of gene function but also allows the development of modern crop plants without the unwanted genetic baggage coming from natural crossing. A major tool to create transgenics is the Agrobacterium system which naturally shuttles and integrates pieces of foreign DNA into its host genome. While the position and number of integrations was relatively easy to track, molecular tools never allowed to see the integrated piece of DNA within a single “picture”. Here we have utilized state-of-the-art DNA sequencing technology to capture the size and structure of multiple DNA insertion events in a plant genome. We discovered that insertion of the anticipated DNA fragment occurred as multiple concatenated full and partial fragments that led in some cases to intra- and interchromosomal rearrangements. Our analysis of the epigenetic landscapes showed variable effects from silencing of the integrated foreign DNA to alterations of chromatin marks and thus chromatin structure and functionality.
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Affiliation(s)
- Florian Jupe
- Genomic Analysis Laboratory, Salk Institute for Biological Studies, La Jolla, CA, United States of America
| | - Angeline C. Rivkin
- Genomic Analysis Laboratory, Salk Institute for Biological Studies, La Jolla, CA, United States of America
| | - Todd P. Michael
- J. Craig Venter Institute, La Jolla, CA, United States of America
| | - Mark Zander
- Genomic Analysis Laboratory, Salk Institute for Biological Studies, La Jolla, CA, United States of America
- Plant Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, United States of America
- Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, CA, United States of America
| | | | - Justin P. Sandoval
- Genomic Analysis Laboratory, Salk Institute for Biological Studies, La Jolla, CA, United States of America
| | - R. Keith Slotkin
- Donald Danforth Plant Science Center, St. Louis, MO, United States of America
| | - Huaming Chen
- Genomic Analysis Laboratory, Salk Institute for Biological Studies, La Jolla, CA, United States of America
| | - Rosa Castanon
- Genomic Analysis Laboratory, Salk Institute for Biological Studies, La Jolla, CA, United States of America
| | - Joseph R. Nery
- Genomic Analysis Laboratory, Salk Institute for Biological Studies, La Jolla, CA, United States of America
| | - Joseph R. Ecker
- Genomic Analysis Laboratory, Salk Institute for Biological Studies, La Jolla, CA, United States of America
- Plant Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, United States of America
- Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, CA, United States of America
- * E-mail:
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10
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Kim JH, Ryu TH, Lee SS, Lee S, Chung BY. Ionizing radiation manifesting DNA damage response in plants: An overview of DNA damage signaling and repair mechanisms in plants. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 278:44-53. [PMID: 30471728 DOI: 10.1016/j.plantsci.2018.10.013] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 09/30/2018] [Accepted: 10/16/2018] [Indexed: 05/23/2023]
Abstract
Plants orchestrate various DNA damage responses (DDRs) to overcome the deleterious impacts of genotoxic agents on genetic materials. Ionizing radiation (IR) is widely used as a potent genotoxic agent in plant DDR research as well as plant breeding and quarantine services for commercial uses. This review aimed to highlight the recent advances in cellular and phenotypic DDRs, especially those induced by IR. Various physicochemical genotoxic agents damage DNA directly or indirectly by inhibiting DNA replication. Among them, IR-induced DDRs are considerably more complicated. Many aspects of such DDRs and their initial transcriptomes are closely related to oxidative stress response. Although many key components of DDR signaling have been characterized in plants, DDRs in plant cells are not understood in detail to allow comparison with those in yeast and mammalian cells. Recent studies have revealed plant DDR signaling pathways including the key regulator SOG1. The SOG1 and its upstream key components ATM and ATR could be functionally characterized by analyzing their knockout DDR phenotypes after exposure to IR. Considering the potent genotoxicity of IR and its various DDR phenotypes, IR-induced DDR studies should help to establish an integrated model for plant DDR signaling pathways by revealing the unknown key components of various DDRs in plants.
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Affiliation(s)
- Jin-Hong Kim
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, 29 Geumgu-gil, Jeongeup-si, Jeollabuk-do, 56212, Republic of Korea; Department of Radiation Biotechnology and Applied Radioisotope Science, University of Science and Technology, 217 Gajeong-ro, Yuseong-gu, Daejeon, 34113, Republic of Korea.
