1
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Puchta H, Houben A. Plant chromosome engineering - past, present and future. THE NEW PHYTOLOGIST 2024; 241:541-552. [PMID: 37984056 DOI: 10.1111/nph.19414] [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: 09/06/2023] [Accepted: 10/24/2023] [Indexed: 11/22/2023]
Abstract
Spontaneous chromosomal rearrangements (CRs) play an essential role in speciation, genome evolution and crop domestication. To be able to use the potential of CRs for breeding, plant chromosome engineering was initiated by fragmenting chromosomes by X-ray irradiation. With the rise of the CRISPR/Cas system, it became possible to induce double-strand breaks (DSBs) in a highly efficient manner at will at any chromosomal position. This has enabled a completely new level of predesigned chromosome engineering. The genetic linkage between specific genes can be broken by inducing chromosomal translocations. Natural inversions, which suppress genetic exchange, can be reverted for breeding. In addition, various approaches for constructing minichromosomes by downsizing regular standard A or supernumerary B chromosomes, which could serve as future vectors in plant biotechnology, have been developed. Recently, a functional synthetic centromere could be constructed. Also, different ways of genome haploidization have been set up, some based on centromere manipulations. In the future, we expect to see even more complex rearrangements, which can be combined with previously developed engineering technologies such as recombinases. Chromosome engineering might help to redefine genetic linkage groups, change the number of chromosomes, stack beneficial genes on mini cargo chromosomes, or set up genetic isolation to avoid outcrossing.
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Affiliation(s)
- Holger Puchta
- Joseph Gottlieb Kölreuter Institute for Plant Sciences (JKIP) - Molecular Biology, Karlsruhe Institute of Technology (KIT), 76131, Karlsruhe, Germany
| | - Andreas Houben
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, 06466, Seeland, Germany
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2
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Gomide MDS, Leitão MDC, Coelho CM. Biocircuits in plants and eukaryotic algae. FRONTIERS IN PLANT SCIENCE 2022; 13:982959. [PMID: 36212277 PMCID: PMC9545776 DOI: 10.3389/fpls.2022.982959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 08/22/2022] [Indexed: 06/16/2023]
Abstract
As one of synthetic biology's foundations, biocircuits are a strategy of genetic parts assembling to recognize a signal and to produce a desirable output to interfere with a biological function. In this review, we revisited the progress in the biocircuits technology basis and its mandatory elements, such as the characterization and assembly of functional parts. Furthermore, for a successful implementation, the transcriptional control systems are a relevant point, and the computational tools help to predict the best combinations among the biological parts planned to be used to achieve the desirable phenotype. However, many challenges are involved in delivering and stabilizing the synthetic structures. Some research experiences, such as the golden crops, biosensors, and artificial photosynthetic structures, can indicate the positive and limiting aspects of the practice. Finally, we envision that the modulatory structural feature and the possibility of finer gene regulation through biocircuits can contribute to the complex design of synthetic chromosomes aiming to develop plants and algae with new or improved functions.
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Affiliation(s)
- Mayna da Silveira Gomide
- Laboratory of Synthetic Biology, Department of Genetics and Morphology, Institute of Biological Science, University of Brasília (UnB), Brasília, Distrito Federal, Brazil
- School of Medicine, Federal University of Juiz de Fora (UFJF), Juiz de Fora, Minas Gerais, Brazil
| | - Matheus de Castro Leitão
- Laboratory of Synthetic Biology, Department of Genetics and Morphology, Institute of Biological Science, University of Brasília (UnB), Brasília, Distrito Federal, Brazil
| | - Cíntia Marques Coelho
- Laboratory of Synthetic Biology, Department of Genetics and Morphology, Institute of Biological Science, University of Brasília (UnB), Brasília, Distrito Federal, Brazil
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3
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Kan M, Huang T, Zhao P. Artificial chromosome technology and its potential application in plants. FRONTIERS IN PLANT SCIENCE 2022; 13:970943. [PMID: 36186059 PMCID: PMC9519882 DOI: 10.3389/fpls.2022.970943] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 08/26/2022] [Indexed: 06/16/2023]
Abstract
Plant genetic engineering and transgenic technology are powerful ways to study the function of genes and improve crop yield and quality in the past few years. However, only a few genes could be transformed by most available genetic engineering and transgenic technologies, so changes still need to be made to meet the demands for high throughput studies, such as investigating the whole genetic pathway of crop traits and avoiding undesirable genes simultaneously in the next generation. Plant artificial chromosome (PAC) technology provides a carrier which allows us to assemble multiple and specific genes to produce a variety of products by minichromosome. However, PAC technology also have limitations that may hinder its further development and application. In this review, we will introduce the current state of PACs technology from PACs formation, factors on PACs formation, problems and potential solutions of PACs and exogenous gene(s) integration.
