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Trinh DC, Melogno I, Martin M, Trehin C, Smith RS, Hamant O. Arabidopsis floral buds are locked through stress-induced sepal tip curving. NATURE PLANTS 2024; 10:1258-1266. [PMID: 39060423 DOI: 10.1038/s41477-024-01760-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 07/03/2024] [Indexed: 07/28/2024]
Abstract
In most plant species, sepals-the outermost floral organs-provide a protective shield for reproductive organs. How the floral bud becomes sealed is unknown. In Arabidopsis, we identified a small region at the sepal tip that is markedly curved inward early on and remains curved even after anthesis. Through modelling and quantitative growth analysis, we find that this hook emerges from growth arrest at the tip at a stage when cortical microtubules align with growth-derived tensile stress. Depolymerizing microtubules specifically at young sepal tips hindered hook formation and resulted in open floral buds. Mutants with defective growth pattern at the tip failed to curve inwards, whereas mutants with enhanced alignment of cortical microtubules at the tip exhibited a stronger hook. We propose that floral buds are locked due to a stress-derived growth arrest event curving the sepal tip and forming a rigid hook early on during flower development.
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Affiliation(s)
- Duy-Chi Trinh
- Laboratoire de Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCBL, INRAE, CNRS, Lyon, France.
- University of Science and Technology of Hanoi, Vietnam Academy of Science and Technology (VAST), Cau Giay, Vietnam.
| | - Isaty Melogno
- Laboratoire de Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCBL, INRAE, CNRS, Lyon, France
| | - Marjolaine Martin
- Laboratoire de Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCBL, INRAE, CNRS, Lyon, France
| | - Christophe Trehin
- Laboratoire de Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCBL, INRAE, CNRS, Lyon, France
| | - Richard S Smith
- Department of Computational and Systems Biology, John Innes Centre, Norwich, UK
| | - Olivier Hamant
- Laboratoire de Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCBL, INRAE, CNRS, Lyon, France.
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Comparative Proteomic Analysis Unveils Critical Pathways Underlying the Role of Nitrogen Fertilizer Treatment in American Elderberry. Proteomes 2019; 7:proteomes7010010. [PMID: 30897755 PMCID: PMC6473435 DOI: 10.3390/proteomes7010010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 03/04/2019] [Accepted: 03/18/2019] [Indexed: 12/24/2022] Open
Abstract
American elderberry (Sambucus nigra subsp. canadensis) is a rapidly growing specialty crop in Missouri and eastern North America. Nitrogen (N) is a major nutrient involved in plant growth and development. However, proteome changes for different genotypes of elder in response to varying levels of N-treatment remain undefined. To reveal plant responses to N, comparative proteomic analyses were performed to determine consistent changes in three genotypes of elderberry leaves (Adams II, Bob Gordon and Wyldewood) grown under different N-fertilizer treatments. 165 proteins separated by two dimensional gel electrophoresis showed significant differences in abundance (p < 0.05 and greater than 2-fold). Principal component analysis of the abundance profiles of these proteins revealed Bob Gordon as a distinct genotype. The 165 proteins were identified by mass spectrometry and showed similar functional distributions in these genotypes underlying the N-treatment. Among the proteins identified, 23 are mainly involved in photosynthesis, protein metabolism and redox homeostasis. Their abundance profiles were not altered upon exposure to N or genotype. These results provide novel insights into plant responses to fertilizer treatment at the proteome level and could lead to a better understanding of molecular mechanisms of elderberry growth.
