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Kobayashi N, Nishikawa SI. Nuclear Fusion in Yeast and Plant Reproduction. PLANTS (BASEL, SWITZERLAND) 2023; 12:3608. [PMID: 37896071 PMCID: PMC10609895 DOI: 10.3390/plants12203608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 10/09/2023] [Accepted: 10/16/2023] [Indexed: 10/29/2023]
Abstract
Nuclear fusion is essential for the sexual reproduction of various organisms, including plants, animals, and fungi. During the life cycle of flowering plants, nuclear fusion occurs three times: once during female gametogenesis and twice during double fertilization, when two sperm cells fertilize the egg and the central cell. Haploid nuclei migrate in an actin filament-dependent manner to become in close contact and, then, two nuclei fuse. The nuclear fusion process in plant reproduction is achieved through sequential nuclear membrane fusion events. Recent molecular genetic analyses using Arabidopsis thaliana showed the conservation of nuclear membrane fusion machinery between plants and the budding yeast Saccharomyces cerevisiae. These include the heat-shock protein 70 in the endoplasmic reticulum and the conserved nuclear membrane proteins. Analyses of the A. thaliana mutants of these components show that the completion of the sperm nuclear fusion at fertilization is essential for proper embryo and endosperm development.
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Affiliation(s)
- Nanami Kobayashi
- Graduate School of Science and Technology, Niigata University, Niigata 950-2181, Japan;
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2
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Zhai X, Bai J, Xu W, Yang X, Jia Z, Xia W, Wu X, Liang Q, Li B, Jia N. The molecular chaperone mtHSC70-1 interacts with DjA30 to regulate female gametophyte development and fertility in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 115:1677-1698. [PMID: 37294615 DOI: 10.1111/tpj.16347] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 05/26/2023] [Indexed: 06/10/2023]
Abstract
Arabidopsis mitochondria-targeted heat shock protein 70 (mtHSC70-1) plays important roles in the establishment of cytochrome c oxidase-dependent respiration and redox homeostasis during the vegetative growth of plants. Here, we report that knocking out the mtHSC70-1 gene led to a decrease in plant fertility; the fertility defect of the mutant was completely rescued by introducing the mtHSC70-1 gene. mtHSC70-1 mutants also showed defects in female gametophyte (FG) development, including delayed mitosis, abnormal nuclear position, and ectopic gene expression in the embryo sacs. In addition, we found that an Arabidopsis mitochondrial J-protein gene (DjA30) mutant, j30+/- , had defects in FG development and fertility similar to those of mtHSC70-1 mutant. mtHSC70-1 and DjA30 had similar expression patterns in FGs and interacted in vivo, suggesting that these two proteins might cooperate during female gametogenesis. Further, respiratory chain complex IV activity in mtHSC70-1 and DjA30 mutant embryo sacs was markedly downregulated; this led to the accumulation of mitochondrial reactive oxygen species (ROS). Scavenging excess ROS by introducing Mn-superoxide dismutase 1 or catalase 1 gene into the mtHSC70-1 mutant rescued FG development and fertility. Altogether, our results suggest that mtHSC70-1 and DjA30 are essential for the maintenance of ROS homeostasis in the embryo sacs and provide direct evidence for the roles of ROS homeostasis in embryo sac maturation and nuclear patterning, which might determine the fate of gametic and accessory cells.
