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Mahapatra K, Roy S. SOG1 and BRCA1 Interdependently Regulate RAD54 Expression for Repairing Salinity-Induced DNA Double-Strand Breaks in Arabidopsis. PLANT & CELL PHYSIOLOGY 2024; 65:708-728. [PMID: 38242160 DOI: 10.1093/pcp/pcae008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 12/04/2023] [Accepted: 01/16/2024] [Indexed: 01/21/2024]
Abstract
As sessile organisms, land plants experience various forms of environmental stresses throughout their life span. Therefore, plants have developed extensive and complicated defense mechanisms, including a robust DNA damage response (DDR) and DNA repair systems for maintaining genome integrity. In Arabidopsis, the NAC [NO APICAL MERISTEM (NAM), ARABIDOPSIS TRANSCRIPTION ACTIVATION FACTOR (ATAF), CUP-SHAPED COTYLEDON (CUC)] domain family transcription factor SUPPRESSOR OF GAMMA RESPONSE 1 (SOG1) plays an important role in regulating DDR. Here, we show that SOG1 plays a key role in regulating the repair of salinity-induced DNA double-strand breaks (DSBs) via the homologous recombination (HR) pathway in Arabidopsis. The sog1-1 mutant seedlings display a considerably slower rate of repair of salinity-induced DSBs. Accumulation of SOG1 protein increases in wild-type Arabidopsis under salinity stress, and it enhances the expression of HR pathway-related genes, including RAD51, RAD54 and BReast CAncer gene 1 (BRCA1), respectively, as found in SOG1 overexpression lines. SOG1 binds specifically to the AtRAD54 promoter at the 5'-(N)4GTCAA(N)3C-3' consensus sequence and positively regulates its expression under salinity stress. The phenotypic responses of sog1-1/atrad54 double mutants suggest that SOG1 functions upstream of RAD54, and both these genes are essential in regulating DDR under salinity stress. Furthermore, SOG1 interacts directly with BRCA1, an important component of the HR-mediated DSB repair pathway in plants, where BRCA1 appears to facilitate the binding of SOG1 to the RAD54 promoter. At the genetic level, SOG1 and BRCA1 function interdependently in modulating RAD54 expression under salinity-induced DNA damage. Together, our results suggest that SOG1 regulates the repair of salinity-induced DSBs via the HR-mediated pathway through genetic interactions with RAD54 and BRCA1 in Arabidopsis.
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Affiliation(s)
- Kalyan Mahapatra
- Department of Botany, UGC Center for Advanced Studies, The University of Burdwan, Golapbag Campus, Burdwan, 713 104 West Bengal, India
| | - Sujit Roy
- Department of Botany, UGC Center for Advanced Studies, The University of Burdwan, Golapbag Campus, Burdwan, 713 104 West Bengal, India
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Samach A, Mafessoni F, Gross O, Melamed-Bessudo C, Filler-Hayut S, Dahan-Meir T, Amsellem Z, Pawlowski WP, Levy AA. CRISPR/Cas9-induced DNA breaks trigger crossover, chromosomal loss, and chromothripsis-like rearrangements. THE PLANT CELL 2023; 35:3957-3972. [PMID: 37497643 PMCID: PMC10615209 DOI: 10.1093/plcell/koad209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 07/10/2023] [Accepted: 07/10/2023] [Indexed: 07/28/2023]
Abstract
DNA double-stranded breaks (DSBs) generated by the Cas9 nuclease are commonly repaired via nonhomologous end-joining (NHEJ) or homologous recombination (HR). However, little is known about unrepaired DSBs and the type of damage they trigger in plants. We designed an assay that detects loss of heterozygosity (LOH) in somatic cells, enabling the study of a broad range of DSB-induced genomic events. The system relies on a mapped phenotypic marker which produces a light purple color (betalain pigment) in all plant tissues. Plants with sectors lacking the Betalain marker upon DSB induction between the marker and the centromere were tested for LOH events. Using this assay, we detected a tomato (Solanum lycopersicum) flower with a twin yellow and dark purple sector, corresponding to a germinally transmitted somatic crossover event. We also identified instances of small deletions of genomic regions spanning the T-DNA and whole chromosome loss. In addition, we show that major chromosomal rearrangements including loss of large fragments, inversions, and translocations were clearly associated with the CRISPR-induced DSB. Detailed characterization of complex rearrangements by whole-genome sequencing and molecular and cytological analyses supports a model in which a breakage-fusion-bridge cycle followed by chromothripsis-like rearrangements had been induced. Our LOH assay provides a tool for precise breeding via targeted crossover detection. It also uncovers CRISPR-mediated chromothripsis-like events in plants.
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Affiliation(s)
- Aviva Samach
- Department of Plant and Environmental Sciences, The Weizmann Institute of Science, Rehovot 7610001,Israel
| | - Fabrizio Mafessoni
- Department of Plant and Environmental Sciences, The Weizmann Institute of Science, Rehovot 7610001,Israel
| | - Or Gross
- Department of Plant and Environmental Sciences, The Weizmann Institute of Science, Rehovot 7610001,Israel
| | - Cathy Melamed-Bessudo
- Department of Plant and Environmental Sciences, The Weizmann Institute of Science, Rehovot 7610001,Israel
| | - Shdema Filler-Hayut
- Department of Plant and Environmental Sciences, The Weizmann Institute of Science, Rehovot 7610001,Israel
| | - Tal Dahan-Meir
- Department of Plant and Environmental Sciences, The Weizmann Institute of Science, Rehovot 7610001,Israel
| | - Ziva Amsellem
- Department of Plant and Environmental Sciences, The Weizmann Institute of Science, Rehovot 7610001,Israel
| | | | - Avraham A Levy
- Department of Plant and Environmental Sciences, The Weizmann Institute of Science, Rehovot 7610001,Israel
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3
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Chen P, De Winne N, De Jaeger G, Ito M, Heese M, Schnittger A. KNO1‐mediated autophagic degradation of the Bloom syndrome complex component RMI1 promotes homologous recombination. EMBO J 2023; 42:e111980. [PMID: 36970874 PMCID: PMC10183828 DOI: 10.15252/embj.2022111980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Revised: 01/30/2023] [Accepted: 03/12/2023] [Indexed: 03/29/2023] Open
Abstract
Homologous recombination (HR) is a key DNA damage repair pathway that is tightly adjusted to the state of a cell. A central regulator of homologous recombination is the conserved helicase-containing Bloom syndrome complex, renowned for its crucial role in maintaining genome integrity. Here, we show that in Arabidopsis thaliana, Bloom complex activity is controlled by selective autophagy. We find that the recently identified DNA damage regulator KNO1 facilitates K63-linked ubiquitination of RMI1, a structural component of the complex, thereby triggering RMI1 autophagic degradation and resulting in increased homologous recombination. Conversely, reduced autophagic activity makes plants hypersensitive to DNA damage. KNO1 itself is also controlled at the level of proteolysis, in this case mediated by the ubiquitin-proteasome system, becoming stabilized upon DNA damage via two redundantly acting deubiquitinases, UBP12 and UBP13. These findings uncover a regulatory cascade of selective and interconnected protein degradation steps resulting in a fine-tuned HR response upon DNA damage.
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Bhushan S, Singh AK, Thakur Y, Baskar R. Persistence of parental age effect on somatic mutation rates across generations in Arabidopsis. BMC PLANT BIOLOGY 2023; 23:152. [PMID: 36944916 PMCID: PMC10031922 DOI: 10.1186/s12870-023-04150-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 03/02/2023] [Indexed: 06/18/2023]
Abstract
In the model plant Arabidopsis thaliana, parental age is known to affect somatic mutation rates in their immediate progeny and here we show that this age dependent effect persists across successive generations. Using a set of detector lines carrying the mutated uidA gene, we examined if a particular parental age maintained across five consecutive generations affected the rates of base substitution (BSR), intrachromosomal recombination (ICR), frameshift mutation (FS), and transposition. The frequency of functional GUS reversions were assessed in seedlings as a function of identical/different parental ages across generations. In the context of a fixed parental age, BSR/ICR rates were unaffected in the first three generations, then dropped significantly in the 4th and increased in most instances in the 5th generation (e.g. BSR (F1 38 = 0.9, F2 38 = 1.14, F3 38 = 1.02, F4 38 = 0.5, F5 38 = 0.76)). On the other hand, with advancing parental ages, BSR/ICR rates remained high in the first two/three generations, with a striking resemblance in the pattern of mutation rates (BSR (F1 38 = 0.9, F1 43 = 0.53, F1 48 = 0.79, F1 53 = 0.83 and F2 38 = 1.14, F2 43 = 0.57, F2 48 = 0.64, F2 53 = 0.94). We adopted a novel approach of identifying and tagging flowers pollinated on a particular day, thereby avoiding biases due to potential emasculation induced stress responses. Our results suggest a time component in counting the number of generations a plant has passed through self-fertilization at a particular age in determining the somatic mutation rates.
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Affiliation(s)
- Shashi Bhushan
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology-Madras, Chennai, 600 036, India
| | - Amit Kumar Singh
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India
- Institut de Biologie Moléculaire des Plantes, UPR2357 CNRS, Université de Strasbourg, 12 rue du Général Zimmer, Strasbourg Cédex, 67084, France
| | - Yogendra Thakur
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology-Madras, Chennai, 600 036, India
| | - Ramamurthy Baskar
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology-Madras, Chennai, 600 036, India.
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Vladejić J, Yang F, Dvořák Tomaštíková E, Doležel J, Palecek JJ, Pecinka A. Analysis of BRCT5 domain-containing proteins reveals a new component of DNA damage repair in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2022; 13:1023358. [PMID: 36578335 PMCID: PMC9791218 DOI: 10.3389/fpls.2022.1023358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 11/14/2022] [Indexed: 06/17/2023]
Abstract
The integrity of plant genetic information is constantly challenged by various internal and external factors. Therefore, plants use a sophisticated molecular network to identify, signal and repair damaged DNA. Here, we report on the identification and analysis of four uncharacterized Arabidopsis BRCT5 DOMAIN CONTAINING PROTEINs (BCPs). Proteins with the BRCT5 domain are frequently involved in the maintenance of genome stability across eukaryotes. The screening for sensitivity to induced DNA damage identified BCP1 as the most interesting candidate. We show that BCP1 loss of function mutants are hypersensitive to various types of DNA damage and accumulate an increased number of dead cells in root apical meristems upon DNA damage. Analysis of publicly available sog1 transcriptomic and SOG1 genome-wide DNA binding data revealed that BCP1 is inducible by gamma radiation and is a direct target of this key DNA damage signaling transcription factor. Importantly, bcp1 plants showed a reduced frequency of somatic homologous recombination in response to both endogenous and induced DNA damage. Altogether, we identified a novel plant-specific DNA repair factor that acts downstream of SOG1 in homology-based repair.