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Park HY, Lee HT, Lee JH, Kim JK. Arabidopsis U2AF65 Regulates Flowering Time and the Growth of Pollen Tubes. FRONTIERS IN PLANT SCIENCE 2019; 10:569. [PMID: 31130976 PMCID: PMC6510283 DOI: 10.3389/fpls.2019.00569] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 04/15/2019] [Indexed: 05/19/2023]
Abstract
During pre-mRNA splicing, U2 small nuclear ribonucleoprotein auxiliary factor 65 (U2AF65) interacts with U2AF35 and splicing factor 1 (SF1), allowing for the recognition of the 3'-splice site by the ternary complex. The functional characterization of U2AF65 homologs has not been performed in Arabidopsis thaliana yet. Here, we show that normal plant development, including floral transition, and male gametophyte development, requires two Arabidopsis U2AF65 isoforms (AtU2AF65a and AtU2AF65b). Loss-of-function mutants of these two isoforms displayed opposite flowering phenotypes: atu2af65a mutants showed late flowering, whereas atu2af65b mutants were characterized by slightly early flowering, as compared to that in the wild-type (Col-0) plants. These abnormal flowering phenotypes were well-correlated with the expression patterns of the flowering time genes such as FLOWERING LOCUS C (FLC) and FLOWERING LOCUS T (FT). However, the two atu2af65 mutants did not display any morphological abnormalities or alterations in abiotic stress tests. Double mutation of the AtU2AF65a and AtU2AF65b genes resulted in non-viable seeds due to defective male gametophyte. In vitro pollen germination test revealed that mutations in both AtU2AF65a and AtU2AF65b genes significantly impaired pollen tube growth. Collectively, our findings suggest that two protein isoforms of AtU2AF65 are differentially involved in regulating flowering time and display a redundant role in pollen tube growth.
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Affiliation(s)
- Hyo-Young Park
- Division of Life Sciences, Korea University, Seoul, South Korea
| | - Hee Tae Lee
- Division of Life Sciences, Korea University, Seoul, South Korea
| | - Jeong Hwan Lee
- Division of Life Science, Chonbuk National University, Jeonju, South Korea
- *Correspondence: Jeong Hwan Lee, Jeong-Kook Kim,
| | - Jeong-Kook Kim
- Division of Life Sciences, Korea University, Seoul, South Korea
- *Correspondence: Jeong Hwan Lee, Jeong-Kook Kim,
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Zhu DZ, Zhao XF, Liu CZ, Ma FF, Wang F, Gao XQ, Zhang XS. Interaction between RNA helicase ROOT INITIATION DEFECTIVE 1 and GAMETOPHYTIC FACTOR 1 is involved in female gametophyte development in Arabidopsis. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:5757-5768. [PMID: 27683728 PMCID: PMC5066494 DOI: 10.1093/jxb/erw341] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
ROOT INITIATION DEFECTIVE 1 (RID1) is an Arabidopsis DEAH/RHA RNA helicase. It functions in hypocotyl de-differentiation, de novo meristem formation, and cell specification of the mature female gametophyte (FG). However, it is unclear how RID1 regulates FG development. In this study, we observed that mutations to RID1 disrupted the developmental synchrony and retarded the progression of FG development. RID1 exhibited RNA helicase activity, with a preference for unwinding double-stranded RNA in the 3' to 5' direction. Furthermore, we found that RID1 interacts with GAMETOPHYTIC FACTOR 1 (GFA1), which is an integral protein of the spliceosome component U5 small nuclear ribonucleoprotein (snRNP) particle. Substitution of specific RID1 amino acids (Y266F and T267I) inhibited the interaction with GFA1. In addition, the mutated RID1 could not complement the seed-abortion phenotype of the rid1 mutant. The rid1 and gfa1 mutants exhibited similar abnormalities in pre-mRNA splicing and down-regulated expression of some genes involved in FG development. Our results suggest that an interaction between RID1 and the U5 snRNP complex regulates essential pre-mRNA splicing of the genes required for FG development. This study provides new information regarding the mechanism underlying the FG developmental process.