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Affiliation(s)
- Manman Kan
- Guangdong Provincial Key Laboratory for Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, Guangdong, China
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, China
| | - Tengbo Huang
- Guangdong Provincial Key Laboratory for Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, Guangdong, China
| | - Panpan Zhao
- Guangdong Provincial Key Laboratory for Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, Guangdong, China
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4
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Kralemann LEM, de Pater S, Shen H, Kloet SL, van Schendel R, Hooykaas PJJ, Tijsterman M. Distinct mechanisms for genomic attachment of the 5' and 3' ends of Agrobacterium T-DNA in plants. NATURE PLANTS 2022; 8:526-534. [PMID: 35534719 DOI: 10.1038/s41477-022-01147-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 03/30/2022] [Indexed: 06/14/2023]
Abstract
Agrobacterium tumefaciens, a pathogenic bacterium capable of transforming plants through horizontal gene transfer, is nowadays the preferred vector for plant genetic engineering. The vehicle for transfer is the T-strand, a single-stranded DNA molecule bound by the bacterial protein VirD2, which guides the T-DNA into the plant's nucleus where it integrates. How VirD2 is removed from T-DNA, and which mechanism acts to attach the liberated end to the plant genome is currently unknown. Here, using newly developed technology that yields hundreds of T-DNA integrations in somatic tissue of Arabidopsis thaliana, we uncover two redundant mechanisms for the genomic capture of the T-DNA 5' end. Different from capture of the 3' end of the T-DNA, which is the exclusive action of polymerase theta-mediated end joining (TMEJ), 5' attachment is accomplished either by TMEJ or by canonical non-homologous end joining (cNHEJ). We further find that TMEJ needs MRE11, whereas cNHEJ requires TDP2 to remove the 5' end-blocking protein VirD2. As a consequence, T-DNA integration is severely impaired in plants deficient for both MRE11 and TDP2 (or other cNHEJ factors). In support of MRE11 and cNHEJ specifically acting on the 5' end, we demonstrate rescue of the integration defect of double-deficient plants by using T-DNAs that are capable of forming telomeres upon 3' capture. Our study provides a mechanistic model for how Agrobacterium exploits the plant's own DNA repair machineries to transform it.
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Affiliation(s)
| | - Sylvia de Pater
- Institute of Biology Leiden, Leiden University, Leiden, The Netherlands
| | - Hexi Shen
- School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan, Shandong, China
| | - Susan L Kloet
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Robin van Schendel
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Paul J J Hooykaas
- Institute of Biology Leiden, Leiden University, Leiden, The Netherlands
| | - Marcel Tijsterman
- Institute of Biology Leiden, Leiden University, Leiden, The Netherlands.
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
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5
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Yin X, Zhang Y, Chen Y, Wang J, Wang RRC, Fan C, Hu Z. Precise Characterization and Tracking of Stably Inherited Artificial Minichromosomes Made by Telomere-Mediated Chromosome Truncation in Brassica napus. FRONTIERS IN PLANT SCIENCE 2021; 12:743792. [PMID: 34671377 PMCID: PMC8521072 DOI: 10.3389/fpls.2021.743792] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 09/08/2021] [Indexed: 06/13/2023]
Abstract
Plant artificial minichromosomes are the next-generation technology for plant genetic engineering and represent an independent platform for expressing foreign genes and the tools for studying the structure and function of chromosomes. Minichromosomes have been successfully produced by telomere-mediated chromosome truncation in several plants. However, previous studies have primarily focused on the construction and rough characterization of minichromosomes, while the development of stably inherited minichromosomes and their precise characterization and tracking over different generations have rarely been demonstrated. In this study, a 0.35-kb direct repeat of the Arabidopsis telomeric sequence was transformed into Brassica napus to produce artificial minichromosomes, which were analyzed by multifluorescence in situ hybridization (multi-FISH), Southern hybridization, and primer extension telomere rapid amplification (PETRA). The stably inherited minichromosomes C2 and C4 were developed by crossing transgenic plants with wild-type plants and then selfing the hybrids. Notably, two truncation sites on chromosomes C2 and C4, respectively, were identified by resequencing; thus, the artificial minichromosomes were tracked over different generations with insertion site-specific PCR. This study provided two stably inherited minichromosomes in oilseed rape and describes approaches to precisely characterize the truncation position and track the minichromosomes in offspring through multi-FISH, genome resequencing, and insertion site-specific PCR.
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Affiliation(s)
- Xiangzhen Yin
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Yingxin Zhang
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China
- College of Agriculture, Yangtze University, Jingzhou, China
| | - Yuhong Chen
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Jingqiao Wang
- Institute of Economical Crops, Yunnan Agricultural Academy, Kunming, China
| | - Richard R.-C. Wang
- Forage and Range Research Laboratory, United States Department of Agriculture, Agricultural Research Service, Utah State University, Logan, UT, United States
| | - Chengming Fan
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Zanmin Hu
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China
- College of Agriculture, University of Chinese Academy of Sciences, Beijing, China
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6
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Birchler JA, Swyers NC. Engineered minichromosomes in plants. Exp Cell Res 2020; 388:111852. [PMID: 31972219 DOI: 10.1016/j.yexcr.2020.111852] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Accepted: 01/14/2020] [Indexed: 11/17/2022]
Abstract
Artificial chromosome platforms are described in plants. Because the function of centromeres is largely epigenetic, attempts to produce artificial chromosomes with plant centromere DNA have failed. The removal of the centromeric sequences from the cell strips off the centromeric histone that is the apparent biochemical marker of centromere activity. Thus, engineered minichromosomes have been produced by telomere mediated chromosomal truncation. The introduction of telomere repeats will cleave the chromosome at the site of insertion and attach the accompanying transgenes in the process. Such truncation events have been documented in maize, Arabidopsis, barley, rice, Brassica and wheat. Truncation of the nonvital supernumerary B chromosome of maize is a favorite target but engineered minichromosomes derived from the normal A chromosomes have also been recovered. Transmission through mitosis of small chromosomes is apparently normal but there is loss during meiosis. Potential solutions to address this issue are discussed. With procedures now well established to produce the foundation for artificial chromosomes in plants, current efforts are directed at building them up to specification using gene stacking methods and editing techniques.
