Functional Properties and Regulatory Complexity of a Minimal RBCS Light-Responsive Unit Activated by Phytochrome, Cryptochrome, and Plastid Signals

• Published in: Plant physiology (Bethesda) Vol. 128; no. 4; pp. 1223 - 1233
• Main Authors: Aída Martínez-Hernández, Luisa López-Ochoa, Gerardo Argüello-Astorga, Herrera-Estrella, Luis
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Biologists 01.04.2002; American Society of Plant Physiologists
• Subjects: Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis - radiation effects; Arabidopsis Proteins; Basic-Leucine Zipper Transcription Factors; Biological and medical sciences; Cell biochemistry; Cell Biology and Signal Transduction; Cell physiology; COP protein; cryptochrome; Cryptochromes; Darkness; Drosophila Proteins; Eye Proteins; Flavoproteins - metabolism; Fundamental and applied biological sciences. Psychology; Gene expression regulation; Gene Expression Regulation, Plant - radiation effects; Genes; Genetic mutation; Glucuronidase - genetics; Glucuronidase - metabolism; HY5 protein; Light; Molecular and cellular biology; Mutation; Nicotiana plumbaginifolia; Nuclear Proteins - genetics; Photoreceptor Cells, Invertebrate; Photoreceptors; Photosynthesis; phytochrome; Phytochrome - metabolism; Plant cells; Plant Leaves - genetics; Plant Leaves - metabolism; Plant Leaves - radiation effects; Plant physiology and development; Plants; Plants, Genetically Modified; Plastids; Plastids - metabolism; Promoter regions; Promoter Regions, Genetic - genetics; rbcS gene; Receptors, G-Protein-Coupled; Response Elements - genetics; Ribulose-Bisphosphate Carboxylase - genetics; Seedlings; Signal Transduction; Structural analysis; Transcription, Genetic - radiation effects; Transgenic plants; Light effect; Transcription promoter; Photoreceptor; Tissue specificity; Activation; Plastid; Cryptochrome; Structure function relationship; Signal transduction; Nicotiana plumbaginifolia; Regulation(control); Dicotyledones; Light; Angiospermae; Phytochrome; Spermatophyta; Solanaceae; Experimental plant; Mechanism of action; Photoregulation
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.010678

Light-inducible promoters are able to respond to a wide spectrum of light through multiple photoreceptor systems. Several cis-acting elements have been identified as components of light-responsive promoter elements; however, none of these regulatory elements by itself appears to be sufficient to confer light responsiveness; rather, the combination of at least two elements seems to be required. Using phylogenetic structural analysis, we have identified conserved DNA modular arrays (CMAs) associated with light-responsive promoter regions that have been conserved throughout the evolutionary radiation of angiosperms. Here, we report the functional characterization of CMA5, a native 52-bp fragment of the Nicotiana plumbaginifolia rbcS 8B promoter, which contains an I- and a G-box cis-element. CMA5 behaves as a light-responsive minimal unit capable of activating a heterologous minimal promoter in a phytochrome-, cryptochrome-, and plastid-dependent manner. We also show that CMA5 light induction requires HY5 and that downstream negative regulators COP (constitutive photomorphogenic)/DET (de-etiolated) regulate its activity. Our results show that the simplest light-responsive promoter element from photosynthesis-associated genes described to date is the common target for different signals involved in light regulation. The possible mechanism involved in light-transcriptional regulation and tissue specificity of combinatorial elements units is discussed.