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Hasegawa J, Sakamoto T, Fujimoto S, Yamashita T, Suzuki T, Matsunaga S. Auxin decreases chromatin accessibility through the TIR1/AFBs auxin signaling pathway in proliferative cells. Sci Rep 2018; 8:7773. [PMID: 29773913 PMCID: PMC5958073 DOI: 10.1038/s41598-018-25963-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 05/02/2018] [Indexed: 11/09/2022] Open
Abstract
Chromatin accessibility is closely associated with chromatin functions such as gene expression, DNA replication, and maintenance of DNA integrity. However, the relationship between chromatin accessibility and plant hormone signaling has remained elusive. Here, based on the correlation between chromatin accessibility and DNA damage, we used the sensitivity to DNA double strand breaks (DSBs) as an indicator of chromatin accessibility and demonstrated that auxin regulates chromatin accessibility through the TIR1/AFBs signaling pathway in proliferative cells. Treatment of proliferating plant cells with an inhibitor of the TIR1/AFBs auxin signaling pathway, PEO-IAA, caused chromatin loosening, indicating that auxin signaling functions to decrease chromatin accessibility. In addition, a transcriptome analysis revealed that several histone H4 genes and a histone chaperone gene, FAS1, are positively regulated through the TIR1/AFBs signaling pathway, suggesting that auxin plays a role in promoting nucleosome assembly. Analysis of the fas1 mutant of Arabidopsis thaliana confirmed that FAS1 is required for the auxin-dependent decrease in chromatin accessibility. These results suggest that the positive regulation of chromatin-related genes mediated by the TIR1/AFBs auxin signaling pathway enhances nucleosome assembly, resulting in decreased chromatin accessibility in proliferative cells.
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Affiliation(s)
- Junko Hasegawa
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba, 278-8510, Japan
| | - Takuya Sakamoto
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba, 278-8510, Japan
| | - Satoru Fujimoto
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba, 278-8510, Japan
| | - Tomoe Yamashita
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba, 278-8510, Japan
| | - Takamasa Suzuki
- College of Bioscience and Biotechnology, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi, 487-8501, Japan
| | - Sachihiro Matsunaga
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba, 278-8510, Japan.
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Yamaoka S, Nishihama R, Yoshitake Y, Ishida S, Inoue K, Saito M, Okahashi K, Bao H, Nishida H, Yamaguchi K, Shigenobu S, Ishizaki K, Yamato KT, Kohchi T. Generative Cell Specification Requires Transcription Factors Evolutionarily Conserved in Land Plants. Curr Biol 2018; 28:479-486.e5. [PMID: 29395928 DOI: 10.1016/j.cub.2017.12.053] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 11/11/2017] [Accepted: 12/22/2017] [Indexed: 12/23/2022]
Abstract
Land plants differentiate germ cells in the haploid gametophyte. In flowering plants, a generative cell is specified as a precursor that subsequently divides into two sperm cells in the developing male gametophyte, pollen. Generative cell specification requires cell-cycle control and microtubule-dependent nuclear relocation (reviewed in [1-3]). However, the generative cell fate determinant and its evolutionary origin are still unknown. In bryophytes, gametophytes produce eggs and sperm in multicellular reproductive organs called archegonia and antheridia, respectively, or collectively called gametangia. Given the monophyletic origin of land plants [4-6], evolutionarily conserved mechanisms may play key roles in these diverse reproductive processes. Here, we showed that a single member of the subfamily VIIIa of basic helix-loop-helix (bHLH) transcription factors in the liverwort Marchantia polymorpha primarily accumulated in the initial cells and controlled their development into gametangia. We then demonstrated that an Arabidopsis thaliana VIIIa bHLH transiently accumulated in the smaller daughter cell after an asymmetric division of the meiosis-derived microspore and was required for generative cell specification redundantly with its paralog. Furthermore, these A. thaliana VIIIa bHLHs were functionally replaceable by the M. polymorpha VIIIa bHLH. These findings suggest the VIIIa bHLH proteins as core regulators for reproductive development, including germ cell differentiation, since an early stage of land plant evolution.
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Affiliation(s)
- Shohei Yamaoka
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Ryuichi Nishihama
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | | | - Sakiko Ishida
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Keisuke Inoue
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Misaki Saito
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Keitaro Okahashi
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Haonan Bao
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Hiroyuki Nishida
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Katsushi Yamaguchi
- Functional Genomics Facility, National Institute for Basic Biology (NIBB), Okazaki, Aichi 444-8585, Japan
| | - Shuji Shigenobu
- Functional Genomics Facility, National Institute for Basic Biology (NIBB), Okazaki, Aichi 444-8585, Japan
| | | | - Katsuyuki T Yamato
- Faculty of Biology-Oriented Science and Technology, Kindai University, Kinokawa, Wakayama 649-6493, Japan
| | - Takayuki Kohchi
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan.
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Glöckle B, Urban WJ, Nagahara S, Andersen ED, Higashiyama T, Grini PE, Schnittger A. Pollen differentiation as well as pollen tube guidance and discharge are independent of the presence of gametes. Development 2018; 145:dev.152645. [PMID: 29217755 PMCID: PMC5825867 DOI: 10.1242/dev.152645] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 11/27/2017] [Indexed: 12/16/2022]
Abstract
After meiosis, an unequal cell division generates the male gamete lineage in flowering plants. The generative cell will undergo a second division, giving rise to the two gametes, i.e. the sperm cells. The other cell will develop into the vegetative cell that plays a crucial role in pollen tube formation and sperm delivery. Recently, the vegetative cell has been suggested to be important for programming of the chromatin state in sperm cells and/or the resulting fertilization products. Blocking the initial unequal division genetically, we first highlight that the default differentiation state after male meiosis is a vegetative fate, which is consistent with earlier work. We find that uni-nucleated mutant microspores differentiated as wild-type vegetative cells, including chromatin remodeling and the transcriptional activation of transposable elements. Moreover, live-cell imaging revealed that this vegetative cell is sufficient for the correct guidance of the pollen tube to the female gametes. Hence, we conclude that vegetative cell differentiation and function does not depend on the formation or presence of the actual gametes but rather on external signals or a cell-autonomous pace keeper. Summary: Cell biological analyses in Arabidopsis show that the vegetative cell differentiates without the presence of the actual gametes, and is solely sufficient for pollen tube germination, guidance, ovule penetration and pollen tube discharge.
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Affiliation(s)
- Barbara Glöckle
- Department of Molecular Mechanisms of Phenotypic Plasticity, Institut de Biologie Moléculaire des Plantes du CNRS, IBMP-CNRS - UPR2357, Université de Strasbourg, 12 Rue du Général Zimmer, 67084 Strasbourg Cedex, France.,Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, 0316 Oslo, Norway
| | - Wojciech J Urban
- University of Hamburg, Biozentrum Klein Flottbek, Department of Developmental Biology, 22609 Hamburg, Germany
| | - Shiori Nagahara
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan
| | - Ellen D Andersen
- Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, 0316 Oslo, Norway
| | - Tetsuya Higashiyama
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan.,JST ERATO Higashiyama Live-Holonics Project, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
| | - Paul E Grini
- Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, 0316 Oslo, Norway
| | - Arp Schnittger
- Department of Molecular Mechanisms of Phenotypic Plasticity, Institut de Biologie Moléculaire des Plantes du CNRS, IBMP-CNRS - UPR2357, Université de Strasbourg, 12 Rue du Général Zimmer, 67084 Strasbourg Cedex, France .,University of Hamburg, Biozentrum Klein Flottbek, Department of Developmental Biology, 22609 Hamburg, Germany
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54
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LeBlanc C, Zhang F, Mendez J, Lozano Y, Chatpar K, Irish VF, Jacob Y. Increased efficiency of targeted mutagenesis by CRISPR/Cas9 in plants using heat stress. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 93:377-386. [PMID: 29161464 DOI: 10.1111/tpj.13782] [Citation(s) in RCA: 138] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 11/08/2017] [Accepted: 11/14/2017] [Indexed: 05/20/2023]
Abstract
The CRISPR/Cas9 system has greatly improved our ability to engineer targeted mutations in eukaryotic genomes. While CRISPR/Cas9 appears to work universally, the efficiency of targeted mutagenesis and the adverse generation of off-target mutations vary greatly between different organisms. In this study, we report that Arabidopsis plants subjected to heat stress at 37°C show much higher frequencies of CRISPR-induced mutations compared to plants grown continuously at the standard temperature (22°C). Using quantitative assays relying on green fluorescent protein (GFP) reporter genes, we found that targeted mutagenesis by CRISPR/Cas9 in Arabidopsis is increased by approximately 5-fold in somatic tissues and up to 100-fold in the germline upon heat treatment. This effect of temperature on the mutation rate is not limited to Arabidopsis, as we observed a similar increase in targeted mutations by CRISPR/Cas9 in Citrus plants exposed to heat stress at 37°C. In vitro assays demonstrate that Cas9 from Streptococcus pyogenes (SpCas9) is more active in creating double-stranded DNA breaks at 37°C than at 22°C, thus indicating a potential contributing mechanism for the in vivo effect of temperature on CRISPR/Cas9. This study reveals the importance of temperature in modulating SpCas9 activity in eukaryotes, and provides a simple method to increase on-target mutagenesis in plants using CRISPR/Cas9.
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Affiliation(s)
- Chantal LeBlanc
- Department of Molecular, Cellular and Developmental Biology, Faculty of Arts and Sciences, Yale University, 219 Prospect Street, New Haven, CT, 06511, USA
| | - Fei Zhang
- Department of Molecular, Cellular and Developmental Biology, Faculty of Arts and Sciences, Yale University, 219 Prospect Street, New Haven, CT, 06511, USA
| | - Josefina Mendez
- Department of Molecular, Cellular and Developmental Biology, Faculty of Arts and Sciences, Yale University, 219 Prospect Street, New Haven, CT, 06511, USA
| | - Yamile Lozano
- Department of Molecular, Cellular and Developmental Biology, Faculty of Arts and Sciences, Yale University, 219 Prospect Street, New Haven, CT, 06511, USA
| | - Krishna Chatpar
- Department of Molecular, Cellular and Developmental Biology, Faculty of Arts and Sciences, Yale University, 219 Prospect Street, New Haven, CT, 06511, USA
| | - Vivian F Irish
- Department of Molecular, Cellular and Developmental Biology, Faculty of Arts and Sciences, Yale University, 219 Prospect Street, New Haven, CT, 06511, USA
| | - Yannick Jacob
- Department of Molecular, Cellular and Developmental Biology, Faculty of Arts and Sciences, Yale University, 219 Prospect Street, New Haven, CT, 06511, USA
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Histone 3 lysine 36 to methionine mutations stably interact with and sequester SDG8 in Arabidopsis thaliana. SCIENCE CHINA-LIFE SCIENCES 2017; 61:225-234. [PMID: 28975546 DOI: 10.1007/s11427-017-9162-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 07/05/2017] [Indexed: 10/18/2022]
Abstract
Post-transcriptional modifications of histones play important roles in various biological processes. Here, we report that Arabidopsis plants overexpressing histone H3 lysine to methionine mutations at histone H3.1K36 (H3.1K36M) and H3.3K36 (H3.3K36M) have serious developmental defects with early-flowering and change in the modifications of endogenous histone H3, including acetylation at lysine 9 (H3K9ac), trimethylation at lysine 27 (H3K27me3), di- and tri-methylation at lysine 36 (H3K36me2 and H3K36me3). In addition, H3K36M mutation alters its subcellular localization and interacts with H3K36 methyltransferase SDG8. Our results support a model in which H3K36M stably interacts with SDG8, and inhibits the activity of SDG8 by sequestering SDG8, resulting in a dominant negative effect to affect the proper expression levels of a variety of genes and plant development.