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Affiliation(s)
- Jovanka Vladejić
- Institute of Experimental Botany (IEB), Czech Acad Sci, Centre of the Region Haná for Biotechnological and Agricultural Research (CRH), Olomouc, Czechia
| | - Fen Yang
- Institute of Experimental Botany (IEB), Czech Acad Sci, Centre of the Region Haná for Biotechnological and Agricultural Research (CRH), Olomouc, Czechia
- Department of Cell Biology and Genetics, Faculty of Science, Palacký University, Olomouc, Czechia
| | - Eva Dvořák Tomaštíková
- Institute of Experimental Botany (IEB), Czech Acad Sci, Centre of the Region Haná for Biotechnological and Agricultural Research (CRH), Olomouc, Czechia
| | - Jaroslav Doležel
- Institute of Experimental Botany (IEB), Czech Acad Sci, Centre of the Region Haná for Biotechnological and Agricultural Research (CRH), Olomouc, Czechia
| | - Jan J. Palecek
- National Centre for Biomolecular Research (NCBR), Faculty of Science, Masaryk University, Brno, Czechia
| | - Ales Pecinka
- Institute of Experimental Botany (IEB), Czech Acad Sci, Centre of the Region Haná for Biotechnological and Agricultural Research (CRH), Olomouc, Czechia
- Department of Cell Biology and Genetics, Faculty of Science, Palacký University, Olomouc, Czechia
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6
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Levy AA, Feldman M. Evolution and origin of bread wheat. THE PLANT CELL 2022; 34:2549-2567. [PMID: 35512194 PMCID: PMC9252504 DOI: 10.1093/plcell/koac130] [Citation(s) in RCA: 51] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 03/18/2022] [Indexed: 05/12/2023]
Abstract
Bread wheat (Triticum aestivum, genome BBAADD) is a young hexaploid species formed only 8,500-9,000 years ago through hybridization between a domesticated free-threshing tetraploid progenitor, genome BBAA, and Aegilops tauschii, the diploid donor of the D subgenome. Very soon after its formation, it spread globally from its cradle in the fertile crescent into new habitats and climates, to become a staple food of humanity. This extraordinary global expansion was probably enabled by allopolyploidy that accelerated genetic novelty through the acquisition of new traits, new intergenomic interactions, and buffering of mutations, and by the attractiveness of bread wheat's large, tasty, and nutritious grain with high baking quality. New genome sequences suggest that the elusive donor of the B subgenome is a distinct (unknown or extinct) species rather than a mosaic genome. We discuss the origin of the diploid and tetraploid progenitors of bread wheat and the conflicting genetic and archaeological evidence on where it was formed and which species was its free-threshing tetraploid progenitor. Wheat experienced many environmental changes throughout its evolution, therefore, while it might adapt to current climatic changes, efforts are needed to better use and conserve the vast gene pool of wheat biodiversity on which our food security depends.
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Targeted Inter-Homologs Recombination in Arabidopsis Euchromatin and Heterochromatin. Int J Mol Sci 2021; 22:ijms222212096. [PMID: 34829981 PMCID: PMC8622013 DOI: 10.3390/ijms222212096] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/04/2021] [Accepted: 11/05/2021] [Indexed: 12/20/2022] Open
Abstract
Homologous recombination (HR) typically occurs during meiosis between homologs, at a few unplanned locations along the chromosomes. In this study, we tested whether targeted recombination between homologous chromosomes can be achieved via Clustered Regulatory Interspaced Short Palindromic Repeat associated protein Cas9 (CRISPR-Cas9)-induced DNA double-strand break (DSB) repair in Arabidopsis thaliana. Our experimental system includes targets for DSB induction in euchromatic and heterochromatic genomic regions of hybrid F1 plants, in one or both parental chromosomes, using phenotypic and molecular markers to measure Non-Homologous End Joining and HR repair. We present a series of evidence showing that targeted DSBs can be repaired via HR using a homologous chromosome as the template in various chromatin contexts including in pericentric regions. Targeted crossover was rare, but gene conversion events were the most frequent outcome of HR and were found in both “hot and cold” regions. The length of the conversion tracts was variable, ranging from 5 to 7505 bp. In addition, a typical feature of these tracks was that they often were interrupted. Our findings pave the way for the use of targeted gene-conversion for precise breeding.
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8
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Jia X, Zhang Q, Jiang M, Huang J, Yu L, Traw MB, Tian D, Hurst LD, Yang S. Mitotic gene conversion can be as important as meiotic conversion in driving genetic variability in plants and other species without early germline segregation. PLoS Biol 2021; 19:e3001164. [PMID: 33750968 PMCID: PMC8016264 DOI: 10.1371/journal.pbio.3001164] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 04/01/2021] [Accepted: 03/02/2021] [Indexed: 12/24/2022] Open
Abstract
In contrast to common meiotic gene conversion, mitotic gene conversion, because it is so rare, is often ignored as a process influencing allelic diversity. We show that if there is a large enough number of premeiotic cell divisions, as seen in many organisms without early germline sequestration, such as plants, this is an unsafe position. From examination of 1.1 million rice plants, we determined that the rate of mitotic gene conversion events, per mitosis, is 2 orders of magnitude lower than the meiotic rate. However, owing to the large number of mitoses between zygote and gamete and because of long mitotic tract lengths, meiotic and mitotic gene conversion can be of approximately equivalent importance in terms of numbers of markers converted from zygote to gamete. This holds even if we assume a low number of premeiotic cell divisions (approximately 40) as witnessed in Arabidopsis. A low mitotic rate associated with long tracts is also seen in yeast, suggesting generality of results. For species with many mitoses between each meiotic event, mitotic gene conversion should not be overlooked. Gene conversion associated with meiosis has long been a focus of attention in population genomics, but mitotic conversion has been relatively overlooked as it was thought to be rare. Analysis in plants suggests that this could be a mistake; long tract lengths and multiple mitoses in species lacking germline sequestration suggest that mitotic conversion, although rare per mitosis, should not be ignored.
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Affiliation(s)
- Xianqing Jia
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, China.,State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Qijun Zhang
- Institute of Food Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Mengmeng Jiang
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Ju Huang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, China
| | - Luyao Yu
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Milton Brian Traw
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, China
| | - Dacheng Tian
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, China.,State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Laurence D Hurst
- The Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Sihai Yang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, China.,State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
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Nibau C, Lloyd A, Dadarou D, Betekhtin A, Tsilimigka F, Phillips DW, Doonan JH. CDKG1 Is Required for Meiotic and Somatic Recombination Intermediate Processing in Arabidopsis. THE PLANT CELL 2020; 32:1308-1322. [PMID: 32047050 PMCID: PMC7145484 DOI: 10.1105/tpc.19.00942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 01/22/2020] [Accepted: 02/08/2020] [Indexed: 05/12/2023]
Abstract
The Arabidopsis (Arabidopsis thaliana) cyclin-dependent kinase G1 (CDKG1) is necessary for recombination and synapsis during male meiosis at high ambient temperature. In the cdkg1-1 mutant, synapsis is impaired and there is a dramatic reduction in the number of class I crossovers, resulting in univalents at metaphase I and pollen sterility. Here, we demonstrate that CDKG1 is necessary for the processing of recombination intermediates in the canonical ZMM recombination pathway and that loss of CDKG1 results in increased class II crossovers. While synapsis and events associated with class I crossovers are severely compromised in a cdkg1-1 mutant, they can be restored by increasing the number of recombination intermediates in the double cdkg1-1 fancm-1 mutant. Despite this, recombination intermediates are not correctly resolved, leading to the formation of chromosome aggregates at metaphase I. Our results show that CDKG1 acts early in the recombination process and is necessary to stabilize recombination intermediates. Finally, we show that the effect on recombination is not restricted to meiosis and that CDKG1 is also required for normal levels of DNA damage-induced homologous recombination in somatic tissues.
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Affiliation(s)
- Candida Nibau
- Institute of Biological, Rural and Environmental Sciences, Aberystwyth University, Gogerddan, Aberystwyth SY23 3EB, United Kingdom
| | - Andrew Lloyd
- Institute of Biological, Rural and Environmental Sciences, Aberystwyth University, Gogerddan, Aberystwyth SY23 3EB, United Kingdom
| | - Despoina Dadarou
- Institute of Biological, Rural and Environmental Sciences, Aberystwyth University, Gogerddan, Aberystwyth SY23 3EB, United Kingdom
| | - Alexander Betekhtin
- Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Katowice 40-007, Poland
| | - Foteini Tsilimigka
- Institute of Biological, Rural and Environmental Sciences, Aberystwyth University, Gogerddan, Aberystwyth SY23 3EB, United Kingdom
| | - Dylan W Phillips
- Institute of Biological, Rural and Environmental Sciences, Aberystwyth University, Gogerddan, Aberystwyth SY23 3EB, United Kingdom
| | - John H Doonan
- Institute of Biological, Rural and Environmental Sciences, Aberystwyth University, Gogerddan, Aberystwyth SY23 3EB, United Kingdom
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Cho YB, Jones SI, Vodkin LO. Nonallelic homologous recombination events responsible for copy number variation within an RNA silencing locus. PLANT DIRECT 2019; 3:e00162. [PMID: 31468028 PMCID: PMC6710647 DOI: 10.1002/pld3.162] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 08/02/2019] [Accepted: 08/05/2019] [Indexed: 05/18/2023]
Abstract
The structure of chalcone synthase (CHS) gene repeats in different alleles of the I (inhibitor) locus in soybean spawns endogenous RNA interference (RNAi) that leads to phenotypic change in seed coat color of this major agronomic crop. Here, we examined CHS gene copy number by digital PCR and single nucleotide polymorphisms (SNPs) through whole genome resequencing of 15 cultivars that varied in alleles of the I locus (I, ii , ik , and i) that control the pattern distribution of pigments in the seed coats. Lines homozygous for the ii allele had the highest copy number followed by the I and ik cultivars which were more related to each other than to the lines with ii alleles. Some of the recessive i alleles were spontaneous mutations, and each revealed a loss of copy number by digital PCR relative to the parent varieties. Amplicon sequencing and whole genome resequencing determined that the breakpoints of several ii to i mutations resulted from nonallelic homologous recombination (NAHR) events between CHS genes located in segmental duplications leading to large 138-kilobase deletions that erase the structure generating the CHS siRNAs along with eight other non-CHS genes. Functional hybrid CHS genes (designated CHS5:1) were formed in the process and represent rare examples of NAHR in higher plants that have been captured by examining spontaneous mutational events in isogenic mutant lines.
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Affiliation(s)
- Young B. Cho
- Department of Crop SciencesUniversity of IllinoisUrbanaIllinois
- Present address:
Carl R. Woese Institute for Genomic BiologyUniversity of IllinoisUrbanaIllinois
| | - Sarah I. Jones
- Department of Crop SciencesUniversity of IllinoisUrbanaIllinois
| | - Lila O. Vodkin
- Department of Crop SciencesUniversity of IllinoisUrbanaIllinois
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11
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Dorn A, Feller L, Castri D, Röhrig S, Enderle J, Herrmann NJ, Block-Schmidt A, Trapp O, Köhler L, Puchta H. An Arabidopsis FANCJ helicase homologue is required for DNA crosslink repair and rDNA repeat stability. PLoS Genet 2019; 15:e1008174. [PMID: 31120885 PMCID: PMC6550410 DOI: 10.1371/journal.pgen.1008174] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 06/05/2019] [Accepted: 05/03/2019] [Indexed: 11/18/2022] Open
Abstract
Proteins of the Fanconi Anemia (FA) complementation group are required for crosslink (CL) repair in humans and their loss leads to severe pathological phenotypes. Here we characterize a homolog of the Fe-S cluster helicase FANCJ in the model plant Arabidopsis, AtFANCJB, and show that it is involved in interstrand CL repair. It acts at a presumably early step in concert with the nuclease FAN1 but independently of the nuclease AtMUS81, and is epistatic to both error-prone and error-free post-replicative repair in Arabidopsis. The simultaneous knock out of FANCJB and the Fe-S cluster helicase RTEL1 leads to induced cell death in root meristems, indicating an important role of the enzymes in replicative DNA repair. Surprisingly, we found that AtFANCJB is involved in safeguarding rDNA stability in plants. In the absence of AtRTEL1 and AtFANCJB, we detected a synergetic reduction to about one third of the original number of 45S rDNA copies. It is tempting to speculate that the detected rDNA instability might be due to deficiencies in G-quadruplex structure resolution and might thus contribute to pathological phenotypes of certain human genetic diseases.