| | - Tae Ho Ryu
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, 29 Geumgu-gil, Jeongeup-si, Jeollabuk-do, 56212, Republic of Korea
| | - Seung Sik Lee
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, 29 Geumgu-gil, Jeongeup-si, Jeollabuk-do, 56212, Republic of Korea; Department of Radiation Biotechnology and Applied Radioisotope Science, University of Science and Technology, 217 Gajeong-ro, Yuseong-gu, Daejeon, 34113, Republic of Korea
| | - Sungbeom Lee
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, 29 Geumgu-gil, Jeongeup-si, Jeollabuk-do, 56212, Republic of Korea; Department of Radiation Biotechnology and Applied Radioisotope Science, University of Science and Technology, 217 Gajeong-ro, Yuseong-gu, Daejeon, 34113, Republic of Korea
| | - Byung Yeoup Chung
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, 29 Geumgu-gil, Jeongeup-si, Jeollabuk-do, 56212, Republic of Korea
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11
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Sakamoto AN, Kaya H, Endo M. Deletion of TLS polymerases promotes homologous recombination in Arabidopsis. PLANT SIGNALING & BEHAVIOR 2018; 13:e1483673. [PMID: 29944437 PMCID: PMC6128680 DOI: 10.1080/15592324.2018.1483673] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Unrepaired DNA damage hinders the maintenance of genome integrity because it blocks the catalytic activity of replicase. The stalled replication fork can be processed through either translesion synthesis (TLS) with specific polymerases, or replication using the undamaged template. To investigate how TLS activities are regulated and how the stalled replication fork is processed in plants, reversion frequencies and homologous recombination (HR) frequencies were analyzed using GUS-based substrates. The HR frequencies in plants deficient in DNA polymerase ζ (Pol ζ) or Rev1 were higher than that in wildtype plants under normal conditions, and were significantly increased by ultraviolet light irradiation. Heat shock protein (HSP) 90 is known to be involved in various stress responses. To examine the role of HSP90 in the regulation of damage tolerance, we analyzed reversion frequencies and HR frequencies in plants grown in the presence of a HSP inhibitor, geldanamycin (GDA). Reversion frequency was lower in GDA-treated plants than in mock-treated plants. Though the HR frequency was higher in GDA-treated wildtype plants than in mock-treated plants, no significant difference was detected in Rev1-deficient plants. In yeast, TLS polymerases interacted with each other or with a replication clump component, proliferating cell nuclear antigen (PCNA). HSP90 interacted with REV1 or REV7 in Nicotiana benthamiana cells. These results suggest that HSP90 interacts with TLS polymerase(s), which promotes error-prone TLS in plants.
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Affiliation(s)
- A. N. Sakamoto
- Department of Radiation-Applied Biology Research, National Institutes for Quantum and Radiological Science and Technology (QST), Takasaki, Gumma, Japan
- CONTACT A. N. Sakamoto Department of Radiation-Applied Biology Research, National Institutes for Quantum and Radiological Science and Technology (QST), Watanuki-machi 1233, Takasaki, Gumma 370-1292, Japan
| | - H. Kaya
- Plant Molecular Biology and Virology, Graduate School of Agriculture, Ehime University, Matsuyama, Ehime, Japan
| | - M. Endo
- Plant Genome Engineering Research Unit, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki, Japan
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12
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Zhang J, Xie S, Cheng J, Lai J, Zhu JK, Gong Z. The Second Subunit of DNA Polymerase Delta Is Required for Genomic Stability and Epigenetic Regulation. PLANT PHYSIOLOGY 2016; 171:1192-208. [PMID: 27208288 PMCID: PMC4902588 DOI: 10.1104/pp.15.01976] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 04/24/2016] [Indexed: 05/08/2023]
Abstract
DNA polymerase δ plays crucial roles in DNA repair and replication as well as maintaining genomic stability. However, the function of POLD2, the second small subunit of DNA polymerase δ, has not been characterized yet in Arabidopsis (Arabidopsis thaliana). During a genetic screen for release of transcriptional gene silencing, we identified a mutation in POLD2. Whole-genome bisulfite sequencing indicated that POLD2 is not involved in the regulation of DNA methylation. POLD2 genetically interacts with Ataxia Telangiectasia-mutated and Rad3-related and DNA polymerase α The pold2-1 mutant exhibits genomic instability with a high frequency of homologous recombination. It also exhibits hypersensitivity to DNA-damaging reagents and short telomere length. Whole-genome chromatin immunoprecipitation sequencing and RNA sequencing analyses suggest that pold2-1 changes H3K27me3 and H3K4me3 modifications, and these changes are correlated with the gene expression levels. Our study suggests that POLD2 is required for maintaining genome integrity and properly establishing the epigenetic markers during DNA replication to modulate gene expression.
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Affiliation(s)
- Jixiang Zhang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China (J.Z., J.C., Z.G.);Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China (S.X., J.-K.Z.);Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana 47906 (S.X., J.-K.Z.); andState Key Laboratory of Agrobiotechnology, China National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, China (J.L.)
| | - Shaojun Xie
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China (J.Z., J.C., Z.G.);Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China (S.X., J.-K.Z.);Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana 47906 (S.X., J.-K.Z.); andState Key Laboratory of Agrobiotechnology, China National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, China (J.L.)
| | - Jinkui Cheng
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China (J.Z., J.C., Z.G.);Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China (S.X., J.-K.Z.);Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana 47906 (S.X., J.-K.Z.); andState Key Laboratory of Agrobiotechnology, China National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, China (J.L.)
| | - Jinsheng Lai
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China (J.Z., J.C., Z.G.);Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China (S.X., J.-K.Z.);Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana 47906 (S.X., J.-K.Z.); andState Key Laboratory of Agrobiotechnology, China National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, China (J.L.)
| | - Jian-Kang Zhu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China (J.Z., J.C., Z.G.);Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China (S.X., J.-K.Z.);Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana 47906 (S.X., J.-K.Z.); andState Key Laboratory of Agrobiotechnology, China National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, China (J.L.)
| | - Zhizhong Gong
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China (J.Z., J.C., Z.G.);Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China (S.X., J.-K.Z.);Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana 47906 (S.X., J.-K.Z.); andState Key Laboratory of Agrobiotechnology, China National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, China (J.L.)