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56
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Shi L, Wen H, Shi X. The Histone Variant H3.3 in Transcriptional Regulation and Human Disease. J Mol Biol 2017; 429:1934-1945. [PMID: 27894815 PMCID: PMC5446305 DOI: 10.1016/j.jmb.2016.11.019] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 11/17/2016] [Accepted: 11/17/2016] [Indexed: 01/19/2023]
Abstract
Histone proteins wrap around DNA to form nucleosomes, which further compact into the higher-order structure of chromatin. In addition to the canonical histones, there are also variant histones that often have pivotal roles in regulating chromatin dynamics and in the accessibility of the underlying DNA. H3.3 is the most common non-centromeric variant of histone H3 that differs from the canonical H3 by just 4-5 aa. Here, we discuss the current knowledge of H3.3 in transcriptional regulation and the recent discoveries and molecular mechanisms of H3.3 mutations in human cancer.
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Affiliation(s)
- Leilei Shi
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Hong Wen
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Xiaobing Shi
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; The University of Texas Graduate School of Biomedical Sciences, Houston, TX 77030, USA.
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57
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Jiang H, Moreno-Romero J, Santos-González J, De Jaeger G, Gevaert K, Van De Slijke E, Köhler C. Ectopic application of the repressive histone modification H3K9me2 establishes post-zygotic reproductive isolation in Arabidopsis thaliana. Genes Dev 2017; 31:1272-1287. [PMID: 28743695 PMCID: PMC5558928 DOI: 10.1101/gad.299347.117] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 06/27/2017] [Indexed: 11/24/2022]
Abstract
Hybrid seed lethality as a consequence of interspecies or interploidy hybridizations is a major mechanism of reproductive isolation in plants. This mechanism is manifested in the endosperm, a dosage-sensitive tissue supporting embryo growth. Deregulated expression of imprinted genes such as ADMETOS (ADM) underpin the interploidy hybridization barrier in Arabidopsis thaliana; however, the mechanisms of their action remained unknown. In this study, we show that ADM interacts with the AT hook domain protein AHL10 and the SET domain-containing SU(VAR)3-9 homolog SUVH9 and ectopically recruits the heterochromatic mark H3K9me2 to AT-rich transposable elements (TEs), causing deregulated expression of neighboring genes. Several hybrid incompatibility genes identified in Drosophila encode for dosage-sensitive heterochromatin-interacting proteins, which has led to the suggestion that hybrid incompatibilities evolve as a consequence of interspecies divergence of selfish DNA elements and their regulation. Our data show that imbalance of dosage-sensitive chromatin regulators underpins the barrier to interploidy hybridization in Arabidopsis, suggesting that reproductive isolation as a consequence of epigenetic regulation of TEs is a conserved feature in animals and plants.
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Affiliation(s)
- Hua Jiang
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Linnean Center of Plant Biology, Uppsala 75007, Sweden
| | - Jordi Moreno-Romero
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Linnean Center of Plant Biology, Uppsala 75007, Sweden
| | - Juan Santos-González
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Linnean Center of Plant Biology, Uppsala 75007, Sweden
| | - Geert De Jaeger
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent 9052, Belgium
- VIB Center for Plant Systems Biology, Ghent 9052, Belgium
| | - Kris Gevaert
- Department of Biochemistry, Ghent University, Ghent 9052, Belgium
- VIB Center for Medical Biotechnology, Ghent 9052, Belgium
| | - Eveline Van De Slijke
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent 9052, Belgium
- VIB Center for Plant Systems Biology, Ghent 9052, Belgium
| | - Claudia Köhler
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Linnean Center of Plant Biology, Uppsala 75007, Sweden
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58
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Wollmann H, Stroud H, Yelagandula R, Tarutani Y, Jiang D, Jing L, Jamge B, Takeuchi H, Holec S, Nie X, Kakutani T, Jacobsen SE, Berger F. The histone H3 variant H3.3 regulates gene body DNA methylation in Arabidopsis thaliana. Genome Biol 2017; 18:94. [PMID: 28521766 PMCID: PMC5437678 DOI: 10.1186/s13059-017-1221-3] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 04/25/2017] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Gene bodies of vertebrates and flowering plants are occupied by the histone variant H3.3 and DNA methylation. The origin and significance of these profiles remain largely unknown. DNA methylation and H3.3 enrichment profiles over gene bodies are correlated and both have a similar dependence on gene transcription levels. This suggests a mechanistic link between H3.3 and gene body methylation. RESULTS We engineered an H3.3 knockdown in Arabidopsis thaliana and observed transcription reduction that predominantly affects genes responsive to environmental cues. When H3.3 levels are reduced, gene bodies show a loss of DNA methylation correlated with transcription levels. To study the origin of changes in DNA methylation profiles when H3.3 levels are reduced, we examined genome-wide distributions of several histone H3 marks, H2A.Z, and linker histone H1. We report that in the absence of H3.3, H1 distribution increases in gene bodies in a transcription-dependent manner. CONCLUSIONS We propose that H3.3 prevents recruitment of H1, inhibiting H1's promotion of chromatin folding that restricts access to DNA methyltransferases responsible for gene body methylation. Thus, gene body methylation is likely shaped by H3.3 dynamics in conjunction with transcriptional activity.
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Affiliation(s)
- Heike Wollmann
- Temasek Lifesciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604, Singapore
- Present address: Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, Singapore, 138673, Singapore
| | - Hume Stroud
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, CA, 90095, USA
- Howard Hughes Medical Institute, University of California, Los Angeles, CA, 90095, USA
| | - Ramesh Yelagandula
- Gregor Mendel Institute, Vienna Biocenter VBC, Dr. Bohr-Gasse 3, 1030, Vienna, Austria
| | - Yoshiaki Tarutani
- Department of Integrated Genetics, National Institute of Genetics, Shizuoka, 411-8540, Japan
- Department of Genetics, School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Shizuoka, 411-8540, Japan
| | - Danhua Jiang
- Gregor Mendel Institute, Vienna Biocenter VBC, Dr. Bohr-Gasse 3, 1030, Vienna, Austria
| | - Li Jing
- Gregor Mendel Institute, Vienna Biocenter VBC, Dr. Bohr-Gasse 3, 1030, Vienna, Austria
- College of Life Science and Technology, Huazhong Agricultural University, No.1, Shizishan Street, Hongshan District Wuhan, Hubei, 430070, China
| | - Bhagyshree Jamge
- Gregor Mendel Institute, Vienna Biocenter VBC, Dr. Bohr-Gasse 3, 1030, Vienna, Austria
| | - Hidenori Takeuchi
- Gregor Mendel Institute, Vienna Biocenter VBC, Dr. Bohr-Gasse 3, 1030, Vienna, Austria
| | - Sarah Holec
- Temasek Lifesciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604, Singapore
| | - Xin Nie
- Temasek Lifesciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604, Singapore
| | - Tetsuji Kakutani
- Department of Integrated Genetics, National Institute of Genetics, Shizuoka, 411-8540, Japan
- Department of Genetics, School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Shizuoka, 411-8540, Japan
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Steven E Jacobsen
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, CA, 90095, USA.
- Howard Hughes Medical Institute, University of California, Los Angeles, CA, 90095, USA.
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, CA, 90095, USA.
| | - Frédéric Berger
- Gregor Mendel Institute, Vienna Biocenter VBC, Dr. Bohr-Gasse 3, 1030, Vienna, Austria.
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Iwakawa H, Carter BC, Bishop BC, Ogas J, Gelvin SB. Perturbation of H3K27me3-Associated Epigenetic Processes Increases Agrobacterium-Mediated Transformation. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2017; 30:35-44. [PMID: 27926813 DOI: 10.1094/mpmi-12-16-0250-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Agrobacterium-mediated transformation is a core technology for basic plant science and agricultural biotechnology. Improving transformation frequency is a major goal for plant transgenesis. We previously showed that T-DNA insertions in some histone genes decreased transformation susceptibility, whereas overexpression of several Arabidopsis H2A and H4 isoforms increased transformation. Overexpression of several histone H2B and H3 isoforms had little effect on transformation frequency. However, overexpression of histone H3-11 (HTR11) enhanced transformation. HTR11 is a unique H3 variant that lacks lysine at positions 9 and 27. The modification status of these lysine residues in canonical H3 proteins plays a critical role in epigenetic determination of gene expression. We mutated histone H3-4 (HTR4), a canonical H3.3 protein that does not increase transformation when overexpressed, by replacing either or both K9 and K27 with the amino acids in HTR11 (either K9I, K27Q, or both). Overexpression of HTR4 with the K27Q but not the K9I substitution enhanced transformation. HTR4K27Q was incorporated into chromatin, and HTR4K27Q overexpression lines exhibited deregulated expression of H3K27me3-enriched genes. These results demonstrate that mutation of K27 in H3.3 is sufficient to perturb H3K27me3-dependent expression in plants as in animals and suggest a distinct epigenetic role for histone HTR11. Further, these observations implicate manipulation of H3K27me3-dependent gene expression as a novel strategy to increase transformation susceptibility.
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Affiliation(s)
| | - Benjamin C Carter
- 2 Biochemistry, Purdue University, West Lafayette, IN 47907-1392, U.S.A
| | - Brett C Bishop
- 2 Biochemistry, Purdue University, West Lafayette, IN 47907-1392, U.S.A
| | - Joe Ogas
- 2 Biochemistry, Purdue University, West Lafayette, IN 47907-1392, U.S.A
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Mikulski P, Komarynets O, Fachinelli F, Weber AP, Schubert D. Characterization of the Polycomb-Group Mark H3K27me3 in Unicellular Algae. FRONTIERS IN PLANT SCIENCE 2017; 8:607. [PMID: 28484477 PMCID: PMC5405695 DOI: 10.3389/fpls.2017.00607] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Accepted: 04/04/2017] [Indexed: 05/03/2023]
Abstract
Polycomb Group (PcG) proteins mediate chromatin repression in plants and animals by catalyzing H3K27 methylation and H2AK118/119 mono-ubiquitination through the activity of the Polycomb repressive complex 2 (PRC2) and PRC1, respectively. PcG proteins were extensively studied in higher plants, but their function and target genes in unicellular branches of the green lineage remain largely unknown. To shed light on PcG function and modus operandi in a broad evolutionary context, we demonstrate phylogenetic relationship of core PRC1 and PRC2 proteins and H3K27me3 biochemical presence in several unicellular algae of different phylogenetic subclades. We focus then on one of the species, the model red alga Cyanidioschizon merolae, and show that H3K27me3 occupies both, genes and repetitive elements, and mediates the strength of repression depending on the differential occupancy over gene bodies. Furthermore, we report that H3K27me3 in C. merolae is enriched in telomeric and subtelomeric regions of the chromosomes and has unique preferential binding toward intein-containing genes involved in protein splicing. Thus, our study gives important insight for Polycomb-mediated repression in lower eukaryotes, uncovering a previously unknown link between H3K27me3 targets and protein splicing.
