Abstract
Photoreceptors, especially the far-red light-absorbing phytochrome A, play a crucial role in early seedling development, triggering the transition from etiolated to photomorphogenic growth. Here, we describe the biological functions of two GRAS proteins from Arabidopsis (Arabidopsis thaliana), SCARECROW-LIKE21 (SCL21) and PHYTOCHROME A SIGNAL TRANSDUCTION1 (PAT1), which are specifically involved in phytochrome A signal transduction. Loss-of-function mutants show an elongated hypocotyl under far-red light and are impaired in other far-red high-irradiance responses. The SCL21 transcript itself is down-regulated by far-red light in a phytochrome A- and PAT1-dependent manner. Our results demonstrate that both SCL21 and PAT1 are positive regulators of phytochrome A signal transduction for several high-irradiance responses. Genetic and biochemical evidence suggest a direct interaction of the two proteins.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Arabidopsis / genetics
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Arabidopsis / metabolism*
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Arabidopsis / radiation effects
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Arabidopsis Proteins / genetics
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Arabidopsis Proteins / metabolism*
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Cell Nucleus / genetics
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Cell Nucleus / metabolism
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Epistasis, Genetic
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Gene Expression Regulation, Plant*
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Genetic Complementation Test
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Hypocotyl / growth & development
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Hypocotyl / radiation effects
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Light
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Molecular Sequence Data
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Phenotype
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Photoreceptors, Plant / genetics
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Photoreceptors, Plant / metabolism
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Phylogeny
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Phytochrome / genetics
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Phytochrome / metabolism*
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Phytochrome A / genetics
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Phytochrome A / metabolism*
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Protein Interaction Mapping
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RNA Interference
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RNA, Messenger / genetics
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RNA, Messenger / metabolism
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Signal Transduction*
Substances
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Arabidopsis Proteins
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PAT1 protein, Arabidopsis
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PHYA protein, Arabidopsis
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Photoreceptors, Plant
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Phytochrome A
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RNA, Messenger
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Phytochrome