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Affiliation(s)
- James A Birchler
- Division of Biological Sciences, University of Missouri, 311 Tucker Hall, Columbia, MO, 65211-7400, USA.
| | - Nathan C Swyers
- Division of Biological Sciences, University of Missouri, 311 Tucker Hall, Columbia, MO, 65211-7400, USA
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7
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Ling YH, Lin Z, Yuen KWY. Genetic and epigenetic effects on centromere establishment. Chromosoma 2019; 129:1-24. [PMID: 31781852 DOI: 10.1007/s00412-019-00727-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 09/24/2019] [Accepted: 10/10/2019] [Indexed: 01/19/2023]
Abstract
Endogenous chromosomes contain centromeres to direct equal chromosomal segregation in mitosis and meiosis. The location and function of existing centromeres is usually maintained through cell cycles and generations. Recent studies have investigated how the centromere-specific histone H3 variant CENP-A is assembled and replenished after DNA replication to epigenetically propagate the centromere identity. However, existing centromeres occasionally become inactivated, with or without change in underlying DNA sequences, or lost after chromosomal rearrangements, resulting in acentric chromosomes. New centromeres, known as neocentromeres, may form on ectopic, non-centromeric chromosomal regions to rescue acentric chromosomes from being lost, or form dicentric chromosomes if the original centromere is still active. In addition, de novo centromeres can form after chromatinization of purified DNA that is exogenously introduced into cells. Here, we review the phenomena of naturally occurring and experimentally induced new centromeres and summarize the genetic (DNA sequence) and epigenetic features of these new centromeres. We compare the characteristics of new and native centromeres to understand whether there are different requirements for centromere establishment and propagation. Based on our understanding of the mechanisms of new centromere formation, we discuss the perspectives of developing more stably segregating human artificial chromosomes to facilitate gene delivery in therapeutics and research.
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Affiliation(s)
- Yick Hin Ling
- School of Biological Sciences, The University of Hong Kong, Kadoorie Biological Sciences Building, Pokfulam Road, Hong Kong
| | - Zhongyang Lin
- School of Biological Sciences, The University of Hong Kong, Kadoorie Biological Sciences Building, Pokfulam Road, Hong Kong
| | - Karen Wing Yee Yuen
- School of Biological Sciences, The University of Hong Kong, Kadoorie Biological Sciences Building, Pokfulam Road, Hong Kong.
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8
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Baby V, Labroussaa F, Lartigue C, Rodrigue S. [Synthetic chromosomes: rewriting the code of life]. Med Sci (Paris) 2019; 35:753-760. [PMID: 31625897 DOI: 10.1051/medsci/2019153] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The past decade has seen vast improvements in DNA synthesis and assembly methods. The creation of synthetic DNA molecules is becoming easier and more affordable, such that entire chromosomes can now be synthesized. These advances mark the beginning of synthetic genomics, a new discipline interested in the construction of complete genomes tailored for the study and application of biological systems. From viral genome synthesis to the reconstruction of the yeast 16 chromosomes, we discuss the main discoveries, the regulations and ethical considerations along with the potential of this emerging discipline for the future.
