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Kurbidaeva A, Purugganan M. Insulators in Plants: Progress and Open Questions. Genes (Basel) 2021; 12:genes12091422. [PMID: 34573404 PMCID: PMC8470105 DOI: 10.3390/genes12091422] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 09/08/2021] [Accepted: 09/14/2021] [Indexed: 11/16/2022] Open
Abstract
The genomes of higher eukaryotes are partitioned into topologically associated domains or TADs, and insulators (also known as boundary elements) are the key elements responsible for their formation and maintenance. Insulators were first identified and extensively studied in Drosophila as well as mammalian genomes, and have also been described in yeast and plants. In addition, many insulator proteins are known in Drosophila, and some have been investigated in mammals. However, much less is known about this important class of non-coding DNA elements in plant genomes. In this review, we take a detailed look at known plant insulators across different species and provide an overview of potential determinants of plant insulator functions, including cis-elements and boundary proteins. We also discuss methods previously used in attempts to identify plant insulators, provide a perspective on their importance for research and biotechnology, and discuss areas of potential future research.
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Li H, Wang Z, Han K, Guo M, Zou Y, Zhang W, Ma W, Hua H. Cloning and functional identification of a Chilo suppressalis-inducible promoter of rice gene, OsHPL2. PEST MANAGEMENT SCIENCE 2020; 76:3177-3187. [PMID: 32336018 DOI: 10.1002/ps.5872] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 03/11/2020] [Accepted: 04/26/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Promoters play a key role in driving insect-resistant genes during breeding of transgenic plants. In current transgenic procedures for breeding rice resistance to striped stem borer (Chilo suppressalis Walker, SSB), the constitutive promoter is used to drive the insect-resistant gene. To reduce the burden of constitutive promoters on plant growth, isolation and identification of insect-inducible promoters are particularly important. However, few promoters are induced specifically by insect feeding. RESULTS We found rice hydroperoxide lyase gene (OsHPL2) (LOC_Os02g12680) was upregulated after feeding by SSB. We subsequently cloned the promoter of OsHPL2 and analysed its expression pattern using the β-glucuronidase (GUS) reporter gene. Histochemical assays and quantitative analyses of GUS activity confirmed that P HPL2 :GUS was activated by SSB, but did not respond to brown planthopper (Nilaparvata lugens Stål, BPH) infestation, mechanical wounding or phytohormone treatments. A series of 5' truncated assays were conducted and three positive regulatory regions (-1452 to -1213, -903 to -624, and -376 to -176) induced by SSB infestation were identified. P2R123-min 35S and P2TR2-min 35S promoters linked with cry1C of transgenic plants showed the highest levels of Cry1C protein expression and SSB larval mortality. CONCLUSION We identified an SSB-inducible promoter and three positive internal regions. Transgenic rice plants with the OsHPL2 promoter and its positive regions driving cry1C exhibited the expected larvicidal effect on SSB. Our study is the first report of an SSB-inducible promoter that could be used as a potential resource for breeding insect-resistant transgenic crops. © 2020 Society of Chemical Industry.
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Affiliation(s)
- Hanpeng Li
- National Key Laboratory of Crop Genetic Improvement, National Centre of Plant Gene Research, Huazhong Agricultural University, Wuhan, China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Zhengjie Wang
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Kehong Han
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Mengjian Guo
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Yulan Zou
- College of Life Science, Huazhong Agricultural University, Wuhan, China
| | - Wei Zhang
- National Key Laboratory of Crop Genetic Improvement, National Centre of Plant Gene Research, Huazhong Agricultural University, Wuhan, China
| | - Weihua Ma
- National Key Laboratory of Crop Genetic Improvement, National Centre of Plant Gene Research, Huazhong Agricultural University, Wuhan, China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Hongxia Hua
- National Key Laboratory of Crop Genetic Improvement, National Centre of Plant Gene Research, Huazhong Agricultural University, Wuhan, China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
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3
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Application and prospects of CRISPR/Cas9-based methods to trace defined genomic sequences in living and fixed plant cells. Chromosome Res 2019; 28:7-17. [PMID: 31792795 DOI: 10.1007/s10577-019-09622-0] [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: 10/13/2019] [Revised: 11/15/2019] [Accepted: 11/19/2019] [Indexed: 02/08/2023]
Abstract
The 3D organization of chromatin plays an important role in genome stability and many other pivotal biological programs. Therefore, the establishment of imaging methods, which enable us to study the dynamics of chromatin in living cells, is necessary. Although primary live cell imaging methods were a breakthrough, there is a need to develop more specific labeling techniques. With the discovery of programmable DNA binding proteins, such zinc finger proteins (ZFP), transcription activator-like effectors (TALE), and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9), a major leap forward was made. Here, we review the applications and potential of fluorescent repressor-operator systems, programmable DNA binding proteins with an emphasis on CRISPR-based chromatin imaging in living and fixed cells, and their potential application in plant science.
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Matzke AJ, Lin WD, Matzke M. Evidence That Ion-Based Signaling Initiating at the Cell Surface Can Potentially Influence Chromatin Dynamics and Chromatin-Bound Proteins in the Nucleus. FRONTIERS IN PLANT SCIENCE 2019; 10:1267. [PMID: 31681370 PMCID: PMC6811650 DOI: 10.3389/fpls.2019.01267] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 09/11/2019] [Indexed: 05/18/2023]
Abstract
We have developed tools and performed pilot experiments to test the hypothesis that an intracellular ion-based signaling pathway, provoked by an extracellular stimulus acting at the cell surface, can influence interphase chromosome dynamics and chromatin-bound proteins in the nucleus. The experimental system employs chromosome-specific fluorescent tags and the genome-encoded fluorescent pH sensor SEpHluorinA227D, which has been targeted to various intracellular membranes and soluble compartments in root cells of Arabidopsis thaliana. We are using this system and three-dimensional live cell imaging to visualize whether fluorescent-tagged interphase chromosome sites undergo changes in constrained motion concurrently with reductions in membrane-associated pH elicited by extracellular ATP, which is known to trigger a cascade of events in plant cells including changes in calcium ion concentrations, pH, and membrane potential. To examine possible effects of the proposed ion-based signaling pathway directly at the chromatin level, we generated a pH-sensitive fluorescent DNA-binding protein that allows pH changes to be monitored at specific genomic sites. Results obtained using these tools support the existence of a rapid, ion-based signaling pathway that initiates at the cell surface and reaches the nucleus to induce alterations in interphase chromatin mobility and the surrounding pH of chromatin-bound proteins. Such a pathway could conceivably act under natural circumstances to allow external stimuli to swiftly influence gene expression by affecting interphase chromosome movement and the structures and/or activities of chromatin-associated proteins.
