Abstract
The 26S proteasome is an essential protease complex responsible for removing most short-lived intracellular proteins, especially those modified with polyubiquitin chains. We show here that an Arabidopsis mutant expressing an altered RPN10 subunit exhibited a pleiotropic phenotype consistent with specific changes in 26S proteasome function. rpn10-1 plants displayed reduced seed germination, growth rate, stamen number, genetic transmission through the male gamete, and hormone-induced cell division, which can be explained partially by a constitutive downregulation of the key cell cycle gene CDKA;1. rpn10-1 also was more sensitive to abscisic acid (ABA), salt, and sucrose stress and to DNA-damaging agents and had decreased sensitivity to cytokinin and auxin. Most of the phenotypes can be explained by a hypersensitivity to ABA, which is reflected at the molecular level by the selective stabilization of the short-lived ABA-signaling protein ABI5. Collectively, these results indicate that RPN10 affects a number of regulatory processes in Arabidopsis likely by directing specific proteins to the 26S proteasome for degradation. A particularly important role may be in regulating the responses to signals promulgated by ABA.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Abscisic Acid / pharmacology*
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Arabidopsis / drug effects
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Arabidopsis / genetics
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Arabidopsis / growth & development*
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Arabidopsis Proteins / genetics*
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Arabidopsis Proteins / metabolism
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Basic-Leucine Zipper Transcription Factors
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Cross-Linking Reagents / pharmacology
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Cyclin-Dependent Kinases / genetics
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Cyclin-Dependent Kinases / metabolism
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DNA Damage / drug effects
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DNA Damage / radiation effects
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Gene Expression Regulation, Developmental / drug effects
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Gene Expression Regulation, Developmental / radiation effects
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Gene Expression Regulation, Plant / drug effects
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Gene Expression Regulation, Plant / radiation effects
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Genetic Complementation Test
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Germination / drug effects
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Germination / radiation effects
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Indoleacetic Acids / pharmacology
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Mitomycin / pharmacology
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Mutation
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Peptide Hydrolases / genetics
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Peptide Hydrolases / metabolism*
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Plant Roots / drug effects
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Plant Roots / genetics
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Plant Roots / growth & development
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Proteasome Endopeptidase Complex*
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Protein Subunits / genetics
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Protein Subunits / metabolism
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Seeds / drug effects
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Seeds / genetics
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Seeds / growth & development
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Signal Transduction
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Sodium Chloride / pharmacology
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Substrate Specificity
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Sucrose / pharmacology
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Transcription Factors / genetics
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Transcription Factors / metabolism
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Ultraviolet Rays
Substances
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ABI5 protein, Arabidopsis
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Arabidopsis Proteins
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Basic-Leucine Zipper Transcription Factors
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Cross-Linking Reagents
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Indoleacetic Acids
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Protein Subunits
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RPN10 protein, Arabidopsis
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Recombinant Fusion Proteins
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Transcription Factors
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Sodium Chloride
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Mitomycin
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Sucrose
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Abscisic Acid
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CDKA1 protein, Arabidopsis
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Cyclin-Dependent Kinases
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Peptide Hydrolases
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Proteasome Endopeptidase Complex
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ATP dependent 26S protease