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Wu R, Song K, Jing R, Du L. The de-ubiquitinase UBQUITIN SPECIFIC PROTEASE 15 (UBP15) interacts with the SCF E3 complex adaptor ARABIDOPSIS SKP1 HOMOLOGUE 1 (ASK1) to regulate petal size and fertility in Arabidopsis thaliana. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2024; 345:112112. [PMID: 38750799 DOI: 10.1016/j.plantsci.2024.112112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 04/14/2024] [Accepted: 05/05/2024] [Indexed: 05/20/2024]
Abstract
Ubiquitination is a pivotal type of post-translational modification, which plays a far-reaching role in plant growth and development, as well as in the response of plants to stress. Just like the two sides of a coin, de-ubiquitination also plays an important role in plant life, which has been gradually discovered in recent years. Here, we demonstrate that the UBQUITIN SPECIFIC PROTEASE 15 (UBP15), which is a UBP-type de-ubiquitinase, interacts with the SCF E3 complex adaptor ARABIDOPSIS SKP1 HOMOLOGUE 1 (ASK1) and influences its protein stability to regulate plant fertility and petal size. The UBP15 is associated with the ASK1 physically, as verified by yeast-two-hybrid (Y2H) and protein pull-down in vitro assays. Disruption of ASK1 by a T-DNA insertion generates some abnormal phenotypes, such as low fertility and small petals. Genetic analysis shows that the UBP15 mutation enhances the low-fertility and small-petal phenotypes of ask1 mutant plants. By proteomic analysis, many types of proteins were identified as potential candidate downstream genes associated with the phenotypes of ubp15 ask1 double mutant plants. Taken together, these findings reveal a molecular relationship between ASK1 and UBP15 and their interaction in the regulation of petal size and fertility, which would benefit in-depth research about the ubiquitin-related pathway in plant physiological processes in the future.
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Affiliation(s)
- Ruihua Wu
- State Key Laboratory of Tree Genetics and Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, College of Biological Sciences and Technology, Beijing Forestry University, No. 35, Qinghua East Road, Beijing 100083, China
| | - Kaixuan Song
- State Key Laboratory of Tree Genetics and Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, College of Biological Sciences and Technology, Beijing Forestry University, No. 35, Qinghua East Road, Beijing 100083, China
| | - Ruotong Jing
- State Key Laboratory of Tree Genetics and Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, College of Biological Sciences and Technology, Beijing Forestry University, No. 35, Qinghua East Road, Beijing 100083, China
| | - Liang Du
- State Key Laboratory of Tree Genetics and Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, College of Biological Sciences and Technology, Beijing Forestry University, No. 35, Qinghua East Road, Beijing 100083, China.
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Yu P, Gao Z, Hua Z. Contrasting Impacts of Ubiquitin Overexpression on Arabidopsis Growth and Development. PLANTS (BASEL, SWITZERLAND) 2024; 13:1485. [PMID: 38891294 PMCID: PMC11174952 DOI: 10.3390/plants13111485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 05/16/2024] [Accepted: 05/26/2024] [Indexed: 06/21/2024]
Abstract
In plants, the ubiquitin (Ub)-26S proteasome system (UPS) regulates numerous biological functions by selectively targeting proteins for ubiquitylation and degradation. However, the regulation of Ub itself on plant growth and development remains unclear. To demonstrate a possible impact of Ub supply, as seen in animals and flies, we carefully analyzed the growth and developmental phenotypes of two different poly-Ub (UBQ) gene overexpression plants of Arabidopsis thaliana. One is transformed with hexa-6His-UBQ (designated 6HU), driven by the cauliflower mosaic virus 35S promoter, while the other expresses hexa-6His-TEV-UBQ (designated 6HTU), driven by the endogenous promoter of UBQ10. We discovered that 6HU and 6HTU had contrasting seed yields. Compared to wildtype (WT), the former exhibited a reduced seed yield, while the latter showed an increased seed production that was attributed to enhanced growth vigor and an elevated silique number per plant. However, reduced seed sizes were common in both 6HU and 6HTU. Differences in the activity and size of the 26S proteasome assemblies in the two transgenic plants were also notable in comparison with WT, suggestive of a contributory role of UBQ expression in proteasome assembly and function. Collectively, our findings demonstrated that exogenous expression of recombinant Ub may optimize plant growth and development by influencing the UPS activities via structural variance, expression patterns, and abundance of free Ub supply.