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Affiliation(s)
| | | | - Marjori Matzke
- *Correspondence: Antonius J.M. Matzke, ; Marjori Matzke,
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5
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Sotelo-Silveira M, Chávez Montes RA, Sotelo-Silveira JR, Marsch-Martínez N, de Folter S. Entering the Next Dimension: Plant Genomes in 3D. TRENDS IN PLANT SCIENCE 2018; 23:598-612. [PMID: 29703667 DOI: 10.1016/j.tplants.2018.03.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 03/19/2018] [Accepted: 03/26/2018] [Indexed: 05/07/2023]
Abstract
After linear sequences of genomes and epigenomic landscape data, the 3D organization of chromatin in the nucleus is the next level to be explored. Different organisms present a general hierarchical organization, with chromosome territories at the top. Chromatin interaction maps, obtained by chromosome conformation capture (3C)-based methodologies, for eight plant species reveal commonalities, but also differences, among them and with animals. The smallest structures, found in high-resolution maps of the Arabidopsis genome, are single genes. Epigenetic marks (histone modification and DNA methylation), transcriptional activity, and chromatin interaction appear to be correlated, and whether structure is the cause or consequence of the function of interacting regions is being actively investigated.
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Affiliation(s)
- Mariana Sotelo-Silveira
- Departamento de Biología Vegetal, Laboratorio de Bioquímica, Facultad de Agronomía, Garzón 809, 12900 Montevideo, Uruguay
| | - Ricardo A Chávez Montes
- Unidad de Genómica Avanzada, Laboratorio Nacional de Genómica para la Biodiversidad (LANGEBIO), Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Km. 9.6 Libramiento Norte, Carretera Irapuato-León, 36824 Irapuato, Guanajuato, Mexico
| | - Jose R Sotelo-Silveira
- Department of Genomics, Instituto de Investigaciones Biológicas Clemente Estable, Av. Italia 3318, 11600 Montevideo, Uruguay; Sección Biología Celular, Dept. Cell and Molecular Biology, Facultad de Ciencias, Universidad de la Republica, Igua 4225, Montevideo, Uruguay
| | - Nayelli Marsch-Martínez
- Departamento de Biotecnología y Bioquímica, Unidad Irapuato, CINVESTAV-IPN, Km. 9.6 Libramiento Norte, Carretera Irapuato-León, 36824 Irapuato, Guanajuato, Mexico
| | - Stefan de Folter
- Unidad de Genómica Avanzada, Laboratorio Nacional de Genómica para la Biodiversidad (LANGEBIO), Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Km. 9.6 Libramiento Norte, Carretera Irapuato-León, 36824 Irapuato, Guanajuato, Mexico.
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6
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When Transcriptomics and Metabolomics Work Hand in Hand: A Case Study Characterizing Plant CDF Transcription Factors. High Throughput 2018; 7:ht7010007. [PMID: 29495643 PMCID: PMC5876533 DOI: 10.3390/ht7010007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 02/21/2018] [Accepted: 02/21/2018] [Indexed: 01/09/2023] Open
Abstract
Over the last three decades, novel “omics” platform technologies for the sequencing of DNA and complementary DNA (cDNA) (RNA-Seq), as well as for the analysis of proteins and metabolites by mass spectrometry, have become more and more available and increasingly found their way into general laboratory life. With this, the ability to generate highly multivariate datasets on the biological systems of choice has increased tremendously. However, the processing and, perhaps even more importantly, the integration of “omics” datasets still remains a bottleneck, although considerable computational and algorithmic advances have been made in recent years. In this mini-review, we use a number of recent “multi-omics” approaches realized in our laboratories as a common theme to discuss possible pitfalls of applying “omics” approaches and to highlight some useful tools for data integration and visualization in the form of an exemplified case study. In the selected example, we used a combination of transcriptomics and metabolomics alongside phenotypic analyses to functionally characterize a small number of Cycling Dof Transcription Factors (CDFs). It has to be remarked that, even though this approach is broadly used, the given workflow is only one of plenty possible ways to characterize target proteins.
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Abstract
The long linear chromosomes of eukaryotic organisms are tightly packed into the nucleus of the cell. Beyond a first organization into nucleosomes and higher-order chromatin fibers, the positioning of nuclear DNA within the three-dimensional space of the nucleus plays a critical role in genome function and gene expression. Different techniques have been developed to assess nanoscale chromatin organization, nuclear position of genomic regions or specific chromatin features and binding proteins as well as higher-order chromatin organization. Here, I present an overview of imaging and molecular techniques applied to study nuclear architecture in plants, with special attention to the related protocols published in the "Plant Chromatin Dynamics" edition from Methods in Molecular Biology.
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Affiliation(s)
- Aline V Probst
- GReD, Université Clermont Auvergne, CNRS, INSERM, 63001, Clermont-Ferrand, France.
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8
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Abstract
The eukaryotic nucleus is enclosed by the nuclear envelope, which is perforated by the nuclear pores, the gateways of macromolecular exchange between the nucleoplasm and cytoplasm. The nucleoplasm is organized in a complex three-dimensional fashion that changes over time and in response to stimuli. Within the cell, the nucleus must be viewed as an organelle (albeit a gigantic one) that is a recipient of cytoplasmic forces and capable of morphological and positional dynamics. The most dramatic reorganization of this organelle occurs during mitosis and meiosis. Although many of these aspects are less well understood for the nuclei of plants than for those of animals or fungi, several recent discoveries have begun to place our understanding of plant nuclei firmly into this broader cell-biological context.
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Affiliation(s)
- Iris Meier
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210;
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, United Kingdom;
| | | | - David E Evans
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, United Kingdom;
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9
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Grob S, Grossniklaus U. Chromosome conformation capture-based studies reveal novel features of plant nuclear architecture. CURRENT OPINION IN PLANT BIOLOGY 2017; 36:149-157. [PMID: 28411415 DOI: 10.1016/j.pbi.2017.03.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 03/13/2017] [Accepted: 03/14/2017] [Indexed: 06/07/2023]
Abstract
Nuclear genome organization has recently received increasing attention due to its manifold functions in basic nuclear processes, such as replication, transcription, and the maintenance of genome integrity. Using technologies based on chromosome conformation capture, such as Hi-C, we now have the possibility to study the three-dimensional organization of the genome at unprecedented resolution, shedding light onto a previously unexplored level of nuclear architecture. In plants, research in this field is still in its infancy but a number of publications provided first insights into basic principles of nuclear genome organization and the factors that influence it. Apart from general aspects, newly discovered three-dimensional conformations, such as the KNOT, raise special interest on how nuclear organization may influence the function of the genome in previously unexpected ways.