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Affiliation(s)
- Xiaoting Zhai
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, China
- Hebei Research Center of the Basic Discipline of Cell Biology, Hebei Normal University, Shijiazhuang, 050024, China
- Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, Hebei Normal University, Shijiazhuang, 050024, China
- College of Agriculture and Forestry, Hebei North University, Zhangjiakou, 075000, China
| | - Jiaoteng Bai
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, China
- Hebei Research Center of the Basic Discipline of Cell Biology, Hebei Normal University, Shijiazhuang, 050024, China
- Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, Hebei Normal University, Shijiazhuang, 050024, China
| | - Wenyan Xu
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, China
- Hebei Research Center of the Basic Discipline of Cell Biology, Hebei Normal University, Shijiazhuang, 050024, China
- Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, Hebei Normal University, Shijiazhuang, 050024, China
| | - Xiujuan Yang
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, China
- Hebei Research Center of the Basic Discipline of Cell Biology, Hebei Normal University, Shijiazhuang, 050024, China
- Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, Hebei Normal University, Shijiazhuang, 050024, China
| | - Zichao Jia
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, China
- Hebei Research Center of the Basic Discipline of Cell Biology, Hebei Normal University, Shijiazhuang, 050024, China
- Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, Hebei Normal University, Shijiazhuang, 050024, China
| | - Wenxuan Xia
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, China
- Hebei Research Center of the Basic Discipline of Cell Biology, Hebei Normal University, Shijiazhuang, 050024, China
- Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, Hebei Normal University, Shijiazhuang, 050024, China
| | - Xiaoqing Wu
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, China
- Hebei Research Center of the Basic Discipline of Cell Biology, Hebei Normal University, Shijiazhuang, 050024, China
- Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, Hebei Normal University, Shijiazhuang, 050024, China
| | - Qi Liang
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, China
- Hebei Research Center of the Basic Discipline of Cell Biology, Hebei Normal University, Shijiazhuang, 050024, China
- Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, Hebei Normal University, Shijiazhuang, 050024, China
| | - Bing Li
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, China
- Hebei Research Center of the Basic Discipline of Cell Biology, Hebei Normal University, Shijiazhuang, 050024, China
- Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, Hebei Normal University, Shijiazhuang, 050024, China
| | - Ning Jia
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
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3
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Jiang J, Stührwohldt N, Liu T, Huang Q, Li L, Zhang L, Gu H, Fan L, Zhong S, Schaller A, Qu LJ. Egg cell-secreted aspartic proteases ECS1/2 promote gamete attachment to prioritize the fertilization of egg cells over central cells in Arabidopsis. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2022; 64:2047-2059. [PMID: 36165344 DOI: 10.1111/jipb.13371] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 09/23/2022] [Indexed: 06/16/2023]
Abstract
Double fertilization is an innovative phenomenon in angiosperms, in which one sperm cell first fuses with the egg cell to produce the embryo, and then the other sperm fuses with the central cell to produce the endosperm. However, the molecular mechanism of the preferential fertilization of egg cells is poorly understood. In this study, we report that two egg cell-secreted aspartic proteases, ECS1 and ECS2, play an important role in promoting preferential fertilization of egg cells in Arabidopsis. We show that simultaneous loss of ECS1 and ECS2 function resulted in an approximately 20% reduction in fertility, which can be complemented by the full-length ECS1/2 but not by corresponding active site mutants or by secretion-defective versions of ECS1/2. Detailed phenotypic analysis revealed that the egg cell-sperm cell attachment was compromised in ecs1 ecs2 siliques. Limited pollination assays with cyclin-dependent kinase a1 (cdka;1) pollen showed that preferential egg cell fertilization was impaired in the ecs1 ecs2 mutant. Taken together, these results demonstrate that egg cells secret two aspartic proteases, ECS1 and ECS2, to facilitate the attachment of sperm cells to egg cells so that preferential fertilization of egg cells is achieved. This study reveals the molecular mechanism of preferential fertilization in Arabidopsis thaliana.