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13
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Iglesias FM, Cerdán PD. Maintaining Epigenetic Inheritance During DNA Replication in Plants. FRONTIERS IN PLANT SCIENCE 2016; 7:38. [PMID: 26870059 PMCID: PMC4735446 DOI: 10.3389/fpls.2016.00038] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 01/11/2016] [Indexed: 05/18/2023]
Abstract
Biotic and abiotic stresses alter the pattern of gene expression in plants. Depending on the frequency and duration of stress events, the effects on the transcriptional state of genes are "remembered" temporally or transmitted to daughter cells and, in some instances, even to offspring (transgenerational epigenetic inheritance). This "memory" effect, which can be found even in the absence of the original stress, has an epigenetic basis, through molecular mechanisms that take place at the chromatin and DNA level but do not imply changes in the DNA sequence. Many epigenetic mechanisms have been described and involve covalent modifications on the DNA and histones, such as DNA methylation, histone acetylation and methylation, and RNAi dependent silencing mechanisms. Some of these chromatin modifications need to be stable through cell division in order to be truly epigenetic. During DNA replication, histones are recycled during the formation of the new nucleosomes and this process is tightly regulated. Perturbations to the DNA replication process and/or the recycling of histones lead to epigenetic changes. In this mini-review, we discuss recent evidence aimed at linking DNA replication process to epigenetic inheritance in plants.
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Affiliation(s)
| | - Pablo D. Cerdán
- Fundación Instituto Leloir, IIBBA-CONICET Buenos Aires, Argentina
- Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires Buenos Aires, Argentina
- *Correspondence: Pablo D. Cerdán,
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14
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Micol-Ponce R, Sánchez-García AB, Xu Q, Barrero JM, Micol JL, Ponce MR. Arabidopsis INCURVATA2 Regulates Salicylic Acid and Abscisic Acid Signaling, and Oxidative Stress Responses. PLANT & CELL PHYSIOLOGY 2015; 56:2207-2219. [PMID: 26423959 DOI: 10.1093/pcp/pcv132] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 09/15/2015] [Indexed: 06/05/2023]
Abstract
Epigenetic regulatory states can persist through mitosis and meiosis, but the connection between chromatin structure and DNA replication remains unclear. Arabidopsis INCURVATA2 (ICU2) encodes the catalytic subunit of DNA polymerase α, and null alleles of ICU2 have an embryo-lethal phenotype. Analysis of icu2-1, a hypomorphic allele of ICU2, demonstrated that ICU2 functions in chromatin-mediated cellular memory; icu2-1 strongly impairs ICU2 function in the maintenance of repressive epigenetic marks but does not seem to affect ICU2 polymerase activity. To better understand the global function of ICU2 in epigenetic regulation, here we performed a microarray analysis of icu2-1 mutant plants. We found that the genes up-regulated in the icu2-1 mutant included genes encoding transcription factors and targets of the Polycomb Repressive Complexes. The down-regulated genes included many known players in salicylic acid (SA) biosynthesis and accumulation, ABA signaling and ABA-mediated responses. In addition, we found that icu2-1 plants had reduced SA levels in normal conditions; infection by Fusarium oxysporum induced SA accumulation in the En-2 wild type but not in the icu2-1 mutant. The icu2-1 plants were also hypersensitive to salt stress and exogenous ABA in seedling establishment, post-germination growth and stomatal closure, and accumulated more ABA than the wild type in response to salt stress. The icu2-1 mutant also showed high tolerance to the oxidative stress produced by 3-amino-1,2,4-triazole (3-AT). Our results uncover a role for ICU2 in the regulation of genes involved in ABA signaling as well as in SA biosynthesis and accumulation.
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Affiliation(s)
- Rosa Micol-Ponce
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, 03202 Elche, Alicante, Spain
| | - Ana Belén Sánchez-García
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, 03202 Elche, Alicante, Spain
| | - Qian Xu
- Commonwealth Scientific and Industrial Research Organization Plant Industry, Canberra, Australian Capital Territory 2601, Australia
| | - José María Barrero
- Commonwealth Scientific and Industrial Research Organization Plant Industry, Canberra, Australian Capital Territory 2601, Australia
| | - José Luis Micol
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, 03202 Elche, Alicante, Spain
| | - María Rosa Ponce
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, 03202 Elche, Alicante, Spain
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15
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Zhang C, Cao L, Rong L, An Z, Zhou W, Ma J, Shen WH, Zhu Y, Dong A. The chromatin-remodeling factor AtINO80 plays crucial roles in genome stability maintenance and in plant development. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 82:655-68. [PMID: 25832737 DOI: 10.1111/tpj.12840] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2015] [Revised: 03/25/2015] [Accepted: 03/25/2015] [Indexed: 05/10/2023]
Abstract
INO80 is a conserved chromatin-remodeling factor in eukaryotes. While a previous study reported that the Arabidopsis thaliana INO80 (AtINO80) is required for somatic homologous recombination (HR), the role of AtINO80 in plant growth and development remains obscure. Here, we identified and characterized two independent atino80 mutant alleles, atino80-5 and atino80-6, which display similar and pleiotropic phenotypes, including smaller plant and organ size, and late flowering. Under standard growth conditions, atino80-5 showed decreased HR; however, after genotoxic treatment, HR in the mutant increased, accompanied by more DNA double-strand breaks and stronger cellular responses. Transcription analysis showed that many developmental and environmental responsive genes are overrepresented in the perturbed genes in atino80-5. These genes significantly overlapped with the category of H2A.Z body-enriched genes. AtINO80 also interacts with H2A.Z, and facilitates the enrichment of H2A.Z at the ends of the key flowering repressor genes FLC and MAF4/5. Our characterization of the atino80-5 and atino80-6 mutants confirms and extends the previous AtINO80 study, and provides perspectives for linking studies of epigenetic mechanisms involved in plant chromatin stability with plant response to developmental and environmental cues.