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Affiliation(s)
- Pawel Mikulski
- Institute of Biology, Free University of BerlinBerlin, Germany
- Institute of Genetics, Heinrich-Heine-Universität DüsseldorfDüsseldorf, Germany
| | - Olga Komarynets
- Institute of Genetics, Heinrich-Heine-Universität DüsseldorfDüsseldorf, Germany
- Faculty of Medicine, University of GenevaGeneva, Switzerland
| | - Fabio Fachinelli
- Institute of Plant Biochemistry, Heinrich-Heine-Universität DüsseldorfDüsseldorf, Germany
| | - Andreas P.M. Weber
- Institute of Plant Biochemistry, Heinrich-Heine-Universität DüsseldorfDüsseldorf, Germany
| | - Daniel Schubert
- Institute of Biology, Free University of BerlinBerlin, Germany
- Institute of Genetics, Heinrich-Heine-Universität DüsseldorfDüsseldorf, Germany
- *Correspondence: Daniel Schubert,
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Kozłowska M, Niedojadło K, Brzostek M, Bednarska-Kozakiewicz E. Epigenetic marks in the Hyacinthus orientalis L. mature pollen grain and during in vitro pollen tube growth. PLANT REPRODUCTION 2016; 29:251-263. [PMID: 27422435 PMCID: PMC4978762 DOI: 10.1007/s00497-016-0289-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 07/04/2016] [Indexed: 06/06/2023]
Abstract
During the sexual reproduction of flowering plants, epigenetic control of gene expression and genome integrity by DNA methylation and histone modifications plays an important role in male gametogenesis. In this study, we compared the chromatin modification patterns of the generative, sperm cells and vegetative nuclei during Hyacinthus orientalis male gametophyte development. Changes in the spatial and temporal distribution of 5-methylcytosine, acetylated histone H4 and histone deacetylase indicated potential differences in the specific epigenetic state of all analysed cells, in both the mature cellular pollen grains and the in vitro growing pollen tubes. Interestingly, we observed unique localization of chromatin modifications in the area of the generative and the vegetative nuclei located near each other in the male germ unit, indicating the precise mechanisms of gene expression regulation in this region. We discuss the differences in the patterns of the epigenetic marks along with our previous reports of nuclear metabolism and changes in chromatin organization and activity in hyacinth male gametophyte cells. We also propose that this epigenetic status of the analysed nuclei is related to the different acquired fates and biological functions of these cells.
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Affiliation(s)
- Marlena Kozłowska
- Department of Cell Biology, Faculty of Biology and Environment Protection, Nicolaus Copernicus University in Toruń, Toruń, Poland
| | - Katarzyna Niedojadło
- Department of Cell Biology, Faculty of Biology and Environment Protection, Nicolaus Copernicus University in Toruń, Toruń, Poland.
| | - Marta Brzostek
- Department of Cell Biology, Faculty of Biology and Environment Protection, Nicolaus Copernicus University in Toruń, Toruń, Poland
| | - Elżbieta Bednarska-Kozakiewicz
- Department of Cell Biology, Faculty of Biology and Environment Protection, Nicolaus Copernicus University in Toruń, Toruń, Poland
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63
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Miao J, Frazier T, Huang L, Zhang X, Zhao B. Identification and Characterization of Switchgrass Histone H3 and CENH3 Genes. FRONTIERS IN PLANT SCIENCE 2016; 7:979. [PMID: 27462323 PMCID: PMC4940616 DOI: 10.3389/fpls.2016.00979] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 06/21/2016] [Indexed: 06/06/2023]
Abstract
Switchgrass is one of the most promising energy crops and only recently has been employed for biofuel production. The draft genome of switchgrass was recently released; however, relatively few switchgrass genes have been functionally characterized. CENH3, the major histone protein found in centromeres, along with canonical H3 and other histones, plays an important role in maintaining genome stability and integrity. Despite their importance, the histone H3 genes of switchgrass have remained largely uninvestigated. In this study, we identified 17 putative switchgrass histone H3 genes in silico. Of these genes, 15 showed strong homology to histone H3 genes including six H3.1 genes, three H3.3 genes, four H3.3-like genes and two H3.1-like genes. The remaining two genes were found to be homologous to CENH3. RNA-seq data derived from lowland cultivar Alamo and upland cultivar Dacotah allowed us to identify SNPs in the histone H3 genes and compare their differential gene expression. Interestingly, we also found that overexpression of switchgrass histone H3 and CENH3 genes in N. benthamiana could trigger cell death of the transformed plant cells. Localization and deletion analyses of the histone H3 and CENH3 genes revealed that nuclear localization of the N-terminal tail is essential and sufficient for triggering the cell death phenotype. Our results deliver insight into the mechanisms underlying the histone-triggered cell death phenotype and provide a foundation for further studying the variations of the histone H3 and CENH3 genes in switchgrass.
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Affiliation(s)
- Jiamin Miao
- Department of Horticulture, Virginia TechBlacksburg, VA, USA
- Department of Grassland Science, Sichuan Agricultural UniversityYa'an, China
| | - Taylor Frazier
- Department of Horticulture, Virginia TechBlacksburg, VA, USA
| | - Linkai Huang
- Department of Grassland Science, Sichuan Agricultural UniversityYa'an, China
| | - Xinquan Zhang
- Department of Grassland Science, Sichuan Agricultural UniversityYa'an, China
| | - Bingyu Zhao
- Department of Horticulture, Virginia TechBlacksburg, VA, USA
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64
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Jiang D, Berger F. Histone variants in plant transcriptional regulation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2016; 1860:123-130. [PMID: 27412913 DOI: 10.1016/j.bbagrm.2016.07.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 06/18/2016] [Accepted: 07/03/2016] [Indexed: 12/28/2022]
Abstract
Chromatin based organization of eukaryotic genome plays a profound role in regulating gene transcription. Nucleosomes form the basic subunits of chromatin by packaging DNA with histone proteins, impeding the access of DNA to transcription factors and RNA polymerases. Exchange of histone variants in nucleosomes alters the properties of nucleosomes and thus modulates DNA exposure during transcriptional regulation. Growing evidence indicates the important function of histone variants in programming transcription during developmental transitions and stress response. Here we review how histone variants and their deposition machineries regulate the nucleosome stability and dynamics, and discuss the link between histone variants and transcriptional regulation in plants. This article is part of a Special Issue entitled: Plant Gene Regulatory Mechanisms and Networks, edited by Dr. Erich Grotewold and Dr. Nathan Springer.
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Affiliation(s)
- Danhua Jiang
- Gregor Mendel Institute, Vienna Biocenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Frédéric Berger
- Gregor Mendel Institute, Vienna Biocenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria.
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65
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Zeng Z, Jiang J. Isolation and Proteomics Analysis of Barley Centromeric Chromatin Using PICh. J Proteome Res 2016; 15:1875-82. [DOI: 10.1021/acs.jproteome.6b00063] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Zixian Zeng
- Department of Horticulture, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Jiming Jiang
- Department of Horticulture, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
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66
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Martínez G, Panda K, Köhler C, Slotkin RK. Silencing in sperm cells is directed by RNA movement from the surrounding nurse cell. NATURE PLANTS 2016; 2:16030. [PMID: 27249563 DOI: 10.1038/nplants.2016.30] [Citation(s) in RCA: 141] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 02/04/2016] [Indexed: 05/23/2023]
Abstract
Plant small interfering RNAs (siRNAs) communicate from cell to cell and travel long distances through the vasculature. However, siRNA movement into germ cells has remained controversial, and has gained interest because the terminally differentiated pollen vegetative nurse cell surrounding the sperm cells undergoes a programmed heterochromatin decondensation and transcriptional reactivation of transposable elements (TEs). Transcription of TEs leads to their post-transcriptional degradation into siRNAs, and it has been proposed that the purpose of this TE reactivation is to generate and load TE siRNAs into the sperm cells. Here, we identify the molecular pathway of TE siRNA production in the pollen grain and demonstrate that siRNAs produced from pollen vegetative cell transcripts can silence TE reporters in the sperm cells. Our data demonstrates that TE siRNAs act non-cell-autonomously, inhibiting TE activity in the germ cells and potentially the next generation.
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Affiliation(s)
- Germán Martínez
- Department of Molecular Genetics and Center for RNA Biology, The Ohio State University, 500 Aronoff Laboratory, 318 West 12th Avenue, Columbus, Ohio 43210, USA
| | - Kaushik Panda
- Department of Molecular Genetics and Center for RNA Biology, The Ohio State University, 500 Aronoff Laboratory, 318 West 12th Avenue, Columbus, Ohio 43210, USA
| | - Claudia Köhler
- Department of Plant Biology, Swedish University of Agricultural Sciences and Linnean Center of Plant Biology, SE-750 07 Uppsala, Sweden
| | - R Keith Slotkin
- Department of Molecular Genetics and Center for RNA Biology, The Ohio State University, 500 Aronoff Laboratory, 318 West 12th Avenue, Columbus, Ohio 43210, USA
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67
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Yang H, Yang N, Wang T. Proteomic analysis reveals the differential histone programs between male germline cells and vegetative cells in Lilium davidii. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 85:660-674. [PMID: 26846354 DOI: 10.1111/tpj.13133] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 01/12/2016] [Accepted: 01/25/2016] [Indexed: 06/05/2023]
Abstract
In flowering plants, male germline fate is determined after asymmetric division of the haploid microspore. Daughter cells have distinct fates: the generative cell (GC) undergoes further mitosis to generate sperm cells (SCs), and the vegetative cell (VC) terminally differentiates. However, our understanding of the mechanisms underlying germline development remains limited. Histone variants and modifications define chromatin states, and contribute to establishing and maintaining cell identities by affecting gene expression. Here, we constructed a lily protein database, then extracted and detailed histone entries into a comprehensive lily histone database. We isolated large amounts of nuclei from VCs, GCs and SCs from lily, and profiled histone variants of all five histone families in all three cell types using proteomics approaches. We revealed 92 identities representing 32 histone variants: six for H1, 11 for H2A, eight for H2B, five for H3 and two for H4. Nine variants, including five H1, two H2B, one H3 and one H4 variant, specifically accumulated in GCs and SCs. We also detected H3 modification patterns in the three cell types. GCs and SCs had almost identical histone profiles and similar H3 modification patterns, which were significantly different from those of VCs. Our study also revealed the presence of multiple isoforms, and differential expression patterns between isoforms of a variant. The results suggest that differential histone programs between the germline and companion VCs may be established following the asymmetric division, and are important for identity establishment and differentiation of the male germline as well as the VC.