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Affiliation(s)
- Jiahao Jiang
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing, 100871, China
| | - Nils Stührwohldt
- Department of Plant Physiology and Biochemistry, Institute of Biology, University of Hohenheim, Stuttgart, 70593, Germany
| | - Tianxu Liu
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing, 100871, China
| | - Qingpei Huang
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing, 100871, China
| | - Ling Li
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing, 100871, China
| | - Li Zhang
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing, 100871, China
| | - Hongya Gu
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing, 100871, China
| | - Liumin Fan
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing, 100871, China
| | - Sheng Zhong
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing, 100871, China
| | - Andreas Schaller
- Department of Plant Physiology and Biochemistry, Institute of Biology, University of Hohenheim, Stuttgart, 70593, Germany
| | - Li-Jia Qu
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing, 100871, China
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Sharma V, Clark AJ, Kawashima T. Insights into the molecular evolution of fertilization mechanism in land plants. PLANT REPRODUCTION 2021; 34:353-364. [PMID: 34061252 DOI: 10.1007/s00497-021-00414-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 05/14/2021] [Indexed: 05/27/2023]
Abstract
Comparative genetics and genomics among green plants, including algae, provide deep insights into the evolution of land plant sexual reproduction. Land plants have evolved successive changes during their conquest of the land and innovations in sexual reproduction have played a major role in their terrestrialization. Recent years have seen many revealing dissections of the molecular mechanisms of sexual reproduction and much new genomics data from the land plant lineage, including early diverging land plants, as well as algae. This new knowledge is being integrated to further understand how sexual reproduction in land plants evolved, identifying highly conserved factors and pathways, but also molecular changes that underpinned the emergence of new modes of sexual reproduction. Here, we review recent advances in the knowledge of land plant sexual reproduction from an evolutionary perspective and also revisit the evolution of angiosperm double fertilization.
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Affiliation(s)
- Vijyesh Sharma
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, 40546, USA
| | - Anthony J Clark
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, 40546, USA
| | - Tomokazu Kawashima
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, 40546, USA.
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5
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Vangalis V, Knop M, Typas MA, Papaioannou IA. Establishment of conidial fusion in the asexual fungus Verticillium dahliae as a useful system for the study of non-sexual genetic interactions. Curr Genet 2021; 67:471-485. [PMID: 33582843 PMCID: PMC8139932 DOI: 10.1007/s00294-021-01157-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/11/2021] [Accepted: 01/22/2021] [Indexed: 02/07/2023]
Abstract
Cell-to-cell fusion is a fundamental biological process across the tree of life. In filamentous fungi, somatic fusion (or anastomosis) is required for the normal development of their syncytial hyphal networks, and it can initiate non-sexual genetic exchange processes, such as horizontal genetic transfer and the parasexual cycle. Although these could be important drivers of the evolution of asexual fungi, this remains a largely unexplored possibility due to the lack of suitable resources for their study in these puzzling organisms. We thus aimed at the characterization of cell fusion in the important asexual fungus Verticillium dahliae via Conidial Anastomosis Tubes (CATs), which can be useful for the analysis of parasexuality. We optimized appropriate procedures for their highly reproducible quantification and live-cell imaging, which were used to characterize their physiology and cell biology, and to start elucidating their underlying genetic machinery. Formation of CATs was shown to depend on growth conditions and require functional Fus3 and Slt2 MAP kinases, as well as the NADPH oxidase NoxA, whereas the GPCR Ste2 and the mating-type protein MAT1-2-1 were dispensable. We show that nuclei and other organelles can migrate through CATs, which often leads to the formation of transient dikaryons. Their nuclei have possible windows of opportunity for genetic interaction before degradation of one by a presumably homeostatic mechanism. We establish here CAT-mediated fusion in V. dahliae as an experimentally convenient system for the cytological analysis of fungal non-sexual genetic interactions. We expect that it will facilitate the dissection of sexual alternatives in asexual fungi.