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Affiliation(s)
- Stefan Grob
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, 8008 Zurich, Switzerland.
| | - Ueli Grossniklaus
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, 8008 Zurich, Switzerland
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10
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Fujimoto S, Sugano SS, Kuwata K, Osakabe K, Matsunaga S. Visualization of specific repetitive genomic sequences with fluorescent TALEs in Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:6101-6110. [PMID: 27811079 PMCID: PMC5100022 DOI: 10.1093/jxb/erw371] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Live imaging of the dynamics of nuclear organization provides the opportunity to uncover the mechanisms responsible for four-dimensional genome architecture. Here, we describe the use of fluorescent protein (FP) fusions of transcription activator-like effectors (TALEs) to visualize endogenous genomic sequences in Arabidopsis thaliana. The ability to engineer sequence-specific TALEs permits the investigation of precise genomic sequences. We could detect TALE-FP signals associated with centromeric, telomeric, and rDNA repeats and the signal distribution was consistent with that observed by fluorescent in situ hybridization. TALE-FPs are advantageous because they permit the observation of intact tissues. We used our TALE-FP method to investigate the nuclei of several multicellular plant tissues including roots, hypocotyls, leaves, and flowers. Because TALE-FPs permit live-cell imaging, we successfully observed the temporal dynamics of centromeres and telomeres in plant organs. Fusing TALEs to multimeric FPs enhanced the signal intensity when observing telomeres. We found that the mobility of telomeres was different in sub-nuclear regions. Transgenic plants stably expressing TALE-FPs will provide new insights into chromatin organization and dynamics in multicellular organisms.
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Affiliation(s)
- Satoru Fujimoto
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, Noda, Chiba 278-8510, Japan
| | - Shigeo S Sugano
- Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
- PRESTO, JST, Saitama 332-0012, Japan
| | - Keiko Kuwata
- Institute of Transformative Bio-Molecules, Nagoya University, Nagoya 464-8601, Japan
| | - Keishi Osakabe
- Faculty of Bioscience and Bioindustry, Tokushima University, Tokushima 770-8513, Japan
| | - Sachihiro Matsunaga
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, Noda, Chiba 278-8510, Japan
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11
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Cheng JK, Lewis AM, Kim DS, Dyess T, Alper HS. Identifying and retargeting transcriptional hot spots in the human genome. Biotechnol J 2016; 11:1100-9. [PMID: 27311394 DOI: 10.1002/biot.201600015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 05/18/2016] [Accepted: 05/30/2016] [Indexed: 01/17/2023]
Abstract
Mammalian cell line development requires streamlined methodologies that will reduce both the cost and time to identify candidate cell lines. Improvements in site-specific genomic editing techniques can result in flexible, predictable, and robust cell line engineering. However, an outstanding question in the field is the specific site of integration. Here, we seek to identify productive loci within the human genome that will result in stable, high expression of heterologous DNA. Using an unbiased, random integration approach and a green fluorescent reporter construct, we identify ten single-integrant, recombinant human cell lines that exhibit stable, high-level expression. From these cell lines, eight unique corresponding integration loci were identified. These loci are concentrated in non-protein coding regions or intronic regions of protein coding genes. Expression mapping of the surrounding genes reveals minimal disruption of endogenous gene expression. Finally, we demonstrate that targeted de novo integration at one of the identified loci, the 12(th) exon-intron region of the GRIK1 gene on chromosome 21, results in superior expression and stability compared to the standard, illegitimate integration approach at levels approaching 4-fold. The information identified here along with recent advances in site-specific genomic editing techniques can lead to expedited cell line development.
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Affiliation(s)
- Joseph K Cheng
- Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas, USA
| | - Amanda M Lewis
- Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas, USA.,Biologics Development, Bristol-Myers Squibb, Devens, MA, USA
| | - Do Soon Kim
- Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas, USA
| | - Timothy Dyess
- Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas, USA
| | - Hal S Alper
- Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas, USA. .,Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, USA.
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12
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Rodriguez-Granados NY, Ramirez-Prado JS, Veluchamy A, Latrasse D, Raynaud C, Crespi M, Ariel F, Benhamed M. Put your 3D glasses on: plant chromatin is on show. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:3205-21. [PMID: 27129951 DOI: 10.1093/jxb/erw168] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The three-dimensional organization of the eukaryotic nucleus and its chromosomal conformation have emerged as important features in the complex network of mechanisms behind gene activity and genome connectivity dynamics, which can be evidenced in the regionalized chromosomal spatial distribution and the clustering of diverse genomic regions with similar expression patterns. The development of chromatin conformation capture (3C) techniques has permitted the elucidation of commonalities between the eukaryotic phyla, as well as important differences among them. The growing number of studies in the field performed in plants has shed light on the structural and regulatory features of these organisms. For instance, it has been proposed that plant chromatin can be arranged into different conformations such as Rabl, Rosette-like, and Bouquet, and that both short- and long-range chromatin interactions occur in Arabidopsis. In this review, we compile the current knowledge about chromosome architecture characteristics in plants, as well as the molecular events and elements (including long non-coding RNAs, histone and DNA modifications, chromatin remodeling complexes, and transcription factors) shaping the genome three-dimensional conformation. Furthermore, we discuss the developmental outputs of genome topology-mediated gene expression regulation. It is becoming increasingly clear that new tools and techniques with higher resolution need to be developed and implemented in Arabidopsis and other model plants in order to better understand chromosome architecture dynamics, from an integrative perspective with other fields of plant biology such as development, stress biology, and finally agriculture.
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Affiliation(s)
- Natalia Y Rodriguez-Granados
- Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Juan S Ramirez-Prado
- Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Alaguraj Veluchamy
- Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - David Latrasse
- Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRA, University Paris-Sud, University of Evry, University Paris-Diderot, Sorbonne Paris-Cite, University of Paris-Saclay, Batiment 630, 91405 Orsay, France
| | - Cécile Raynaud
- Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRA, University Paris-Sud, University of Evry, University Paris-Diderot, Sorbonne Paris-Cite, University of Paris-Saclay, Batiment 630, 91405 Orsay, France
| | - Martin Crespi
- Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRA, University Paris-Sud, University of Evry, University Paris-Diderot, Sorbonne Paris-Cite, University of Paris-Saclay, Batiment 630, 91405 Orsay, France
| | - Federico Ariel
- Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRA, University Paris-Sud, University of Evry, University Paris-Diderot, Sorbonne Paris-Cite, University of Paris-Saclay, Batiment 630, 91405 Orsay, France
| | - Moussa Benhamed
- Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRA, University Paris-Sud, University of Evry, University Paris-Diderot, Sorbonne Paris-Cite, University of Paris-Saclay, Batiment 630, 91405 Orsay, France
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13
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Smith S, Galinha C, Desset S, Tolmie F, Evans D, Tatout C, Graumann K. Marker gene tethering by nucleoporins affects gene expression in plants. Nucleus 2015; 6:471-8. [PMID: 26652762 DOI: 10.1080/19491034.2015.1126028] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
In non-plant systems, chromatin association with the nuclear periphery affects gene expression, where interactions with nuclear envelope proteins can repress and interactions with nucleoporins can enhance transcription. In plants, both hetero- and euchromatin can localize at the nuclear periphery, but the effect of proximity to the nuclear periphery on gene expression remains largely unknown. This study explores the putative function of Seh1 and Nup50a nucleoporins on gene expression by using the Lac Operator / Lac Repressor (LacI-LacO) system adapted to Arabidopsis thaliana. We used LacO fused to the luciferase reporter gene (LacO:Luc) to investigate whether binding of the LacO:Luc transgene to nucleoporin:LacI protein fusions alters luciferase expression. Two separate nucleoporin-LacI-YFP fusions were introduced into single insert, homozygous LacO:Luc Arabidopsis plants. Homozygous plants carrying LacO:Luc and a single insert of either Seh1-LacI-YFP or Nup50a-LacI-YFP were tested for luciferase activity and compared to plants containing LacO:Luc only. Seh1-LacI-YFP increased, while Nup50a-LacI-YFP decreased luciferase activity. Seh1-LacI-YFP accumulated at the nuclear periphery as expected, while Nup50a-LacI-YFP was nucleoplasmic and was not selected for further study. Protein and RNA levels of luciferase were quantified by western blotting and RT-qPCR, respectively. Increased luciferase activity in LacO:Luc+Seh1-LacI-YFP plants was correlated with increased luciferase protein and RNA levels. This change of luciferase expression was abolished by disruption of LacI-LacO binding by treating with IPTG in young seedlings, rosette leaves and inflorescences. This study suggests that association with the nuclear periphery is involved in the regulation of gene expression in plants.