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Affiliation(s)
- Chi Zhang
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, International Associated Laboratory of CNRS-Fudan-HUNAU on Plant Epigenome Research, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 20043, China
| | - Lin Cao
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, International Associated Laboratory of CNRS-Fudan-HUNAU on Plant Epigenome Research, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 20043, China
| | - Liang Rong
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 20043, China
| | - Zengxuan An
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, International Associated Laboratory of CNRS-Fudan-HUNAU on Plant Epigenome Research, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 20043, China
| | - Wangbin Zhou
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, International Associated Laboratory of CNRS-Fudan-HUNAU on Plant Epigenome Research, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 20043, China
| | - Jinbiao Ma
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 20043, China
| | - Wen-Hui Shen
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, International Associated Laboratory of CNRS-Fudan-HUNAU on Plant Epigenome Research, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 20043, China
- Institut de Biologie Moléculaire des Plantes, UPR2357 CNRS, Université de Strasbourg, 12 rue du Général Zimmer, 67084, Strasbourg Cédex, France
| | - Yan Zhu
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, International Associated Laboratory of CNRS-Fudan-HUNAU on Plant Epigenome Research, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 20043, China
| | - Aiwu Dong
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, International Associated Laboratory of CNRS-Fudan-HUNAU on Plant Epigenome Research, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 20043, China
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16
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Iglesias FM, Bruera NA, Dergan-Dylon S, Marino-Buslje C, Lorenzi H, Mateos JL, Turck F, Coupland G, Cerdán PD. The arabidopsis DNA polymerase δ has a role in the deposition of transcriptionally active epigenetic marks, development and flowering. PLoS Genet 2015; 11:e1004975. [PMID: 25693187 PMCID: PMC4334202 DOI: 10.1371/journal.pgen.1004975] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 12/29/2014] [Indexed: 11/18/2022] Open
Abstract
DNA replication is a key process in living organisms. DNA polymerase α (Polα) initiates strand synthesis, which is performed by Polε and Polδ in leading and lagging strands, respectively. Whereas loss of DNA polymerase activity is incompatible with life, viable mutants of Polα and Polε were isolated, allowing the identification of their functions beyond DNA replication. In contrast, no viable mutants in the Polδ polymerase-domain were reported in multicellular organisms. Here we identify such a mutant which is also thermosensitive. Mutant plants were unable to complete development at 28°C, looked normal at 18°C, but displayed increased expression of DNA replication-stress marker genes, homologous recombination and lysine 4 histone 3 trimethylation at the SEPALLATA3 (SEP3) locus at 24°C, which correlated with ectopic expression of SEP3. Surprisingly, high expression of SEP3 in vascular tissue promoted FLOWERING LOCUS T (FT) expression, forming a positive feedback loop with SEP3 and leading to early flowering and curly leaves phenotypes. These results strongly suggest that the DNA polymerase δ is required for the proper establishment of transcriptionally active epigenetic marks and that its failure might affect development by affecting the epigenetic control of master genes. Three DNA polymerases replicate DNA in Eukaryotes. DNA polymerase α (Polα) initiates strand synthesis, which is performed by Polε and Polδ in leading and lagging strands, respectively. Not only the information encoded in the DNA, but also the inheritance of chromatin states is essential during development. Loss of function mutants in DNA polymerases lead to lethal phenotypes. Hence, hypomorphic alleles are necessary to study their roles beyond DNA replication. Here we identify a thermosensitive mutant of the Polδ in the model plant Arabidopsis thaliana, which bears an aminoacid substitution in the polymerase-domain. The mutants were essentially normal at 18°C but arrested development at 28°C. Interestingly, at 24°C we were able to study the roles of Polδ in epigenetic inheritance and plant development. We observed a tight connection between DNA replication stress and an increase the deposition of transcriptionally active chromatin marks in the SEPALLATA3 (SEP3) locus. Finally, we tested by genetic means that the ectopic expression of SEP3 was indeed the cause of early flowering and the leaf phenotypes by promoting the expression of FLOWERING LOCUS T (FT). These results link Polδ activity to the proper establishment of transcriptionally active epigenetic marks, which then impact the development of multicellular organisms.