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Affiliation(s)
- Vasileios Vangalis
- Department of Genetics and Biotechnology, Faculty of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Michael Knop
- Center for Molecular Biology of Heidelberg University (ZMBH), Heidelberg, Germany.,German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Milton A Typas
- Department of Genetics and Biotechnology, Faculty of Biology, National and Kapodistrian University of Athens, Athens, Greece
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Cabral LM, Masuda HP, Ballesteros HF, de Almeida-Engler J, Alves-Ferreira M, De Toni KLG, Bizotto FM, Ferreira PCG, Hemerly AS. ABAP1 Plays a Role in the Differentiation of Male and Female Gametes in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2021; 12:642758. [PMID: 33643370 PMCID: PMC7903899 DOI: 10.3389/fpls.2021.642758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 01/22/2021] [Indexed: 05/07/2023]
Abstract
The correct development of a diploid sporophyte body and a haploid gametophyte relies on a strict coordination between cell divisions in space and time. During plant reproduction, these divisions have to be temporally and spatially coordinated with cell differentiation processes, to ensure a successful fertilization. Armadillo BTB Arabidopsis protein 1 (ABAP1) is a plant exclusive protein that has been previously reported to control proliferative cell divisions during leaf growth in Arabidopsis. Here, we show that ABAP1 binds to different transcription factors that regulate male and female gametophyte differentiation, repressing their target genes expression. During male gametogenesis, the ABAP1-TCP16 complex represses CDT1b transcription, and consequently regulates microspore first asymmetric mitosis. In the female gametogenesis, the ABAP1-ADAP complex represses EDA24-like transcription, regulating polar nuclei fusion to form the central cell. Therefore, besides its function during vegetative development, this work shows that ABAP1 is also involved in differentiation processes during plant reproduction, by having a dual role in regulating both the first asymmetric cell division of male gametophyte and the cell differentiation (or cell fusion) of female gametophyte.
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Affiliation(s)
- Luiz M. Cabral
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
- Departamento de Biologia Celular e Molecular, Instituto de Biologia, Universidade Federal Fluminense, Niterói, Brazil
| | - Hana P. Masuda
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, São Bernardo do Campo, Brazil
| | - Helkin F. Ballesteros
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Janice de Almeida-Engler
- Institut National de la Recherche Agronomique, Centre National de la Recherche Scientifique, Institut Sophia Agrobiotech, Université Côte d’Azur, Sophia Antipolis, France
| | - Márcio Alves-Ferreira
- Departamento de Genética, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Karen L. G. De Toni
- Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Fernanda M. Bizotto
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, São Bernardo do Campo, Brazil
| | - Paulo C. G. Ferreira
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Adriana S. Hemerly
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
- *Correspondence: Adriana S. Hemerly, ;
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Kariyawasam T, Joo S, Lee J, Toor D, Gao AF, Noh KC, Lee JH. TALE homeobox heterodimer GSM1/GSP1 is a molecular switch that prevents unwarranted genetic recombination in Chlamydomonas. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 100:938-953. [PMID: 31368133 DOI: 10.1111/tpj.14486] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 07/23/2019] [Accepted: 07/24/2019] [Indexed: 06/10/2023]
Abstract
Eukaryotic sexual life cycles alternate between haploid and diploid stages, the transitions between which are delineated by cell fusion and meiotic division. Transcription factors in the TALE-class homeobox family, GSM1 and GSP1, predominantly control gene expression for the haploid-to-diploid transition during sexual reproduction in the unicellular green alga, Chlamydomonas reinhardtii. To understand the roles that GSM1 and GSP1 play in zygote development, we used gsm1 and gsp1 mutants and examined fused gametes that normally undergo the multiple organellar fusions required for the genetic unity of the zygotes. In gsm1 and gsp1 zygotes, no fusion was observed for the nucleus and chloroplast. Surprisingly, mitochondria and endoplasmic reticulum, which undergo dynamic autologous fusion/fission, did not undergo heterologous fusions in gsm1 or gsp1 zygotes. Furthermore, the mutants failed to resorb their flagella, an event that normally renders the zygotes immotile. When gsm1 and gsp1 zygotes resumed the mitotic cycle, their two nuclei fused prior to mitosis, but neither chloroplastic nor mitochondrial fusion took place, suggesting that these fusions are specifically turned on by GSM1/GSP1. Taken together, this study shows that organellar restructuring during zygotic diploidization does not occur by default but is triggered by a combinatorial switch, the GSM1/GSP1 dyad. This switch may represent an ancient mechanism that evolved to restrict genetic recombination during sexual development.