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Affiliation(s)
- Hao Yang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ning Yang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Tai Wang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
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68
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Higo A, Niwa M, Yamato KT, Yamada L, Sawada H, Sakamoto T, Kurata T, Shirakawa M, Endo M, Shigenobu S, Yamaguchi K, Ishizaki K, Nishihama R, Kohchi T, Araki T. Transcriptional Framework of Male Gametogenesis in the Liverwort Marchantia polymorpha L. PLANT & CELL PHYSIOLOGY 2016; 57:325-38. [PMID: 26858289 DOI: 10.1093/pcp/pcw005] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 12/31/2015] [Indexed: 05/19/2023]
Abstract
In land plants, there are two types of male gametes: one is a non-motile sperm cell which is delivered to the egg cell by a pollen tube, and the other is a motile sperm cell with flagella. The molecular mechanism underlying the sexual reproduction with the egg and pollen-delivered sperm cell is well understood from studies using model plants such as Arabidopsis and rice. On the other hand, the sexual reproduction with motile sperm has remained poorly characterized, due to the lack of suitable models. Marchantia polymorpha L. is a model basal land plant with sexual reproduction involving an egg cell and bi-flagellated motile sperm. To understand the differentiation process of plant motile sperm, we analyzed the gene expression profile of developing antheridia of M. polymorpha. We performed RNA-sequencing experiments and compared transcript profiles of the male sexual organ (antheridiophore and antheridium contained therein), female sexual organ (archegoniophore) and a vegetative organ (thallus). Transcriptome analysis showed that the antheridium expresses nearly half of the protein-coding genes predicted in the genome, but it also has unique features. The antheridium transcriptome shares some common features with male gamete transcriptomes of angiosperms and animals, and homologs of genes involved in male gamete formation and function in angiosperms and animals were identified. In addition, we showed that some of them had distinct expression patterns in the spermatogenous tissue of developing antheridia. This study provides a transcriptional framework on which to study the molecular mechanism of plant motile sperm development in M. polymorpha as a model.
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Affiliation(s)
- Asuka Higo
- Graduate School of Biostudies, Kyoto University, Kyoto, 606-8501 Japan
| | - Masaki Niwa
- Graduate School of Biostudies, Kyoto University, Kyoto, 606-8501 Japan
| | - Katsuyuki T Yamato
- Faculty of Biology-Oriented Science and Technology, Kinki University, Kinokawa, 649-6493 Japan
| | - Lixy Yamada
- Sugashima Marine Biological Laboratory, Graduate School of Science, Nagoya University, Toba, 517-0004 Japan
| | - Hitoshi Sawada
- Sugashima Marine Biological Laboratory, Graduate School of Science, Nagoya University, Toba, 517-0004 Japan
| | - Tomoaki Sakamoto
- Plant Global Education Project, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, 630-0192 Japan Present address: Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, 603-8555 Japan
| | - Tetsuya Kurata
- Plant Global Education Project, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, 630-0192 Japan Present address: Graduate School of Life Sciences, Tohoku University, Sendai, 980-8578 Japan
| | - Makoto Shirakawa
- Graduate School of Biostudies, Kyoto University, Kyoto, 606-8501 Japan Present address: Department of Botany, Faculty of Science, University of British Columbia, Vancouver, Canada V6T 1Z4
| | - Motomu Endo
- Graduate School of Biostudies, Kyoto University, Kyoto, 606-8501 Japan
| | - Shuji Shigenobu
- National Institute for Basic Biology, Okazaki, 444-8585 Japan
| | | | | | - Ryuichi Nishihama
- Graduate School of Biostudies, Kyoto University, Kyoto, 606-8501 Japan
| | - Takayuki Kohchi
- Graduate School of Biostudies, Kyoto University, Kyoto, 606-8501 Japan
| | - Takashi Araki
- Graduate School of Biostudies, Kyoto University, Kyoto, 606-8501 Japan
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69
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Finnegan EJ. Time-dependent stabilization of the +1 nucleosome is an early step in the transition to stable cold-induced repression of FLC. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 84:875-885. [PMID: 26437570 DOI: 10.1111/tpj.13044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 09/08/2015] [Accepted: 09/24/2015] [Indexed: 06/05/2023]
Abstract
In vernalized Arabidopsis, the extent of FLC repression and promotion of flowering are correlated with the length of winter (low temperature exposure), but how plants measure the duration of winter is unknown. Repression of FLC occurs in two phases: establishment and maintenance. This study investigates the early events in the transition between establishment and maintenance of repression. Initial repression was rapid but transient; within 24 h of being placed at low temperatures FLC transcription was reduced by 40% and repression was complete after 5 days in the cold. The extent to which repression was maintained depended on the length of the cold treatment. Occupancy of the +1 nucleosome in FLC chromatin increased in a time-dependent manner over a 4-week low temperature treatment concomitant with decreased histone acetylation and increased trimethylation of histone H3 lysine 27 (H3K27me3). Mutant analyses showed that increased nucleosome occupancy occurred independent of histone deacetylation and increased H3K27me3, suggesting that it is an early step in the switch between transient and stable repression. Both altered histone composition and deacetylation contributed to increased nucleosome occupancy. The time-dependency of the steps required for the switch between transient and stable repression suggests that the duration of winter is measured by the chromatin state at FLC. A chromatin-based switch is consistent with finding that each FLC allele in a cell undergoes this transition independently.
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Affiliation(s)
- E Jean Finnegan
- CSIRO, Agriculture, GPO Box 1600, Canberra, ACT, 2601, Australia
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70
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Intercellular communication in Arabidopsis thaliana pollen discovered via AHG3 transcript movement from the vegetative cell to sperm. Proc Natl Acad Sci U S A 2015; 112:13378-83. [PMID: 26466609 DOI: 10.1073/pnas.1510854112] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
An Arabidopsis pollen grain (male gametophyte) consists of three cells: the vegetative cell, which forms the pollen tube, and two sperm cells enclosed within the vegetative cell. It is still unclear if there is intercellular communication between the vegetative cell and the sperm cells. Here we show that ABA-hypersensitive germination3 (AHG3), encoding a protein phosphatase, is specifically transcribed in the vegetative cell but predominantly translated in sperm cells. We used a series of deletion constructs and promoter exchanges to document transport of AHG3 transcripts from the vegetative cell to sperm and showed that their transport requires sequences in both the 5' UTR and the coding region. Thus, in addition its known role in transporting sperm during pollen tube growth, the vegetative cell also contributes transcripts to the sperm cells.
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71
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Analysis of Histones H3 and H4 Reveals Novel and Conserved Post-Translational Modifications in Sugarcane. PLoS One 2015; 10:e0134586. [PMID: 26226299 PMCID: PMC4520453 DOI: 10.1371/journal.pone.0134586] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 07/10/2015] [Indexed: 11/29/2022] Open
Abstract
Histones are the main structural components of the nucleosome, hence targets of many regulatory proteins that mediate processes involving changes in chromatin. The functional outcome of many pathways is “written” in the histones in the form of post-translational modifications that determine the final gene expression readout. As a result, modifications, alone or in combination, are important determinants of chromatin states. Histone modifications are accomplished by the addition of different chemical groups such as methyl, acetyl and phosphate. Thus, identifying and characterizing these modifications and the proteins related to them is the initial step to understanding the mechanisms of gene regulation and in the future may even provide tools for breeding programs. Several studies over the past years have contributed to increase our knowledge of epigenetic gene regulation in model organisms like Arabidopsis, yet this field remains relatively unexplored in crops. In this study we identified and initially characterized histones H3 and H4 in the monocot crop sugarcane. We discovered a number of histone genes by searching the sugarcane ESTs database. The proteins encoded correspond to canonical histones, and their variants. We also purified bulk histones and used them to map post-translational modifications in the histones H3 and H4 using mass spectrometry. Several modifications conserved in other plants, and also novel modified residues, were identified. In particular, we report O-acetylation of serine, threonine and tyrosine, a recently identified modification conserved in several eukaryotes. Additionally, the sub-nuclear localization of some well-studied modifications (i.e., H3K4me3, H3K9me2, H3K27me3, H3K9ac, H3T3ph) is described and compared to other plant species. To our knowledge, this is the first report of histones H3 and H4 as well as their post-translational modifications in sugarcane, and will provide a starting point for the study of chromatin regulation in this crop.
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72
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Wang J, Meng X, Yuan C, Harrison AP, Chen M. The roles of cross-talk epigenetic patterns in Arabidopsis thaliana. Brief Funct Genomics 2015; 15:278-87. [PMID: 26141715 DOI: 10.1093/bfgp/elv025] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The epigenetic mechanisms, including histone modifications, DNA cytosine methylation, histone variants and noncoding RNAs (ncRNAs), play a key role in determining transcriptional outcomes. Recently, many studies have demonstrated that the different epigenetic mechanisms interplay with each other rather than work independently. In this article, we outline a framework for how different epigenetic mechanisms work with each other in Arabidopsis thalianaWe build a network of cross-talk between chromatin marks based on six classes of cross-talk interactions. The first pattern details coordinated modifications that act together to enhance or repress gene expression. The second pattern details bivalent modifications that act antagonistically toward gene expression. The third pattern is for unilateral promotion of one modification by the existence of another modification. The fourth pattern is for unilateral inhibition of one modification by another modification. The fifth pattern is for mutual inhibitory patterns. The sixth pattern is for epigenetic modifications that appear independent.We also explore the mutual regulation between chromatin marks and ncRNAs in various ways. These regulations can be divided into six parts: how ncRNA affects the binding of chromatin mark, such as miR2Epi, siR2Epi and lncR2Epi; how chromatin mark regulates ncRNA, such as Epi2miR, Epi2siR and Epi2lncR.A comprehensive network of cross-talk between different epigenetic mechanisms will help in fully understanding the functional roles and biological impacts of epigenetic regulation.
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73
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Borg M, Berger F. Chromatin remodelling during male gametophyte development. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 83:177-188. [PMID: 25892182 DOI: 10.1111/tpj.12856] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 04/10/2015] [Accepted: 04/14/2015] [Indexed: 05/28/2023]
Abstract
The plant life cycle alternates between a diploid sporophytic phase and haploid gametophytic phase, with the latter giving rise to the gametes. Male gametophyte development encompasses two mitotic divisions that results in a simple three-celled structure knows as the pollen grain, in which two sperm cells are encased within a larger vegetative cell. Both cell types exhibit a very different type of chromatin organization - highly condensed in sperm cell nuclei and highly diffuse in the vegetative cell. Distinct classes of histone variants have dynamic and differential expression in the two cell lineages of the male gametophyte. Here we review how the dynamics of histone variants are linked to reprogramming of chromatin activities in the male gametophyte, compaction of the sperm cell genome and zygotic transitions post-fertilization.
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Affiliation(s)
- Michael Borg
- Gregor Mendel Institute, Vienna Biocenter, Dr. Bohr-Gasse 3, 1030, Vienna, Austria
| | - Frédéric Berger
- Gregor Mendel Institute, Vienna Biocenter, Dr. Bohr-Gasse 3, 1030, Vienna, Austria
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74
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Huang J, Ju Y, Wang X, Zhang Q. A one-step rectification of sperm cell targeting ensures the success of double fertilization. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2015; 57:496-503. [PMID: 25532459 DOI: 10.1111/jipb.12322] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2014] [Accepted: 12/17/2014] [Indexed: 06/04/2023]
Abstract
Successful fertilization in animals depends on competition among millions of sperm cells, whereas double fertilization in flowering plants usually involves just one pollen tube releasing two immobile sperm cells. It is largely a mystery how the plant sperm cells fuse efficiently with their female targets within an embryo sac. We show that the initial positioning of sperm cells upon discharge from the pollen tube is usually inopportune for gamete fusions and that adjustment of sperm cell targeting occurs through release and re-adhesion of one sperm cell, while the other connected sperm cell remains in stagnation. This enables proper adhesion of each sperm cell to a female gamete and coordinates the gamete fusions. Our findings reveal inner embryo sac dynamics that ensure the reproductive success of flowering plants and suggest a requirement for sperm cell differentiation as the basis of double fertilization.