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Affiliation(s)
- Peifeng Yu
- Department of Environmental and Plant Biology, Ohio University, Athens, OH 45701, USA; (P.Y.); (Z.G.)
- Interdisciplinary Program in Molecular and Cellular Biology, Ohio University, Athens, OH 45701, USA
| | - Zhenyu Gao
- Department of Environmental and Plant Biology, Ohio University, Athens, OH 45701, USA; (P.Y.); (Z.G.)
- State Key Laboratory of Rice Biology and Breeding, China National Rice Research Institute, Hangzhou 310006, China
| | - Zhihua Hua
- Department of Environmental and Plant Biology, Ohio University, Athens, OH 45701, USA; (P.Y.); (Z.G.)
- Interdisciplinary Program in Molecular and Cellular Biology, Ohio University, Athens, OH 45701, USA
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Sun L, Cao S, Zheng N, Kao TH. Analyses of Cullin1 homologs reveal functional redundancy in S-RNase-based self-incompatibility and evolutionary relationships in eudicots. THE PLANT CELL 2023; 35:673-699. [PMID: 36478090 PMCID: PMC9940881 DOI: 10.1093/plcell/koac357] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 12/05/2022] [Indexed: 06/17/2023]
Abstract
In Petunia (Solanaceae family), self-incompatibility (SI) is regulated by the polymorphic S-locus, which contains the pistil-specific S-RNase and multiple pollen-specific S-Locus F-box (SLF) genes. SLFs assemble into E3 ubiquitin ligase complexes known as Skp1-Cullin1-F-box complexes (SCFSLF). In pollen tubes, these complexes collectively mediate ubiquitination and degradation of all nonself S-RNases, but not self S-RNase, resulting in cross-compatible, but self-incompatible, pollination. Using Petunia inflata, we show that two pollen-expressed Cullin1 (CUL1) proteins, PiCUL1-P and PiCUL1-B, function redundantly in SI. This redundancy is lost in Petunia hybrida, not because of the inability of PhCUL1-B to interact with SSK1, but due to a reduction in the PhCUL1-B transcript level. This is possibly caused by the presence of a DNA transposon in the PhCUL1-B promoter region, which was inherited from Petunia axillaris, one of the parental species of Pe. hybrida. Phylogenetic and syntenic analyses of Cullin genes in various eudicots show that three Solanaceae-specific CUL1 genes share a common origin, with CUL1-P dedicated to S-RNase-related reproductive processes. However, CUL1-B is a dispersed duplicate of CUL1-P present only in Petunia, and not in the other species of the Solanaceae family examined. We suggest that the CUL1s involved (or potentially involved) in the SI response in eudicots share a common origin.