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Affiliation(s)
| | - Sunjoo Joo
- Department of Botany, University of British Columbia, Vancouver, Canada
| | - Jenny Lee
- Department of Botany, University of British Columbia, Vancouver, Canada
| | - Deepak Toor
- Department of Botany, University of British Columbia, Vancouver, Canada
| | - Ally F Gao
- Department of Botany, University of British Columbia, Vancouver, Canada
| | - Kyung-Chul Noh
- Department of Biology, Washington University, St. Louis, MO, USA
| | - Jae-Hyeok Lee
- Department of Botany, University of British Columbia, Vancouver, Canada
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8
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Ohnishi Y, Kokubu I, Kinoshita T, Okamoto T. Sperm Entry into the Egg Cell Induces the Progression of Karyogamy in Rice Zygotes. PLANT & CELL PHYSIOLOGY 2019; 60:1656-1665. [PMID: 31076767 DOI: 10.1093/pcp/pcz077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 04/16/2019] [Indexed: 05/11/2023]
Abstract
Karyogamy is a prerequisite event for plant embryogenesis, in which dynamic changes in nuclear architecture and the establishment of appropriate gene expression patterns must occur. However, the precise role of the male and female gametes in the progression of karyogamy still remains elusive. Here, we show that the sperm cell possesses the unique property to drive steady and swift nuclear fusion. When we fertilized egg cells with sperm cells in vitro, the immediate fusion of the male and female nuclei in the zygote progressed. This rapid nuclear fusion did not occur when two egg cells were artificially fused. However, the nuclear fusion of two egg nuclei could be accelerated by additional sperm entry or the exogenous application of calcium, suggesting that possible increase of cytosolic Ca2+ level via sperm entry into the egg cell efficiently can facilitate karyogamy. In contrast to zygotes, the egg-egg fusion cells failed to proliferate beyond an early developmental stage. Our transcriptional analyses also revealed the rapid activation of zygotic genes in zygotes, whereas there was no expression in fused cells without the male contribution. Thus, the male sperm cell has the ability to cause immediate karyogamy and to establish appropriate gene expression patterns in the zygote.
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Affiliation(s)
- Yukinosuke Ohnishi
- Department of Biological Sciences, Tokyo Metropolitan University, Minami-osawa 1-1, Hachioji, Tokyo, Japan
- Kihara Institute for Biological Research, Yokohama City University, Maioka 641-12, Totsuka, Yokohama, Kanagawa, Japan
| | - Iwao Kokubu
- Department of Biological Sciences, Tokyo Metropolitan University, Minami-osawa 1-1, Hachioji, Tokyo, Japan
| | - Tetsu Kinoshita
- Kihara Institute for Biological Research, Yokohama City University, Maioka 641-12, Totsuka, Yokohama, Kanagawa, Japan
| | - Takashi Okamoto
- Department of Biological Sciences, Tokyo Metropolitan University, Minami-osawa 1-1, Hachioji, Tokyo, Japan
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9
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Brukman NG, Uygur B, Podbilewicz B, Chernomordik LV. How cells fuse. J Cell Biol 2019; 218:1436-1451. [PMID: 30936162 PMCID: PMC6504885 DOI: 10.1083/jcb.201901017] [Citation(s) in RCA: 113] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 03/05/2019] [Accepted: 03/08/2019] [Indexed: 12/11/2022] Open
Abstract
Brukman et al. review cell–cell fusion mechanisms, focusing on the identity of the fusogens that mediate these processes and the regulation of their activities. Cell–cell fusion remains the least understood type of membrane fusion process. However, the last few years have brought about major advances in understanding fusion between gametes, myoblasts, macrophages, trophoblasts, epithelial, cancer, and other cells in normal development and in diseases. While different cell fusion processes appear to proceed via similar membrane rearrangements, proteins that have been identified as necessary and sufficient for cell fusion (fusogens) use diverse mechanisms. Some fusions are controlled by a single fusogen; other fusions depend on several proteins that either work together throughout the fusion pathway or drive distinct stages. Furthermore, some fusions require fusogens to be present on both fusing membranes, and in other fusions, fusogens have to be on only one of the membranes. Remarkably, some of the proteins that fuse cells also sculpt single cells, repair neurons, promote scission of endocytic vesicles, and seal phagosomes. In this review, we discuss the properties and diversity of the known proteins mediating cell–cell fusion and highlight their different working mechanisms in various contexts.