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Affiliation(s)
- Sarah Smith
- a Department of Biological and Medical Sciences ; Faculty of Health and Life Sciences; Oxford Brookes University ; Headington , Oxford , UK
| | - Carla Galinha
- a Department of Biological and Medical Sciences ; Faculty of Health and Life Sciences; Oxford Brookes University ; Headington , Oxford , UK
| | - Sophie Desset
- b UMR CNRS 6247; INSERM U931 GReD Clermont Universités 24 ; Aubiere , France
| | - Frances Tolmie
- a Department of Biological and Medical Sciences ; Faculty of Health and Life Sciences; Oxford Brookes University ; Headington , Oxford , UK
| | - David Evans
- a Department of Biological and Medical Sciences ; Faculty of Health and Life Sciences; Oxford Brookes University ; Headington , Oxford , UK
| | - Christophe Tatout
- b UMR CNRS 6247; INSERM U931 GReD Clermont Universités 24 ; Aubiere , France
| | - Katja Graumann
- a Department of Biological and Medical Sciences ; Faculty of Health and Life Sciences; Oxford Brookes University ; Headington , Oxford , UK
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14
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Light-regulated gene repositioning in Arabidopsis. Nat Commun 2015; 5:3027. [PMID: 24390011 DOI: 10.1038/ncomms4027] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 11/27/2013] [Indexed: 11/08/2022] Open
Abstract
Plant genomes are extremely sensitive to, and can be developmentally reprogrammed by environmental light cues. Here using rolling-circle amplification of gene-specific circularizable oligonucleotides coupled with fluorescence in situ hybridization, we demonstrate that light triggers a rapid repositioning of the Arabidopsis light-inducible chlorophyll a/b-binding proteins (CAB) locus from the nuclear interior to the nuclear periphery during its transcriptional activation. CAB repositioning is mediated by the red/far-red photoreceptors phytochromes (PHYs) and is inhibited by repressors of PHY signalling, including COP1, DET1 and PIFs. CAB repositioning appears to be a separate regulatory step occurring before its full transcriptional activation. Moreover, the light-inducible loci RBCS, PC and GUN5 undergo similar repositioning behaviour during their transcriptional activation. Our study supports a light-dependent gene regulatory mechanism in which PHYs activate light-inducible loci by relocating them to the nuclear periphery; it also provides evidence for the biological importance of gene positioning in the plant kingdom.
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Abstract
Methods that use high-throughput sequencing have begun to reveal features of the three-dimensional structure of genomes at a resolution that goes far beyond that of traditional microscopy. Integration of these methods with other molecular tools has advanced our knowledge of both global and local chromatin packing in plants, and has revealed how patterns of chromatin packing correlate with the genomic and epigenomic landscapes. This update reports recent progress made in this area in plants, and suggests new research directions.
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Affiliation(s)
- Chang Liu
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany.
| | - Detlef Weigel
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany.
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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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17
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Schubert V, Rudnik R, Schubert I. Chromatin associations in Arabidopsis interphase nuclei. Front Genet 2014; 5:389. [PMID: 25431580 PMCID: PMC4230181 DOI: 10.3389/fgene.2014.00389] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 10/23/2014] [Indexed: 11/30/2022] Open
Abstract
The arrangement of chromatin within interphase nuclei seems to be caused by topological constraints and related to gene expression depending on tissue and developmental stage. In yeast and animals it was found that homologous and heterologous chromatin association are required to realize faithful expression and DNA repair. To test whether such associations are present in plants we analyzed Arabidopsis thaliana interphase nuclei by FISH using probes from different chromosomes. We found that chromatin fiber movement and variable associations, although in general relatively seldom, may occur between euchromatin segments along chromosomes, sometimes even over large distances. The combination of euchromatin segments bearing high or low co-expressing genes did not reveal different association frequencies probably due to adjacent genes of deviating expression patterns. Based on previous data and on FISH analyses presented here, we conclude that the global interphase chromatin organization in A. thaliana is relatively stable, due to the location of its 10 centromeres at the nuclear periphery and of the telomeres mainly at the centrally localized nucleolus. Nevertheless, chromatin movement enables a flexible spatial genome arrangement in plant nuclei.
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Affiliation(s)
- Veit Schubert
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben Stadt Seeland, Germany
| | - Radoslaw Rudnik
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben Stadt Seeland, Germany
| | - Ingo Schubert
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben Stadt Seeland, Germany ; Faculty of Science and Central European Institute of Technology, Masaryk University Brno, Czech Republic
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18
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Wang C, Liu C, Roqueiro D, Grimm D, Schwab R, Becker C, Lanz C, Weigel D. Genome-wide analysis of local chromatin packing in Arabidopsis thaliana. Genome Res 2014; 25:246-56. [PMID: 25367294 PMCID: PMC4315298 DOI: 10.1101/gr.170332.113] [Citation(s) in RCA: 203] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The spatial arrangement of interphase chromosomes in the nucleus is important for gene expression and genome function in animals and in plants. The recently developed Hi-C technology is an efficacious method to investigate genome packing. Here we present a detailed Hi-C map of the three-dimensional genome organization of the plant Arabidopsis thaliana. We find that local chromatin packing differs from the patterns seen in animals, with kilobasepair-sized segments that have much higher intrachromosome interaction rates than neighboring regions, representing a dominant local structural feature of genome conformation in A. thaliana. These regions, which appear as positive strips on two-dimensional representations of chromatin interaction, are enriched in epigenetic marks H3K27me3, H3.1, and H3.3. We also identify more than 400 insulator-like regions. Furthermore, although topologically associating domains (TADs), which are prominent in animals, are not an obvious feature of A. thaliana genome packing, we found more than 1000 regions that have properties of TAD boundaries, and a similar number of regions analogous to the interior of TADs. The insulator-like, TAD-boundary-like, and TAD-interior-like regions are each enriched for distinct epigenetic marks and are each correlated with different gene expression levels. We conclude that epigenetic modifications, gene density, and transcriptional activity combine to shape the local packing of the A. thaliana nuclear genome.
