Abstract
Brassinosteroids are a class of growth-promoting regulators that play a key role throughout plant development. Despite their importance, nothing is known of the mechanism of action of these steroid hormones. We describe the identification of 18 Arabidopsis dwarf mutants that are unable to respond to exogenously added brassinosteroid, a phenotype that might be expected for brassinosteroid signaling mutants. All 18 mutations define alleles of a single previously described gene, BRI1. We cloned BRI1 and examined its expression pattern. It encodes a ubiquitously expressed putative receptor kinase. The extracellular domain contains 25 tandem leucine-rich repeats that resemble repeats found in animal hormone receptors, plant disease resistance genes, and genes involved in unknown signaling pathways controlling plant development.
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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Arabidopsis / enzymology
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Arabidopsis / genetics
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Arabidopsis Proteins*
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Base Sequence
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Brassinosteroids
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Cholestanols* / metabolism
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Chromosome Mapping
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DNA Mutational Analysis
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Gene Expression / physiology
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Histidine / metabolism
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Leucine / genetics
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Molecular Sequence Data
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Phosphotransferases / genetics
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Phosphotransferases / metabolism
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Plant Growth Regulators / genetics*
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Plant Proteins*
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Protein Kinases / genetics*
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Protein Kinases / metabolism
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Receptors, Steroid / chemistry
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Receptors, Steroid / genetics*
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Repetitive Sequences, Nucleic Acid*
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Sequence Homology, Amino Acid
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Signal Transduction / physiology*
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Steroids, Heterocyclic* / metabolism
Substances
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Arabidopsis Proteins
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Brassinosteroids
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Cholestanols
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Plant Growth Regulators
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Plant Proteins
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Receptors, Steroid
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Steroids, Heterocyclic
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Histidine
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Phosphotransferases
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Protein Kinases
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SERK protein, plant
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BRI1 protein, Arabidopsis
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Leucine
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brassinolide