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Affiliation(s)
| | | | | | | | - Hernán Lorenzi
- J. Craig Venter Institute, Rockville, Maryland, United States of America
| | - Julieta L. Mateos
- Fundación Instituto Leloir, IIBBA-CONICET, Buenos Aires, Argentina
- Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Franziska Turck
- Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - George Coupland
- Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Pablo D. Cerdán
- Fundación Instituto Leloir, IIBBA-CONICET, Buenos Aires, Argentina
- Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- * E-mail:
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17
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Kalhorzadeh P, Hu Z, Cools T, Amiard S, Willing EM, De Winne N, Gevaert K, De Jaeger G, Schneeberger K, White CI, De Veylder L. Arabidopsis thaliana RNase H2 deficiency counteracts the needs for the WEE1 checkpoint kinase but triggers genome instability. THE PLANT CELL 2014; 26:3680-92. [PMID: 25217508 PMCID: PMC4213155 DOI: 10.1105/tpc.114.128108] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The WEE1 kinase is an essential cell cycle checkpoint regulator in Arabidopsis thaliana plants experiencing replication defects. Whereas under non-stress conditions WEE1-deficient plants develop normally, they fail to adapt to replication inhibitory conditions, resulting in the accumulation of DNA damage and loss of cell division competence. We identified mutant alleles of the genes encoding subunits of the ribonuclease H2 (RNase H2) complex, known for its role in removing ribonucleotides from DNA-RNA duplexes, as suppressor mutants of WEE1 knockout plants. RNase H2 deficiency triggered an increase in homologous recombination (HR), correlated with the accumulation of γ-H2AX foci. However, as HR negatively impacts the growth of WEE1-deficient plants under replication stress, it cannot account for the rescue of the replication defects of the WEE1 knockout plants. Rather, the observed increase in ribonucleotide incorporation in DNA indicates that the substitution of deoxynucleotide with ribonucleotide abolishes the need for WEE1 under replication stress. Strikingly, increased ribonucleotide incorporation in DNA correlated with the occurrence of small base pair deletions, identifying the RNase H2 complex as an important suppressor of genome instability.
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Affiliation(s)
- Pooneh Kalhorzadeh
- Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), B-9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium
| | - Zhubing Hu
- Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), B-9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium
| | - Toon Cools
- Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), B-9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium
| | - Simon Amiard
- Génétique, Reproduction et Développement, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 6293-Clermont Université-Institut National de la Santé et de la Recherche Médicale U1103, F-63177 Aubière, France
| | - Eva-Maria Willing
- Department for Plant Developmental Biology, Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany
| | - Nancy De Winne
- Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), B-9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium
| | - Kris Gevaert
- Department of Medical Protein Research, Flanders Institute for Biotechnology (VIB), B-9000 Ghent, Belgium Department of Biochemistry, Ghent University, B-9000 Ghent, Belgium
| | - Geert De Jaeger
- Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), B-9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium
| | - Korbinian Schneeberger
- Department for Plant Developmental Biology, Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany
| | - Charles I White
- Génétique, Reproduction et Développement, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 6293-Clermont Université-Institut National de la Santé et de la Recherche Médicale U1103, F-63177 Aubière, France
| | - Lieven De Veylder
- Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), B-9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium
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18
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Chen N, Zhou WB, Wang YX, Dong AW, Yu Y. Polycomb-group histone methyltransferase CLF is required for proper somatic recombination in Arabidopsis. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2014; 56:550-558. [PMID: 24393343 DOI: 10.1111/jipb.12157] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 12/30/2013] [Indexed: 06/03/2023]
Abstract
Homologous recombination (HR) is a key process during meiosis in reproductive cells and the DNA damage repair process in somatic cells. Although chromatin structure is thought to be crucial for HR, only a small number of chromatin modifiers have been studied in HR regulation so far. Here, we investigated the function of CURLY LEAF (CLF), a Polycomb-group (PcG) gene responsible for histone3 lysine 27 trimethylation (H3K27me3), in somatic and meiotic HR in Arabidopsis thaliana. Although fluorescent protein reporter assays in pollen and seeds showed that the frequency of meiotic cross-over in the loss-of-function mutant clf-29 was not significantly different from that in wild type, there was a lower frequency of HR in clf-29 than in wild type under normal conditions and under bleomycin treatment. The DNA damage levels were comparable between clf-29 and wild type, even though several DNA damage repair genes (e.g. ATM, BRCA2a, RAD50, RAD51, RAD54, and PARP2) were expressed at lower levels in clf-29. Under bleomycin treatment, the expression levels of DNA repair genes were similar in clf-29 and wild type, thus CLF may also regulate HR via other mechanisms. These findings expand the current knowledge of PcG function and contribute to general interests of epigenetic regulation in genome stability regulation.