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Affiliation(s)
- Dong Zi Zhu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian 271018, China
| | - Xue Fang Zhao
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian 271018, China
| | - Chang Zhen Liu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian 271018, China
| | - Fang Fang Ma
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian 271018, China
| | - Fang Wang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian 271018, China
| | - Xin-Qi Gao
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian 271018, China
| | - Xian Sheng Zhang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian 271018, China
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Fujii S, Suzuki T, Giegé P, Higashiyama T, Koizuka N, Shikanai T. The Restorer-of-fertility-like 2 pentatricopeptide repeat protein and RNase P are required for the processing of mitochondrial orf291 RNA in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 86:504-13. [PMID: 27122350 DOI: 10.1111/tpj.13185] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 04/14/2016] [Indexed: 05/27/2023]
Abstract
Eukaryotes harbor mitochondria obtained via ancient symbiosis events. The successful evolution of energy production in mitochondria has been dependent on the control of mitochondrial gene expression by the nucleus. In flowering plants, the nuclear-encoded pentatricopeptide repeat (PPR) superfamily proteins are widely involved in mitochondrial RNA metabolism. Here, we show that an Arabidopsis nuclear-encoded RNA-binding protein, Restorer-of-fertility-like PPR protein 2 (RFL2), is required for RNA degradation of the mitochondrial orf291 transcript via endonucleolytic cleavage of the transcript in the middle of its reading frame. Both in vivo and in vitro, this RNA cleavage requires the activity of mitochondrial proteinaceous RNase P, which is possibly recruited to the site by RFL2. The site of RNase P cleavage likely forms a tRNA-like structure in the orf291 transcript. This study presents an example of functional collaboration between a PPR protein and an endonuclease in RNA cleavage. Furthermore, we show that the RFL2-binding region within the orf291 gene is hypervariable in the family Brassicaceae, possibly correlated with the rapid evolution of the RNA-recognition interfaces of the RFL proteins.
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Affiliation(s)
- Sota Fujii
- Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, 630-0192, Japan
| | - Takamasa Suzuki
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8602, Japan
- Japan Science and Technology Agency, ERATO, Higashiyama Live-Holonics Project, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8602, Japan
| | - Philippe Giegé
- Institut de Biologie Moléculaire des Plantes, 12 Rue du Général Zimmer, Strasbourg, 67084, France
| | - Tetsuya Higashiyama
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8602, Japan
- Japan Science and Technology Agency, ERATO, Higashiyama Live-Holonics Project, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8602, Japan
- WPI-ITbM, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8602, Japan
| | - Nobuya Koizuka
- Faculty of Agriculture, Tamagawa University, 6-1-1 Tamagawa-Gakuen, Machida, Tokyo, 194-8610, Japan
| | - Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
- CREST, Japan Science and Technology Agency, Chiyoda-ku, Tokyo, 102-0076, Japan
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Tsugeki R, Tanaka-Sato N, Maruyama N, Terada S, Kojima M, Sakakibara H, Okada K. CLUMSY VEIN, the Arabidopsis DEAH-box Prp16 ortholog, is required for auxin-mediated development. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 81:183-97. [PMID: 25384462 DOI: 10.1111/tpj.12721] [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: 01/06/2014] [Revised: 10/29/2014] [Accepted: 10/31/2014] [Indexed: 05/25/2023]
Abstract
Pre-messenger RNA (pre-mRNA) splicing is essential in eukaryotic cells. In animals and yeasts, the DEAH-box RNA-dependent ATPase Prp16 mediates conformational change of the spliceosome, thereby facilitating pre-mRNA splicing. In yeasts, Prp16 also plays an important role in splicing fidelity. Conversely, PRP16 orthologs in Chlamydomonas reinhardtii and nematode do not have an important role in general pre-mRNA splicing, but are required for gene silencing and sex determination, respectively. Functions of PRP16 orthologs in higher plants have not been described until now. Here we show that the CLUMSY VEIN (CUV) gene encoding the unique Prp16 ortholog in Arabidopsis thaliana facilitates auxin-mediated development including male-gametophyte transmission, apical-basal patterning of embryonic and gynoecium development, stamen development, phyllotactic flower positioning, and vascular development. cuv-1 mutation differentially affects splicing and expression of genes involved in auxin biosynthesis, polar auxin transport, auxin perception and auxin signaling. The cuv-1 mutation does not have an equal influence on pre-mRNA substrates. We propose that Arabidopsis PRP16/CUV differentially facilitates expression of genes, which include genes involved in auxin biosynthesis, transport, perception and signaling, thereby collectively influencing auxin-mediated development.