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Affiliation(s)
- Annika Dorn
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Laura Feller
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Dominique Castri
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Sarah Röhrig
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Janina Enderle
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Natalie J. Herrmann
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Astrid Block-Schmidt
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Oliver Trapp
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Laura Köhler
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Holger Puchta
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany
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12
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Chen P, Sjogren CA, Larsen PB, Schnittger A. A multi-level response to DNA damage induced by aluminium. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 98:479-491. [PMID: 30657222 PMCID: PMC6850279 DOI: 10.1111/tpj.14231] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 12/03/2018] [Accepted: 12/18/2018] [Indexed: 05/17/2023]
Abstract
Aluminium (Al) ions are one of the primary growth-limiting factors for plants on acid soils, globally restricting agriculture. Despite its impact, little is known about Al action in planta. Earlier work has indicated that, among other effects, Al induces DNA damage. However, the loss of major DNA damage response regulators, such SOG1, partially suppressed the growth reduction in plants seen on Al-containing media. This raised the question whether Al actually causes DNA damage and, if so, how. Here, we provide cytological and genetic data corroborating that exposure to Al leads to DNA double-strand breaks. We find that the Al-induced damage specifically involves homology-dependent (HR) recombination repair. Using an Al toxicity assay that delivers higher Al concentrations than used in previous tests, we find that sog1 mutants become highly sensitive to Al. This indicates a multi-level response to Al-induced DNA damage in plants.
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Affiliation(s)
- Poyu Chen
- Department of Developmental BiologyUniversity of HamburgHamburg22609Germany
| | | | - Paul B. Larsen
- Department of BiochemistryUniversity of CaliforniaRiversideCA92521USA
| | - Arp Schnittger
- Department of Developmental BiologyUniversity of HamburgHamburg22609Germany
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13
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Enderle J, Dorn A, Beying N, Trapp O, Puchta H. The Protease WSS1A, the Endonuclease MUS81, and the Phosphodiesterase TDP1 Are Involved in Independent Pathways of DNA-protein Crosslink Repair in Plants. THE PLANT CELL 2019; 31:775-790. [PMID: 30760561 PMCID: PMC6501609 DOI: 10.1105/tpc.18.00824] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 01/08/2019] [Accepted: 02/11/2019] [Indexed: 05/04/2023]
Abstract
DNA-protein crosslinks (DPCs) represent a severe threat to the genome integrity; however, the main mechanisms of DPC repair were only recently elucidated in humans and yeast. Here we define the pathways for DPC repair in plants. Using CRISPR/Cas9, we could show that only one of two homologs of the universal repair proteases SPARTAN/ weak suppressor of smt3 (Wss1), WSS1A, is essential for DPC repair in Arabidopsis (Arabidopsis thaliana). WSS1A defective lines exhibit developmental defects and are hypersensitive to camptothecin (CPT) and cis-platin. Interestingly, the CRISPR/Cas9 mutants of TYROSYL-DNA PHOSPHODIESTERASE 1 (TDP1) are insensitive to CPT, and only the wss1A tdp1 double mutant reveals a higher sensitivity than the wss1A single mutant. This indicates that TDP1 defines a minor backup pathway in the repair of DPCs. Moreover, we found that knock out of the endonuclease METHYL METHANESULFONATE AND UV SENSITIVE PROTEIN 81 (MUS81) results in a strong sensitivity to DPC-inducing agents. The fact that wss1A mus81 and tdp1 mus81 double mutants exhibit growth defects and an increase in dead cells in root meristems after CPT treatment demonstrates that there are three independent pathways for DPC repair in Arabidopsis. These pathways are defined by their different biochemical specificities, as main actors, the DNA endonuclease MUS81 and the protease WSS1A, and the phosphodiesterase TDP1 as backup.
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Affiliation(s)
- Janina Enderle
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Fritz-Haber-Weg 4, Karlsruhe 76131, Germany
| | - Annika Dorn
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Fritz-Haber-Weg 4, Karlsruhe 76131, Germany
| | - Natalja Beying
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Fritz-Haber-Weg 4, Karlsruhe 76131, Germany
| | - Oliver Trapp
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Fritz-Haber-Weg 4, Karlsruhe 76131, Germany
| | - Holger Puchta
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Fritz-Haber-Weg 4, Karlsruhe 76131, Germany
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14
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Dorn A, Röhrig S, Papp K, Schröpfer S, Hartung F, Knoll A, Puchta H. The topoisomerase 3α zinc-finger domain T1 of Arabidopsis thaliana is required for targeting the enzyme activity to Holliday junction-like DNA repair intermediates. PLoS Genet 2018; 14:e1007674. [PMID: 30222730 PMCID: PMC6160208 DOI: 10.1371/journal.pgen.1007674] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 09/27/2018] [Accepted: 08/31/2018] [Indexed: 12/18/2022] Open
Abstract
Topoisomerase 3α, a class I topoisomerase, consists of a TOPRIM domain, an active centre and a variable number of zinc-finger domains (ZFDs) at the C-terminus, in multicellular organisms. Whereas the functions of the TOPRIM domain and the active centre are known, the specific role of the ZFDs is still obscure. In contrast to mammals where a knockout of TOP3α leads to lethality, we found that CRISPR/Cas induced mutants in Arabidopsis are viable but show growth retardation and meiotic defects, which can be reversed by the expression of the complete protein. However, complementation with AtTOP3α missing either the TOPRIM-domain or carrying a mutation of the catalytic tyrosine of the active centre leads to embryo lethality. Surprisingly, this phenotype can be overcome by the simultaneous removal of the ZFDs from the protein. In combination with a mutation of the nuclease AtMUS81, the TOP3α knockout proved to be also embryo lethal. Here, expression of TOP3α without ZFDs, and in particular without the conserved ZFD T1, leads to only a partly complementation in root growth-in contrast to the complete protein, that restores root length to mus81-1 mutant level. Expressing the E. coli resolvase RusA in this background, which is able to process Holliday junction (HJ)-like recombination intermediates, we could rescue this root growth defect. Considering all these results, we conclude that the ZFD T1 is specifically required for targeting the topoisomerase activity to HJ like recombination intermediates to enable their processing. In the case of an inactivated enzyme, this leads to cell death due to the masking of these intermediates, hindering their resolution by MUS81.
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Affiliation(s)
- Annika Dorn
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Sarah Röhrig
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Kristin Papp
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Susan Schröpfer
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Frank Hartung
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Alexander Knoll
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Holger Puchta
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany
- * E-mail:
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15
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Wiedemann G, van Gessel N, Köchl F, Hunn L, Schulze K, Maloukh L, Nogué F, Decker EL, Hartung F, Reski R. RecQ Helicases Function in Development, DNA Repair, and Gene Targeting in Physcomitrella patens. THE PLANT CELL 2018; 30:717-736. [PMID: 29514942 PMCID: PMC5894843 DOI: 10.1105/tpc.17.00632] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 02/16/2018] [Accepted: 03/06/2018] [Indexed: 05/18/2023]
Abstract
RecQ DNA helicases are genome surveillance proteins found in all kingdoms of life. They are characterized best in humans, as mutations in RecQ genes lead to developmental abnormalities and diseases. To better understand RecQ functions in plants we concentrated on Arabidopsis thaliana and Physcomitrella patens, the model species predominantly used for studies on DNA repair and gene targeting. Phylogenetic analysis of the six P. patens RecQ genes revealed their orthologs in humans and plants. Because Arabidopsis and P. patens differ in their RecQ4 and RecQ6 genes, reporter and deletion moss mutants were generated and gene functions studied in reciprocal cross-species and cross-kingdom approaches. Both proteins can be found in meristematic moss tissues, although at low levels and with distinct expression patterns. PpRecQ4 is involved in embryogenesis and in subsequent development as demonstrated by sterility of ΔPpRecQ4 mutants and by morphological aberrations. Additionally, ΔPpRecQ4 displays an increased sensitivity to DNA damages and an increased rate of gene targeting. Therefore, we conclude that PpRecQ4 acts as a repressor of recombination. In contrast, PpRecQ6 is not obviously important for moss development or DNA repair but does function as a potent enhancer of gene targeting.
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Affiliation(s)
- Gertrud Wiedemann
- Plant Biotechnology, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Nico van Gessel
- Plant Biotechnology, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Fabian Köchl
- Plant Biotechnology, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Lisa Hunn
- Plant Biotechnology, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Katrin Schulze
- Julius Kuehn Institute, Institute for Biosafety in Plant Biotechnology, 06484 Quedlinburg, Germany
| | - Lina Maloukh
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000 Versailles, France
| | - Fabien Nogué
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000 Versailles, France
| | - Eva L Decker
- Plant Biotechnology, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Frank Hartung
- Julius Kuehn Institute, Institute for Biosafety in Plant Biotechnology, 06484 Quedlinburg, Germany
| | - Ralf Reski
- Plant Biotechnology, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
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16
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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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17
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Agapito-Tenfen S, Lopez FR, Mallah N, Abou-Slemayne G, Trtikova M, Nodari RO, Wickson F. Transgene flow in Mexican maize revisited: Socio-biological analysis across two contrasting farmer communities and seed management systems. Ecol Evol 2017; 7:9461-9472. [PMID: 29187982 PMCID: PMC5696427 DOI: 10.1002/ece3.3415] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 08/23/2017] [Accepted: 08/25/2017] [Indexed: 12/04/2022] Open
Abstract
The flow of transgenes into landraces and wild relatives is an important biosafety concern. The case of transgene flow into local maize varieties in Mexico (the center of origin of maize) has been intensively debated over the past 15 years, including legal, political, and environmental disputes fanned by the existence of a significant scientific controversy over the methods used for the detection of transgenes. The use of diverse approaches and a lack of harmonized methods specific to the detection and monitoring of transgenes in landraces have generated both positive and negative results regarding contamination of Mexican maize with genetically modified material over the years. In this paper, we revisit the case of transgene contamination in Mexican maize and present a novel research approach based on socio‐biological analysis of contrasting communities and seed management systems. Two communities were used to investigate how different social and biological factors can affect transgene flow and impact transgene spread in Mexico. Our results show the presence of transgenes in one community and thus support the position that transgenes are highly likely to be present in Mexican maize landraces. However, our work also demonstrates that the extent and frequency with which transgenes can be found will significantly depend on the societal characteristics and seed management systems of the local communities. Therefore, we argue that future analysis of transgene presence should include social research on the seed management practices in the sampling area so that more robust and comprehensive understandings and conclusions can be drawn.
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Affiliation(s)
| | - Flor R Lopez
- GenØk Center for Biosafety Siva Innovasjonssenter Tromsø Norway
| | - Narmeen Mallah
- Department of Laboratory Science and Technology American University of Science and Technology Ashrafieh Lebanon
| | - Gretta Abou-Slemayne
- Department of Laboratory Science and Technology American University of Science and Technology Ashrafieh Lebanon
| | - Miluse Trtikova
- Institut für Integrative Biologie ETH Zurich Zürich Switzerland
| | - Rubens O Nodari
- Departamento de Fitotecnia Universidade Federal de Santa Catarina Florianópolis Brazil
| | - Fern Wickson
- GenØk Center for Biosafety Siva Innovasjonssenter Tromsø Norway
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18
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Targeted recombination between homologous chromosomes for precise breeding in tomato. Nat Commun 2017; 8:15605. [PMID: 28548094 PMCID: PMC5458649 DOI: 10.1038/ncomms15605] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 04/05/2017] [Indexed: 01/10/2023] Open
Abstract
Homologous recombination (HR) between parental chromosomes occurs stochastically. Here, we report on targeted recombination between homologous chromosomes upon somatic induction of DNA double-strand breaks (DSBs) via CRISPR-Cas9. We demonstrate this via a visual and molecular assay whereby DSB induction between two alleles carrying different mutations in the PHYTOENE SYNTHASE (PSY1) gene results in yellow fruits with wild type red sectors forming via HR-mediated DSB repair. We also show that in heterozygote plants containing one psy1 allele immune and one sensitive to CRISPR, repair of the broken allele using the unbroken allele sequence template is a common outcome. In another assay, we show evidence of a somatically induced DSB in a cross between a psy1 edible tomato mutant and wild type Solanum pimpinellifolium, targeting only the S. pimpinellifolium allele. This enables characterization of germinally transmitted targeted somatic HR events, demonstrating that somatically induced DSBs can be exploited for precise breeding of crops. Targeted homologous recombination between parental chromosomes could facilitate precision breeding of crop plants. Here, Filler Hayut et al. show that CRISPR-Cas9 can be used to induce DNA double strand breaks in somatic tissue and achieve targeted recombination between homologs at an endogenous locus in tomato.
