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Arabidopsis Ubiquitin-Conjugating Enzymes UBC4, UBC5, and UBC6 Have Major Functions in Sugar Metabolism and Leaf Senescence. Int J Mol Sci 2022; 23:ijms231911143. [PMID: 36232444 PMCID: PMC9569852 DOI: 10.3390/ijms231911143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 09/15/2022] [Accepted: 09/19/2022] [Indexed: 11/23/2022] Open
Abstract
The ubiquitin-conjugating enzyme (E2) is required for protein ubiquitination. Arabidopsis has 37 E2s grouped into 14 subfamilies and the functions for many of them are unknown. We utilized genetic and biochemical methods to study the roles of Arabidopsis UBC4, UBC5, and UBC6 of the E2 subfamily IV. The Arabidopsis ubc4/5/6 triple mutant plants had higher levels of glucose, sucrose, and starch than the control plants, as well as a higher protein level of a key gluconeogenic enzyme, cytosolic fructose 1,6-bisphosphatase 1 (cyFBP). In an in vitro assay, the proteasome inhibitor MG132 inhibited the degradation of recombinant cyFBP whereas ATP promoted cyFBP degradation. In the quadruple mutant ubc4/5/6 cyfbp, the sugar levels returned to normal, suggesting that the increased sugar levels in the ubc4/5/6 mutant were due to an increased cyFBPase level. In addition, the ubc4/5/6 mutant plants showed early leaf senescence at late stages of plant development as well as accelerated leaf senescence using detached leaves. Further, the leaf senescence phenotype remained in the quadruple ubc4/5/6 cyfbp mutant. Our results suggest that UBC4/5/6 have two lines of important functions, in sugar metabolism through regulating the cyFBP protein level and in leaf senescence likely through a cyFBP-independent mechanism.
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Viana AAB, Fragoso RR, Guimarães LM, Pontes N, Oliveira-Neto OB, Artico S, Nardeli SM, Alves-Ferreira M, Batista JAN, Silva MCM, Grossi-de-Sa MF. Isolation and functional characterization of a cotton ubiquitination-related promoter and 5'UTR that drives high levels of expression in root and flower tissues. BMC Biotechnol 2011; 11:115. [PMID: 22115195 PMCID: PMC3239415 DOI: 10.1186/1472-6750-11-115] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Accepted: 11/24/2011] [Indexed: 05/06/2023] Open
Abstract
BACKGROUND Cotton (Gossypium spp.) is an important crop worldwide that provides raw material to 40% of the textile fiber industry. Important traits have been studied aiming the development of genetically modified crops including resistance to insect and diseases, and tolerance to drought, cold and herbicide. Therefore, the characterization of promoters and regulatory regions is also important to achieve high gene expression and/or a specific expression pattern. Commonly, genes involved in ubiquitination pathways are highly and differentially expressed. In this study, we analyzed the expression of a cotton ubiquitin-conjugating enzyme (E2) family member with no previous characterization. RESULTS Nucleotide analysis revealed high identity with cotton E2 homologues. Multiple alignment showed a premature stop codon, which prevents the encoding of the conserved cysteine residue at the E2 active site, and an intron that is spliced in E2 homologues, but not in GhGDRP85. The GhGDRP85 gene is highly expressed in different organs of cotton plants, and has high transcript levels in roots. Its promoter (uceApro2) and the 5'UTR compose a regulatory region named uceA1.7, and were isolated from cotton and studied in Arabidopsis thaliana. uceA1.7 shows strong expression levels, equaling or surpassing the expression levels of CaMV35S. The uceA1.7 regulatory sequence drives GUS expression 7-fold higher in flowers, 2-fold in roots and at similar levels in leaves and stems. GUS expression levels are decreased 7- to 15-fold when its 5'UTR is absent in uceApro2. CONCLUSIONS uceA1.7 is a strong constitutive regulatory sequence composed of a promoter (uceApro2) and its 5'UTR that will be useful in genetic transformation of dicots, having high potential to drive high levels of transgene expression in crops, particularly for traits desirable in flower and root tissues.