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Affiliation(s)
- Congmao Wang
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Chang Liu
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany;
| | - Damian Roqueiro
- Machine Learning and Computational Biology Research Group, Max Planck Institute for Developmental Biology and Max Planck Institute for Intelligent Systems, 72076 Tübingen, Germany
| | - Dominik Grimm
- Machine Learning and Computational Biology Research Group, Max Planck Institute for Developmental Biology and Max Planck Institute for Intelligent Systems, 72076 Tübingen, Germany
| | - Rebecca Schwab
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Claude Becker
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Christa Lanz
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Detlef Weigel
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany;
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19
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Luo C, Dong J, Zhang Y, Lam E. Decoding the role of chromatin architecture in development: coming closer to the end of the tunnel. FRONTIERS IN PLANT SCIENCE 2014; 5:374. [PMID: 25191327 PMCID: PMC4140164 DOI: 10.3389/fpls.2014.00374] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Accepted: 07/11/2014] [Indexed: 06/03/2023]
Abstract
Form and function in biology are intimately related aspects that are often difficult to untangle. While the structural aspects of chromatin organization were apparent from early cytological observations long before the molecular details of chromatin functions were deciphered, the extent to which genome architecture may impact its output remains unclear. A major roadblock to resolve this issue is the divergent scales, both temporal and spatial, of the experimental approaches for examining these facets of chromatin biology. Recent advances in high-throughput sequencing and informatics to model and monitor genome-wide chromatin contact sites provide the much-needed platform to close this gap. This mini-review will focus on discussing recent efforts applying new technologies to elucidate the roles of genome architecture in coordinating global gene expression output. Our discussion will emphasize the potential roles of differential genome 3-D structure as a driver for cell fate specification of multicellular organisms. An integrated approach that combines multiple new methodologies may finally have the necessary temporal and spatial resolution to provide clarity on the roles of chromatin architecture during development.
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Affiliation(s)
- Chongyuan Luo
- Department of Plant Biology and Pathology, Rutgers the State University of New JerseyNew Brunswick, NJ, USA
| | - Juan Dong
- Department of Plant Biology and Pathology, Rutgers the State University of New JerseyNew Brunswick, NJ, USA
- The Waksman Institute of Microbiology, Rutgers the State University of New JerseyPiscataway, NJ, USA
| | - Yi Zhang
- Department of Plant Biology and Pathology, Rutgers the State University of New JerseyNew Brunswick, NJ, USA
| | - Eric Lam
- Department of Plant Biology and Pathology, Rutgers the State University of New JerseyNew Brunswick, NJ, USA
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20
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Del Prete S, Arpón J, Sakai K, Andrey P, Gaudin V. Nuclear architecture and chromatin dynamics in interphase nuclei of Arabidopsis thaliana. Cytogenet Genome Res 2014; 143:28-50. [PMID: 24992956 DOI: 10.1159/000363724] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The interphase cell nucleus is extraordinarily complex, ordered, and dynamic. In the last decade, remarkable progress has been made in deciphering the functional organisation of the cell nucleus, and intricate relationships between genome functions (transcription, DNA repair, or replication) and various nuclear compartments have been revealed. In this review, we describe the architecture of the Arabidopsis thaliana interphase cell nucleus and discuss the dynamic nature of its organisation. We underline the need for further developments in quantitative and modelling approaches to nuclear organization.
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Affiliation(s)
- Stefania Del Prete
- INRA, UMR1318-AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), INRA-Centre de Versailles-Grignon, Versailles, France
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21
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Heger P, Wiehe T. New tools in the box: An evolutionary synopsis of chromatin insulators. Trends Genet 2014; 30:161-71. [DOI: 10.1016/j.tig.2014.03.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 03/24/2014] [Accepted: 03/25/2014] [Indexed: 01/19/2023]
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22
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Insights into chromatin structure and dynamics in plants. BIOLOGY 2013; 2:1378-410. [PMID: 24833230 PMCID: PMC4009787 DOI: 10.3390/biology2041378] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 11/15/2013] [Accepted: 11/18/2013] [Indexed: 11/17/2022]
Abstract
The packaging of chromatin into the nucleus of a eukaryotic cell requires an extraordinary degree of compaction and physical organization. In recent years, it has been shown that this organization is dynamically orchestrated to regulate responses to exogenous stimuli as well as to guide complex cell-type-specific developmental programs. Gene expression is regulated by the compartmentalization of functional domains within the nucleus, by distinct nucleosome compositions accomplished via differential modifications on the histone tails and through the replacement of core histones by histone variants. In this review, we focus on these aspects of chromatin organization and discuss novel approaches such as live cell imaging and photobleaching as important tools likely to give significant insights into our understanding of the very dynamic nature of chromatin and chromatin regulatory processes. We highlight the contribution plant studies have made in this area showing the potential advantages of plants as models in understanding this fundamental aspect of biology.
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23
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Chénais B, Caruso A, Hiard S, Casse N. The impact of transposable elements on eukaryotic genomes: from genome size increase to genetic adaptation to stressful environments. Gene 2012; 509:7-15. [PMID: 22921893 DOI: 10.1016/j.gene.2012.07.042] [Citation(s) in RCA: 195] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 07/16/2012] [Accepted: 07/25/2012] [Indexed: 11/25/2022]
Abstract
Transposable elements (TEs) are present in roughly all genomes. These mobile DNA sequences are able to invade genomes and their impact on genome evolution is substantial. The mobility of TEs can induce the appearance of deleterious mutations, gene disruption and chromosome rearrangements, but transposition activity also has positive aspects and the mutational activities of TEs contribute to the genetic diversity of organisms. This short review aims to give a brief overview of the impact TEs may have on animal and plant genome structure and expression, and the relationship between TEs and the stress response of organisms, including insecticide resistance.
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Affiliation(s)
- Benoît Chénais
- Université du Maine, EA2160 Mer Molécules Santé, UFR Sciences et Techniques, Avenue Olivier Messiaen, F-72085 Le Mans, France.
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24
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He F, Zhang X, Hu J, Turck F, Dong X, Goebel U, Borevitz J, de Meaux J. Genome-wide analysis of cis-regulatory divergence between species in the Arabidopsis genus. Mol Biol Evol 2012; 29:3385-95. [PMID: 22641789 DOI: 10.1093/molbev/mss146] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Cis-regulatory DNA has been suspected to play a preeminent role in adaptive evolution, but understanding the role of cis-regulatory mutations in gene expression divergence first requires an accurate analysis of the functional differences associated with these regions. We analyzed allele-specific expression (ASE) in leaf and floral tissues of F1 interspecific hybrids generated between the two closely related species Arabidopsis thaliana and A. lyrata with a whole-genome SNP (single nucleotide polymorphism) tiling array. We observed 2,205 genes showing ASE pattern in at least one tissue. Nearly 90% of genes displaying ASE preferentially expressed the allele of A. lyrata. Genome-wide comparison of sequence divergence revealed that genes displaying ASE had a higher ratio of nonsynonymous to synonymous substitutions in coding regions. We further observe that the epigenetic landscape of histone methylation in A. thaliana genome associate with ASE. The asymmetry in the direction of allele-specific expression suggests interspecific differences in the efficiency of gene silencing in F1 hybrids.