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19
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UVR2 ensures transgenerational genome stability under simulated natural UV-B in Arabidopsis thaliana. Nat Commun 2016; 7:13522. [PMID: 27905394 PMCID: PMC5146273 DOI: 10.1038/ncomms13522] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 10/11/2016] [Indexed: 11/24/2022] Open
Abstract
Ground levels of solar UV-B radiation induce DNA damage. Sessile phototrophic organisms such as vascular plants are recurrently exposed to sunlight and require UV-B photoreception, flavonols shielding, direct reversal of pyrimidine dimers and nucleotide excision repair for resistance against UV-B radiation. However, the frequency of UV-B-induced mutations is unknown in plants. Here we quantify the amount and types of mutations in the offspring of Arabidopsis thaliana wild-type and UV-B-hypersensitive mutants exposed to simulated natural UV-B over their entire life cycle. We show that reversal of pyrimidine dimers by UVR2 photolyase is the major mechanism required for sustaining plant genome stability across generations under UV-B. In addition to widespread somatic expression, germline-specific UVR2 activity occurs during late flower development, and is important for ensuring low mutation rates in male and female cell lineages. This allows plants to maintain genome integrity in the germline despite exposure to UV-B. As sessile organisms, plants are exposed to recurrent solar UV-B radiation that can induce DNA damage. Here, the authors characterize mutations that occur in Arabidopsis under light regimes simulating natural UV-B exposure and find that the UVR2 photolyase is the major component required to maintain genome stability.
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20
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Zhou W, Gao J, Ma J, Cao L, Zhang C, Zhu Y, Dong A, Shen WH. Distinct roles of the histone chaperones NAP1 and NRP and the chromatin-remodeling factor INO80 in somatic homologous recombination in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 88:397-410. [PMID: 27352805 DOI: 10.1111/tpj.13256] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 06/24/2016] [Indexed: 05/10/2023]
Abstract
Homologous recombination (HR) of nuclear DNA occurs within the context of a highly complex chromatin structure. Despite extensive studies of HR in diverse organisms, mechanisms regulating HR within the chromatin context remain poorly elucidated. Here we investigate the role and interplay of the histone chaperones NUCLEOSOME ASSEMBLY PROTEIN1 (NAP1) and NAP1-RELATED PROTEIN (NRP) and the ATP-dependent chromatin-remodeling factor INOSITOL AUXOTROPHY80 (INO80) in regulating somatic HR in Arabidopsis thaliana. We show that simultaneous knockout of the four AtNAP1 genes and the two NRP genes in the sextuple mutant m123456-1 barely affects normal plant growth and development. Interestingly, compared with the respective AtNAP1 (m123-1 and m1234-1) or NRP (m56-1) loss-of-function mutants, the sextuple mutant m123456-1 displays an enhanced plant hypersensitivity to UV or bleomycin treatments. Using HR reporter constructs, we show that AtNAP1 and NRP act in parallel to synergistically promote somatic HR. Distinctively, the AtINO80 loss-of-function mutation (atino80-5) is epistatic to m56-1 in plant phenotype and telomere length but hypostatic to m56-1 in HR determinacy. Further analyses show that expression of HR machinery genes and phosphorylation of H2A.X (γ-H2A.X) are not impaired in the mutants. Collectively, our study indicates that NRP and AtNAP1 synergistically promote HR upstream of AtINO80-mediated chromatin remodeling after the formation of γ-H2A.X foci during DNA damage repair.
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Affiliation(s)
- Wangbin Zhou
- Department of Biochemistry, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, International Associated Laboratory of CNRS-Fudan-HUNAU on Plant Epigenome Research, School of Life Sciences, Institute of Plant Biology, Fudan University, Shanghai, 20043, China
| | - Juan Gao
- Department of Biochemistry, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, International Associated Laboratory of CNRS-Fudan-HUNAU on Plant Epigenome Research, School of Life Sciences, Institute of Plant Biology, Fudan University, Shanghai, 20043, China
- Institut de Biologie Moléculaire des Plantes (IBMP), UPR2357 CNRS, Université de Strasbourg, 12 rue du Général Zimmer, Strasbourg Cédex, 67084, France
- School of Life Sciences, Shanghai Key Laboratory of Bio-Energy Crops, Shanghai University, Shanghai, 200444, China
| | - Jing Ma
- Department of Biochemistry, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, International Associated Laboratory of CNRS-Fudan-HUNAU on Plant Epigenome Research, School of Life Sciences, Institute of Plant Biology, Fudan University, Shanghai, 20043, China
| | - Lin Cao
- Department of Biochemistry, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, International Associated Laboratory of CNRS-Fudan-HUNAU on Plant Epigenome Research, School of Life Sciences, Institute of Plant Biology, Fudan University, Shanghai, 20043, China
| | - Chi Zhang
- Department of Biochemistry, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, International Associated Laboratory of CNRS-Fudan-HUNAU on Plant Epigenome Research, School of Life Sciences, Institute of Plant Biology, Fudan University, Shanghai, 20043, China
| | - Yan Zhu
- Department of Biochemistry, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, International Associated Laboratory of CNRS-Fudan-HUNAU on Plant Epigenome Research, School of Life Sciences, Institute of Plant Biology, Fudan University, Shanghai, 20043, China
| | - Aiwu Dong
- Department of Biochemistry, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, International Associated Laboratory of CNRS-Fudan-HUNAU on Plant Epigenome Research, School of Life Sciences, Institute of Plant Biology, Fudan University, Shanghai, 20043, China
| | - Wen-Hui Shen
- Department of Biochemistry, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, International Associated Laboratory of CNRS-Fudan-HUNAU on Plant Epigenome Research, School of Life Sciences, Institute of Plant Biology, Fudan University, Shanghai, 20043, China
- Institut de Biologie Moléculaire des Plantes (IBMP), UPR2357 CNRS, Université de Strasbourg, 12 rue du Général Zimmer, Strasbourg Cédex, 67084, France
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21
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Röhrig S, Schröpfer S, Knoll A, Puchta H. The RTR Complex Partner RMI2 and the DNA Helicase RTEL1 Are Both Independently Involved in Preserving the Stability of 45S rDNA Repeats in Arabidopsis thaliana. PLoS Genet 2016; 12:e1006394. [PMID: 27760121 PMCID: PMC5070779 DOI: 10.1371/journal.pgen.1006394] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 09/29/2016] [Indexed: 11/18/2022] Open
Abstract
The stability of repetitive sequences in complex eukaryotic genomes is safeguarded by factors suppressing homologues recombination. Prominent in this is the role of the RTR complex. In plants, it consists of the RecQ helicase RECQ4A, the topoisomerase TOP3α and RMI1. Like mammals, but not yeast, plants harbor an additional complex partner, RMI2. Here, we demonstrate that, in Arabidopsis thaliana, RMI2 is involved in the repair of aberrant replication intermediates in root meristems as well as in intrastrand crosslink repair. In both instances, RMI2 is involved independently of the DNA helicase RTEL1. Surprisingly, simultaneous loss of RMI2 and RTEL1 leads to loss of male fertility. As both the RTR complex and RTEL1 are involved in suppression of homologous recombination (HR), we tested the efficiency of HR in the double mutant rmi2-2 rtel1-1 and found a synergistic enhancement (80-fold). Searching for natural target sequences we found that RTEL1 is required for stabilizing 45S rDNA repeats. In the double mutant with rmi2-2 the number of 45S rDNA repeats is further decreased sustaining independent roles of both factors in this process. Thus, loss of suppression of HR does not only lead to a destabilization of rDNA repeats but might be especially deleterious for tissues undergoing multiple cell divisions such as the male germline. The Bloom syndrome and Hoyeraal Hreidarsson syndrome are severe diseases in humans that are correlated with genome instability. Interestingly, plants harbor homologs of factors that are defective in the respective diseases. In the model plant A. thaliana these proteins play important roles in various aspects of the repair of genetic information and the maintenance of repetitive elements. Here, we show that the concomitant loss of function of two specific factors that are representative for each syndrome leads in plants to male sterility, due to somatic catastrophe leading to instability and cell death. This defect is correlated with a massive loss of repetitive genes involved in general protein production. It has been shown before for mammals that loss of certain other factors involved in genome stability leads to a defect in neural development. Our results now demonstrate that genome instability can also result in organ-specific defects in plants, in our case during flower development, leading to a defect in the cell proliferation of the premeiotic male germline.
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Affiliation(s)
- Sarah Röhrig
- Botanical Institute II, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Susan Schröpfer
- Botanical Institute II, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Alexander Knoll
- Botanical Institute II, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Holger Puchta
- Botanical Institute II, Karlsruhe Institute of Technology, Karlsruhe, Germany
- * E-mail:
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22
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Zimina OV, Parii MF, Alkhimova OG. Loss of heterozygosity at individual loci in Arabidopsis thaliana regenerants cultured with para-fluorophenylalanine. CYTOL GENET+ 2016. [DOI: 10.3103/s0095452716050157] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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23
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Weimer AK, Biedermann S, Harashima H, Roodbarkelari F, Takahashi N, Foreman J, Guan Y, Pochon G, Heese M, Van Damme D, Sugimoto K, Koncz C, Doerner P, Umeda M, Schnittger A. The plant-specific CDKB1-CYCB1 complex mediates homologous recombination repair in Arabidopsis. EMBO J 2016; 35:2068-2086. [PMID: 27497297 PMCID: PMC5048351 DOI: 10.15252/embj.201593083] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Accepted: 07/14/2016] [Indexed: 01/30/2023] Open
Abstract
Upon DNA damage, cyclin‐dependent kinases (CDKs) are typically inhibited to block cell division. In many organisms, however, it has been found that CDK activity is required for DNA repair, especially for homology‐dependent repair (HR), resulting in the conundrum how mitotic arrest and repair can be reconciled. Here, we show that Arabidopsis thaliana solves this dilemma by a division of labor strategy. We identify the plant‐specific B1‐type CDKs (CDKB1s) and the class of B1‐type cyclins (CYCB1s) as major regulators of HR in plants. We find that RADIATION SENSITIVE 51 (RAD51), a core mediator of HR, is a substrate of CDKB1‐CYCB1 complexes. Conversely, mutants in CDKB1 and CYCB1 fail to recruit RAD51 to damaged DNA. CYCB1;1 is specifically activated after DNA damage and we show that this activation is directly controlled by SUPPRESSOR OF GAMMA RESPONSE 1 (SOG1), a transcription factor that acts similarly to p53 in animals. Thus, while the major mitotic cell‐cycle activity is blocked after DNA damage, CDKB1‐CYCB1 complexes are specifically activated to mediate HR.