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Affiliation(s)
- Na Chen
- State Key Laboratory of Genetic Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 200433, China
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19
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Bashir T, Sailer C, Gerber F, Loganathan N, Bhoopalan H, Eichenberger C, Grossniklaus U, Baskar R. Hybridization alters spontaneous mutation rates in a parent-of-origin-dependent fashion in Arabidopsis. PLANT PHYSIOLOGY 2014; 165:424-37. [PMID: 24664208 PMCID: PMC4012600 DOI: 10.1104/pp.114.238451] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 03/22/2014] [Indexed: 05/18/2023]
Abstract
Over 70 years ago, increased spontaneous mutation rates were observed in Drosophila spp. hybrids, but the genetic basis of this phenomenon is not well understood. The model plant Arabidopsis (Arabidopsis thaliana) offers unique opportunities to study the types of mutations induced upon hybridization and the frequency of their occurrence. Understanding the mutational effects of hybridization is important, as many crop plants are grown as hybrids. Besides, hybridization is important for speciation and its effects on genome integrity could be critical, as chromosomal rearrangements can lead to reproductive isolation. We examined the rates of hybridization-induced point and frameshift mutations as well as homologous recombination events in intraspecific Arabidopsis hybrids using a set of transgenic mutation detector lines that carry mutated or truncated versions of a reporter gene. We found that hybridization alters the frequency of different kinds of mutations. In general, Columbia (Col)×Cape Verde Islands and Col×C24 hybrid progeny had decreased T→G and T→A transversion rates but an increased C→T transition rate. Significant changes in frameshift mutation rates were also observed in some hybrids. In Col×C24 hybrids, there is a trend for increased homologous recombination rates, except for the hybrids from one line, while in Col×Cape Verde Islands hybrids, this rate is decreased. The overall genetic distance of the parents had no influence on mutation rates in the progeny, as closely related accessions on occasion displayed higher mutation rates than accessions that are separated farther apart. However, reciprocal hybrids had significantly different mutation rates, suggesting parent-of-origin-dependent effects on the mutation frequency.
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20
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Rosa M, Von Harder M, Aiese Cigliano R, Schlögelhofer P, Mittelsten Scheid O. The Arabidopsis SWR1 chromatin-remodeling complex is important for DNA repair, somatic recombination, and meiosis. THE PLANT CELL 2013; 25:1990-2001. [PMID: 23780875 PMCID: PMC3723608 DOI: 10.1105/tpc.112.104067] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
All processes requiring interaction with DNA are attuned to occur within the context of the complex chromatin structure. As it does for programmed transcription and replication, this also holds true for unscheduled events, such as repair of DNA damage. Lesions such as double-strand breaks occur randomly; their repair requires that enzyme complexes access DNA at potentially any genomic site. This is achieved by chromatin remodeling factors that can locally slide, evict, or change nucleosomes. Here, we show that the Swi2/Snf2-related (SWR1 complex), known to deposit histone H2A.Z, is also important for DNA repair in Arabidopsis thaliana. Mutations in genes for Arabidopsis SWR1 complex subunits photoperiod-independent Early Flowering1, actin-related protein6, and SWR1 complex6 cause hypersensitivity to various DNA damaging agents. Even without additional genotoxic stress, these mutants show symptoms of DNA damage accumulation. The reduced DNA repair capacity is connected with impaired somatic homologous recombination, in contrast with the hyper-recombinogenic phenotype of yeast SWR1 mutants. This suggests functional diversification between lower and higher eukaryotes. Finally, reduced fertility and irregular gametogenesis in the Arabidopsis SWR1 mutants indicate an additional role for the chromatin-remodeling complex during meiosis. These results provide evidence for the importance of Arabidopsis SWR1 in somatic DNA repair and during meiosis.
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Affiliation(s)
- Marisa Rosa
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, 1030 Vienna, Austria
| | - Mona Von Harder
- Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
| | - Riccardo Aiese Cigliano
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, 1030 Vienna, Austria
| | | | - Ortrun Mittelsten Scheid
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, 1030 Vienna, Austria
- Address correspondence to
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Kwon YI, Abe K, Endo M, Osakabe K, Ohtsuki N, Nishizawa-Yokoi A, Tagiri A, Saika H, Toki S. DNA replication arrest leads to enhanced homologous recombination and cell death in meristems of rice OsRecQl4 mutants. BMC PLANT BIOLOGY 2013; 13:62. [PMID: 23586618 PMCID: PMC3648487 DOI: 10.1186/1471-2229-13-62] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 04/03/2013] [Indexed: 05/18/2023]
Abstract
BACKGROUND Mammalian BLM helicase is involved in DNA replication, DNA repair and homologous recombination (HR). These DNA transactions are associated tightly with cell division and are important for maintaining genome stability. However, unlike in mammals, cell division in higher plants is restricted mainly to the meristem, thus genome maintenance at the meristem is critical. The counterpart of BLM in Arabidopsis (AtRecQ4A) has been identified and its role in HR and in the response to DNA damage has been confirmed. However, the function of AtRecQ4A in the meristem during replication stress has not yet been well elucidated. RESULTS We isolated the BLM counterpart gene OsRecQl4 from rice and analyzed its function using a reverse genetics approach. Osrecql4 mutant plants showed hypersensitivity to DNA damaging agents and enhanced frequency of HR compared to wild-type (WT) plants. We further analyzed the effect of aphidicolin--an inhibitor of S-phase progression via its inhibitory effect on DNA polymerases--on genome stability in the root meristem in osrecql4 mutant plants and corresponding WT plants. The following effects were observed upon aphidicolin treatment: a) comet assay showed induction of DNA double-strand breaks (DSBs) in mutant plants, b) TUNEL assay showed enhanced DNA breaks at the root meristem in mutant plants, c) a recombination reporter showed enhanced HR frequency in mutant calli, d) propidium iodide (PI) staining of root tips revealed an increased incidence of cell death in the meristem of mutant plants. CONCLUSIONS These results demonstrate that the aphidicolin-sensitive phenotype of osrecql4 mutants was in part due to induced DSBs and cell death, and that OsRecQl4 plays an important role as a caretaker, maintaining genome stability during DNA replication stress in the rice meristem.