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Affiliation(s)
- Ryuji Tsugeki
- Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
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Jang YH, Park HY, Lee KC, Thu MP, Kim SK, Suh MC, Kang H, Kim JK. A homolog of splicing factor SF1 is essential for development and is involved in the alternative splicing of pre-mRNA in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 78:591-603. [PMID: 24580679 DOI: 10.1111/tpj.12491] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 02/13/2014] [Accepted: 02/19/2014] [Indexed: 05/20/2023]
Abstract
During initial spliceosome assembly, SF1 binds to intron branch points and interacts with U2 snRNP auxiliary factor 65 (U2AF65). Here, we present evidence indicating that AtSF1, the Arabidopsis SF1 homolog, interacts with AtU2AF65a and AtU2AF65b, the Arabidopsis U2AF65 homologs. A mutant allele of AtSF1 (At5g51300) that contains a T-DNA insertion conferred pleiotropic developmental defects, including early flowering and abnormal sensitivity to abscisic acid. An AtSF1 promoter-driven GUS reporter assay showed that AtSF1 promoter activity was temporally and spatially altered, and that full AtSF1 promoter activity required a significant proportion of the coding region. DNA chip analyses showed that only a small proportion of the transcriptome was altered by more than twofold in either direction in the AtSF1 mutant. Expression of the mRNAs of many heat shock proteins was more than fourfold higher in the mutant strain; these mRNAs were among those whose expression was increased most in the mutant strain. An RT-PCR assay revealed an altered alternative splicing pattern for heat shock transcription factor HsfA2 (At2g26150) in the mutant; this altered splicing is probably responsible for the increased expression of the target genes induced by HsfA2. Altered alternative splicing patterns were also detected for the transcripts of other genes in the mutant strain. These results suggest that AtSF1 has functional similarities to its yeast and metazoan counterparts.
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Affiliation(s)
- Yun Hee Jang
- Plant Signaling Network Research Center, School of Life Sciences and Biotechnology, Korea University, Seoul, 136-701, Korea
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Tsukaya H, Byrne ME, Horiguchi G, Sugiyama M, Van Lijsebettens M, Lenhard M. How do 'housekeeping' genes control organogenesis?--Unexpected new findings on the role of housekeeping genes in cell and organ differentiation. JOURNAL OF PLANT RESEARCH 2013; 126:3-15. [PMID: 22922868 DOI: 10.1007/s10265-012-0518-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 07/31/2012] [Indexed: 05/08/2023]
Abstract
In recent years, an increasing number of mutations in what would appear to be 'housekeeping genes' have been identified as having unexpectedly specific defects in multicellular organogenesis. This is also the case for organogenesis in seed plants. Although it is not surprising that loss-of-function mutations in 'housekeeping' genes result in lethality or growth retardation, it is surprising when (1) the mutant phenotype results from the loss of function of a 'housekeeping' gene and (2) the mutant phenotype is specific. In this review, by defining housekeeping genes as those encoding proteins that work in basic metabolic and cellular functions, we discuss unexpected links between housekeeping genes and specific developmental processes. In a surprising number of cases housekeeping genes coding for enzymes or proteins with functions in basic cellular processes such as transcription, post-transcriptional modification, and translation affect plant development.
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Affiliation(s)
- Hirokazu Tsukaya
- Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan.
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Koncz C, deJong F, Villacorta N, Szakonyi D, Koncz Z. The spliceosome-activating complex: molecular mechanisms underlying the function of a pleiotropic regulator. FRONTIERS IN PLANT SCIENCE 2012; 3:9. [PMID: 22639636 PMCID: PMC3355604 DOI: 10.3389/fpls.2012.00009] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Accepted: 01/09/2012] [Indexed: 05/18/2023]
Abstract
Correct interpretation of the coding capacity of RNA polymerase II transcribed eukaryotic genes is determined by the recognition and removal of intronic sequences of pre-mRNAs by the spliceosome. Our current knowledge on dynamic assembly and subunit interactions of the spliceosome mostly derived from the characterization of yeast, Drosophila, and human spliceosomal complexes formed on model pre-mRNA templates in cell extracts. In addition to sequential structural rearrangements catalyzed by ATP-dependent DExH/D-box RNA helicases, catalytic activation of the spliceosome is critically dependent on its association with the NineTeen Complex (NTC) named after its core E3 ubiquitin ligase subunit PRP19. NTC, isolated recently from Arabidopsis, occurs in a complex with the essential RNA helicase and GTPase subunits of the U5 small nuclear RNA particle that are required for both transesterification reactions of splicing. A compilation of mass spectrometry data available on the composition of NTC and spliceosome complexes purified from different organisms indicates that about half of their conserved homologs are encoded by duplicated genes in Arabidopsis. Thus, while mutations of single genes encoding essential spliceosome and NTC components lead to cell death in other organisms, differential regulation of some of their functionally redundant Arabidopsis homologs permits the isolation of partial loss of function mutations. Non-lethal pleiotropic defects of these mutations provide a unique means for studying the roles of NTC in co-transcriptional assembly of the spliceosome and its crosstalk with DNA repair and cell death signaling pathways.