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Affiliation(s)
- Fei He
- Max Planck Institute for Plant Breeding Research, Carl-von-Linné weg 10, 50829 Cologne, Germany
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25
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Bolle C, Schneider A, Leister D. Perspectives on Systematic Analyses of Gene Function in Arabidopsis thaliana: New Tools, Topics and Trends. Curr Genomics 2011; 12:1-14. [PMID: 21886450 PMCID: PMC3129038 DOI: 10.2174/138920211794520187] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Revised: 10/28/2010] [Accepted: 11/23/2010] [Indexed: 11/22/2022] Open
Abstract
Since the sequencing of the nuclear genome of Arabidopsis thaliana ten years ago, various large-scale analyses of gene function have been performed in this model species. In particular, the availability of collections of lines harbouring random T-DNA or transposon insertions, which include mutants for almost all of the ~27,000 A. thaliana genes, has been crucial for the success of forward and reverse genetic approaches. In the foreseeable future, genome-wide phenotypic data from mutant analyses will become available for Arabidopsis, and will stimulate a flood of novel in-depth gene-function analyses. In this review, we consider the present status of resources and concepts for systematic studies of gene function in A. thaliana. Current perspectives on the utility of loss-of-function and gain-of-function mutants will be discussed in light of the genetic and functional redundancy of many A. thaliana genes.
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Affiliation(s)
- C Bolle
- Lehrstuhl für Molekularbiologie der Pflanzen (Botanik), Department Biologie I, Ludwig-Maximilians-Universität München, Großhaderner Str. 2, D-82152 Planegg-Martinsried, Germany
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26
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Pairing of lacO tandem repeats in Arabidopsis thaliana nuclei requires the presence of hypermethylated, large arrays at two chromosomal positions, but does not depend on H3-lysine-9-dimethylation. Chromosoma 2011; 120:609-19. [DOI: 10.1007/s00412-011-0335-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2011] [Revised: 07/12/2011] [Accepted: 07/20/2011] [Indexed: 10/17/2022]
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27
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Schubert I, Shaw P. Organization and dynamics of plant interphase chromosomes. TRENDS IN PLANT SCIENCE 2011; 16:273-81. [PMID: 21393049 DOI: 10.1016/j.tplants.2011.02.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 02/01/2011] [Accepted: 02/05/2011] [Indexed: 05/23/2023]
Abstract
Eukaryotic chromosomes occupy distinct territories within interphase nuclei. The arrangement of chromosome territories (CTs) is important for replication, transcription, repair and recombination processes. Our knowledge about interphase chromatin arrangement is mainly based on results from in situ labeling approaches. The phylogenetic affiliation of a species, cell cycle, differentiation status and environmental factors are all likely to influence interphase nuclear architecture. In this review we survey current data about relative positioning of CTs, somatic pairing of homologs, and sister chromatid alignment in meristematic and differentiated tissues, using data derived mainly from Arabidopsis thaliana, wheat (Triticum aestivum) and their relatives. We discuss morphological constraints and epigenetic impacts on nuclear architecture, the evolutionary stability of CT arrangements, and alterations of nuclear architecture during transcription and repair.
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Affiliation(s)
- Ingo Schubert
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, D06466 Gatersleben, Germany.
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28
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Abstract
Advances in sequencing technology have led to the availability of complete genome sequences of many different plant species. In order to make sense of this deluge of information, functional genomics efforts have been intensified on many fronts. With improvements in plant transformation technologies, T-DNA and/or transposon-based gene and enhancer-tagged populations in various crop species are being developed to augment functional annotation of genes and also to help clone important genes. State-of-the-art cloning and sequencing technologies, which would help identify T-DNA or transposon junction sequences in large genomes, have also been initiated. This chapter gives a brief history of enhancer trapping and then proceeds to describe gene and enhancer tagging in plants. The significance of reporter gene fusion populations in plant genomics, especially in important cereal crops, is discussed.
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29
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Skupsky R, Burnett JC, Foley JE, Schaffer DV, Arkin AP. HIV promoter integration site primarily modulates transcriptional burst size rather than frequency. PLoS Comput Biol 2010; 6:e1000952. [PMID: 20941390 PMCID: PMC2947985 DOI: 10.1371/journal.pcbi.1000952] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2010] [Accepted: 09/07/2010] [Indexed: 12/11/2022] Open
Abstract
Mammalian gene expression patterns, and their variability across populations of cells, are regulated by factors specific to each gene in concert with its surrounding cellular and genomic environment. Lentiviruses such as HIV integrate their genomes into semi-random genomic locations in the cells they infect, and the resulting viral gene expression provides a natural system to dissect the contributions of genomic environment to transcriptional regulation. Previously, we showed that expression heterogeneity and its modulation by specific host factors at HIV integration sites are key determinants of infected-cell fate and a possible source of latent infections. Here, we assess the integration context dependence of expression heterogeneity from diverse single integrations of a HIV-promoter/GFP-reporter cassette in Jurkat T-cells. Systematically fitting a stochastic model of gene expression to our data reveals an underlying transcriptional dynamic, by which multiple transcripts are produced during short, infrequent bursts, that quantitatively accounts for the wide, highly skewed protein expression distributions observed in each of our clonal cell populations. Interestingly, we find that the size of transcriptional bursts is the primary systematic covariate over integration sites, varying from a few to tens of transcripts across integration sites, and correlating well with mean expression. In contrast, burst frequencies are scattered about a typical value of several per cell-division time and demonstrate little correlation with the clonal means. This pattern of modulation generates consistently noisy distributions over the sampled integration positions, with large expression variability relative to the mean maintained even for the most productive integrations, and could contribute to specifying heterogeneous, integration-site-dependent viral production patterns in HIV-infected cells. Genomic environment thus emerges as a significant control parameter for gene expression variation that may contribute to structuring mammalian genomes, as well as be exploited for survival by integrating viruses.