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Affiliation(s)
- Yong-Ik Kwon
- Plant Genome Engineering Research Unit, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki, 305-8602, Japan
- Graduate School of Nanobioscience, Yokohama City University, 22-2, Seto, Kanazawa, Yokohama, 236-0027, Japan
- Kihara Institute for Biological Research, Yokohama City University, 641-12 Maioka, Yokohama, 244-0813, Japan
| | - Kiyomi Abe
- Functional Plant Research Unit, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki, 305-8602, Japan
| | - Masaki Endo
- Plant Genome Engineering Research Unit, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki, 305-8602, Japan
| | - Keishi Osakabe
- Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura, Saitama, 338-8570, Japan
| | - Namie Ohtsuki
- Plant Genome Engineering Research Unit, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki, 305-8602, Japan
| | - Ayako Nishizawa-Yokoi
- Plant Genome Engineering Research Unit, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki, 305-8602, Japan
| | - Akemi Tagiri
- Plant Genome Engineering Research Unit, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki, 305-8602, Japan
| | - Hiroaki Saika
- Plant Genome Engineering Research Unit, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki, 305-8602, Japan
| | - Seiichi Toki
- Plant Genome Engineering Research Unit, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki, 305-8602, Japan
- Graduate School of Nanobioscience, Yokohama City University, 22-2, Seto, Kanazawa, Yokohama, 236-0027, Japan
- Kihara Institute for Biological Research, Yokohama City University, 641-12 Maioka, Yokohama, 244-0813, Japan
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Puchta H, Hohn B. In planta somatic homologous recombination assay revisited: a successful and versatile, but delicate tool. THE PLANT CELL 2012; 24:4324-31. [PMID: 23144182 PMCID: PMC3531836 DOI: 10.1105/tpc.112.101824] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Marker-transgene-dependent lines of Arabidopsis thaliana measuring somatic homologous recombination (SHR) have been available for almost two decades. Here we discuss mechanisms of marker-gene restoration, comment on results obtained using the reporter lines, and stress how caution must be applied to avoid experimental problems or false interpretation in the use of SHR reporter lines. Although theoretically possible, we conclude that explanations other than SHR are unlikely to account for restoration of marker gene expression in the SHR lines when used with appropriate controls. We provide an overview of some of the most important achievements obtained with the SHR lines, give our view of the limitations of the system, and supply the reader with suggestions on the proper handling of the SHR lines. We are convinced that SHR lines are and will remain in the near future a valuable tool to explore the mechanism and influence of external and internal factors on genome stability and DNA repair in plants.
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Affiliation(s)
- Holger Puchta
- Botanical Institute II, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany.
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23
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Gao J, Zhu Y, Zhou W, Molinier J, Dong A, Shen WH. NAP1 family histone chaperones are required for somatic homologous recombination in Arabidopsis. THE PLANT CELL 2012; 24:1437-47. [PMID: 22534127 PMCID: PMC3407980 DOI: 10.1105/tpc.112.096792] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Homologous recombination (HR) is essential for maintaining genome integrity and variability. To orchestrate HR in the context of chromatin is a challenge, both in terms of DNA accessibility and restoration of chromatin organization after DNA repair. Histone chaperones function in nucleosome assembly/disassembly and could play a role in HR. Here, we show that the NUCLEOSOME ASSEMBLY PROTEIN1 (NAP1) family histone chaperones are required for somatic HR in Arabidopsis thaliana. Depletion of either the NAP1 group or NAP1-RELATED PROTEIN (NRP) group proteins caused a reduction in HR in plants under normal growth conditions as well as under a wide range of genotoxic or abiotic stresses. This contrasts with the hyperrecombinogenic phenotype caused by the depletion of the CHROMATIN ASSEMBLY FACTOR-1 (CAF-1) histone chaperone. Furthermore, we show that the hyperrecombinogenic phenotype caused by CAF-1 depletion relies on NRP1 and NRP2, but the telomere shortening phenotype does not. Our analysis of DNA lesions, H3K56 acetylation, and expression of DNA repair genes argues for a role of NAP1 family histone chaperones in nucleosome disassembly/reassembly during HR. Our study highlights distinct functions for different families of histone chaperones in the maintenance of genome stability and establishes a crucial function for NAP1 family histone chaperones in somatic HR.