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Affiliation(s)
- Jilei Huang
- Key Laboratory of Cell Proliferation and Differentiation (Ministry of Education), College of Life Sciences, Peking University, Beijing, 100871, China; Instrumental Analysis and Research Center, South China Agricultural University, Guangzhou, 510642, China
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75
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Genome-wide identification, evolutionary, and expression analyses of histone H3 variants in plants. BIOMED RESEARCH INTERNATIONAL 2015; 2015:341598. [PMID: 25815311 PMCID: PMC4357034 DOI: 10.1155/2015/341598] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 02/05/2015] [Indexed: 11/17/2022]
Abstract
Histone variants alter the nucleosome structure and play important roles in chromosome segregation, transcription, DNA repair, and sperm compaction. Histone H3 is encoded by many genes in most eukaryotic species and is the histone that contains the largest variety of posttranslational modifications. Compared with the metazoan H3 variants, little is known about the complex evolutionary history of H3 variants proteins in plants. Here, we study the identification, evolutionary, and expression analyses of histone H3 variants from genomes in major branches in the plant tree of life. Firstly we identified all the histone three related (HTR) genes from the examined genomes, then we classified the four groups variants: centromeric H3, H3.1, H3.3 and H3-like, by phylogenetic analysis, intron information, and alignment. We further demonstrated that the H3 variants have evolved under strong purifying selection, indicating the conservation of HTR proteins. Expression analysis revealed that the HTR has a wide expression profile in maize and rice development and plays important roles in development.
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76
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Histone variants: the artists of eukaryotic chromatin. SCIENCE CHINA-LIFE SCIENCES 2015; 58:232-9. [DOI: 10.1007/s11427-015-4817-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 01/23/2015] [Indexed: 10/24/2022]
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77
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Russell SD, Jones DS. The male germline of angiosperms: repertoire of an inconspicuous but important cell lineage. FRONTIERS IN PLANT SCIENCE 2015; 6:173. [PMID: 25852722 PMCID: PMC4367165 DOI: 10.3389/fpls.2015.00173] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Accepted: 03/03/2015] [Indexed: 05/03/2023]
Abstract
The male germline of flowering plants constitutes a specialized lineage of diminutive cells initiated by an asymmetric division of the initial microspore cell that sequesters the generative cell from the pollen vegetative cell. The generative cell subsequently divides to form the two male gametes (non-motile sperm cells) that fuse with the two female gametophyte target cells (egg and central cells) to form the zygote and endosperm. Although these male gametes can be as little as 1/800th of the volume of their female counterpart, they encode a highly distinctive and rich transcriptome, translate proteins, and display a novel suite of gamete-distinctive control elements that create a unique chromatin environment in the male lineage. Sperm-expressed transcripts also include a high proportion of transposable element-related sequences that may be targets of non-coding RNA including miRNA and silencing elements from peripheral cells. The number of sperm-encoded transcripts is somewhat fewer than the number present in the egg cell, but are remarkably distinct compared to other cell types according to principal component and other analyses. The molecular role of the male germ lineage cells is just beginning to be understood and appears more complex than originally anticipated.
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Affiliation(s)
- Scott D. Russell
- *Correspondence: Scott D. Russell, Department of Microbiology and Plant Biology, University of Oklahoma, Norman, 770 Van Vleet Oval, OK 73019, USA
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78
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Liu J, Feng L, Li J, He Z. Genetic and epigenetic control of plant heat responses. FRONTIERS IN PLANT SCIENCE 2015; 6:267. [PMID: 25964789 PMCID: PMC4408840 DOI: 10.3389/fpls.2015.00267] [Citation(s) in RCA: 160] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 04/03/2015] [Indexed: 05/18/2023]
Abstract
Plants have evolved sophisticated genetic and epigenetic regulatory systems to respond quickly to unfavorable environmental conditions such as heat, cold, drought, and pathogen infections. In particular, heat greatly affects plant growth and development, immunity and circadian rhythm, and poses a serious threat to the global food supply. According to temperatures exposing, heat can be usually classified as warm ambient temperature (about 22-27°C), high temperature (27-30°C) and extremely high temperature (37-42°C, also known as heat stress) for the model plant Arabidopsis thaliana. The genetic mechanisms of plant responses to heat have been well studied, mainly focusing on elevated ambient temperature-mediated morphological acclimation and acceleration of flowering, modulation of circadian clock and plant immunity by high temperatures, and thermotolerance to heat stress. Recently, great progress has been achieved on epigenetic regulation of heat responses, including DNA methylation, histone modifications, histone variants, ATP-dependent chromatin remodeling, histone chaperones, small RNAs, long non-coding RNAs and other undefined epigenetic mechanisms. These epigenetic modifications regulate the expression of heat-responsive genes and function to prevent heat-related damages. This review focuses on recent progresses regarding the genetic and epigenetic control of heat responses in plants, and pays more attention to the role of the major epigenetic mechanisms in plant heat responses. Further research perspectives are also discussed.
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Affiliation(s)
- Junzhong Liu
- National Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences – Chinese Academy of SciencesShanghai, China
| | - Lili Feng
- School of Life Science and Technology, ShanghaiTech UniversityShanghai, China
| | - Jianming Li
- Plant Signaling Laboratory, The Plant Stress Biology Center, Shanghai Institutes for Biological Sciences – Chinese Academy of SciencesShanghai, China
- *Correspondence: Zuhua He, National Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences – Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China ; Jianming Li, Plant Signaling Laboratory, The Plant Stress Biology Center, Shanghai Institutes for Biological Sciences – Chinese Academy of Sciences, 3888 Chenhua Road, Songjiang District, Shanghai 201602, China
| | - Zuhua He
- National Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences – Chinese Academy of SciencesShanghai, China
- *Correspondence: Zuhua He, National Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences – Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China ; Jianming Li, Plant Signaling Laboratory, The Plant Stress Biology Center, Shanghai Institutes for Biological Sciences – Chinese Academy of Sciences, 3888 Chenhua Road, Songjiang District, Shanghai 201602, China
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79
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Hu Y, Lai Y. Identification and expression analysis of rice histone genes. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2015; 86:55-65. [PMID: 25461700 DOI: 10.1016/j.plaphy.2014.11.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2014] [Accepted: 11/17/2014] [Indexed: 05/10/2023]
Abstract
Histones, acting as the core of nucleosome, are the chief protein component of chromatin. They play an important role in gene regulation by covalent modification at several sites and histone variants replacement. Five major families of histones exist: H1, H2A, H2B, H3 and H4. The protein sequences within each family appear to be highly conserved. In this paper, we identified 60 histone proteins in rice (Oryza sativa) including 14 H2A, 15 H2B, 16 H3, 11 H4 and 4 H1. Sequence analysis indicates that histone protein sequences in plant are more variable than in animal. Interestingly, we found a rice-specific H4 variant which showed several amino acid substitutions with canonical protein and was expressed in different tissues in a low level. Expression analysis indicates that a subset of histone genes were expressed in a similar pattern and many of them responded to stress conditions. Specifically, we found that two H2A.Z genes were down-regulated by stress in leaves but not in roots suggesting that they might be involved in stress response.
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Affiliation(s)
- Yongfeng Hu
- Jingchu University of Technology, 448000 Jingmen, China.
| | - Yan Lai
- Jingchu University of Technology, 448000 Jingmen, China
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80
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Yin K, Ueda M, Takagi H, Kajihara T, Sugamata Aki S, Nobusawa T, Umeda-Hara C, Umeda M. A dual-color marker system for in vivo visualization of cell cycle progression in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 80:541-52. [PMID: 25158977 DOI: 10.1111/tpj.12652] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 08/18/2014] [Accepted: 08/20/2014] [Indexed: 05/08/2023]
Abstract
Visualization of the spatiotemporal pattern of cell division is crucial to understand how multicellular organisms develop and how they modify their growth in response to varying environmental conditions. The mitotic cell cycle consists of four phases: S (DNA replication), M (mitosis and cytokinesis), and the intervening G1 and G2 phases; however, only G2/M-specific markers are currently available in plants, making it difficult to measure cell cycle duration and to analyze changes in cell cycle progression in living tissues. Here, we developed another cell cycle marker that labels S-phase cells by manipulating Arabidopsis CDT1a, which functions in DNA replication origin licensing. Truncations of the CDT1a coding sequence revealed that its carboxy-terminal region is responsible for proteasome-mediated degradation at late G2 or in early mitosis. We therefore expressed this region as a red fluorescent protein fusion protein under the S-specific promoter of a histone 3.1-type gene, HISTONE THREE RELATED2 (HTR2), to generate an S/G2 marker. Combining this marker with the G2/M-specific CYCB1-GFP marker enabled us to visualize both S to G2 and G2 to M cell cycle stages, and thus yielded an essential tool for time-lapse imaging of cell cycle progression. The resultant dual-color marker system, Cell Cycle Tracking in Plant Cells (Cytrap), also allowed us to identify root cells in the last mitotic cell cycle before they entered the endocycle. Our results demonstrate that Cytrap is a powerful tool for in vivo monitoring of the plant cell cycle, and thus for deepening our understanding of cell cycle regulation in particular cell types during organ development.
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Affiliation(s)
- Ke Yin
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Takayama 8916-5, Ikoma, Nara, 630-0192, Japan
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81
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Zheng B, He H, Zheng Y, Wu W, McCormick S. An ARID domain-containing protein within nuclear bodies is required for sperm cell formation in Arabidopsis thaliana. PLoS Genet 2014; 10:e1004421. [PMID: 25057814 PMCID: PMC4109846 DOI: 10.1371/journal.pgen.1004421] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 04/20/2014] [Indexed: 12/17/2022] Open
Abstract
In plants, each male meiotic product undergoes mitosis, and then one of the resulting cells divides again, yielding a three-celled pollen grain comprised of a vegetative cell and two sperm cells. Several genes have been found to act in this process, and DUO1 (DUO POLLEN 1), a transcription factor, plays a key role in sperm cell formation by activating expression of several germline genes. But how DUO1 itself is activated and how sperm cell formation is initiated remain unknown. To expand our understanding of sperm cell formation, we characterized an ARID (AT-Rich Interacting Domain)-containing protein, ARID1, that is specifically required for sperm cell formation in Arabidopsis. ARID1 localizes within nuclear bodies that are transiently present in the generative cell from which sperm cells arise, coincident with the timing of DUO1 activation. An arid1 mutant and antisense arid1 plants had an increased incidence of pollen with only a single sperm-like cell and exhibited reduced fertility as well as reduced expression of DUO1. In vitro and in vivo evidence showed that ARID1 binds to the DUO1 promoter. Lastly, we found that ARID1 physically associates with histone deacetylase 8 and that histone acetylation, which in wild type is evident only in sperm, expanded to the vegetative cell nucleus in the arid1 mutant. This study identifies a novel component required for sperm cell formation in plants and uncovers a direct positive regulatory role of ARID1 on DUO1 through association with histone acetylation. For all eukaryotes, gamete formation is an essential aspect of sexual reproduction. Unlike in animals, where meiotic products directly become gametes, the germline in plants is established by two consecutive mitotic divisions after meiosis is completed. The first mitosis is asymmetric, forming a larger vegetative cell and a smaller generative cell. The smaller generative cell then divides to produce two sperm cells. Current knowledge indicates DUO1 (DUO POLLEN 1), a transcription factor, plays a key role in this process by controlling expression of other germline genes. But how DUO1 is activated in the generative cell is unknown. To better understand the mechanisms that govern sperm cell formation and activate DUO1 expression, we characterized, ARID1, encoding an ARID (AT-Rich Interacting Domain)-containing protein. We show that ARID1 is required for DUO1 activation and sperm cell formation in Arabidopsis. Furthermore, ARID1 physically associates with a histone deacetylase, facilitating the maintenance of histone acetylation between the vegetative nucleus and sperm nuclei. Thus, our study shows that a pollen-specific ARID protein plays an important role during sperm cell formation in a dual manner: as a transcription factor to activate DUO1 and as a potential component of the histone modification machinery to maintain epigenetic status in pollen.
