Identical Amino Acid Substitutions in the Repression Domain of Auxin/Indole-3-Acetic Acid Proteins Have Contrasting Effects on Auxin Signaling
| Autor: | Shiv B. Tiwari, Hanbing Li, Tom J. Guilfoyle, Gretchen Hagen |
|---|---|
| Rok vydání: | 2011 |
| Předmět: |
Physiology
Arabidopsis Plant Science Models Biological chemistry.chemical_compound Transformation Genetic Protein structure Gene Expression Regulation Plant Auxin Genetics Arabidopsis thaliana heterocyclic compounds Transgenes Promoter Regions Genetic Psychological repression Derepression chemistry.chemical_classification Indoleacetic Acids biology Arabidopsis Proteins Development and Hormone Action fungi food and beverages Plants Genetically Modified biology.organism_classification Protein Structure Tertiary Amino acid Repressor Proteins Phenotype Amino Acid Substitution chemistry Biochemistry Mutation Indole-3-acetic acid Signal Transduction |
| Zdroj: | Plant Physiology. 155:1252-1263 |
| ISSN: | 1532-2548 |
| DOI: | 10.1104/pp.110.171322 |
| Popis: | Auxin/indole-3-acetic acid (Aux/IAA) proteins function as repressors of auxin response gene expression when auxin concentrations in a cell are low. At elevated auxin concentrations, these repressors are destroyed via the ubiquitin-proteasome pathway, resulting in derepression/activation of auxin response genes. Most Aux/IAA repressors contain four conserved domains, with one of these being an active, portable repression domain (domain I) and a second being an auxin-dependent instability domain (domain II). Here, we have analyzed the effects of amino acid substitutions in the repression domain of selected Aux/IAA proteins. We show that stabilized versions of Aux/IAA proteins with amino acid substitutions in domain I display contrasting phenotypes when expressed in transformed Arabidopsis (Arabidopsis thaliana) plants. An alanine-for-leucine substitution in the LxLxL (where L is leucine and x is another amino acid) repression domain of IAA3, IAA6, or IAA19 confers enhanced auxin response gene expression and “high-auxin” phenotypes when expressed from the 35S or IAA19 promoter (as tested with IAA19) in transformed Arabidopsis plants. In marked contrast, a single alanine-for-leucine substitution in domain I of IAA12 or IAA17 confers repression of auxin response genes and “low-auxin” phenotypes. These results point to intrinsic differences in the repression domain(s) of IAA proteins and suggest that some IAA proteins have stronger or more complex repression domains than others. |
| Databáze: | OpenAIRE |
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