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Affiliation(s)
- Vincent Baby
- INRA, UMR 1332 de biologie du fruit et pathologie, 71 avenue E. Bourlaux, 33140 Villenave d'Ornon, France - Univ. Bordeaux, UMR 1332 de biologie du fruit et pathologie, 71 avenue E. Bourlaux 33140 Villenave d'Ornon, France
| | - Fabien Labroussaa
- Institute of veterinary bacteriology of Bern, Vetsuisse Faculty, University of Bern, 3001 Berne, Suisse
| | - Carole Lartigue
- INRA, UMR 1332 de biologie du fruit et pathologie, 71 avenue E. Bourlaux, 33140 Villenave d'Ornon, France - Univ. Bordeaux, UMR 1332 de biologie du fruit et pathologie, 71 avenue E. Bourlaux 33140 Villenave d'Ornon, France
| | - Sébastien Rodrigue
- Département de biologie, Université de Sherbrooke, 2500 boulevard de l'Université, J1K 2R1 Sherbrooke, Québec, Canada
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9
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The Mechanism of T-DNA Integration: Some Major Unresolved Questions. Curr Top Microbiol Immunol 2018; 418:287-317. [DOI: 10.1007/82_2018_98] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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10
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Site-specific transfer of chromosomal segments and genes in wheat engineered chromosomes. J Genet Genomics 2017; 44:531-539. [DOI: 10.1016/j.jgg.2017.08.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 07/30/2017] [Accepted: 08/07/2017] [Indexed: 11/18/2022]
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11
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Yan X, Li C, Yang J, Wang L, Jiang C, Wei W. Induction of telomere-mediated chromosomal truncation and behavior of truncated chromosomes in Brassica napus. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 91:700-713. [PMID: 28500683 DOI: 10.1111/tpj.13598] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 05/09/2017] [Indexed: 06/07/2023]
Abstract
Engineered minichromosomes could be stably inherited and serve as a platform for simultaneously transferring and stably expressing multiple genes. Chromosomal truncation mediated by repeats of telomeric sequences is a promising approach for the generation of minichromosomes. In the present work, direct repetitive sequences of Arabidopsis telomere were used to study telomere-mediated truncation of chromosomes in Brassica napus. Transgenes containing alien Arabidopsis telomere were successfully obtained, and Southern blotting and fluorescence in situ hybridization (FISH) results show that the transgenes resulted in successful chromosomal truncation in B. napus. In addition, truncated chromosomes were inherited at rates lower than that predicted by Mendelian rules. To determine the potential manipulations and applications of the engineered chromosomes, such as the stacking of multiple transgenes and the Cre/lox and FRT/FLP recombination systems, both amenable to genetic manipulations through site-specific recombination in somatic cells, were tested for their ability to undergo recombination in B. napus. These results demonstrate that alien Arabidopsis telomere is able to mediate chromosomal truncation in B. napus. This technology would be feasible for chromosomal engineering and for studies on chromosome structure and function in B. napus.
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Affiliation(s)
- Xiaohong Yan
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences/Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, 430062, China
| | - Chen Li
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences/Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, 430062, China
- College of Life Science and Technology, Henan Institute of Science and Technology/Collaborative Innovation Center of Modern Biological Breeding of Henan Province, Xinxiang, 453003, China
- College of Food Science and Technology, Agricultural University of Hebei, Baoding, 071001, China
| | - Jie Yang
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences/Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, 430062, China
| | - Lijun Wang
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences/Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, 430062, China
| | - Chenghong Jiang
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences/Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, 430062, China
| | - Wenhui Wei
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences/Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, 430062, China
- College of Life Science and Technology, Henan Institute of Science and Technology/Collaborative Innovation Center of Modern Biological Breeding of Henan Province, Xinxiang, 453003, China
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12
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Swyers NC, Cody JP, McCaw ME, Graham ND, Zhao C, Gaeta RT, Birchler JA. Telomere-Mediated Chromosomal Truncation for Generating Engineered Minichromosomes in Maize. CURRENT PROTOCOLS IN PLANT BIOLOGY 2016; 1:488-500. [PMID: 31725959 DOI: 10.1002/cppb.20031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Minichromosomes have been generated in maize using telomere-mediated truncation. Telomere DNA, because of its repetitive nature, can be difficult to manipulate. The protocols in this unit describe two methods for generating the telomere DNA required for the initiation of telomere-mediated truncation. The resulting DNA can then be used with truncation cassettes for introduction into maize via transformation. © 2016 by John Wiley & Sons, Inc.
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Affiliation(s)
- Nathan C Swyers
- Division of Biological Sciences, University of Missouri, Columbia, Missouri
| | - Jon P Cody
- Division of Biological Sciences, University of Missouri, Columbia, Missouri
| | - Morgan E McCaw
- Division of Biological Sciences, University of Missouri, Columbia, Missouri
| | - Nathaniel D Graham
- Division of Biological Sciences, University of Missouri, Columbia, Missouri
| | - Changzeng Zhao
- Division of Biological Sciences, University of Missouri, Columbia, Missouri
| | - Robert T Gaeta
- Division of Biological Sciences, University of Missouri, Columbia, Missouri
| | - James A Birchler
- Division of Biological Sciences, University of Missouri, Columbia, Missouri
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13
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Puchta H. Using CRISPR/Cas in three dimensions: towards synthetic plant genomes, transcriptomes and epigenomes. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 87:5-15. [PMID: 26677816 DOI: 10.1111/tpj.13100] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 11/23/2015] [Accepted: 11/25/2015] [Indexed: 05/21/2023]
Abstract
It is possible to target individual sequence motives within genomes by using synthetic DNA-binding domains. This one-dimensional approach has been used successfully in plants to induce mutations or for the transcriptional regulation of single genes. When the CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 system was discovered, a tool became available allowing the extension of this approach from one to three dimensions and to construct at least partly synthetic entities on the genome, epigenome and transcriptome levels. The second dimension can be obtained by targeting the Cas9 protein to multiple unique genomic sites by applying multiple different single guiding (sg) RNAs, each defining a different DNA-binding site. Finally, the simultaneous use of phylogenetically different Cas9 proteins or sgRNAs that harbour different types of protein binding motives, allows for a third dimension of control. Thus, different types of enzyme activities - fused either to one type of Cas9 orthologue or to one type of RNA-binding domain specific to one type of sgRNA - can be targeted to multiple different genomic sites simultaneously. Thus, it should be possible to induce quantitatively different levels of expression of certain sets of genes and at the same time to repress other genes, redefining the nuclear transcriptome. Likewise, by the use of different types of histone-modifying and/or DNA (de)methylating activities, the epigenome of plants should be reprogrammable. On our way to synthetic plant genomes, the next steps will be to use complex genome engineering approaches within or between species borders to restructure and recombine natural or artificial chromosomes.