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Affiliation(s)
- Binglian Zheng
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, China
- Plant Gene Expression Center, USDA/ARS and Dept. of Plant and Microbial Biology, UC-Berkeley, Albany, California, United States of America
| | - Hui He
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, China
| | - Yanhua Zheng
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, China
| | - Wenye Wu
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, China
| | - Sheila McCormick
- Plant Gene Expression Center, USDA/ARS and Dept. of Plant and Microbial Biology, UC-Berkeley, Albany, California, United States of America
- * E-mail:
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82
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Otero S, Desvoyes B, Gutierrez C. Histone H3 dynamics in plant cell cycle and development. Cytogenet Genome Res 2014; 143:114-24. [PMID: 25060842 DOI: 10.1159/000365264] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Chromatin is a macromolecular complex where DNA associates with histone proteins and a variety of non-histone proteins. Among the 4 histone types present in nucleosomes, histone H3 is encoded by a large number of genes in most eukaryotic species and is the histone that contains the largest variety of potential post-translational modifications in the N-terminal amino acid residues. In addition to centromeric histone H3, 2 major types of histone H3 exist, namely the canonical H3.1 and the variant H3.3. In this article, we review the most recent observations on the distinctive features of plant H3 proteins in terms of their expression and dynamics during the cell cycle and at various developmental stages. We also include a discussion on the histone H3 chaperones that actively participate in H3 deposition, in particular CAF-1, HIRA and ASF1, and on the putative plant homologs of human ATRX and DEK chaperones. Accumulating evidence confirms that the balanced deposition of H3.1 and H3.3 is of primary relevance for cell differentiation during plant organogenesis.
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Affiliation(s)
- Sofía Otero
- Department of Genome Dynamics and Function, Centro de Biologia Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain
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83
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Shu H, Nakamura M, Siretskiy A, Borghi L, Moraes I, Wildhaber T, Gruissem W, Hennig L. Arabidopsis replacement histone variant H3.3 occupies promoters of regulated genes. Genome Biol 2014; 15:R62. [PMID: 24708891 PMCID: PMC4054674 DOI: 10.1186/gb-2014-15-4-r62] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 03/21/2014] [Indexed: 12/16/2022] Open
Abstract
Background Histone variants establish structural and functional diversity of chromatin by affecting nucleosome stability and histone-protein interactions. H3.3 is an H3 histone variant that is incorporated into chromatin outside of S-phase in various eukaryotes. In animals, H3.3 is associated with active transcription and possibly maintenance of transcriptional memory. Plant H3 variants, which evolved independently of their animal counterparts, are much less well understood. Results We profile the H3.3 distribution in Arabidopsis at mono-nucleosomal resolution using native chromatin immunoprecipitation. This results in the precise mapping of H3.3-containing nucleosomes, which are not only enriched in gene bodies as previously reported, but also at a subset of promoter regions and downstream of the 3′ ends of active genes. While H3.3 presence within transcribed regions is strongly associated with transcriptional activity, H3.3 at promoters is often independent of transcription. In particular, promoters with GA motifs carry H3.3 regardless of the gene expression levels. H3.3 on promoters of inactive genes is associated with H3K27me3 at gene bodies. In addition, H3.3-enriched plant promoters often contain RNA Pol II considerably upstream of the transcriptional start site. H3.3 and RNA Pol II are found on active as well as on inactive promoters and are enriched at strongly regulated genes. Conclusions In animals and plants, H3.3 organizes chromatin in transcribed regions and in promoters. The results suggest a function of H3.3 in transcriptional regulation and support a model that a single ancestral H3 evolved into H3 variants with similar sub-functionalization patterns in plants and animals.
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84
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Evolutionarily conserved mechanisms of male germline development in flowering plants and animals. Biochem Soc Trans 2014; 42:377-82. [DOI: 10.1042/bst20130261] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Sexual reproduction is the main reproductive strategy of the overwhelming majority of eukaryotes. This suggests that the last eukaryotic common ancestor was able to reproduce sexually. Sexual reproduction reflects the ability to perform meiosis, and ultimately generating gametes, which are cells that carry recombined half sets of the parental genome and are able to fertilize. These functions have been allocated to a highly specialized cell lineage: the germline. Given its significant evolutionary conservation, it is to be expected that the germline programme shares common molecular bases across extremely divergent eukaryotic species. In the present review, we aim to identify the unifying principles of male germline establishment and development by comparing two very disparate kingdoms: plants and animals. We argue that male meiosis defines two temporally regulated gene expression programmes: the first is required for meiotic commitment, and the second is required for the acquisition of fertilizing ability. Small RNA pathways are a further key communality, ultimately ensuring the epigenetic stability of the information conveyed by the male germline.
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85
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Histone variants and chromatin assembly in plant abiotic stress responses. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1819:343-348. [PMID: 24459736 DOI: 10.1016/j.bbagrm.2011.07.012] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Genome organization into nucleosomes and higher-order chromatin structures has profound implications for the regulation of gene expression, DNA replication and repair. The structure of chromatin can be remodeled by several mechanisms; among others, nucleosome assembly/disassembly and replacement of canonical histones with histone variants constitute important ones. In this review, we provide a brief description on the current knowledge about histone chaperones involved in nucleosome assembly/disassembly and histone variants in Arabidopsis thaliana. We discuss recent advances in revealing crucial functions of histone chaperones, nucleosome assembly/disassembly and histone variants in plant response to abiotic stresses. It appears that chromatin structure remodeling may provide a flexible, global and stable means for the regulation of gene transcription to help plants more effectively cope with environmental stresses. This article is part of a Special Issue entitled: Histone chaperones and chromatin assembly.
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86
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Anderson SN, Johnson CS, Jones DS, Conrad LJ, Gou X, Russell SD, Sundaresan V. Transcriptomes of isolated Oryza sativa gametes characterized by deep sequencing: evidence for distinct sex-dependent chromatin and epigenetic states before fertilization. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 76:729-41. [PMID: 24215296 DOI: 10.1111/tpj.12336] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 09/12/2013] [Accepted: 09/19/2013] [Indexed: 05/19/2023]
Abstract
The formation of a zygote by the fusion of egg and sperm involves the two gametic transcriptomes. In flowering plants, the embryo sac embedded within the ovule contains the egg cell, whereas the pollen grain contains two sperm cells inside a supporting vegetative cell. The difficulties of collecting isolated gametes and consequent low recovery of RNA have restricted in-depth analysis of gametic transcriptomes in flowering plants. We isolated living egg cells, sperm cells and pollen vegetative cells from Oryza sativa (rice), and identified transcripts for approximately 36 000 genes by deep sequencing. The three transcriptomes are highly divergent, with about three-quarters of those genes differentially expressed in the different cell types. Distinctive expression profiles were observed for genes involved in chromatin conformation, including an unexpected expression in the sperm cell of genes associated with active chromatin. Furthermore, both the sperm cell and the pollen vegetative cell were deficient in expression of key RNAi components. Differences in gene expression were also observed for genes for hormonal signaling and cell cycle regulation. The egg cell and sperm cell transcriptomes reveal major differences in gene expression to be resolved in the zygote, including pathways affecting chromatin configuration, hormones and cell cycle. The sex-specific differences in the expression of RNAi components suggest that epigenetic silencing in the zygote might act predominantly through female-dependent pathways. More generally, this study provides a detailed gene expression landscape for flowering plant gametes, enabling the identification of specific gametic functions, and their contributions to zygote and seed development.
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Affiliation(s)
- Sarah N Anderson
- Department of Plant Biology, University of California, Davis, CA, 95616, USA
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87
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Zhao X, Yang N, Wang T. Comparative proteomic analysis of generative and sperm cells reveals molecular characteristics associated with sperm development and function specialization. J Proteome Res 2013; 12:5058-71. [PMID: 23879389 DOI: 10.1021/pr400291p] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In flowering plants, two sperm cells (SCs) are generated from a generative cell (GC) in the developing pollen grain or growing pollen tube and are then delivered to the embryo sac to initiate double fertilization. SC development and function specialization involve the strict control of the protein (gene) expression program and coordination of diverse cellular processes. However, because methods for collecting a large amount of highly purified GCs and SCs for proteomic and transcriptomic studies from a plant are not available, molecular information about the program and the interconnections is lacking. Here, we describe a method for obtaining a large quantity of highly purified GCs and SCs from just-germinated lily pollen grains and growing pollen tubes for proteomic analysis. Our observation showed that SCs had less condensed chromatin and more vacuole-like structures than GCs and that mature SCs were arrested at the G2 phase. Comparison of SC and GC proteomes revealed 101 proteins differentially expressed in the two proteomes. These proteins are involved in diverse cellular and metabolic processes, with preferential involvement in metabolism, the cell cycle, signaling, the ubiquitin/proteasome pathway, and chromatin remodeling. Impressively, almost all proteins in SCF complex-mediated proteolysis and the cell cycle were up-regulated in SCs, whereas those in chromatin remodeling and stress response were down-regulated. Our data also reveal the coordination of SCF complex-mediated proteolysis, cell cycle progression, and DNA repair in SC development and function specialization. This study revealed for the first time a difference in protein profiles between GCs and SCs.
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Affiliation(s)
- Xin Zhao
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences and National Center for Plant Gene Research , Beijing 100093, China
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88
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Moes D, Gatti S, Hoffmann C, Dieterle M, Moreau F, Neumann K, Schumacher M, Diederich M, Grill E, Shen WH, Steinmetz A, Thomas C. A LIM domain protein from tobacco involved in actin-bundling and histone gene transcription. MOLECULAR PLANT 2013; 6:483-502. [PMID: 22930731 PMCID: PMC3603003 DOI: 10.1093/mp/sss075] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Accepted: 06/10/2012] [Indexed: 05/18/2023]
Abstract
The two LIM domain-containing proteins from plants (LIMs) typically exhibit a dual cytoplasmic-nuclear distribution, suggesting that, in addition to their previously described roles in actin cytoskeleton organization, they participate in nuclear processes. Using a south-western blot-based screen aimed at identifying factors that bind to plant histone gene promoters, we isolated a positive clone containing the tobacco LIM protein WLIM2 (NtWLIM2) cDNA. Using both green fluorescent protein (GFP) fusion- and immunology-based strategies, we provide clear evidence that NtWLIM2 localizes to the actin cytoskeleton, the nucleus, and the nucleolus. Interestingly, the disruption of the actin cytoskeleton by latrunculin B significantly increases NtWLIM2 nuclear fraction, pinpointing a possible novel cytoskeletal-nuclear crosstalk. Biochemical and electron microscopy experiments reveal the ability of NtWLIM2 to directly bind to actin filaments and to crosslink the latter into thick actin bundles. Electrophoretic mobility shift assays show that NtWLIM2 specifically binds to the conserved octameric cis-elements (Oct) of the Arabidopsis histone H4A748 gene promoter and that this binding largely relies on both LIM domains. Importantly, reporter-based experiments conducted in Arabidopsis and tobacco protoplasts confirm the ability of NtWLIM2 to bind to and activate the H4A748 gene promoter in live cells. Expression studies indicate the constitutive presence of NtWLIM2 mRNA and NtWLIM2 protein during tobacco BY-2 cell proliferation and cell cycle progression, suggesting a role of NtWLIM2 in the activation of basal histone gene expression. Interestingly, both live cell and in vitro data support NtWLIM2 di/oligomerization. We propose that NtWLIM2 functions as an actin-stabilizing protein, which, upon cytoskeleton remodeling, shuttles to the nucleus in order to modify gene expression.