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Affiliation(s)
- Annika K Weimer
- Department of Molecular Mechanisms of Phenotypic Plasticity, Institut de Biologie Moléculaire des Plantes du CNRS, IBMP-CNRS UPR2357, Université de Strasbourg, Strasbourg Cedex, France
| | - Sascha Biedermann
- Department of Molecular Mechanisms of Phenotypic Plasticity, Institut de Biologie Moléculaire des Plantes du CNRS, IBMP-CNRS UPR2357, Université de Strasbourg, Strasbourg Cedex, France
| | | | | | - Naoki Takahashi
- Plant Growth Regulation Laboratory, Nara Institute of Science and Technology, Graduate School of Biological Sciences, Ikoma, Nara, Japan
| | - Julia Foreman
- School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Yonsheng Guan
- Department of Molecular Mechanisms of Phenotypic Plasticity, Institut de Biologie Moléculaire des Plantes du CNRS, IBMP-CNRS UPR2357, Université de Strasbourg, Strasbourg Cedex, France
| | - Gaëtan Pochon
- Department of Developmental Biology, Biozentrum Klein Flottbek, University of Hamburg, Hamburg, Germany
| | - Maren Heese
- Department of Developmental Biology, Biozentrum Klein Flottbek, University of Hamburg, Hamburg, Germany
| | - Daniël Van Damme
- Department of Plant Systems Biology, VIB, Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
| | - Keiko Sugimoto
- RIKEN Center for Sustainable Resource Science, Tsurumi, Yokohama, Japan
| | - Csaba Koncz
- Max-Planck-Institut für Pflanzenzüchtungsforschung, Köln, Germany
| | - Peter Doerner
- School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Masaaki Umeda
- Plant Growth Regulation Laboratory, Nara Institute of Science and Technology, Graduate School of Biological Sciences, Ikoma, Nara, Japan JST, CREST, Ikoma, Nara, Japan
| | - Arp Schnittger
- Department of Molecular Mechanisms of Phenotypic Plasticity, Institut de Biologie Moléculaire des Plantes du CNRS, IBMP-CNRS UPR2357, Université de Strasbourg, Strasbourg Cedex, France Department of Developmental Biology, Biozentrum Klein Flottbek, University of Hamburg, Hamburg, Germany Trinationales Institut für Pflanzenforschung, Institut de Biologie Moléculaire des Plantes du CNRS, IBMP-CNRS, Strasbourg Cedex, France
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Pradillo M, Knoll A, Oliver C, Varas J, Corredor E, Puchta H, Santos JL. Involvement of the Cohesin Cofactor PDS5 (SPO76) During Meiosis and DNA Repair in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2015; 6:1034. [PMID: 26648949 PMCID: PMC4664637 DOI: 10.3389/fpls.2015.01034] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 11/06/2015] [Indexed: 05/23/2023]
Abstract
Maintenance and precise regulation of sister chromatid cohesion is essential for faithful chromosome segregation during mitosis and meiosis. Cohesin cofactors contribute to cohesin dynamics and interact with cohesin complexes during cell cycle. One of these, PDS5, also known as SPO76, is essential during mitosis and meiosis in several organisms and also plays a role in DNA repair. In yeast, the complex Wapl-Pds5 controls cohesion maintenance and colocalizes with cohesin complexes into chromosomes. In Arabidopsis, AtWAPL proteins are essential during meiosis, however, the role of AtPDS5 remains to be ascertained. Here we have isolated mutants for each of the five AtPDS5 genes (A-E) and obtained, after different crosses between them, double, triple, and even quadruple mutants (Atpds5a Atpds5b Atpds5c Atpds5e). Depletion of AtPDS5 proteins has a weak impact on meiosis, but leads to severe effects on development, fertility, somatic homologous recombination (HR) and DNA repair. Furthermore, this cohesin cofactor could be important for the function of the AtSMC5/AtSMC6 complex. Contrarily to its function in other species, our results suggest that AtPDS5 is dispensable during the meiotic division of Arabidopsis, although it plays an important role in DNA repair by HR.
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Affiliation(s)
- Mónica Pradillo
- Departamento de Genética, Facultad de Biología, Universidad ComplutenseMadrid, Spain
| | - Alexander Knoll
- Botanical Institute II, Karlsruhe Institute of TechnologyKarlsruhe, Germany
| | - Cecilia Oliver
- Departamento de Genética, Facultad de Biología, Universidad ComplutenseMadrid, Spain
| | - Javier Varas
- Departamento de Genética, Facultad de Biología, Universidad ComplutenseMadrid, Spain
| | - Eduardo Corredor
- Departamento de Genética, Facultad de Biología, Universidad ComplutenseMadrid, Spain
| | - Holger Puchta
- Botanical Institute II, Karlsruhe Institute of TechnologyKarlsruhe, Germany
| | - Juan L. Santos
- Departamento de Genética, Facultad de Biología, Universidad ComplutenseMadrid, Spain
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25
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Piofczyk T, Jeena G, Pecinka A. Arabidopsis thaliana natural variation reveals connections between UV radiation stress and plant pathogen-like defense responses. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2015; 93:34-43. [PMID: 25656510 DOI: 10.1016/j.plaphy.2015.01.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 01/21/2015] [Indexed: 05/12/2023]
Abstract
UV radiation is a ubiquitous component of solar radiation that affects plant growth and development. Here we studied growth related traits of 345 Arabidopsis thaliana accessions in response to UV radiation stress. We analyzed the genetic basis of this natural variation by genome-wide association studies, which suggested a specific candidate genomic region. RNA-sequencing of three sensitive and three resistant accessions combined with mutant analysis revealed five large effect genes. Mutations in PHE ammonia lyase 1 (PAL1) and putative kinase At1g76360 rendered Arabidopsis hypersensitive to UV stress, while loss of function from putative methyltransferase At4g22530, novel plant snare 12 (NPSN12) and defense gene activated disease resistance 2 (ADR2) conferred higher UV stress resistance. Three sensitive accessions showed strong ADR2 transcriptional activation, accumulation of salicylic acid (SA) and dwarf growth upon UV stress, while these phenotypes were much less affected in resistant plants. The phenotype of sensitive accessions resembles autoimmune reactions due to overexpression of defense related genes, and suggests that natural variation in response to UV radiation stress is driven by pathogen-like responses in Arabidopsis.
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Affiliation(s)
- Thomas Piofczyk
- Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, D-50829 Cologne, Germany
| | - Ganga Jeena
- Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, D-50829 Cologne, Germany
| | - Ales Pecinka
- Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, D-50829 Cologne, Germany.
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26
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Liu CH, Finke A, Díaz M, Rozhon W, Poppenberger B, Baubec T, Pecinka A. Repair of DNA Damage Induced by the Cytidine Analog Zebularine Requires ATR and ATM in Arabidopsis. THE PLANT CELL 2015; 27:1788-800. [PMID: 26023162 PMCID: PMC4498198 DOI: 10.1105/tpc.114.135467] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 05/11/2015] [Indexed: 05/04/2023]
Abstract
DNA damage repair is an essential cellular mechanism that maintains genome stability. Here, we show that the nonmethylable cytidine analog zebularine induces a DNA damage response in Arabidopsis thaliana, independent of changes in DNA methylation. In contrast to genotoxic agents that induce damage in a cell cycle stage-independent manner, zebularine induces damage specifically during strand synthesis in DNA replication. The signaling of this damage is mediated by additive activity of ATAXIA TELANGIECTASIA MUTATED AND RAD3-RELATED and ATAXIA TELANGIECTASIA MUTATED kinases, which cause postreplicative cell cycle arrest and increased endoreplication. The repair requires a functional STRUCTURAL MAINTENANCE OF CHROMOSOMES5 (SMC5)-SMC6 complex and is accomplished predominantly by synthesis-dependent strand-annealing homologous recombination. Here, we provide insight into the response mechanism for coping with the genotoxic effects of zebularine and identify several components of the zebularine-induced DNA damage repair pathway.
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Affiliation(s)
- Chun-Hsin Liu
- Department of Plant Breeding and Genetics, Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany
| | - Andreas Finke
- Department of Plant Breeding and Genetics, Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany
| | - Mariana Díaz
- Department of Plant Breeding and Genetics, Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany
| | - Wilfried Rozhon
- Biotechnology of Horticultural Crops, Technische Universität München, 85354 Freising, Germany
| | - Brigitte Poppenberger
- Biotechnology of Horticultural Crops, Technische Universität München, 85354 Freising, Germany
| | | | - Ales Pecinka
- Department of Plant Breeding and Genetics, Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany
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27
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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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Herrmann NJ, Knoll A, Puchta H. The nuclease FAN1 is involved in DNA crosslink repair in Arabidopsis thaliana independently of the nuclease MUS81. Nucleic Acids Res 2015; 43:3653-66. [PMID: 25779053 PMCID: PMC4402529 DOI: 10.1093/nar/gkv208] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 03/01/2015] [Indexed: 01/06/2023] Open
Abstract
Fanconi anemia is a severe genetic disorder. Mutations in one of several genes lead to defects in DNA crosslink (CL) repair in human cells. An essential step in CL repair is the activation of the pathway by the monoubiquitination of the heterodimer FANCD2/FANCI, which recruits the nuclease FAN1 to the CL site. Surprisingly, FAN1 function is not conserved between different eukaryotes. No FAN1 homolog is present in Drosophila and Saccharomyces cerevisiae. The FAN1 homolog in Schizosaccharomyces pombe is involved in CL repair; a homolog is present in Xenopus but is not involved in CL repair. Here we show that a FAN1 homolog is present in plants and it is involved in CL repair in Arabidopsis thaliana. Both the virus-type replication-repair nuclease and the ubiquitin-binding ubiquitin-binding zinc finger domains are essential for this function. FAN1 likely acts upstream of two sub-pathways of CL repair. These pathways are defined by the Bloom syndrome homolog RECQ4A and the ATPase RAD5A, which is involved in error-free post-replicative repair. Mutations in both FAN1 and the endonuclease MUS81 resulted in greater sensitivity against CLs than in the respective single mutants. These results indicate that the two nucleases define two independent pathways of CL repair in plants.
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Affiliation(s)
- Natalie J Herrmann
- Botanical Institute II, Karlsruhe Institute of Technology, Hertzstrasse 16, Karlsruhe, 76187, Germany
| | - Alexander Knoll
- Botanical Institute II, Karlsruhe Institute of Technology, Hertzstrasse 16, Karlsruhe, 76187, Germany
| | - Holger Puchta
- Botanical Institute II, Karlsruhe Institute of Technology, Hertzstrasse 16, Karlsruhe, 76187, Germany
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Hu Z, Cools T, Kalhorzadeh P, Heyman J, De Veylder L. Deficiency of the Arabidopsis helicase RTEL1 triggers a SOG1-dependent replication checkpoint in response to DNA cross-links. THE PLANT CELL 2015; 27:149-61. [PMID: 25595823 PMCID: PMC4330584 DOI: 10.1105/tpc.114.134312] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
To maintain genome integrity, DNA replication is executed and regulated by a complex molecular network of numerous proteins, including helicases and cell cycle checkpoint regulators. Through a systematic screening for putative replication mutants, we identified an Arabidopsis thaliana homolog of human Regulator of Telomere Length 1 (RTEL1), which functions in DNA replication, DNA repair, and recombination. RTEL1 deficiency retards plant growth, a phenotype including a prolonged S-phase duration and decreased cell proliferation. Genetic analysis revealed that rtel1 mutant plants show activated cell cycle checkpoints, specific sensitivity to DNA cross-linking agents, and increased homologous recombination, but a lack of progressive shortening of telomeres, indicating that RTEL1 functions have only been partially conserved between mammals and plants. Surprisingly, RTEL1 deficiency induces tolerance to the deoxynucleotide-depleting drug hydroxyurea, which could be mimicked by DNA cross-linking agents. This resistance does not rely on the essential replication checkpoint regulator WEE1 but could be blocked by a mutation in the SOG1 transcription factor. Taken together, our data indicate that RTEL1 is required for DNA replication and that its deficiency activates a SOG1-dependent replication checkpoint.