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Affiliation(s)
- Ron Skupsky
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, California, United States of America
| | - John C. Burnett
- Department of Chemical Engineering, University of California, Berkeley, Berkeley, California, United States of America
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, California, United States of America
| | - Jonathan E. Foley
- UCB/UCSF Joint-Graduate-Group-in-Bioengineering, University of California, Berkeley, Berkeley, California, United States of America
| | - David V. Schaffer
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, California, United States of America
- Department of Chemical Engineering, University of California, Berkeley, Berkeley, California, United States of America
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, California, United States of America
- Department of Bioengineering, University of California, Berkeley, Berkeley, California, United States of America
| | - Adam P. Arkin
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, California, United States of America
- Department of Bioengineering, University of California, Berkeley, Berkeley, California, United States of America
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
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30
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She W, Lin W, Zhu Y, Chen Y, Jin W, Yang Y, Han N, Bian H, Zhu M, Wang J. The gypsy insulator of Drosophila melanogaster, together with its binding protein suppressor of Hairy-wing, facilitate high and precise expression of transgenes in Arabidopsis thaliana. Genetics 2010; 185:1141-50. [PMID: 20516496 PMCID: PMC2922898 DOI: 10.1534/genetics.110.117960] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2010] [Accepted: 05/28/2010] [Indexed: 02/04/2023] Open
Abstract
The variation of expression pattern exhibited by a transgene as a result of random integration, known as position effect, is, among other mechanisms, a particular challenge to reverse genetics. We present a strategy to counteract position effect in Arabidopsis thaliana by flanking the transgenes with the gypsy insulator from Drosophila melanogaster. In addition, Suppressor of Hairy-wing [Su(Hw)], the binding protein of the gypsy insulator, was coexpressed. Results indicated that the gypsy insulators could efficiently improve the expression levels of reporter genes driven by various kinds of promoters by 8- to 13-fold. Coexpression of the Su(Hw) protein led to a more uniform expression level of transgenes, as the coefficient of variation of expression levels was reduced further. The gypsy-Su(Hw) system enhanced expression levels, but did not alter the specificity of promoter activities, as experimentally evidenced by the promoters of the PIN and the AFB gene families. Interestingly, the gypsy insulator was also able to improve the expression of a selectable marker gene outside the insulated region, which facilitated the screen of transformants. Our system will likely decrease the number of lines that experimenters need to create and examine for a given transgene by contributing to relatively high and precise expression of transgenes in plants. Certain features of the gypsy insulator in Arabidopsis also provide new perspectives on the insulator field.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Junhui Wang
- Department of Biotechnology, College of Life Sciences, Zhejiang University, Zijingang Campus, Hangzhou 310058, China
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31
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Andrey P, Kiêu K, Kress C, Lehmann G, Tirichine L, Liu Z, Biot E, Adenot PG, Hue-Beauvais C, Houba-Hérin N, Duranthon V, Devinoy E, Beaujean N, Gaudin V, Maurin Y, Debey P. Statistical analysis of 3D images detects regular spatial distributions of centromeres and chromocenters in animal and plant nuclei. PLoS Comput Biol 2010; 6:e1000853. [PMID: 20628576 PMCID: PMC2900307 DOI: 10.1371/journal.pcbi.1000853] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Accepted: 06/03/2010] [Indexed: 12/16/2022] Open
Abstract
In eukaryotes, the interphase nucleus is organized in morphologically and/or functionally distinct nuclear "compartments". Numerous studies highlight functional relationships between the spatial organization of the nucleus and gene regulation. This raises the question of whether nuclear organization principles exist and, if so, whether they are identical in the animal and plant kingdoms. We addressed this issue through the investigation of the three-dimensional distribution of the centromeres and chromocenters. We investigated five very diverse populations of interphase nuclei at different differentiation stages in their physiological environment, belonging to rabbit embryos at the 8-cell and blastocyst stages, differentiated rabbit mammary epithelial cells during lactation, and differentiated cells of Arabidopsis thaliana plantlets. We developed new tools based on the processing of confocal images and a new statistical approach based on G- and F- distance functions used in spatial statistics. Our original computational scheme takes into account both size and shape variability by comparing, for each nucleus, the observed distribution against a reference distribution estimated by Monte-Carlo sampling over the same nucleus. This implicit normalization allowed similar data processing and extraction of rules in the five differentiated nuclei populations of the three studied biological systems, despite differences in chromosome number, genome organization and heterochromatin content. We showed that centromeres/chromocenters form significantly more regularly spaced patterns than expected under a completely random situation, suggesting that repulsive constraints or spatial inhomogeneities underlay the spatial organization of heterochromatic compartments. The proposed technique should be useful for identifying further spatial features in a wide range of cell types.
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Affiliation(s)
- Philippe Andrey
- INRA, UMR1197 Neurobiologie de l'Olfaction et de la Prise Alimentaire, Jouy-en-Josas, France
- Université Paris-Sud 11, UMR 1197, Orsay, France
- IFR144 Neuro-Sud Paris, France
- UPMC, Université Paris 06, France
| | - Kiên Kiêu
- INRA, UR341, Mathématiques et Informatique Appliquées, Jouy-en-Josas, France
| | - Clémence Kress
- INRA, UR1196 Génomique et Physiologie de la Lactation, Jouy-en-Josas, France
| | - Gaëtan Lehmann
- INRA, UMR1198 Biologie du Développement et Reproduction, Jouy-en-Josas, France
- ENVA, Maisons Alfort, France
| | - Leïla Tirichine
- INRA, Institut J.-P. Bourgin, UMR1318 INRA-AgroParisTech, Versailles, France
| | - Zichuan Liu
- INRA, UMR1198 Biologie du Développement et Reproduction, Jouy-en-Josas, France
- ENVA, Maisons Alfort, France
| | - Eric Biot
- INRA, UMR1197 Neurobiologie de l'Olfaction et de la Prise Alimentaire, Jouy-en-Josas, France
- Université Paris-Sud 11, UMR 1197, Orsay, France
- IFR144 Neuro-Sud Paris, France
- INRA, Institut J.-P. Bourgin, UMR1318 INRA-AgroParisTech, Versailles, France
| | - Pierre-Gaël Adenot
- INRA, UMR1198 Biologie du Développement et Reproduction, Jouy-en-Josas, France
- ENVA, Maisons Alfort, France
| | - Cathy Hue-Beauvais
- INRA, UR1196 Génomique et Physiologie de la Lactation, Jouy-en-Josas, France
| | - Nicole Houba-Hérin
- INRA, Institut J.-P. Bourgin, UMR1318 INRA-AgroParisTech, Versailles, France
| | - Véronique Duranthon
- INRA, UMR1198 Biologie du Développement et Reproduction, Jouy-en-Josas, France
- ENVA, Maisons Alfort, France
| | - Eve Devinoy
- INRA, UR1196 Génomique et Physiologie de la Lactation, Jouy-en-Josas, France
| | - Nathalie Beaujean
- INRA, UMR1198 Biologie du Développement et Reproduction, Jouy-en-Josas, France
- ENVA, Maisons Alfort, France
| | - Valérie Gaudin
- INRA, Institut J.-P. Bourgin, UMR1318 INRA-AgroParisTech, Versailles, France
| | - Yves Maurin
- INRA, UMR1197 Neurobiologie de l'Olfaction et de la Prise Alimentaire, Jouy-en-Josas, France
- Université Paris-Sud 11, UMR 1197, Orsay, France
- IFR144 Neuro-Sud Paris, France
| | - Pascale Debey
- INRA, UMR1198 Biologie du Développement et Reproduction, Jouy-en-Josas, France
- ENVA, Maisons Alfort, France
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32