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Affiliation(s)
- Danièle Moes
- Centre de Recherche Public-Santé, 84, Val Fleuri, L-1526 Luxembourg, Luxembourg.
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89
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Dual binding of chromomethylase domains to H3K9me2-containing nucleosomes directs DNA methylation in plants. Cell 2012; 151:167-80. [PMID: 23021223 DOI: 10.1016/j.cell.2012.07.034] [Citation(s) in RCA: 334] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Revised: 07/06/2012] [Accepted: 07/31/2012] [Indexed: 11/21/2022]
Abstract
DNA methylation and histone modification exert epigenetic control over gene expression. CHG methylation by CHROMOMETHYLASE3 (CMT3) depends on histone H3K9 dimethylation (H3K9me2), but the mechanism underlying this relationship is poorly understood. Here, we report multiple lines of evidence that CMT3 interacts with H3K9me2-containing nucleosomes. CMT3 genome locations nearly perfectly correlated with H3K9me2, and CMT3 stably associated with H3K9me2-containing nucleosomes. Crystal structures of maize CMT3 homolog ZMET2, in complex with H3K9me2 peptides, showed that ZMET2 binds H3K9me2 via both bromo adjacent homology (BAH) and chromo domains. The structures reveal an aromatic cage within both BAH and chromo domains as interaction interfaces that capture H3K9me2. Mutations that abolish either interaction disrupt CMT3 binding to nucleosomes and show a complete loss of CMT3 activity in vivo. Our study establishes dual recognition of H3K9me2 marks by BAH and chromo domains and reveals a distinct mechanism of interplay between DNA methylation and histone modification.
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90
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Ueda K, Ono M, Iwashita J, Wabiko H, Inoue M. Generative cell-specific activation of the histone gH2A gene promoter of Lilium longiflorum in tobacco. SEXUAL PLANT REPRODUCTION 2012; 25:247-55. [PMID: 22820801 DOI: 10.1007/s00497-012-0194-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 06/25/2012] [Indexed: 01/02/2023]
Abstract
The Lilium longiflorum gH2A promoter is active exclusively in the generative cells of mature pollen in transgenic tobacco expressing the gH2A promoter::GUS (β-glucuronidase) construct as a reporter gene. Temporal and spatial aspects of gH2A promoter activity examined during pollen development in transgenic tobacco reveal that GUS reporter activity was not detected until developing pollen entered the early bicellular developmental stage. Activity was first detected in generative cells at early-mid stages and gradually increased to maximum levels at mid-bicellular stages. The patterns of appearance and longevity of GUS activity in tobacco were very similar to those of gH2A mRNA during pollen development in Lilium. Exogenous treatment with colchicine, a well-known microtubule depolymerize, blocked microspore mitosis and inhibited generative cell differentiation. No GUS signal was detected in the resulting anomalous pollen, which lacked generative cell differentiation. These data strongly suggest that normal generative cell development is essential for activation of the gH2A promoter. Furthermore, these results indicate that common transcriptional activator(s) of the gH2A promoter may be present in both Lilium and Nicotiana, and that such putative factor(s) activates the gH2A promoter only when generative cells undergo normal development.
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Affiliation(s)
- Kenji Ueda
- Akita Prefectural University, Akita, 010-0195, Japan.
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91
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Borges F, Gardner R, Lopes T, Calarco JP, Boavida LC, Slotkin RK, Martienssen RA, Becker JD. FACS-based purification of Arabidopsis microspores, sperm cells and vegetative nuclei. PLANT METHODS 2012; 8:44. [PMID: 23075219 PMCID: PMC3502443 DOI: 10.1186/1746-4811-8-44] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Accepted: 10/08/2012] [Indexed: 05/19/2023]
Abstract
BACKGROUND The male germline in flowering plants differentiates by asymmetric division of haploid uninucleated microspores, giving rise to a vegetative cell enclosing a smaller generative cell, which eventually undergoes a second mitosis to originate two sperm cells. The vegetative cell and the sperm cells activate distinct genetic and epigenetic mechanisms to control pollen tube growth and germ cell specification, respectively. Therefore, a comprehensive characterization of these processes relies on efficient methods to isolate each of the different cell types throughout male gametogenesis. RESULTS We developed stable transgenic Arabidopsis lines and reliable purification tools based on Fluorescence-Activated Cell Sorting (FACS) in order to isolate highly pure and viable fractions of each cell/nuclei type before and after pollen mitosis. In the case of mature pollen, this was accomplished by expressing GFP and RFP in the sperm and vegetative nuclei, respectively, resulting in 99% pure sorted populations. Microspores were also purified by FACS taking advantage of their characteristic small size and autofluorescent properties, and were confirmed to be 98% pure. CONCLUSIONS We provide simple and efficient FACS-based purification protocols for Arabidopsis microspores, vegetative nuclei and sperm cells. This paves the way for subsequent molecular analysis such as transcriptomics, DNA methylation analysis and chromatin immunoprecipitation, in the developmental context of microgametogenesis in Arabidopsis.
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Affiliation(s)
- Filipe Borges
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156, Oeiras, Portugal
| | - Rui Gardner
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156, Oeiras, Portugal
| | - Telma Lopes
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156, Oeiras, Portugal
| | - Joseph P Calarco
- Cold Spring Harbor Laboratory, 1 Bungtown Road, 11724, Cold Spring Harbor, NY, USA
| | - Leonor C Boavida
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156, Oeiras, Portugal
| | - R Keith Slotkin
- Department of Molecular Genetics, The Ohio State University, 43210, Columbus, OH, USA
| | - Robert A Martienssen
- Cold Spring Harbor Laboratory, 1 Bungtown Road, 11724, Cold Spring Harbor, NY, USA
| | - Jörg D Becker
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156, Oeiras, Portugal
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Russell SD, Gou X, Wong CE, Wang X, Yuan T, Wei X, Bhalla PL, Singh MB. Genomic profiling of rice sperm cell transcripts reveals conserved and distinct elements in the flowering plant male germ lineage. THE NEW PHYTOLOGIST 2012; 195:560-573. [PMID: 22716952 DOI: 10.1111/j.1469-8137.2012.04199.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Genomic assay of sperm cell RNA provides insight into functional control, modes of regulation, and contributions of male gametes to double fertilization. Sperm cells of rice (Oryza sativa) were isolated from field-grown, disease-free plants and RNA was processed for use with the full-genome Affymetrix microarray. Comparison with Gene Expression Omnibus (GEO) reference arrays confirmed expressionally distinct gene profiles. A total of 10,732 distinct gene sequences were detected in sperm cells, of which 1668 were not expressed in pollen or seedlings. Pathways enriched in male germ cells included ubiquitin-mediated pathways, pathways involved in chromatin modeling including histones, histone modification and nonhistone epigenetic modification, and pathways related to RNAi and gene silencing. Genome-wide expression patterns in angiosperm sperm cells indicate common and divergent themes in the male germline that appear to be largely self-regulating through highly up-regulated chromatin modification pathways. A core of highly conserved genes appear common to all sperm cells, but evidence is still emerging that another class of genes have diverged in expression between monocots and dicots since their divergence. Sperm cell transcripts present at fusion may be transmitted through plasmogamy during double fertilization to effect immediate post-fertilization expression of early embryo and (or) endosperm development.
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Affiliation(s)
- Scott D Russell
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA
| | - Xiaoping Gou
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA
| | - Chui E Wong
- Plant Molecular Biology and Biotechnology Laboratory, Australian Research Council Centre of Excellence for Integrative Legume Research, Melbourne School of Land and Environment, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Xinkun Wang
- Higuchi Biosciences Center, University of Kansas, Lawrence, KS 66047, USA
| | - Tong Yuan
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA
| | - Xiaoping Wei
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA
| | - Prem L Bhalla
- Plant Molecular Biology and Biotechnology Laboratory, Australian Research Council Centre of Excellence for Integrative Legume Research, Melbourne School of Land and Environment, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Mohan B Singh
- Plant Molecular Biology and Biotechnology Laboratory, Australian Research Council Centre of Excellence for Integrative Legume Research, Melbourne School of Land and Environment, University of Melbourne, Parkville, Victoria 3010, Australia
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93
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Talbert PB, Ahmad K, Almouzni G, Ausió J, Berger F, Bhalla PL, Bonner WM, Cande WZ, Chadwick BP, Chan SWL, Cross GAM, Cui L, Dimitrov SI, Doenecke D, Eirin-López JM, Gorovsky MA, Hake SB, Hamkalo BA, Holec S, Jacobsen SE, Kamieniarz K, Khochbin S, Ladurner AG, Landsman D, Latham JA, Loppin B, Malik HS, Marzluff WF, Pehrson JR, Postberg J, Schneider R, Singh MB, Smith MM, Thompson E, Torres-Padilla ME, Tremethick DJ, Turner BM, Waterborg JH, Wollmann H, Yelagandula R, Zhu B, Henikoff S. A unified phylogeny-based nomenclature for histone variants. Epigenetics Chromatin 2012; 5:7. [PMID: 22650316 PMCID: PMC3380720 DOI: 10.1186/1756-8935-5-7] [Citation(s) in RCA: 228] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2012] [Accepted: 05/31/2012] [Indexed: 12/02/2022] Open
Abstract
Histone variants are non-allelic protein isoforms that play key roles in diversifying chromatin structure. The known number of such variants has greatly increased in recent years, but the lack of naming conventions for them has led to a variety of naming styles, multiple synonyms and misleading homographs that obscure variant relationships and complicate database searches. We propose here a unified nomenclature for variants of all five classes of histones that uses consistent but flexible naming conventions to produce names that are informative and readily searchable. The nomenclature builds on historical usage and incorporates phylogenetic relationships, which are strong predictors of structure and function. A key feature is the consistent use of punctuation to represent phylogenetic divergence, making explicit the relationships among variant subtypes that have previously been implicit or unclear. We recommend that by default new histone variants be named with organism-specific paralog-number suffixes that lack phylogenetic implication, while letter suffixes be reserved for structurally distinct clades of variants. For clarity and searchability, we encourage the use of descriptors that are separate from the phylogeny-based variant name to indicate developmental and other properties of variants that may be independent of structure.