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Affiliation(s)
- Zhubing Hu
- Department of Plant Systems Biology, VIB, B-9052 Gent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Gent, Belgium
| | - Toon Cools
- Department of Plant Systems Biology, VIB, B-9052 Gent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Gent, Belgium
| | - Pooneh Kalhorzadeh
- Department of Plant Systems Biology, VIB, B-9052 Gent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Gent, Belgium
| | - Jefri Heyman
- Department of Plant Systems Biology, VIB, B-9052 Gent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Gent, Belgium
| | - Lieven De Veylder
- Department of Plant Systems Biology, VIB, B-9052 Gent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Gent, Belgium
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30
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Recker J, Knoll A, Puchta H. The Arabidopsis thaliana homolog of the helicase RTEL1 plays multiple roles in preserving genome stability. THE PLANT CELL 2014; 26:4889-902. [PMID: 25516598 PMCID: PMC4311205 DOI: 10.1105/tpc.114.132472] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
In humans, mutations in the DNA helicase Regulator of Telomere Elongation Helicase1 (RTEL1) lead to Hoyeraal-Hreidarsson syndrome, a severe, multisystem disorder. Here, we demonstrate that the RTEL1 homolog in Arabidopsis thaliana plays multiple roles in preserving genome stability. RTEL1 suppresses homologous recombination in a pathway parallel to that of the DNA translocase FANCM. Cytological analyses of root meristems indicate that RTEL1 is involved in processing DNA replication intermediates independently from FANCM and the nuclease MUS81. Moreover, RTEL1 is involved in interstrand and intrastrand DNA cross-link repair independently from FANCM and (in intrastrand cross-link repair) parallel to MUS81. RTEL1 contributes to telomere homeostasis; the concurrent loss of RTEL1 and the telomerase TERT leads to rapid, severe telomere shortening, which occurs much more rapidly than it does in the single-mutant line tert, resulting in developmental arrest after four generations. The double mutant rtel1-1 recq4A-4 exhibits massive growth defects, indicating that this RecQ family helicase, which is also involved in the suppression of homologous recombination and the repair of DNA lesions, can partially replace RTEL1 in the processing of DNA intermediates. The requirement for RTEL1 in multiple pathways to preserve genome stability in plants can be explained by its putative role in the destabilization of DNA loop structures, such as D-loops and T-loops.
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Affiliation(s)
- Julia Recker
- Botanical Institute II, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Alexander Knoll
- Botanical Institute II, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Holger Puchta
- Botanical Institute II, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
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31
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Hoenicka H, Lehnhardt D, Nilsson O, Hanelt D, Fladung M. Successful crossings with early flowering transgenic poplar: interspecific crossings, but not transgenesis, promoted aberrant phenotypes in offspring. PLANT BIOTECHNOLOGY JOURNAL 2014; 12:1066-74. [PMID: 24975279 DOI: 10.1111/pbi.12213] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 04/15/2014] [Accepted: 05/09/2014] [Indexed: 05/20/2023]
Abstract
In forest tree species, the reproductive phase is reached only after many years or even decades of juvenile growth. Different early flowering systems based on the genetic transfer of heat-shock promoter driven flowering-time genes have been proposed for poplar; however, no fertile flowers were reported until now. Here, we studied flower and pollen development in both HSP::AtFT and wild-type male poplar in detail and developed an optimized heat treatment protocol to obtain fertile HSP::AtFT flowers. Anthers from HSP::AtFT poplar flowers containing fertile pollen grains showed arrested development in stage 12 instead of reaching phase 13 as do wild-type flowers. Pollen grains could be isolated under the binocular microscope and were used for intra- and interspecific crossings with wild-type poplar. F1-seedlings segregating the HSP::AtFT gene construct according to Mendelian laws were obtained. A comparison between intra- and interspecific crossings revealed that genetic transformation had no detrimental effects on F1-seedlings. However, interspecific crossings, a broadly accepted breeding method, produced 47% seedlings with an aberrant phenotype. The early flowering system presented in this study opens new possibilities for accelerating breeding of poplar and other forest tree species. Fast breeding and the selection of transgene-free plants, once the breeding process is concluded, can represent an attractive alternative even under very restrictive regulations.
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Affiliation(s)
- Hans Hoenicka
- Thünen Institute of Forest Genetics, Grosshansdorf, Germany
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32
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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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Dangel NJ, Knoll A, Puchta H. MHF1 plays Fanconi anaemia complementation group M protein (FANCM)-dependent and FANCM-independent roles in DNA repair and homologous recombination in plants. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 78:822-833. [PMID: 24635147 DOI: 10.1111/tpj.12507] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 02/28/2014] [Accepted: 03/06/2014] [Indexed: 06/03/2023]
Abstract
Fanconi anaemia complementation group M protein (FANCM), a component of the human Fanconi anemia pathway, acts as DNA translocase that is essential during the repair of DNA interstrand cross-links. The DNA-damage-binding function of FANCM is strongly enhanced by the histone fold-containing FANCM-associated protein MHF1. We identified a single homologue of MHF1 in the genome of Arabidopsis thaliana. Similar to the loss of AtFANCM, the loss of AtMHF1 leads to several meiotic defects, such as chromosome bridges between bivalents and an unequal distribution of chromosomes. Moreover, MHF1, together with FANCM, is involved in interstrand cross-link repair in plants. This phenotype is detectable only in double mutants of the RecQ helicase and BLM homologue RECQ4A, which appears to function in a parallel pathway to the FANCM/MHF1 complex. However, in somatic cells, FANCM has an MHF1-independent function in replicative repair in a parallel pathway to the endonuclease MUS81. Furthermore, MHF1 is required for efficient somatic homologous recombination (HR) - a role antagonistic to FANCM. FANCM and RECQ4A define two parallel pathways of HR suppression in Arabidopsis. Hyperrecombination in the fancm but not the recq4A mutant can be abolished by MHF1 mutations. This finding indicates that MHF1 and FANCM act at different steps of a single, common, HR pathway.
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Affiliation(s)
- Natalie J Dangel
- Botanical Institute II, Karlsruhe Institute of Technology, Hertzstr. 16, Karlsruhe, 76187, Germany
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Richter KS, Kleinow T, Jeske H. Somatic homologous recombination in plants is promoted by a geminivirus in a tissue-selective manner. Virology 2014; 452-453:287-96. [PMID: 24606706 DOI: 10.1016/j.virol.2014.01.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 12/15/2013] [Accepted: 01/25/2014] [Indexed: 01/11/2023]
Abstract
Four transgenic Arabidopsis thaliana lines carrying different reporter gene constructs based on split glucuronidase genes were used to monitor the frequency of somatic homologous recombination after geminivirus infections. Euphorbia mosaic virus and Cleome leaf crumple virus were chosen as examples, because they induce only mild symptoms and are expected to induce less general stress responses than other geminiviruses. After comparing the different plant lines and viruses as well as optimizing the infection procedure, Euphorbia mosaic virus enhanced recombination rates significantly in the transgenic reporter line 1445. The effect was tissue-specific in cells of the leaf veins as expected for this phloem-limited virus. The advantage for geminiviruses to activate a general recombination pathway is discussed with reference to an increased fitness by generating virus recombinants which have been observed frequently as an epidemiologic driving force.
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Affiliation(s)
- K S Richter
- Biologisches Institut, Abteilung für Molekularbiologie und Virologie der Pflanzen, Universität Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart, Germany
| | - T Kleinow
- Biologisches Institut, Abteilung für Molekularbiologie und Virologie der Pflanzen, Universität Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart, Germany
| | - H Jeske
- Biologisches Institut, Abteilung für Molekularbiologie und Virologie der Pflanzen, Universität Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart, Germany.
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35
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Schröpfer S, Kobbe D, Hartung F, Knoll A, Puchta H. Defining the roles of the N-terminal region and the helicase activity of RECQ4A in DNA repair and homologous recombination in Arabidopsis. Nucleic Acids Res 2013; 42:1684-97. [PMID: 24174542 PMCID: PMC3919593 DOI: 10.1093/nar/gkt1004] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
RecQ helicases are critical for the maintenance of genomic stability. The Arabidopsis RecQ helicase RECQ4A is the functional counterpart of human BLM, which is mutated in the genetic disorder Bloom’s syndrome. RECQ4A performs critical roles in regulation of homologous recombination (HR) and DNA repair. Loss of RECQ4A leads to elevated HR frequencies and hypersensitivity to genotoxic agents. Through complementation studies, we were now able to demonstrate that the N-terminal region and the helicase activity of RECQ4A are both essential for the cellular response to replicative stress induced by methyl methanesulfonate and cisplatin. In contrast, loss of helicase activity or deletion of the N-terminus only partially complemented the mutant hyper-recombination phenotype. Furthermore, the helicase-deficient protein lacking its N-terminus did not complement the hyper-recombination phenotype at all. Therefore, RECQ4A seems to possess at least two different and independent sub-functions involved in the suppression of HR. By in vitro analysis, we showed that the helicase core was able to regress an artificial replication fork. Swapping of the terminal regions of RECQ4A with the closely related but functionally distinct helicase RECQ4B indicated that in contrast to the C-terminus, the N-terminus of RECQ4A was required for its specific functions in DNA repair and recombination.
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Affiliation(s)
- Susan Schröpfer
- Botanical Institute II, Karlsruhe Institute of Technology, Hertzstrasse 16, Karlsruhe 76187, Germany and Institute for Biosafety in Plant Biotechnology, Julius Kühn Institute (JKI), Erwin-Baur-Strasse 27, Quedlinburg 06484, Germany
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Bonnet S, Knoll A, Hartung F, Puchta H. Different functions for the domains of the Arabidopsis thaliana RMI1 protein in DNA cross-link repair, somatic and meiotic recombination. Nucleic Acids Res 2013; 41:9349-60. [PMID: 23956219 PMCID: PMC3814364 DOI: 10.1093/nar/gkt730] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Recombination intermediates, such as double Holliday junctions, can be resolved by nucleases or dissolved by the combined action of a DNA helicase and a topoisomerase. In eukaryotes, dissolution is mediated by the RTR complex consisting of a RecQ helicase, a type IA topoisomerase and the structural protein RecQ-mediated genome instability 1 (RMI1). Throughout eukaryotes, the RTR complex is involved in DNA repair and in the suppression of homologous recombination (HR) in somatic cells. Surprisingly, Arabidopsis thaliana mutants of topoisomerase 3α and RMI1 are also sterile due to extensive chromosome breakage in meiosis I, indicating that both proteins are essential for meiotic recombination in plants. AtRMI1 harbours an N-terminal DUF1767 domain and two oligosaccharide binding (OB)-fold domains. To define specific roles for these individual domains, we performed complementation experiments on Atrmi1 mutants with an AtRMI1 full-length open reading frame (ORF) or deletion constructs lacking specific domains. We show that the DUF1767 domain and the OB-fold domain 1 are both essential for the function of AtRMI1 in DNA cross-link repair as well as meiotic recombination, but partially dispensable for somatic HR suppression. The OB-fold domain 2 is not necessary for either somatic or meiotic HR, but it seems to have a minor function in DNA cross-link repair.