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Affiliation(s)
- Holger Puchta
- Botanical Institute II, Karlsruhe Institute of Technology, POB 6980, 76049, Karlsruhe, Germany
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14
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Xu C, Yu W. Artificial Chromosomes in Rice (Oryza sativa). CURRENT PROTOCOLS IN PLANT BIOLOGY 2016; 1:107-120. [PMID: 31725987 DOI: 10.1002/cppb.20008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Chromosomes are the carriers of genetic material in biological organisms. Each chromosome has three essential components: a centromere, telomeres, and origins of replication. The understanding of the essential structural and functional organization of chromosomes has made it possible to produce artificial chromosomes (ACs), which are human-engineered minichromosomes. There are two approaches to make ACs: de novo assembly (bottom-up) and truncation of existing chromosomes (top-down). Rice (Oryza sativa) ACs are produced by telomere-mediated chromosome truncation, and may have many applications, such as genetic engineering to stack and express multiple genes in rice to combat diseases caused by bacteria, fungi, and viruses, to enhance tolerance of rice to environmental stresses such as drought, heat, and salinity, and to improve yield and quality. © 2016 by John Wiley & Sons, Inc.
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Affiliation(s)
- Chunhui Xu
- School of Life Sciences, Shandong University, Jinan, Shandong, China
| | - Weichang Yu
- Shenzhen Research Institute of The Chinese University of Hong Kong, Shenzhen, China
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15
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Murata M. Artificial Chromosome Preparation in Arabidopsis. CURRENT PROTOCOLS IN PLANT BIOLOGY 2016; 1:53-66. [PMID: 31725989 DOI: 10.1002/cppb.20010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In Arabidopsis thaliana, various attempts have been made to create artificial chromosomes as a new tool for cytological and genetic analyses. However, most of the efforts have been unsuccessful until recently. Most eukaryotic chromosomes are linear, and therefore the Arabidopsis artificial chromosomes have also been designed to be linear and to carry the telomere structure at both ends. In contrast, circular artificial chromosomes were successfully created by the Cre/LoxP system combined with Ac/Ds transposon system, on the basis of the discovery that ring minichromosomes are relatively stable and transmissible to the next generations in A. thaliana. Because ring minichromosomes ∼1 to 6 Mb in size have been generated, in this article, the protocol for inducing large chromosomal rearrangements resulting in ring chromosome formation is described. © 2016 by John Wiley & Sons, Inc.
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Affiliation(s)
- Minoru Murata
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Japan
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16
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Yu W, Yau YY, Birchler JA. Plant artificial chromosome technology and its potential application in genetic engineering. PLANT BIOTECHNOLOGY JOURNAL 2016; 14:1175-1182. [PMID: 26369910 DOI: 10.1111/pbi.12466] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 07/16/2015] [Accepted: 08/07/2015] [Indexed: 06/05/2023]
Abstract
Genetic engineering with just a few genes has changed agriculture in the last 20 years. The most frequently used transgenes are the herbicide resistance genes for efficient weed control and the Bt toxin genes for insect resistance. The adoption of the first-generation genetically engineered crops has been very successful in improving farming practices, reducing the application of pesticides that are harmful to both human health and the environment, and producing more profit for farmers. However, there is more potential for genetic engineering to be realized by technical advances. The recent development of plant artificial chromosome technology provides a super vector platform, which allows the management of a large number of genes for the next generation of genetic engineering. With the development of other tools such as gene assembly, genome editing, gene targeting and chromosome delivery systems, it should become possible to engineer crops with multiple genes to produce more agricultural products with less input of natural resources to meet future demands.