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Affiliation(s)
- Nicolas G Brukman
- Department of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Berna Uygur
- Section on Membrane Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | | | - Leonid V Chernomordik
- Section on Membrane Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
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10
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Selles B, Michaud C, Xiong TC, Leblanc O, Ingouff M. Arabidopsis pollen tube germination and growth depend on the mitochondrial calcium uniporter complex. THE NEW PHYTOLOGIST 2018; 219:58-65. [PMID: 29701876 DOI: 10.1111/nph.15189] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 03/27/2018] [Indexed: 05/18/2023]
Abstract
The mitochondrial calcium uniporter complex (MCUc) was recently characterized in details in metazoans and consists of pore-forming units (MCUs) and regulatory factors that channel calcium (Ca2+ ) ion into the mitochondria. MCUs participate in many stress and developmentally related processes involving Ca2+ . Although multiple homologues of MCUs and one regulatory subunit are usually present in plants, the first functional characterization and contribution to Ca2+ related processes of these proteins have been reported recently. Here, we focused on two predicted Arabidopsis MCUs and studied their role in the germination and the growth of pollen tube, a tip-growing cell type highly dependent on Ca2+ homeostasis. Heterologous expression of MCU1 or MCU2 in yeast is sufficient to generate a mitochondrial Ca2+ influx. MCU1 and MCU2 fluorescent reporters are co-expressed in the vegetative cell mitochondria of the pollen grain but are undetectable in the embryo sac. We demonstrate that MCU1 and MCU2 can form a heterotypic complex. Phenotypic analyses revealed an impaired pollen tube germination and growth in vitro only for the mcu2 mutants suggesting a predominant role of MCU2. Our results show that mitochondrial Ca2+ controlled by MCUs is an additional player in Arabidopsis pollen tube germination and growth.
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Affiliation(s)
- Benjamin Selles
- DIADE, Institut de Recherche pour le Développement, Université de Montpellier, Montpellier, France
| | - Caroline Michaud
- DIADE, Institut de Recherche pour le Développement, Université de Montpellier, Montpellier, France
| | - Tou-Cheu Xiong
- Institut National de la Recherche Agronomique (UMR 386), BPMP, Université de Montpellier, Centre National de la Recherche Scientifique (UMR 5004), Institut National de la Recherche Agronomique, Montpellier SupAgro, F-34060, Montpellier Cedex 2, France
| | - Olivier Leblanc
- DIADE, Institut de Recherche pour le Développement, Université de Montpellier, Montpellier, France
| | - Mathieu Ingouff
- DIADE, Institut de Recherche pour le Développement, Université de Montpellier, Montpellier, France
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11
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Motomura K, Kawashima T, Berger F, Kinoshita T, Higashiyama T, Maruyama D. A pharmacological study of Arabidopsis cell fusion between the persistent synergid and endosperm. J Cell Sci 2018; 131:jcs.204123. [PMID: 28808086 DOI: 10.1242/jcs.204123] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 08/08/2017] [Indexed: 01/30/2023] Open
Abstract
Cell fusion is a pivotal process in fertilization and multinucleate cell formation. A plant cell is ubiquitously surrounded by a hard cell wall, and very few cell fusions have been observed except for gamete fusions. We recently reported that the fertilized central cell (the endosperm) absorbs the persistent synergid, a highly differentiated cell necessary for pollen tube attraction. The synergid-endosperm fusion (SE fusion) appears to eliminate the persistent synergid from fertilized ovule in Arabidopsis thaliana Here, we analyzed the effects of various inhibitors on SE fusion in an in vitro culture system. Different from other cell fusions, neither disruption of actin polymerization nor protein secretion impaired SE fusion. However, transcriptional and translational inhibitors decreased the SE fusion success rate and also inhibited endosperm division. Failures of SE fusion and endosperm nuclear proliferation were also induced by roscovitine, an inhibitor of cyclin-dependent kinases (CDK). These data indicate unique aspects of SE fusion such as independence of filamentous actin support and the importance of CDK-mediated mitotic control.
