Abstract
The Z-box is one of the light-responsive elements (LREs) found in the promoters of light inducible genes. We have studied the light responsive characteristics of Z-box containing synthetic as well as native promoters. We show that promoters with Z-box as a single LRE or paired with another LRE can respond to a broad spectrum of light. The response is primarily mediated by phyA, phyB and CRY1 photoreceptors at their respective wavelengths of light. We have demonstrated that CAB1 and Z-GATA containing promoters are down-regulated in hy5 mutants in the light. On the other hand, a promoter with Z-box alone is down-regulated in hy5 mutants both in dark and in light conditions, suggesting involvement of a similar regulatory system in the regulation of the promoter in two distinct developmental pathways: skotomorphogenesis and photomorphogenesis. Furthermore, similar to the CAB1 promoter, a Z-GATA containing promoter is derepressed in cop1 mutants in the dark. DNA-protein interaction studies reveal the presence of a DNA-binding activity that is specific to Z-box. These results provide insights into the regulation of the Z-box LRE mediated by various light signaling components.
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 / genetics
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Arabidopsis / physiology*
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Arabidopsis / radiation effects
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Arabidopsis Proteins*
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Basic-Leucine Zipper Transcription Factors
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Cryptochromes
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DNA-Binding Proteins / genetics
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Darkness
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Drosophila Proteins*
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Eye Proteins*
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Flavoproteins / metabolism
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Flavoproteins / radiation effects
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Glucuronidase / genetics
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Glucuronidase / metabolism
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Light
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Mutation
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Nuclear Proteins / genetics
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Nuclear Proteins / physiology*
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Photoreceptor Cells*
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Photoreceptor Cells, Invertebrate*
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Photosynthetic Reaction Center Complex Proteins / genetics
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Photosynthetic Reaction Center Complex Proteins / metabolism*
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Photosynthetic Reaction Center Complex Proteins / radiation effects
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Phytochrome / metabolism
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Phytochrome / radiation effects
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Phytochrome A
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Phytochrome B
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Promoter Regions, Genetic / genetics*
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Receptors, G-Protein-Coupled
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Signal Transduction / physiology
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Transcription Factors / genetics
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Zinc Fingers / genetics*
Substances
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Arabidopsis Proteins
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Basic-Leucine Zipper Transcription Factors
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CRY1 protein, Arabidopsis
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Cryptochromes
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DNA-Binding Proteins
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Drosophila Proteins
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Eye Proteins
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Flavoproteins
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HY5 protein, Arabidopsis
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Nuclear Proteins
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PHYA protein, Arabidopsis
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PHYB protein, Arabidopsis
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Photosynthetic Reaction Center Complex Proteins
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Phytochrome A
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Receptors, G-Protein-Coupled
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Recombinant Fusion Proteins
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Transcription Factors
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cry protein, Drosophila
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Phytochrome
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Phytochrome B
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Glucuronidase