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Affiliation(s)
- Linhan Sun
- Intercollege Graduate Degree Program in Plant Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Shiyun Cao
- Howard Hughes Medical Institute, Department of Pharmacology, University of Washington, Seattle, Washington 98195, USA
| | - Ning Zheng
- Howard Hughes Medical Institute, Department of Pharmacology, University of Washington, Seattle, Washington 98195, USA
| | - Teh-hui Kao
- Intercollege Graduate Degree Program in Plant Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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Li Y, Yapa MM, Hua Z. A Machine Learning Approach to Prioritizing Functionally Active F-box Members in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2021; 12:639253. [PMID: 34122469 PMCID: PMC8192846 DOI: 10.3389/fpls.2021.639253] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 04/12/2021] [Indexed: 06/12/2023]
Abstract
Protein degradation through the Ubiquitin (Ub)-26S Proteasome System (UPS) is a major gene expression regulatory pathway in plants. In this pathway, the 76-amino acid Ub proteins are covalently linked onto a large array of UPS substrates with the help of three enzymes (E1 activating, E2 conjugating, and E3 ligating enzymes) and direct them for turnover in the 26S proteasome complex. The S-phase Kinase-associated Protein 1 (Skp1), CUL1, F-box (FBX) protein (SCF) complexes have been identified as the largest E3 ligase group in plants due to the dramatic number expansion of the FBX genes in plant genomes. Since it is the FBX proteins that recognize and determine the specificity of SCF substrates, much effort has been done to characterize their genomic, physiological, and biochemical roles in the past two decades of functional genomic studies. However, the sheer size and high sequence diversity of the FBX gene family demands new approaches to uncover unknown functions. In this work, we first identified 82 known FBX members that have been functionally characterized up to date in Arabidopsis thaliana. Through comparing the genomic structure, evolutionary selection, expression patterns, domain compositions, and functional activities between known and unknown FBX gene members, we developed a neural network machine learning approach to predict whether an unknown FBX member is likely functionally active in Arabidopsis, thereby facilitating its future functional characterization.
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Affiliation(s)
- Yang Li
- Department of Environmental and Plant Biology, Ohio University, Athens, OH, United States
| | - Madhura M. Yapa
- Department of Environmental and Plant Biology, Ohio University, Athens, OH, United States
| | - Zhihua Hua
- Department of Environmental and Plant Biology, Ohio University, Athens, OH, United States
- Interdisciplinary Program in Molecular and Cellular Biology, Ohio University, Athens, OH, United States
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Hua Z. Diverse Evolution in 111 Plant Genomes Reveals Purifying and Dosage Balancing Selection Models for F-Box Genes. Int J Mol Sci 2021; 22:E871. [PMID: 33467195 PMCID: PMC7829749 DOI: 10.3390/ijms22020871] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/13/2021] [Accepted: 01/13/2021] [Indexed: 12/14/2022] Open
Abstract
The F-box proteins function as substrate receptors to determine the specificity of Skp1-Cul1-F-box ubiquitin ligases. Genomic studies revealed large and diverse sizes of the F-box gene superfamily across plant species. Our previous studies suggested that the plant F-box gene superfamily is under genomic drift evolution promoted by epigenomic programming. However, how the size of the superfamily drifts across plant genomes is currently unknown. Through a large-scale genomic and phylogenetic comparison of the F-box gene superfamily covering 110 green plants and one red algal species, I discovered four distinct groups of plant F-box genes with diverse evolutionary processes. While the members in Clusters 1 and 2 are species/lineage-specific, those in Clusters 3 and 4 are present in over 46 plant genomes. Statistical modeling suggests that F-box genes from the former two groups are skewed toward fewer species and more paralogs compared to those of the latter two groups whose presence frequency and sizes in plant genomes follow a random statistical model. The enrichment of known Arabidopsis F-box genes in Clusters 3 and 4, along with comprehensive biochemical evidence showing that Arabidopsis members in Cluster 4 interact with the Arabidopsis Skp1-like 1 (ASK1), demonstrates over-representation of active F-box genes in these two groups. Collectively, I propose purifying and dosage balancing selection models to explain the lineage/species-specific duplications and expansions of F-box genes in plant genomes. The purifying selection model suggests that most, if not all, lineage/species-specific F-box genes are detrimental and are thus kept at low frequencies in plant genomes.
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Affiliation(s)
- Zhihua Hua
- Interdisciplinary Program in Molecular and Cellular Biology, Department of Environmental and Plant Biology, Ohio University, Athens, OH 45701, USA
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