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Affiliation(s)
- Antonio AB Viana
- Laboratório de Interação Molecular Planta-Praga, Embrapa Recursos Genéticos e Biotecnologia, PqEB final W5 Norte, Brasília/DF, 70770-900, Brasil
- Universidade Católica de Brasília, QS 07 Lote 01 EPCT, Taguatinga/DF, 71966-700, Brasil
| | - Rodrigo R Fragoso
- Embrapa Cerrados, Rodovia Brasília/Fortaleza BR 020, Km18, Planaltina/DF, 73310-970, Brasil
- Depto. Biologia Celular, Universidade de Brasília, IB, Campus Universitário Darcy Ribeiro, Brasília/DF, 70910-900, Brasil
| | - Luciane M Guimarães
- Laboratório de Interação Molecular Planta-Praga, Embrapa Recursos Genéticos e Biotecnologia, PqEB final W5 Norte, Brasília/DF, 70770-900, Brasil
| | - Naiara Pontes
- Laboratório de Interação Molecular Planta-Praga, Embrapa Recursos Genéticos e Biotecnologia, PqEB final W5 Norte, Brasília/DF, 70770-900, Brasil
| | - Osmundo B Oliveira-Neto
- Laboratório de Interação Molecular Planta-Praga, Embrapa Recursos Genéticos e Biotecnologia, PqEB final W5 Norte, Brasília/DF, 70770-900, Brasil
| | - Sinara Artico
- Depto. Genética, Universidade Federal do Rio de Janeiro, Centro de Ciências da Saúde (CCS), Bloco A, 2° andar, Sala 85, Ilha do Fundão, Rio de Janeiro/RJ, 21941-570, Brasil
| | - Sarah M Nardeli
- Depto. Genética, Universidade Federal do Rio de Janeiro, Centro de Ciências da Saúde (CCS), Bloco A, 2° andar, Sala 85, Ilha do Fundão, Rio de Janeiro/RJ, 21941-570, Brasil
| | - Marcio Alves-Ferreira
- Depto. Genética, Universidade Federal do Rio de Janeiro, Centro de Ciências da Saúde (CCS), Bloco A, 2° andar, Sala 85, Ilha do Fundão, Rio de Janeiro/RJ, 21941-570, Brasil
| | - João AN Batista
- Depto. Botânica, Universidade Federal de Minas Gerais, Instituto de Ciências Biológicas, Av. Antônio Carlos 6627, Pampulha, Belo Horizonte/MG, 31270-901, Brasil
| | - Maria CM Silva
- Laboratório de Interação Molecular Planta-Praga, Embrapa Recursos Genéticos e Biotecnologia, PqEB final W5 Norte, Brasília/DF, 70770-900, Brasil
| | - Maria F Grossi-de-Sa
- Laboratório de Interação Molecular Planta-Praga, Embrapa Recursos Genéticos e Biotecnologia, PqEB final W5 Norte, Brasília/DF, 70770-900, Brasil
- Universidade Católica de Brasília, QS 07 Lote 01 EPCT, Taguatinga/DF, 71966-700, Brasil
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Thoma S, Sullivan ML, Vierstra RD. Members of two gene families encoding ubiquitin-conjugating enzymes, AtUBC1-3 and AtUBC4-6, from Arabidopsis thaliana are differentially expressed. PLANT MOLECULAR BIOLOGY 1996; 31:493-505. [PMID: 8790283 DOI: 10.1007/bf00042223] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Covalent attachment of ubiquitin to other intracellular proteins is essential for many physiological processes in eukaryotes, including selective protein degradation. Selection of proteins for ubiquitin conjugation is accomplished, in part, by a group of enzymes designated E2s or ubiquitin-conjugating enzymes (UBCs). At least six types of E2s have been identified in the plant Arabidopsis thaliana; each type is encoded by a small gene family. Previously, we described the isolation and characterization of two three-member gene families, designated AtUBC1-3 and AtUBC4-6, encoding two of these E2 types. Here, we investigated the expression patterns, of the AtUBC1-3 and AtUBC4-6 genes by the histochemical analysis of transgenic Arabidopsis containing the corresponding promoters fused to the beta-glucuronidase-coding region. Staining patterns showed that these genes are active in many stages of development and some aspects of cell death, but are not induced by heat stress. Within the two gene families, individual members exhibited both overlapping and complementary expression patterns, indicating that at least one member of each gene family is expressed in most cell types and at most developmental stages. Different composite patterns of expression were observed between the AtUBC1-3 and AtUBC4-6 families, suggesting distinct biochemical and/or physiological functions for the encoded E2s in Arabidopsis.
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Affiliation(s)
- S Thoma
- Department of Horticulture, University of Wisconsin-Madison 53706, USA
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