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Affiliation(s)
- Kazuki Motomura
- Institute of Transformative Bio-Molecules (ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
| | - Tomokazu Kawashima
- Department of Plant and Soil Sciences, University of Kentucky, 321 Plant Science Building, 1405 Veterans Dr., Lexington, KY 40546, USA
| | - Frédéric Berger
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Tetsu Kinoshita
- Kihara Institute for Biological Research, Yokohama City University, 641-12 Maioka-cho, Totsuka-ku, Yokohama, Kanagawa 244-0813, Japan
| | - Tetsuya Higashiyama
- Institute of Transformative Bio-Molecules (ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan.,Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
| | - Daisuke Maruyama
- Kihara Institute for Biological Research, Yokohama City University, 641-12 Maioka-cho, Totsuka-ku, Yokohama, Kanagawa 244-0813, Japan
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Cheng P, Li H, Yuan L, Li H, Xi L, Zhang J, Liu J, Wang Y, Zhao H, Zhao H, Han S. The ERA-Related GTPase AtERG2 Associated with Mitochondria 18S RNA Is Essential for Early Embryo Development in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2018; 9:182. [PMID: 29497438 PMCID: PMC5818394 DOI: 10.3389/fpls.2018.00182] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 01/31/2018] [Indexed: 05/03/2023]
Abstract
The ERA (E. coli RAS-like protein)-related GTPase (ERG) is a nuclear-encoded GTPase with two conserved domains: a GTPase domain and a K Homology (KH) domain. ERG plays a vital role in early seed development in Antirrhinum majus. However, the mechanism that regulates seed development remains unclear. Blasting the genome sequence revealed two homologies of ERG, AtERG1, and AtERG2 in Arabidopsis. In this study, we found that AtERG2 is localized in the mitochondria and binds mitochondrial 18S RNA. Promoter and transcript analyses indicated that AtERG2 was mainly expressed in the leaf vein, trichome, and ovule. The T-DNA insertion lines of AtERG2 showed silique shortage, early seed abortion, and sporophytic maternal effects (SME), in which some seeds arrested in the zygotic stage at 1.5 days after pollination (DAP) and aborted at 2.0 DAP in aterg2-1 +/-. We further showed that the ovules of these arrested seeds presented unusual tissue degradation inside the embryo sacs. Reactive oxygen species (ROS) accumulated at 1.0 and 1.5 DAP in the arrested seeds, and the transcription of several ROS-responsive genes, WRKY40, ANAC017, and AOX1a, was up-regulated in the aterg2-1 +/- arrested seeds at 1.5 and 2.0 DAP, but not in wild-type (WT) and aterg2-1 +/- developed seeds. The cell death-related gene BAG6 was also transcriptionally activated in aterg2-1 +/- seeds arrested at 2.0 DAP. Additionally, the protein level of mitochondria protein ATPase Subunit 6 was lower in 2-DAP siliques of aterg2-1 +/- than it was in those of WT. These results suggested that AtERG2 promotes early seed development by affecting the maturation of the mitochondria ribosome small subunit and mitochondrial protein translation in Arabidopsis.