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Affiliation(s)
- Paul B Talbert
- Howard Hughes Medical Institute, Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, 98109, USA.
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94
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Howe ES, Clemente TE, Bass HW. Maize histone H2B-mCherry: a new fluorescent chromatin marker for somatic and meiotic chromosome research. DNA Cell Biol 2012; 31:925-38. [PMID: 22662764 PMCID: PMC3378959 DOI: 10.1089/dna.2011.1514] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 01/26/2012] [Accepted: 01/26/2012] [Indexed: 11/12/2022] Open
Abstract
Cytological studies of fluorescent proteins are rapidly yielding insights into chromatin structure and dynamics. Here we describe the production and cytological characterization of new transgenic maize lines expressing a fluorescent histone fusion protein, H2B-mCherry. The transgene is expressed under the control of the maize ubiquitin1 promoter, including its first exon and intron. Polymerase chain reaction-based genotyping and root-tip microscopy showed that most of the lines carrying the transgene also expressed it, producing bright uniform staining of nuclei. Further, plants showing expression in root tips at the seedling stage also showed expression during meiosis, late in the life cycle. Detailed high-resolution three-dimensional imaging of cells and nuclei from various somatic and meiotic cell types showed that H2B-mCherry produced remarkably clear images of chromatin and chromosome fiber morphology, as seen in somatic, male meiotic prophase, and early microgametophyte cells. H2B-mCherry also yielded distinct nucleolus staining and was shown to be compatible with fluorescence in situ hybridization. We found several instances where H2B-mCherry was superior to DAPI as a generalized chromatin stain. Our study establishes these histone H2B-mCherry lines as new biological reagents for visualizing chromatin structure, chromosome morphology, and nuclear dynamics in fixed and living cells in a model plant genetic system.
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Affiliation(s)
- Elizabeth S. Howe
- Department of Biological Science, Florida State University, Tallahassee, Florida
| | - Thomas E. Clemente
- Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Hank W. Bass
- Department of Biological Science, Florida State University, Tallahassee, Florida
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95
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Dynamic deposition of histone variant H3.3 accompanies developmental remodeling of the Arabidopsis transcriptome. PLoS Genet 2012; 8:e1002658. [PMID: 22570629 PMCID: PMC3342937 DOI: 10.1371/journal.pgen.1002658] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2011] [Accepted: 03/04/2012] [Indexed: 12/21/2022] Open
Abstract
In animals, replication-coupled histone H3.1 can be distinguished from replication-independent histone H3.3. H3.3 variants are enriched at active genes and their promoters. Furthermore, H3.3 is specifically incorporated upon gene activation. Histone H3 variants evolved independently in plants and animals, and it is unclear whether different replication-independent H3.3 variants developed similar properties in both phyla. We studied Arabidopsis H3 variants in order to find core properties of this class of histones. Here we present genome-wide maps of H3.3 and H3.1 enrichment and the dynamic changes of their profiles upon cell division arrest. We find H3.3 enrichment to positively correlate with gene expression and to be biased towards the transcription termination site. In contrast with H3.1, heterochromatic regions are mostly depleted of H3.3. We report that, in planta, dynamic changes in H3.3 profiles are associated with the extensive remodeling of the transcriptome that occurs during cell differentiation. We propose that H3.3 dynamics are linked to transcription and are involved in resetting covalent histone marks at a genomic scale during plant development. Our study suggests that H3 variants properties likely result from functionally convergent evolution. Histone proteins are assembled into nucleosomes to build the skeleton of chromosomes. Beyond their role as DNA scaffold, histones participate in the regulation of gene activity. Studies in animals have shown that the deposition of two different histone H3 variants, H3.1 and H3.3, requires distinct pathways and results in distinct profiles throughout the genome. H3 variants evolved independently in plants and animals. Hence, H3 variants' properties shared by plants and animals would reflect core functions that have been selected during evolution. Our study indicates that these core properties include the high enrichment of H3.3 at active genes and a relative low deposition of H3.3 over regions deprived of genes or with inactive genes. In contrast with H3.1, H3.3 incorporation is dynamic and accompanies global changes of gene activity at major developmental transitions. We anticipate that the dynamic link between H3.3 variants and transcription enables remodeling of histone modifications that contribute to developmental transitions.
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96
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Stroud H, Otero S, Desvoyes B, Ramírez-Parra E, Jacobsen SE, Gutierrez C. Genome-wide analysis of histone H3.1 and H3.3 variants in Arabidopsis thaliana. Proc Natl Acad Sci U S A 2012; 109:5370-5. [PMID: 22431625 PMCID: PMC3325649 DOI: 10.1073/pnas.1203145109] [Citation(s) in RCA: 167] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Nucleosomes package eukaryotic DNA and are composed of four different histone proteins, designated H3, H4, H2A, and H2B. Histone H3 has two main variants, H3.1 and H3.3, which show different genomic localization patterns in animals. We profiled H3.1 and H3.3 variants in the genome of the plant Arabidopsis thaliana and found that the localization of these variants shows broad similarity in plants and animals, along with some unique features. H3.1 was enriched in silent areas of the genome, including regions containing the repressive chromatin modifications H3 lysine 27 methylation, H3 lysine 9 methylation, and DNA methylation. In contrast, H3.3 was enriched in actively transcribed genes, especially peaking at the 3' end of genes, and correlated with histone modifications associated with gene activation, such as histone H3 lysine 4 methylation and H2B ubiquitylation, as well as RNA Pol II occupancy. Surprisingly, both H3.1 and H3.3 were enriched on defined origins of replication, as was overall nucleosome density, suggesting a novel characteristic of plant origins. Our results are broadly consistent with the hypothesis that H3.1 acts as the canonical histone that is incorporated during DNA replication, whereas H3.3 acts as the replacement histone that can be incorporated outside of S-phase during chromatin-disrupting processes like transcription.
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Affiliation(s)
- Hume Stroud
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, CA 90095
| | - Sofía Otero
- Centro de Biologia Molecular Severo Ochoa, Consejo Superior de Investigaciones Cientificas, Universidad Autónoma de Madrid, Nicolas Cabrera 1, 28049 Madrid, Spain
| | - Bénédicte Desvoyes
- Centro de Biologia Molecular Severo Ochoa, Consejo Superior de Investigaciones Cientificas, Universidad Autónoma de Madrid, Nicolas Cabrera 1, 28049 Madrid, Spain
| | - Elena Ramírez-Parra
- Centro de Biologia Molecular Severo Ochoa, Consejo Superior de Investigaciones Cientificas, Universidad Autónoma de Madrid, Nicolas Cabrera 1, 28049 Madrid, Spain
| | - Steven E. Jacobsen
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, CA 90095
- Howard Hughes Medical Institute, University of California, Los Angeles, CA 90095; and
- Eli & Edythe Broad Center of Regenerative Medicine & Stem Cell Research, University of California, Los Angeles, CA 90095
| | - Crisanto Gutierrez
- Centro de Biologia Molecular Severo Ochoa, Consejo Superior de Investigaciones Cientificas, Universidad Autónoma de Madrid, Nicolas Cabrera 1, 28049 Madrid, Spain
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97
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Van Ex F, Jacob Y, Martienssen RA. Multiple roles for small RNAs during plant reproduction. CURRENT OPINION IN PLANT BIOLOGY 2011; 14:588-93. [PMID: 21807552 PMCID: PMC3389783 DOI: 10.1016/j.pbi.2011.07.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Revised: 07/10/2011] [Accepted: 07/11/2011] [Indexed: 05/05/2023]
Abstract
Germline development and early embryogenesis in eukaryotes are characterized by large-scale genome reprogramming events. In companion cells of the Arabidopsis male gametophyte, epigenome reorganization leads to loss of heterochromatin and production of a distinct small RNA (sRNA) population. A specific class of sRNA derived from transposons appears to be mobile and can accumulate in germ cells. In the germline of maize, rice, and Arabidopsis, specific ARGONAUTE-sRNA silencing complexes appear to play key roles in reproductive development, including meiosis and regulation of germ cell fate. These results reveal new roles for sRNAs during plant reproduction and suggest that mobility of sRNAs could be critical for some of these functions.
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Affiliation(s)
- Frédéric Van Ex
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA
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98
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Maternal epigenetic pathways control parental contributions to Arabidopsis early embryogenesis. Cell 2011; 145:707-19. [PMID: 21620136 DOI: 10.1016/j.cell.2011.04.014] [Citation(s) in RCA: 170] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Revised: 03/28/2011] [Accepted: 04/15/2011] [Indexed: 11/24/2022]
Abstract
Defining the contributions and interactions of paternal and maternal genomes during embryo development is critical to understand the fundamental processes involved in hybrid vigor, hybrid sterility, and reproductive isolation. To determine the parental contributions and their regulation during Arabidopsis embryogenesis, we combined deep-sequencing-based RNA profiling and genetic analyses. At the 2-4 cell stage there is a strong, genome-wide dominance of maternal transcripts, although transcripts are contributed by both parental genomes. At the globular stage the relative paternal contribution is higher, largely due to a gradual activation of the paternal genome. We identified two antagonistic maternal pathways that control these parental contributions. Paternal alleles are initially downregulated by the chromatin siRNA pathway, linked to DNA and histone methylation, whereas transcriptional activation requires maternal activity of the histone chaperone complex CAF1. Our results define maternal epigenetic pathways controlling the parental contributions in plant embryos, which are distinct from those regulating genomic imprinting.
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99
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Four amino acids guide the assembly or disassembly of Arabidopsis histone H3.3-containing nucleosomes. Proc Natl Acad Sci U S A 2011; 108:10574-8. [PMID: 21670303 DOI: 10.1073/pnas.1017882108] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The histone variant H3.3 and the canonical histone H3.1, which differ in only 4- to 5-aa positions, are coexpressed in complex multicellular eukaryotes from fly to human and plant. H3.3 is mainly associated with active chromatin by replacing H3.1 through chaperones such as histone regulator A, death domain associated protein DAXX, thalassemia/mental retardation syndrome X-linked homolog ATRX, or proto-oncogene protein DEK and plays important roles in the germline, epigenetic memory, and reprogramming. However, the signals within H3.3 that serve as a guide for its dynamic deposition or depletion in plant chromatin are not clear. Here, we show that Arabidopsis histone H3.3 differs from H3.1 by 4-aa sites: amino acids 31, 41, 87, and 90. Although histone H3.1 is highly enriched in chromocenters, H3.3 is present in nucleolar foci in addition to being diffusely distributed in the nucleoplasm. We have evaluated the function of the 4 aa that differ between H3.1 and H3.3. We show that amino acid residue 87, and to some extent residue 90, of Arabidopsis histone H3.3 are critical for its deposition into rDNA arrays. When RNA polymerase I-directed nucleolar transcription is inhibited, wild type H3.3, but not H3.3 containing mutations at residues 31 and 41, is depleted from the rDNA arrays. Together, our results are consistent with a model in which amino acids 87 and 90 in the core domain of H3.3 guide nucleosome assembly, whereas amino acids 31 and 41 in the N-terminal tail of Arabidopsis H3.3 guide nucleosome disassembly in nucleolar rDNA.
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100
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Abstract
Large-scale histone H3 reprogramming during male germline differentiation is conserved between animals and plants. A new report now shows that histone H3 reprogramming also occurs in the female germline of the flowering plant Arabidopsis thaliana.
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