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Affiliation(s)
- Weichang Yu
- Shenzhen Research Institute, Chinese University of Hong Kong, Shenzhen, China
| | - Yuan-Yeu Yau
- Department of Natural Sciences, Northeastern State University, Broken Arrow, OK, USA
| | - James A Birchler
- Division of Biological Sciences, University of Missouri, Columbia, MO, USA
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Plant minichromosomes. Curr Opin Biotechnol 2016; 37:135-142. [DOI: 10.1016/j.copbio.2015.11.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 11/06/2015] [Accepted: 11/23/2015] [Indexed: 11/23/2022]
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18
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Fujimoto S, Matsunaga S. Which Is a Reliable Approach in the Generation of Artificial Minichromosomes, Bottom-Up or Top-Down? CYTOLOGIA 2016. [DOI: 10.1508/cytologia.81.251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Satoru Fujimoto
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science
| | - Sachihiro Matsunaga
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science
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19
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Promises and pitfalls of synthetic chromosomes in plants. Trends Biotechnol 2015; 33:189-94. [DOI: 10.1016/j.tibtech.2014.12.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 12/21/2014] [Accepted: 12/30/2014] [Indexed: 12/28/2022]
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20
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Abstract
Engineered minimal chromosomes with sufficient mitotic and meiotic stability have an enormous potential as vectors for stacking multiple genes required for complex traits in plant biotechnology. Proof of principle for essential steps in chromosome engineering such as truncation of chromosomes by T-DNA-mediated telomere seeding and de novo formation of centromeres by cenH3 fusion protein tethering has been recently obtained. In order to generate robust protocols for application in plant biotechnology, these steps need to be combined and supplemented with additional methods such as site-specific recombination for the directed transfer of multiple genes of interest on the minichromosomes. At the same time, the development of these methods allows new insight into basic aspects of plant chromosome functions such as how centromeres assure proper distribution of chromosomes to daughter cells or how telomeres serve to cap the chromosome ends to prevent shortening of ends over DNA replication cycles and chromosome end fusion.
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Affiliation(s)
- Michael Florian Mette
- Research Group Chromosome Structure and Function, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstr. 3, 06466, Stadt Seeland OT Gatersleben, Germany,
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22
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Cuacos M, H. Franklin FC, Heckmann S. Atypical centromeres in plants-what they can tell us. FRONTIERS IN PLANT SCIENCE 2015; 6:913. [PMID: 26579160 PMCID: PMC4620154 DOI: 10.3389/fpls.2015.00913] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Accepted: 10/12/2015] [Indexed: 05/20/2023]
Abstract
The centromere, visible as the primary constriction of condensed metaphase chromosomes, is a defined chromosomal locus essential for genome stability. It mediates transient assembly of a multi-protein complex, the kinetochore, which enables interaction with spindle fibers and thus faithful segregation of the genetic information during nuclear divisions. Centromeric DNA varies in extent and sequence composition among organisms, but a common feature of almost all active eukaryotic centromeres is the presence of the centromeric histone H3 variant cenH3 (a.k.a. CENP-A). These typical centromere features apply to most studied species. However, a number of species display "atypical" centromeres, such as holocentromeres (centromere extension along almost the entire chromatid length) or neocentromeres (ectopic centromere activity). In this review, we provide an overview of different atypical centromere types found in plants including holocentromeres, de novo formed centromeres and terminal neocentromeres as well as di-, tri- and metapolycentromeres (more than one centromere per chromosomes). We discuss their specific and common features and compare them to centromere types found in other eukaryotic species. We also highlight new insights into centromere biology gained in plants with atypical centromeres such as distinct mechanisms to define a holocentromere, specific adaptations in species with holocentromeres during meiosis or various scenarios leading to neocentromere formation.
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23
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Birchler JA. Engineered minichromosomes in plants. CURRENT OPINION IN PLANT BIOLOGY 2014; 19:76-80. [PMID: 24906050 DOI: 10.1016/j.pbi.2014.05.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 04/23/2014] [Accepted: 05/06/2014] [Indexed: 06/03/2023]
Abstract
Platforms for the development of synthetic chromosomes in plants have been produced in several species using telomere mediated chromosomal truncation with the simultaneous inclusion of sites that facilitate further additions to the newly generated minichromosome. By utilizing truncated supernumerary or B chromosomes, the output of the genes on the minichromosome can be amplified. Proof of concept experiments have been successful illustrating that minichromosome platforms can be modified in vivo. Engineered minichromosomes can likely be combined with haploid breeding if they are incorporated into inducer lines given that the observations that basically inert chromosomes from haploid inducer lines can be recovered at workable frequencies in otherwise haploid plants. Future needs of synthetic chromosome development are discussed.
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Affiliation(s)
- James A Birchler
- Division of Biological Sciences, University of Missouri, Columbia, MO 65211, United States.
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25
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Abstract
Basic research has provided a much better understanding of the genetic networks and regulatory hierarchies in plants. To meet the challenges of agriculture, we must be able to rapidly translate this knowledge into generating improved plants. Therefore, in this Review, we discuss advanced tools that are currently available for use in plant biotechnology to produce new products in plants and to generate plants with new functions. These tools include synthetic promoters, 'tunable' transcription factors, genome-editing tools and site-specific recombinases. We also review some tools with the potential to enable crop improvement, such as methods for the assembly and synthesis of large DNA molecules, plant transformation with linked multigenes and plant artificial chromosomes. These genetic technologies should be integrated to realize their potential for applications to pressing agricultural and environmental problems.