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Affiliation(s)
- Csaba Koncz
- Department of Plant Developmental Biology, Max-Planck Institute for Plant Breeding ResearchCologne, Germany
- Institute of Plant Biology, Biological Research Center of Hungarian Academy of SciencesSzeged, Hungary
- *Correspondence: Csaba Koncz, Department of Plant Developmental Biology, Max-Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, D-59829 Cologne, Germany. e-mail:
| | - Femke deJong
- Department of Plant Developmental Biology, Max-Planck Institute for Plant Breeding ResearchCologne, Germany
| | - Nicolas Villacorta
- Department of Plant Developmental Biology, Max-Planck Institute for Plant Breeding ResearchCologne, Germany
| | - Dóra Szakonyi
- Department of Plant Developmental Biology, Max-Planck Institute for Plant Breeding ResearchCologne, Germany
| | - Zsuzsa Koncz
- Department of Plant Developmental Biology, Max-Planck Institute for Plant Breeding ResearchCologne, Germany
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Shi DQ, Yang WC. Ovule development in Arabidopsis: progress and challenge. CURRENT OPINION IN PLANT BIOLOGY 2011; 14:74-80. [PMID: 20884278 DOI: 10.1016/j.pbi.2010.09.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Revised: 08/31/2010] [Accepted: 09/01/2010] [Indexed: 05/18/2023]
Abstract
Female gametophyte, the central core of the ovule, is a simple seven-celled reproductive structure. Its stereotyped ontogeny provides a traceable model system to study mechanisms controlling cell growth, cell division, cell fate, pattern formation, and perhaps the function of essential genes in plants. An auxin concentration gradient was demonstrated for the first time in the embryo sac to control gametic cell fate. Mutant analysis also indicates a role of RNA processing in the mitotic progression of the gametophytic generation and cell fate determination in the embryo sac. Combined studies of genetics and transcriptome analysis revealed recently that epigenetic pathways play a critical role in female gametophyte development. In addition, the discovery that a large number of small secreted cysteine-rich proteins are enriched in embryo sac is of special interest. Except these insights and progresses, challenge ahead is to reveal the signaling pathways and their interactions that lead to the patterning of the female gametophyte.
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Affiliation(s)
- Dong-Qiao Shi
- Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 1 West Beichen Road, Chaoyang District, Beijing 100101, China.
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Abstract
The flowering plant germline is produced during the haploid gametophytic stage. Defining the germline is complicated by the extreme reduction of the male and female gametophytes, also referred to as pollen and embryo sac, respectively. Both male and female gamete progenitors are segregated by an asymmetric cell division, as is the case for the germline in animals. Genetic studies and access to the transcriptome of isolated gametes have provided a regulatory framework for the mechanisms that define the male germline. What specifies female germline identity remains unknown. Recent evidence indicates that an auxin gradient provides positional information and plays a role in defining the identity of the female gamete lineage. The animal germline is also marked by production of small RNAs, and recent evidence indicates that this trait might be shared with the plant gamete lineage.