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Matzke AJM, Watanabe K, van der Winden J, Naumann U, Matzke M. High frequency, cell type-specific visualization of fluorescent-tagged genomic sites in interphase and mitotic cells of living Arabidopsis plants. PLANT METHODS 2010; 6:2. [PMID: 20148117 PMCID: PMC2820019 DOI: 10.1186/1746-4811-6-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Accepted: 01/19/2010] [Indexed: 05/21/2023]
Abstract
BACKGROUND Interphase chromosome organization and dynamics can be studied in living cells using fluorescent tagging techniques that exploit bacterial operator/repressor systems and auto-fluorescent proteins. A nuclear-localized Repressor Protein-Fluorescent Protein (RP-FP) fusion protein binds to operator repeats integrated as transgene arrays at defined locations in the genome. Under a fluorescence microscope, the tagged sites appear as bright fluorescent dots in living cells. This technique has been used successfully in plants, but is often hampered by low expression of genes encoding RP-FP fusion proteins, perhaps owing to one or more gene silencing mechanisms that are prevalent in plant cells. RESULTS We used two approaches to overcome this problem. First, we tested mutations in four factors involved in different types of gene silencing and/or epigenetic modifications for their effects on nuclear fluorescence. Only mutations in DDM1, a chromatin remodelling ATPase involved in repeat-induced heterochromatin formation and DNA methylation, released silencing of the RP-FP fusion protein. This result suggested that the operator repeats can trigger silencing of the adjacent gene encoding the RP-FP fusion protein. In the second approach, we transformed the tagged lines with a second T-DNA encoding the RP-FP fusion protein but lacking operator repeats. This strategy avoided operator repeat-induced gene silencing and increased the number of interphase nuclei displaying fluorescent dots. In a further extension of the technique, we show that green fluorescent-tagged sites can be visualized on moving mitotic chromosomes stained with red fluorescent-labelled histone H2B. CONCLUSIONS The results illustrate the propensity of operator repeat arrays to form heterochromatin that can silence the neighbouring gene encoding the RP-FP fusion protein. Supplying the RP-FP fusion protein in trans from a second T-DNA largely alleviates this problem. Depending on the promoter used to drive expression of the RP-FP fusion protein gene, the fluorescent tagged sites can be visualized at high frequency in different cell types. The ability to observe fluorescent dots on both interphase and mitotic chromosomes allows tagged sites to be tracked throughout the cell cycle. These improvements enhance the versatility of the fluorescent tagging technique for future studies of chromosome arrangement and dynamics in living plants.
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Affiliation(s)
- Antonius JM Matzke
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Dr. Bohr-Gasse 3, A-1030 Vienna, Austria
| | - Koichi Watanabe
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Dr. Bohr-Gasse 3, A-1030 Vienna, Austria
- Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK), Correnstrasse 3, D-O6466 Gatersleben, Germany
| | - Johannes van der Winden
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Dr. Bohr-Gasse 3, A-1030 Vienna, Austria
| | - Ulf Naumann
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Dr. Bohr-Gasse 3, A-1030 Vienna, Austria
| | - Marjori Matzke
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Dr. Bohr-Gasse 3, A-1030 Vienna, Austria
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Abstract
To tackle the question of how chromatin organization is involved in global regulation of genome-related processes such as transcription, we have recently created a collection of 277 transposon-tagged Arabidopsis lines comprised of a single insert with a common luciferase reporter cassette and a LacO repeat array for visual tracking of the tagged region via fluorescent protein fusion technology. Using this collection of plants, one can begin to map transgene position effects as well as global epigenetic control in response to developmental or externally applied cues. In this chapter, we will outline the approach and methods for deploying this novel resource for the study of global gene control, using Arabidopsis as a convenient model system.
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Luo C, Durgin BG, Watanabe N, Lam E. Defining the functional network of epigenetic regulators in Arabidopsis thaliana. MOLECULAR PLANT 2009; 2:661-674. [PMID: 19825647 DOI: 10.1093/mp/ssp017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Development of ChIP-chip and ChIP-seq technologies has allowed genome-wide high-resolution profiling of chromatin-associated marks and binding sites for epigenetic regulators. However, signals for directing epigenetic modifiers to their target sites are not understood. In this paper, we tested the hypothesis that genome location can affect the involvement of epigenetic regulators using Chromatin Charting (CC) Lines, which have an identical transgene construct inserted at different locations in the Arabidopsis genome. Four CC lines that showed evidence for epigenetic silencing of the luciferase reporter gene were transformed with RNAi vectors individually targeting epigenetic regulators LHP1, MOM1, CMT3, DRD1, DRM2, SUVH2, CLF, and HD1. Involvement of a particular epigenetic regulator in silencing the transgene locus in a CC line was determined by significant alterations in luciferase expression after suppression of the regulator's expression. Our results suggest that the targeting of epigenetic regulators can be influenced by genome location as well as sequence context. In addition, the relative importance of an epigenetic regulator can be influenced by tissue identity. We also report a novel approach to predict interactions between epigenetic regulators through clustering analysis of the regulators using alterations in gene expression of putative downstream targets, including endogenous loci and transgenes, in epigenetic mutants or RNAi lines. Our data support the existence of a complex and dynamic network of epigenetic regulators that serves to coordinate and control global gene expression in higher plants.
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Affiliation(s)
- Chongyuan Luo
- Biotechnology Center for Agriculture and the Environment, Rutgers The State University of New Jersey, 59 Dudley Road, New Brunswick, NJ 08901, USA; Department of Plant Biology and Pathology, Rutgers The State University of New Jersey, 59 Dudley Road, New Brunswick, NJ 08901, USA
| | - Brittany G Durgin
- Biotechnology Center for Agriculture and the Environment, Rutgers The State University of New Jersey, 59 Dudley Road, New Brunswick, NJ 08901, USA
| | - Naohide Watanabe
- Biotechnology Center for Agriculture and the Environment, Rutgers The State University of New Jersey, 59 Dudley Road, New Brunswick, NJ 08901, USA
| | - Eric Lam
- Biotechnology Center for Agriculture and the Environment, Rutgers The State University of New Jersey, 59 Dudley Road, New Brunswick, NJ 08901, USA; Department of Plant Biology and Pathology, Rutgers The State University of New Jersey, 59 Dudley Road, New Brunswick, NJ 08901, USA.
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Lam E, Luo C, Watanabe N. Charting functional and physical properties of chromatin in living cells. Curr Opin Genet Dev 2009; 19:135-41. [PMID: 19327981 DOI: 10.1016/j.gde.2009.02.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2009] [Revised: 02/10/2009] [Accepted: 02/16/2009] [Indexed: 01/13/2023]
Abstract
With the vast transcriptome database now available, global patterns of gene expression have been mapped in various species to reveal higher order structures in the genome. Location-dependent control of gene expression has also been studied in human cell cultures and in Arabidopsis plants using well-characterized insertion and transposition cell line collections. With the added genome-wide mapping of chromatin features at a high resolution, via advanced microarray and sequencing technologies, comprehensive analysis of structure-function relationships deduced from chromatin organization and gene expression data is now feasible. This has begun to reveal micro-heterogeneity in the genome with respect to structural and functional segmentations.
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Affiliation(s)
- Eric Lam
- Biotechnology Center for Agriculture and the Environment, Rutgers University, New Brunswick, NJ 08901, USA.
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