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26
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Murata M, Shibata F, Hironaka A, Kashihara K, Fujimoto S, Yokota E, Nagaki K. Generation of an artificial ring chromosome in Arabidopsis by Cre/LoxP-mediated recombination. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 74:363-371. [PMID: 23360080 DOI: 10.1111/tpj.12128] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 01/21/2013] [Accepted: 01/24/2013] [Indexed: 06/01/2023]
Abstract
A eukaryotic chromosome consists of a centromere, two telomeres and a number of replication origins, and 'artificial chromosomes' may be created in yeast and mammals when these three elements are artificially joined and introduced into cells. Plant artificial chromosomes (PACs) have been suggested as new vectors for the development of new crops and as tools for basic research on chromosomes. However, indisputable PAC formation has not yet been confirmed. Here, we present a method for generating PACs in the model plant Arabidopsis thaliana using the Cre/LoxP and Activator/Dissociation element systems. The successfully generated PAC, designated AtARC1 (A. thaliana artificial ring chromosome 1), originated from a centromeric edge of the long arm of chromosome 2, but its size (2.85 Mb) is much smaller than that of the original chromosome (26.3 Mb). Although AtARC1 contains only a short centromere domain consisting of 180 bp repeats approximately 250 kb in length, compared with the 3 Mb domain on the original chromosome 2, centromere-specific histone H3 (HTR12) was detected on the centromeric region. This result supported the observed stability of the PAC during mitosis in the absence of selection, and transmission of the PAC to the next generation through meiosis. Because AtARC1 contains a unique LoxP site driven by the CaMV 35S promoter, it is possible to introduce a selectable marker and desired transgenes into AtARC1 at the LoxP site using Cre recombinase. Therefore, AtARC1 meets the criteria for a PAC and is a promising vector.
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Affiliation(s)
- Minoru Murata
- Institute of Plant Science and Resources, Okayama University, Kurashiki 710-0046, Japan.
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27
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De novo generation of plant centromeres at tandem repeats. Chromosoma 2013; 122:233-41. [PMID: 23525657 DOI: 10.1007/s00412-013-0406-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 03/03/2013] [Accepted: 03/06/2013] [Indexed: 10/27/2022]
Abstract
Artificial minichromosomes are highly desirable tools for basic research, breeding, and biotechnology purposes. We present an option to generate plant artificial minichromosomes via de novo engineering of plant centromeres in Arabidopsis thaliana by targeting kinetochore proteins to tandem repeat arrays at non-centromeric positions. We employed the bacterial lactose repressor/lactose operator system to guide derivatives of the centromeric histone H3 variant cenH3 to LacO operator sequences. Tethering of cenH3 to non-centromeric loci led to de novo assembly of kinetochore proteins and to dicentric carrier chromosomes which potentially form anaphase bridges. This approach will be further developed and may contribute to generating minichromosomes from preselected genomic regions, potentially even in a diploid background.
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28
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In vivo modification of a maize engineered minichromosome. Chromosoma 2013; 122:221-32. [DOI: 10.1007/s00412-013-0403-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2012] [Revised: 02/25/2013] [Accepted: 02/27/2013] [Indexed: 10/27/2022]
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Nelson ADL, Shippen DE. Surprises from the chromosome front: lessons from Arabidopsis on telomeres and telomerase. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2013; 77:7-15. [PMID: 23460576 DOI: 10.1101/sqb.2013.77.017053] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Telomeres serve two vital functions: They act as a buffer against the end-replication problem, and they prevent chromosome ends from being recognized as double-strand DNA (dsDNA) breaks. These functions are orchestrated by the telomerase reverse transcriptase and a variety of telomere protein complexes. Here, we discuss our recent studies with Arabidopsis thaliana that uncovered a new and highly conserved telomere complex called CST (Cdc13/CTC1, STN1, TEN1). Formerly believed to be yeast specific, CST has now been identified as a key component of both plant and vertebrate telomeres, which is essential for genome integrity and stem cell viability. We also describe the unexpected discovery of alternative telomerase ribonucleoprotein complexes in Arabidopsis. Fueled by duplication and diversification of the telomerase RNA subunit and telomerase accessory proteins, these telomerase complexes act in concert to maintain genome stability. In addition to the canonical telomerase enzyme, one of two alternative telomerase ribonucleoprotein (RNP) complexes functions as a novel negative regulator of enzyme activity in response to genotoxic stress. These contributions highlight the immense potential of Arabidopsis in probing the depths of the chromosome end.
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Affiliation(s)
- A D L Nelson
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128, USA
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30
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Xu C, Cheng Z, Yu W. Construction of rice mini-chromosomes by telomere-mediated chromosomal truncation. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 70:1070-1079. [PMID: 22268496 DOI: 10.1111/j.1365-313x.2012.04916.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Telomere truncation has been shown to be an efficient technology for the creation of mini-chromosomes that can be used as artificial chromosome platforms for genetic engineering. Artificial chromosome-based genetic engineering is considered to be superior to the existing techniques of randomized gene integration by Agrobacterium or biolistic-mediated genetic transformation. It organizes multiple transgenes as a unique genetic linkage block for subsequent manipulations in breeding. Telomere truncation technology relies on three components: the telomere sequence that mediates chromosomal truncation, a selection marker that allows the selection of transgenic events, and a site-specific recombination system that can be used to accept future genes into the mini-chromosome by gene targeting. These elements are usually pre-assembled before transformation, a process that is both time and labor consuming. We found in this research that the three elements could be mixed to transform plant cells in a biolistic transformation, and produced efficient chromosomal truncations and mini-chromosomes in rice. This system will allow rapid construction of mini-chromosomes with a flexible selection of resistant markers, site-specific recombination systems and other desirable elements. In addition, a rice telotrisomic line was used as the starting material for chromosomal truncations. Mini-chromosomes from the truncations of both the telocentric chromosome and other chromosomes were recovered. The mini-chromosomes remained stable during 2 years of subculture. The construction of mini-chromosomes in rice, an economically important crop, will provide a platform for future artificial chromosome-based genetic engineering of rice for stacking multiple genes.