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Affiliation(s)
- Frédéric Berger
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117604
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Monaghan J, Xu F, Xu S, Zhang Y, Li X. Two putative RNA-binding proteins function with unequal genetic redundancy in the MOS4-associated complex. PLANT PHYSIOLOGY 2010; 154:1783-93. [PMID: 20943852 PMCID: PMC2996007 DOI: 10.1104/pp.110.158931] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Accepted: 10/07/2010] [Indexed: 05/20/2023]
Abstract
The MOS4-associated complex (MAC) is a highly conserved nuclear protein complex associated with the spliceosome. We recently purified the MAC from Arabidopsis (Arabidopsis thaliana) nuclei, identified its potential components by mass spectrometry, and showed that at least five core proteins in the MAC are required for defense responses in plants. Here, we report the characterization of a putative RNA-binding protein identified in the MAC named MAC5A and its close homolog MAC5B. We confirmed that MAC5A is a component of the MAC through coimmunoprecipitation with the previously described MAC protein CELL DIVISION CYCLE5 from Arabidopsis. In addition, like all other characterized MAC proteins, MAC5A fused to the Green Fluorescent Protein localizes to the nucleus. Double mutant analysis revealed that MAC5A and MAC5B are unequally redundant and that a double mac5a mac5b mutant results in lethality. Probably due to this partial redundancy, mac5a and mac5b single mutants do not exhibit enhanced susceptibility to virulent or avirulent pathogen infection. However, like other MAC mutations, mac5a-1 partially suppresses the autoimmune phenotypes of suppressor of npr1-1, constitutive1 (snc1), a gain-of-function mutant that expresses a deregulated Resistance protein. Our results suggest that MAC5A is a component of the MAC that contributes to snc1- mediated autoimmunity.
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Affiliation(s)
| | | | | | | | - Xin Li
- Corresponding author; e-mail
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Li HJ, Liu NY, Shi DQ, Liu J, Yang WC. YAO is a nucleolar WD40-repeat protein critical for embryogenesis and gametogenesis in Arabidopsis. BMC PLANT BIOLOGY 2010; 10:169. [PMID: 20699009 PMCID: PMC3095302 DOI: 10.1186/1471-2229-10-169] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2010] [Accepted: 08/11/2010] [Indexed: 05/18/2023]
Abstract
BACKGROUND In flowering plants, gametogenesis generates multicellular male and female gametophytes. In the model system Arabidopsis, the male gametophyte or pollen grain contains two sperm cells and a vegetative cell. The female gametophyte or embryo sac contains seven cells, namely one egg, two synergids, one central cell and three antipodal cells. Double fertilization of the central cell and egg produces respectively a triploid endosperm and a diploid zygote that develops further into an embryo. The genetic control of the early embryo patterning, especially the initiation of the first zygotic division and the positioning of the cell plate, is largely unknown. RESULTS Here we report the characterization of a mutation, yaozhe (yao), that causes zygote arrest and misplacement of cell plate of the zygote, leading to early embryo lethality. In addition, gametophyte development is partially impaired. A small portion of the mutant embryo sacs are arrested at four-nucleate stage with aberrant nuclear positioning. Furthermore, the competence of male gametophytes is also compromised. YAO encodes a nucleolar protein with seven WD-repeats. Its homologues in human and yeast have been shown to be components of the U3 snoRNP complex and function in 18S rRNA processing. YAO is expressed ubiquitously, with high level of expression in tissues under active cell divisions, including embryo sacs, pollen, embryos, endosperms and root tips. CONCLUSIONS Phenotypic analysis indicated that YAO is required for the correct positioning of the first zygotic division plane and plays a critical role in gametogenesis in Arabidopsis. Since YAO is a nucleolar protein and its counterparts in yeast and human are components of the U3 snoRNP complex, we therefore postulate that YAO is most likely involved in rRNA processing in plants as well.
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Affiliation(s)
- Hong-Ju Li
- Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, the Chinese Academy of Sciences, Beijing 100101, China
- Gradute University, the Chinese Academy of Sciences, Beijing 100049, China
| | - Nai-You Liu
- Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, the Chinese Academy of Sciences, Beijing 100101, China
| | - Dong-Qiao Shi
- Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, the Chinese Academy of Sciences, Beijing 100101, China
| | - Jie Liu
- Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, the Chinese Academy of Sciences, Beijing 100101, China
| | - Wei-Cai Yang
- Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, the Chinese Academy of Sciences, Beijing 100101, China
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