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Affiliation(s)
- Pengyu Cheng
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Hongjuan Li
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Linlin Yuan
- Xinjiang Key Laboratory of Special Species Conservation and Regulatory Biology, College of Life Science, Xinjiang Normal University, Urumqi, China
| | - Huiyong Li
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Lele Xi
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Junjie Zhang
- Key Laboratory of Cell Proliferation and Regulation Biology, Ministry of Education, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Jin Liu
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Yingdian Wang
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Heping Zhao
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing, China
- *Correspondence: Heping Zhao
| | - Huixin Zhao
- Xinjiang Key Laboratory of Special Species Conservation and Regulatory Biology, College of Life Science, Xinjiang Normal University, Urumqi, China
- Huixin Zhao
| | - Shengcheng Han
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing, China
- Shengcheng Han
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13
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Valansi C, Moi D, Leikina E, Matveev E, Graña M, Chernomordik LV, Romero H, Aguilar PS, Podbilewicz B. Arabidopsis HAP2/GCS1 is a gamete fusion protein homologous to somatic and viral fusogens. J Cell Biol 2017; 216:571-581. [PMID: 28137780 PMCID: PMC5350521 DOI: 10.1083/jcb.201610093] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 12/27/2016] [Accepted: 01/18/2017] [Indexed: 01/08/2023] Open
Abstract
Cell-cell fusion is inherent to sexual reproduction. Loss of HAPLESS 2/GENERATIVE CELL SPECIFIC 1 (HAP2/GCS1) proteins results in gamete fusion failure in diverse organisms, but their exact role is unclear. In this study, we show that Arabidopsis thaliana HAP2/GCS1 is sufficient to promote mammalian cell-cell fusion. Hemifusion and complete fusion depend on HAP2/GCS1 presence in both fusing cells. Furthermore, expression of HAP2 on the surface of pseudotyped vesicular stomatitis virus results in homotypic virus-cell fusion. We demonstrate that the Caenorhabditis elegans Epithelial Fusion Failure 1 (EFF-1) somatic cell fusogen can replace HAP2/GCS1 in one of the fusing membranes, indicating that HAP2/GCS1 and EFF-1 share a similar fusion mechanism. Structural modeling of the HAP2/GCS1 protein family predicts that they are homologous to EFF-1 and viral class II fusion proteins (e.g., Zika virus). We name this superfamily Fusexins: fusion proteins essential for sexual reproduction and exoplasmic merger of plasma membranes. We suggest a common origin and evolution of sexual reproduction, enveloped virus entry into cells, and somatic cell fusion.
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Affiliation(s)
- Clari Valansi
- Department of Biology, Technion- Israel Institute of Technology, Haifa 32000, Israel
| | - David Moi
- Laboratorio de Biología Celular de Membranas, Instituto de Investigaciones Biotecnologicas "Dr. Rodolfo A. Ugalde," Universidad Nacional de San Martin, Buenos Aires, CP1650, Argentina
| | - Evgenia Leikina
- Section on Membrane Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | - Elena Matveev
- Department of Biology, Technion- Israel Institute of Technology, Haifa 32000, Israel
| | - Martín Graña
- Unidad de Bioinformática, Institut Pasteur Montevideo, Montevideo 11400, Uruguay
| | - Leonid V Chernomordik
- Section on Membrane Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | - Héctor Romero
- Laboratorio de Organización y Evolución del Genoma, Unidad de Genómica Evolutiva, Departamento Ecología y Evolución, Facultad de Ciencias/Centro Universitario Regional del Este, Universidad de la República, Montevideo 11400, Uruguay
| | - Pablo S Aguilar
- Laboratorio de Biología Celular de Membranas, Instituto de Investigaciones Biotecnologicas "Dr. Rodolfo A. Ugalde," Universidad Nacional de San Martin, Buenos Aires, CP1650, Argentina
| | - Benjamin Podbilewicz
- Department of Biology, Technion- Israel Institute of Technology, Haifa 32000, Israel
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