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Affiliation(s)
- Simone Bonnet
- Karlsruhe Institute of Technology, Botanical Institute II, Hertzstrasse 16, 76187 Karlsruhe, Germany
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Zhang J, Zuo T, Peterson T. Generation of tandem direct duplications by reversed-ends transposition of maize ac elements. PLoS Genet 2013; 9:e1003691. [PMID: 23966872 PMCID: PMC3744419 DOI: 10.1371/journal.pgen.1003691] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 06/18/2013] [Indexed: 11/19/2022] Open
Abstract
Tandem direct duplications are a common feature of the genomes of eukaryotes ranging from yeast to human, where they comprise a significant fraction of copy number variations. The prevailing model for the formation of tandem direct duplications is non-allelic homologous recombination (NAHR). Here we report the isolation of a series of duplications and reciprocal deletions isolated de novo from a maize allele containing two Class II Ac/Ds transposons. The duplication/deletion structures suggest that they were generated by alternative transposition reactions involving the termini of two nearby transposable elements. The deletion/duplication breakpoint junctions contain 8 bp target site duplications characteristic of Ac/Ds transposition events, confirming their formation directly by an alternative transposition mechanism. Tandem direct duplications and reciprocal deletions were generated at a relatively high frequency (~0.5 to 1%) in the materials examined here in which transposons are positioned nearby each other in appropriate orientation; frequencies would likely be much lower in other genotypes. To test whether this mechanism may have contributed to maize genome evolution, we analyzed sequences flanking Ac/Ds and other hAT family transposons and identified three small tandem direct duplications with the structural features predicted by the alternative transposition mechanism. Together these results show that some class II transposons are capable of directly inducing tandem sequence duplications, and that this activity has contributed to the evolution of the maize genome.
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Affiliation(s)
- Jianbo Zhang
- Department of Genetics, Development and Cell Biology, Department of Agronomy, Iowa State University, Ames, Iowa, United States of America
| | - Tao Zuo
- Department of Genetics, Development and Cell Biology, Department of Agronomy, Iowa State University, Ames, Iowa, United States of America
| | - Thomas Peterson
- Department of Genetics, Development and Cell Biology, Department of Agronomy, Iowa State University, Ames, Iowa, United States of America
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Nishizawa-Yokoi A, Nonaka S, Saika H, Kwon YI, Osakabe K, Toki S. Suppression of Ku70/80 or Lig4 leads to decreased stable transformation and enhanced homologous recombination in rice. THE NEW PHYTOLOGIST 2012; 196:1048-1059. [PMID: 23050791 PMCID: PMC3532656 DOI: 10.1111/j.1469-8137.2012.04350.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 08/23/2012] [Indexed: 05/13/2023]
Abstract
Evidence for the involvement of the nonhomologous end joining (NHEJ) pathway in Agrobacterium-mediated transferred DNA (T-DNA) integration into the genome of the model plant Arabidopsis remains inconclusive. Having established a rapid and highly efficient Agrobacterium-mediated transformation system in rice (Oryza sativa) using scutellum-derived calli, we examined here the involvement of the NHEJ pathway in Agrobacterium-mediated stable transformation in rice. Rice calli from OsKu70, OsKu80 and OsLig4 knockdown (KD) plants were infected with Agrobacterium harboring a sensitive emerald luciferase (LUC) reporter construct to evaluate stable expression and a green fluorescent protein (GFP) construct to monitor transient expression of T-DNA. Transient expression was not suppressed, but stable expression was reduced significantly, in KD plants. Furthermore, KD-Ku70 and KD-Lig4 calli exhibited an increase in the frequency of homologous recombination (HR) compared with control calli. In addition, suppression of OsKu70, OsKu80 and OsLig4 induced the expression of HR-related genes on treatment with DNA-damaging agents. Our findings suggest strongly that NHEJ is involved in Agrobacterium-mediated stable transformation in rice, and that there is a competitive and complementary relationship between the NHEJ and HR pathways for DNA double-strand break repair in rice.
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Affiliation(s)
- Ayako Nishizawa-Yokoi
- Plant Genome Engineering Research Unit, National Institute of Agrobiological Sciences2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan
| | - Satoko Nonaka
- Plant Genome Engineering Research Unit, National Institute of Agrobiological Sciences2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan
- Graduate School of Life and Environmental Sciences, University of Tsukuba1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
| | - Hiroaki Saika
- Plant Genome Engineering Research Unit, National Institute of Agrobiological Sciences2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan
| | - Yong-Ik Kwon
- Plant Genome Engineering Research Unit, National Institute of Agrobiological Sciences2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan
- Kihara Institute for Biological Research, Yokohama City University641-12 Maioka-cho, Yokohama 244-0813, Japan
| | - Keishi Osakabe
- Plant Genome Engineering Research Unit, National Institute of Agrobiological Sciences2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan
- Institute for Environmental Science and Technology, Saitama UniversityShimo-Okubo 255, Sakura-ku, Saitama-shi, 338-8570 Japan
| | - Seiichi Toki
- Plant Genome Engineering Research Unit, National Institute of Agrobiological Sciences2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan
- Kihara Institute for Biological Research, Yokohama City University641-12 Maioka-cho, Yokohama 244-0813, Japan
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Ülker B, Hommelsheim CM, Berson T, Thomas S, Chandrasekar B, Olcay AC, Berendzen KW, Frantzeskakis L. Reevaluation of the reliability and usefulness of the somatic homologous recombination reporter lines. THE PLANT CELL 2012; 24:4314-23. [PMID: 23144181 PMCID: PMC3531835 DOI: 10.1105/tpc.112.100404] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 05/15/2012] [Accepted: 10/18/2012] [Indexed: 05/25/2023]
Abstract
A widely used approach for assessing genome instability in plants makes use of somatic homologous recombination (SHR) reporter lines. Here, we review the published characteristics and uses of SHR lines. We found a lack of detailed information on these lines and a lack of sufficient evidence that they report only homologous recombination. We postulate that instead of SHR, these lines might be reporting a number of alternative stress-induced stochastic events known to occur at transcriptional, posttranscriptional, and posttranslational levels. We conclude that the reliability and usefulness of the somatic homologous recombination reporter lines requires revision. Thus, more detailed information about these reporter lines is needed before they can be used with confidence to measure genome instability, including the complete sequences of SHR constructs, the genomic location of reporter genes and, importantly, molecular evidence that reconstituted gene expression in these lines is indeed a result of somatic recombination.
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Affiliation(s)
- Bekir Ülker
- Plant Molecular Engineering Group, Institute of Cellular and Molecular Botany, University of Bon, 53115 Bon, Germany.
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40
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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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41
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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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42
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Knoll A, Higgins JD, Seeliger K, Reha SJ, Dangel NJ, Bauknecht M, Schröpfer S, Franklin FCH, Puchta H. The Fanconi anemia ortholog FANCM ensures ordered homologous recombination in both somatic and meiotic cells in Arabidopsis. THE PLANT CELL 2012; 24:1448-64. [PMID: 22547783 PMCID: PMC3398556 DOI: 10.1105/tpc.112.096644] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Revised: 04/12/2012] [Accepted: 04/17/2012] [Indexed: 05/18/2023]
Abstract
The human hereditary disease Fanconi anemia leads to severe symptoms, including developmental defects and breakdown of the hematopoietic system. It is caused by single mutations in the FANC genes, one of which encodes the DNA translocase FANCM (for Fanconi anemia complementation group M), which is required for the repair of DNA interstrand cross-links to ensure replication progression. We identified a homolog of FANCM in Arabidopsis thaliana that is not directly involved in the repair of DNA lesions but suppresses spontaneous somatic homologous recombination via a RecQ helicase (At-RECQ4A)-independent pathway. In addition, it is required for double-strand break-induced homologous recombination. The fertility of At-fancm mutant plants is compromised. Evidence suggests that during meiosis At-FANCM acts as antirecombinase to suppress ectopic recombination-dependent chromosome interactions, but this activity is antagonized by the ZMM pathway to enable the formation of interference-sensitive crossovers and chromosome synapsis. Surprisingly, mutation of At-FANCM overcomes the sterility phenotype of an At-MutS homolog4 mutant by apparently rescuing a proportion of crossover-designated recombination intermediates via a route that is likely At-MMS and UV sensitive81 dependent. However, this is insufficient to ensure the formation of an obligate crossover. Thus, At-FANCM is not only a safeguard for genome stability in somatic cells but is an important factor in the control of meiotic crossover formation.
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Affiliation(s)
- Alexander Knoll
- Botanical Institute II, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - James D. Higgins
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Katharina Seeliger
- Botanical Institute II, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Sarah J. Reha
- Botanical Institute II, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Natalie J. Dangel
- Botanical Institute II, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Markus Bauknecht
- Botanical Institute II, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Susan Schröpfer
- Botanical Institute II, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | | | - Holger Puchta
- Botanical Institute II, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
- Address correspondence to
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Homologous recombination is stimulated by a decrease in dUTPase in Arabidopsis. PLoS One 2011; 6:e18658. [PMID: 21541310 PMCID: PMC3082524 DOI: 10.1371/journal.pone.0018658] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2010] [Accepted: 03/07/2011] [Indexed: 11/19/2022] Open
Abstract
Deoxyuridine triphosphatase (dUTPase) enzyme is an essential enzyme that protects DNA against uracil incorporation. No organism can tolerate the absence of this activity. In this article, we show that dUTPase function is conserved between E. coli (Escherichia coli), yeast (Saccharomyces cerevisiae) and Arabidopsis (Arabidopsis thaliana) and that it is essential in Arabidopsis as in both micro-organisms. Using a RNA interference strategy, plant lines were generated with a diminished dUTPase activity as compared to the wild-type. These plants are sensitive to 5-fluoro-uracil. As an indication of DNA damage, inactivation of dUTPase results in the induction of AtRAD51 and AtPARP2, which are involved in DNA repair. Nevertheless, RNAi/DUT1 constructs are compatible with a rad51 mutation. Using a TUNEL assay, DNA damage was observed in the RNAi/DUT1 plants. Finally, plants carrying a homologous recombination (HR) exclusive substrate transformed with the RNAi/DUT1 construct exhibit a seven times increase in homologous recombination events. Increased HR was only detected in the plants that were the most sensitive to 5-fluoro-uracils, thus establishing a link between uracil incorporation in the genomic DNA and HR. Our results show for the first time that genetic instability provoked by the presence of uracils in the DNA is poorly tolerated and that this base misincorporation globally stimulates HR in plants.
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Yang Z, Tang L, Li M, Chen L, Xu J, Wu G, Li H. Monitoring homologous recombination in rice (Oryza sativa L.). Mutat Res 2010; 691:55-63. [PMID: 20670635 DOI: 10.1016/j.mrfmmm.2010.07.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2009] [Revised: 04/11/2010] [Accepted: 07/09/2010] [Indexed: 05/29/2023]
Abstract
Here we describe a system to assay homologous recombination during the complete life cycle of rice (Oryza sativa L.). Rice plants were transformed with two copies of non-functional GUS reporter overlap fragments as recombination substrate. Recombination was observed in all plant organs examined, from the seed stage until the flowering stage of somatic plant development. Embryogenic cells exhibited the highest recombination ability with an average of 3x10(-5) recombination events per genome, which is about 10-fold of that observed in root cells, and two orders of that observed in leaf cells. Histological analysis revealed that recombination events occurred in diverse cell types, but preferentially in cells with small size. Examples of this included embryogenic cells in callus, phloem cells in the leaf vein, and cells located in the root apical meristem. Steady state RNA analysis revealed that the expression levels of rice Rad51 homologs are positively correlated with increased recombination rates in embryogenic calli, roots and anthers. Finally, radiation treatment of plantlets from distinct recombination lines increased the recombination frequency to different extents. These results showed that homologous recombination frequency can be effectively measured in rice using a transgene reporter assay. This system will facilitate the study of DNA damage signaling and homologous recombination in rice, a model monocot.