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Affiliation(s)
- Chunhui Xu
- State Key Laboratory for Agrobiotechnology, Institute of Plant Molecular Biology and Agricultural Biotechnology, School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong
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31
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Birchler JA, Presting GG. Retrotransposon insertion targeting: a mechanism for homogenization of centromere sequences on nonhomologous chromosomes. Genes Dev 2012; 26:638-40. [PMID: 22474258 DOI: 10.1101/gad.191049.112] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The centromeres of most eukaryotic organisms consist of highly repetitive arrays that are similar across nonhomologous chromosomes. These sequences evolve rapidly, thus posing a mystery as to how such arrays can be homogenized. Recent work in species in which centromere-enriched retrotransposons occur indicates that these elements preferentially insert into the centromeric regions. In two different Arabidopsis species, a related element was recognized in which the specificity for such targeting was altered. These observations provide a partial explanation for how homogenization of centromere DNA sequences occurs.
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Affiliation(s)
- James A Birchler
- Division of Biological Sciences, University of Missouri at Columbia, Columbia, Missouri 65211, USA.
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32
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Dittrich ACN, Devarenne TP. Characterization of a PDK1 homologue from the moss Physcomitrella patens. PLANT PHYSIOLOGY 2012; 158:1018-33. [PMID: 22158524 PMCID: PMC3271739 DOI: 10.1104/pp.111.184572] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The serine/threonine protein kinase 3-phosphoinositide-dependent protein kinase 1 (PDK1) is a highly conserved eukaryotic kinase that is a central regulator of many AGC kinase subfamily members. Through its regulation of AGC kinases, PDK1 controls many basic cellular processes, from translation to cell survival. While many of these PDK1-regulated processes are conserved across kingdoms, it is not well understood how PDK1 may have evolved within kingdoms. In order to better understand PDK1 evolution within plants, we have isolated and characterized the PDK1 gene from the moss Physcomitrella patens (PpPDK1), a nonvascular representative of early land plants. PpPDK1 is similar to other plant PDK1s in that it can functionally complement a yeast PDK1 knockout line. However, unlike PDK1 from other plants, the P. patens PDK1 protein does not bind phospholipids due to a lack of the lipid-binding pleckstrin homology domain, which is used for lipid-mediated regulation of PDK1 activity. Sequence analysis of several PDK1 proteins suggests that lipid regulation of PDK1 may not commonly occur in algae and nonvascular land plants. PpPDK1 can phosphorylate AGC kinase substrates from tomato (Solanum lycopersicum) and P. patens at the predicted PDK1 phosphorylation site, indicating that the PpPDK1 substrate phosphorylation site is conserved with higher plants. We have also identified residues within the PpPDK1 kinase domain that affect kinase activity and show that a mutant with highly reduced kinase activity can still confer cell viability in both yeast and P. patens. These studies lay the foundation for further analysis of the evolution of PDK1 within plants.
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33
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Kapusi E, Ma L, Teo CH, Hensel G, Himmelbach A, Schubert I, Mette MF, Kumlehn J, Houben A. Telomere-mediated truncation of barley chromosomes. Chromosoma 2011; 121:181-90. [PMID: 22080935 DOI: 10.1007/s00412-011-0351-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Revised: 10/19/2011] [Accepted: 10/25/2011] [Indexed: 12/18/2022]
Abstract
Engineered minichromosomes offer an enormous opportunity to plant biotechnology as they have the potential to simultaneously transfer and stably express multiple genes. Following a top-down approach, we truncated endogenous chromosomes in barley (Hordeum vulgare) by Agrobacterium-mediated transfer of T-DNA constructs containing telomere sequences. Blocks of Arabidopsis-like telomeric repeats were inserted into a binary vector suitable for stable transformation. After transfer of these constructs into immature embryos of diploid and tetraploid barley, chromosome truncation by T-DNA-induced de novo formation of telomeres could be confirmed by fluorescent in situ hybridisation, primer extension telomere repeat amplification and DNA gel blot analysis in regenerated plants. Telomere seeding connected to chromosome truncation was found in tetraploid plants only, indicating that genetic redundancy facilitates recovery of shortened chromosomes. Truncated chromosomes were transmissible in sexual reproduction, but were inherited at rates lower than expected according to Mendelian rules.
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Affiliation(s)
- Eszter Kapusi
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
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34
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Eckardt NA. De novo telomere formation in Arabidopsis tetraploids. THE PLANT CELL 2011; 23:2008. [PMID: 21666001 PMCID: PMC3160016 DOI: 10.1105/tpc.111.230611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
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