Abstract
The abi2-1 (abscisic acid insensitive) mutant of Arabidopsis thaliana shows abscisic acid (ABA) insensitivity with respect to seed germination and vegetative ABA responses. We identified the ABI2 gene by a combination of positional mapping and homology to ABI1. The ABI2 protein shows 80% amino acid sequence identity to ABI1, a protein phosphatase 2C (PP2C) involved in ABA signaling. The mutation that confers the abi2-1 phenotype is equivalent to the mutation previously identified in abi1-1 and the resulting Gly168Asp abi2 protein shows a reduced PP2C activity. Thus, a pair of highly homologous PP2Cs regulate ABA signaling.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Abscisic Acid / metabolism*
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Amino Acid Sequence
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Arabidopsis / enzymology
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Arabidopsis / genetics
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Arabidopsis / metabolism*
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Arabidopsis Proteins*
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Chromosome Mapping
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Cloning, Molecular
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Molecular Sequence Data
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Phosphoprotein Phosphatases / genetics*
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Phosphoprotein Phosphatases / metabolism
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Protein Phosphatase 2
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Protein Phosphatase 2C
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Saccharomyces cerevisiae Proteins*
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Sequence Homology, Amino Acid
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Signal Transduction*
Substances
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Arabidopsis Proteins
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Saccharomyces cerevisiae Proteins
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Abscisic Acid
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ABI1 protein, Arabidopsis
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ABI2 protein, Arabidopsis
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PTC1 protein, S cerevisiae
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Phosphoprotein Phosphatases
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Protein Phosphatase 2
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Protein Phosphatase 2C