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Affiliation(s)
- Juan Gao
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200433, People’s Republic of China
- Institut de Biologie Moléculaire des Plantes du Centre National de la Recherche Scientifique, Université de Strasbourg, 67084 Strasbourg, France
| | - Yan Zhu
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200433, People’s Republic of China
| | - Wangbin Zhou
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200433, People’s Republic of China
| | - Jean Molinier
- Institut de Biologie Moléculaire des Plantes du Centre National de la Recherche Scientifique, Université de Strasbourg, 67084 Strasbourg, France
| | - Aiwu Dong
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200433, People’s Republic of China
| | - Wen-Hui Shen
- Institut de Biologie Moléculaire des Plantes du Centre National de la Recherche Scientifique, Université de Strasbourg, 67084 Strasbourg, France
- Address correspondence to
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24
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Haworth J, Alver RC, Anderson M, Bielinsky AK. Ubc4 and Not4 regulate steady-state levels of DNA polymerase-α to promote efficient and accurate DNA replication. Mol Biol Cell 2010; 21:3205-19. [PMID: 20660159 PMCID: PMC2938386 DOI: 10.1091/mbc.e09-06-0452] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
DNA polymerase-alpha (pol-alpha) is essential for eukaryotic replication but lacks proofreading activity. Its turnover is regulated by the E2 Ubc4 and the E3 Not4, which are known transcriptional regulators. This pathway likely prevents accumulation of the potential mutator pol-alpha to promote genome stability. The accurate duplication of chromosomal DNA is required to maintain genomic integrity. However, from an evolutionary point of view, a low mutation rate during DNA replication is desirable. One way to strike the right balance between accuracy and limited mutagenesis is to use a DNA polymerase that lacks proofreading activity but contributes to DNA replication in a very restricted manner. DNA polymerase-α fits this purpose exactly, but little is known about its regulation at the replication fork. Minichromosome maintenance protein (Mcm) 10 regulates the stability of the catalytic subunit of pol-α in budding yeast and human cells. Cdc17, the catalytic subunit of pol-α in yeast, is rapidly degraded after depletion of Mcm10. Here we show that Ubc4 and Not4 are required for Cdc17 destabilization. Disruption of Cdc17 turnover resulted in sensitivity to hydroxyurea, suggesting that this pathway is important for DNA replication. Furthermore, overexpression of Cdc17 in ubc4 and not4 mutants caused slow growth and synthetic dosage lethality, respectively. Our data suggest that Cdc17 levels are very tightly regulated through the opposing forces of Ubc4 and Not4 (destabilization) and Mcm10 (stabilization). We conclude that regular turnover of Cdc17 via Ubc4 and Not4 is required for proper cell proliferation.
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Affiliation(s)
- Justin Haworth
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
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25
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Liu Q, Wang J, Miki D, Xia R, Yu W, He J, Zheng Z, Zhu JK, Gong Z. DNA replication factor C1 mediates genomic stability and transcriptional gene silencing in Arabidopsis. THE PLANT CELL 2010; 22:2336-52. [PMID: 20639449 PMCID: PMC2929113 DOI: 10.1105/tpc.110.076349] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Revised: 06/18/2010] [Accepted: 06/28/2010] [Indexed: 05/18/2023]
Abstract
Genetic screening identified a suppressor of ros1-1, a mutant of REPRESSOR OF SILENCING1 (ROS1; encoding a DNA demethylation protein). The suppressor is a mutation in the gene encoding the largest subunit of replication factor C (RFC1). This mutation of RFC1 reactivates the unlinked 35S-NPTII transgene, which is silenced in ros1 and also increases expression of the pericentromeric Athila retrotransposons named transcriptional silent information in a DNA methylation-independent manner. rfc1 is more sensitive than the wild type to the DNA-damaging agent methylmethane sulphonate and to the DNA inter- and intra- cross-linking agent cisplatin. The rfc1 mutant constitutively expresses the G2/M-specific cyclin CycB1;1 and other DNA repair-related genes. Treatment with DNA-damaging agents mimics the rfc1 mutation in releasing the silenced 35S-NPTII, suggesting that spontaneously induced genomic instability caused by the rfc1 mutation might partially contribute to the released transcriptional gene silencing (TGS). The frequency of somatic homologous recombination is significantly increased in the rfc1 mutant. Interestingly, ros1 mutants show increased telomere length, but rfc1 mutants show decreased telomere length and reduced expression of telomerase. Our results suggest that RFC1 helps mediate genomic stability and TGS in Arabidopsis thaliana.
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Affiliation(s)
- Qian Liu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Junguo Wang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Daisuke Miki
- Institute for Integrative Genome Biology and Department of Botany and Plant Sciences, University of California, Riverside, California 92521
- Center for Plant Stress Genomics and Technology, 4700 King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Ran Xia
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Wenxiang Yu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Junna He
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Zhimin Zheng
- Institute for Integrative Genome Biology and Department of Botany and Plant Sciences, University of California, Riverside, California 92521
- Center for Plant Stress Genomics and Technology, 4700 King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Jian-Kang Zhu
- Institute for Integrative Genome Biology and Department of Botany and Plant Sciences, University of California, Riverside, California 92521
- Center for Plant Stress Genomics and Technology, 4700 King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
- China Agricultural University–University of California, Riverside Center for Biological Sciences and Biotechnology, Beijing 100193, China
| | - Zhizhong Gong
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
- China Agricultural University–University of California, Riverside Center for Biological Sciences and Biotechnology, Beijing 100193, China
- National Center for Plant Gene Research, Beijing 100193, China
- Address correspondence to
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