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Affiliation(s)
- Zhuanying Yang
- Guangdong Provincial Key Lab of Biotechnology for Plant Development, College of Life Sciences, South China Normal University, Guangzhou 510631, China
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45
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Block-Schmidt AS, Dukowic-Schulze S, Wanieck K, Reidt W, Puchta H. BRCC36A is epistatic to BRCA1 in DNA crosslink repair and homologous recombination in Arabidopsis thaliana. Nucleic Acids Res 2010; 39:146-54. [PMID: 20817926 PMCID: PMC3017590 DOI: 10.1093/nar/gkq722] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BRCA1 is a well-known tumor suppressor protein in mammals, involved in multiple cellular processes such as DNA repair, chromosome segregation and chromatin remodeling. Interestingly, homologs of BRCA1 and several of its complex partners are also found in plants. As the respective mutants are viable, in contrast to mammalian mutants, detailed analyses of their biological role is possible. Here we demonstrate that the model plant Arabidopsis thaliana harbors two homologs of the mammalian BRCA1 interaction partner BRCC36, AtBRCC36A and AtBRCC36B. Mutants of both genes as well as the double mutants are fully fertile and show no defects in development. We were able to show that mutation of one of the homologs, AtBRCC36A, leads to a severe defect in intra- and interchromosomal homologous recombination (HR). A HR defect is also apparent in Atbrca1 mutants. As the Atbrcc36a/Atbrca1 double mutant behaves like the single mutants of AtBRCA1 and AtBRCC36A both proteins seem to be involved in a common pathway in the regulation of HR. AtBRCC36 is also epistatic to AtBRCA1 in DNA crosslink repair. Upon genotoxic stress, AtBRCC36A is transferred into the nucleus.
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Schuermann D, Fritsch O, Lucht JM, Hohn B. Replication stress leads to genome instabilities in Arabidopsis DNA polymerase delta mutants. THE PLANT CELL 2009; 21:2700-14. [PMID: 19789281 PMCID: PMC2768921 DOI: 10.1105/tpc.109.069682] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Revised: 08/25/2009] [Accepted: 09/09/2009] [Indexed: 05/19/2023]
Abstract
Impeded DNA replication or a deficiency of its control may critically threaten the genetic information of cells, possibly resulting in genome alterations, such as gross chromosomal translocations, microsatellite instabilities, or increased rates of homologous recombination (HR). We examined an Arabidopsis thaliana line derived from a forward genetic screen, which exhibits an elevated frequency of somatic HR. These HR events originate from replication stress in endoreduplicating cells caused by reduced expression of the gene coding for the catalytic subunit of the DNA polymerase delta (POLdelta1). The analysis of recombination types induced by diverse alleles of poldelta1 and by replication inhibitors allows the conclusion that two not mutually exclusive mechanisms lead to the generation of recombinogenic breaks at replication forks. In plants with weak poldelta1 alleles, we observe genome instabilities predominantly at sites with inverted repeats, suggesting the formation and processing of aberrant secondary DNA structures as a result of the accumulation of unreplicated DNA. Stalled and collapsed replication forks account for the more drastic enhancement of HR in plants with strong poldelta1 mutant alleles. Our data suggest that efficient progression of DNA replication, foremost on the lagging strand, relies on the physiological level of the polymerase delta complex and that even a minor disturbance of the replication process critically threatens genomic integrity of Arabidopsis cells.
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Affiliation(s)
- David Schuermann
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.
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47
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Pecinka A, Rosa M, Schikora A, Berlinger M, Hirt H, Luschnig C, Scheid OM. Transgenerational stress memory is not a general response in Arabidopsis. PLoS One 2009; 4:e5202. [PMID: 19381297 PMCID: PMC2668180 DOI: 10.1371/journal.pone.0005202] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Accepted: 03/09/2009] [Indexed: 12/25/2022] Open
Abstract
Adverse conditions can trigger DNA damage as well as DNA repair responses in plants. A variety of stress factors are known to stimulate homologous recombination, the most accurate repair pathway, by increasing the concentration of necessary enzymatic components and the frequency of events. This effect has been reported to last into subsequent generations not exposed to the stress. To establish a basis for a genetic analysis of this transgenerational stress memory, a broad range of treatments was tested for quantitative effects on homologous recombination in the progeny. Several Arabidopsis lines, transgenic for well-established recombination traps, were exposed to 10 different physical and chemical stress treatments, and scored for the number of somatic homologous recombination (SHR) events in the treated generation as well as in the two subsequent generations that were not treated. These numbers were related to the expression level of genes involved in homologous recombination and repair. SHR was enhanced after the majority of treatments, confirming previous data and adding new effective stress types, especially interference with chromatin. Compounds that directly modify DNA stimulated SHR to values exceeding previously described induction rates, concomitant with an induction of genes involved in SHR. In spite of the significant stimulation in the stressed generations, the two subsequent non-treated generations only showed a low and stochastic increase in SHR that did not correlate with the degree of stimulation in the parental plants. Transcripts coding for SHR enzymes generally returned to pre-treatment levels in the progeny. Thus, transgenerational effects on SHR frequency are not a general response to abiotic stress in Arabidopsis and may require special conditions.
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Affiliation(s)
- Ales Pecinka
- Gregor Mendel Institute of Molecular Plant Biology (GMI), Austrian Academy of Sciences, Vienna, Austria
| | - Marisa Rosa
- Gregor Mendel Institute of Molecular Plant Biology (GMI), Austrian Academy of Sciences, Vienna, Austria
| | - Adam Schikora
- INRA – URGV, Plant Genomics Research Unit, Evry, France
| | - Marc Berlinger
- University of Natural Resources and Applied Life Sciences (BOKU), Vienna, Austria
| | - Heribert Hirt
- INRA – URGV, Plant Genomics Research Unit, Evry, France
| | - Christian Luschnig
- University of Natural Resources and Applied Life Sciences (BOKU), Vienna, Austria
| | - Ortrun Mittelsten Scheid
- Gregor Mendel Institute of Molecular Plant Biology (GMI), Austrian Academy of Sciences, Vienna, Austria
- * E-mail:
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48
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Wehrkamp-Richter S, Degroote F, Laffaire JB, Paul W, Perez P, Picard G. Characterisation of a new reporter system allowing high throughput in planta screening for recombination events before and after controlled DNA double strand break induction. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2009; 47:248-255. [PMID: 19136269 DOI: 10.1016/j.plaphy.2008.11.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2008] [Revised: 11/26/2008] [Accepted: 11/28/2008] [Indexed: 05/27/2023]
Abstract
DNA double strand breaks (DSBs) are created either by DNA damaging reagents or in a programmed manner, for example during meiosis. Homologous recombination (HR) can be used to repair DSBs, a process vital both for cell survival and for genetic rearrangement during meiosis. In order to easily quantify this mechanism, a new HR reporter gene that is suitable for the detection of rare recombination events in high-throughput screens was developed in Arabidopsis thaliana. This reporter, pPNP, is composed of two mutated Pat genes and has also one restriction site for the meganuclease I-SceI. A functional Pat gene can be reconstituted by an HR event giving plants which are resistant to the herbicide glufosinate. The basal frequency of intra-chromosomal recombination is very low (10(-5)) and can be strongly increased by the expression of I-SceI which creates a DSB. Expression of I-SceI under the control of the 35S CaMV promoter dramatically increases HR frequency (10,000 fold); however the measured recombinant events are in majority somatic. In contrast only germinal recombination events were measured when the meganuclease was expressed from a floral-specific promoter. Finally, the reporter was used to test a dexamethasone inducible I-SceI which could produce up to 200x more HR events after induction. This novel inducible I-SceI should be useful in fundamental studies of the mechanism of repair of DSBs and for biotechnological applications.
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Hartung F, Suer S, Knoll A, Wurz-Wildersinn R, Puchta H. Topoisomerase 3alpha and RMI1 suppress somatic crossovers and are essential for resolution of meiotic recombination intermediates in Arabidopsis thaliana. PLoS Genet 2008; 4:e1000285. [PMID: 19096507 PMCID: PMC2588661 DOI: 10.1371/journal.pgen.1000285] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Accepted: 10/28/2008] [Indexed: 11/18/2022] Open
Abstract
Topoisomerases are enzymes with crucial functions in DNA metabolism. They are ubiquitously present in prokaryotes and eukaryotes and modify the steady-state level of DNA supercoiling. Biochemical analyses indicate that Topoisomerase 3α (TOP3α) functions together with a RecQ DNA helicase and a third partner, RMI1/BLAP75, in the resolution step of homologous recombination in a process called Holliday Junction dissolution in eukaryotes. Apart from that, little is known about the role of TOP3α in higher eukaryotes, as knockout mutants show early lethality or strong developmental defects. Using a hypomorphic insertion mutant of Arabidopsis thaliana (top3α-2), which is viable but completely sterile, we were able to define three different functions of the protein in mitosis and meiosis. The top3α-2 line exhibits fragmented chromosomes during mitosis and sensitivity to camptothecin, suggesting an important role in chromosome segregation partly overlapping with that of type IB topoisomerases. Furthermore, AtTOP3α, together with AtRECQ4A and AtRMI1, is involved in the suppression of crossover recombination in somatic cells as well as DNA repair in both mammals and A. thaliana. Surprisingly, AtTOP3α is also essential for meiosis. The phenotype of chromosome fragmentation, bridges, and telophase I arrest can be suppressed by AtSPO11 and AtRAD51 mutations, indicating that the protein is required for the resolution of recombination intermediates. As Atrmi1 mutants have a similar meiotic phenotype to Attop3α mutants, both proteins seem to be involved in a mechanism safeguarding the entangling of homologous chromosomes during meiosis. The requirement of AtTOP3α and AtRMI1 in a late step of meiotic recombination strongly hints at the possibility that the dissolution of double Holliday Junctions via a hemicatenane intermediate is indeed an indispensable step of meiotic recombination. The topoisomerases of the class IA are present in all three eukaryotic kingdoms—plants, fungi, and animals—and are involved in DNA replication and DNA repair. During the course of their action, they introduce transient single-strand nicks into DNA. In higher eukaryotes, two different classes of the enzymes are present: TOP3α and TOP3β. TOP3α is essential, as disruption of its function usually results in lethality of the affected organism. Using a mutant of TOP3α that retains some activity, we show that the protein has multiple, different functions in the model plant A. thaliana. Besides its action in somatic cells, where it is required for mitosis as well as DNA repair, we demonstrate that TOP3α together with its protein partner RMI1 is essential for meiosis. Here, both proteins are involved in DNA recombination—the exchange of information between parental chromosomes. Disruption of either TOP3α or RMI1 leads to grave defects and an early termination of meiosis, resulting in the sterility of the mutant plants. Our detailed analysis indicates that both proteins are involved in a late step of meiotic recombination, in a mechanism that prevents entanglement of the parental chromosomes. Thus, meiotic recombination seems to be more complex than previously anticipated.
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Affiliation(s)
- Frank Hartung
- Botany II, University of Karlsruhe, Karlsruhe, Germany
| | - Stefanie Suer
- Botany II, University of Karlsruhe, Karlsruhe, Germany
| | | | | | - Holger Puchta
- Botany II, University of Karlsruhe, Karlsruhe, Germany
- * E-mail:
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Sun X, Zhang Y, Yang S, Chen JQ, Hohn B, Tian D. Insertion DNA Promotes Ectopic Recombination during Meiosis in Arabidopsis. Mol Biol Evol 2008; 25:2079-83. [PMID: 18641394 DOI: 10.1093/molbev/msn158] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Nucleotide insertion/deletions are common polymorphisms in living organisms; however, little is known about their genetic behavior during meiosis. Here, the recombination frequency (RF) of isogenic strains of transgenic Arabidopsis thaliana, that differ in the presence or absence of an insertion, was compared. We screened over 6 million seedlings and found that during meiosis the unpaired DNA insertions paired with ectopic homologues demonstrated a 13.8 times higher RF than that of noninsertion DNA. The direct measurement of recombination events provided the first evidence that a large piece of insertion DNA had a unique genetic behavior during meiosis. This pattern was consistently observed in different lines varying in overlapping sequence, construct orientation, chromosome location, and crossing direction. We suggest that higher ectopic recombination is promoted by DNA insertions and that this mechanism exists commonly in plants. Therefore, insertion DNA plays a nontrivial role in shaping genetic variation, chromosome instability, and genome evolution.
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