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Light, in a quality- and quantity-dependent fashion, induces nuclear import of the plant photoreceptors phytochrome, promotes interaction of phytochrome A (phyA) and phyB with transcription factors including phytochrome interacting factor 3 (PIF3), and is thought to trigger a transcriptional cascade to regulate the expression of approximately 2500 genes in(More)
The phytochrome family of red/far-red photoreceptors is involved in the regulation of a wide range of developmental responses in plants. The Arabidopsis genome contains five phytochromes (phyA-E), among which phyA and phyB play the most important roles. Phytochromes localize to the cytosol in the dark and accumulate in the nucleus under light conditions,(More)
The phytochrome family of red/far-red (R/FR)-responsive photoreceptors plays a key role throughout the life cycle of plants . Arabidopsis has five phytochromes, phyA-phyE, among which phyA and phyB play the most predominant functions . Light-regulated nuclear accumulation of the phytochromes is an important regulatory step of this pathway, but to this date(More)
To optimize their growth and survival, plants perceive and respond to ultraviolet-B (UV-B) radiation. However, neither the molecular identity of the UV-B photoreceptor nor the photoperception mechanism is known. Here we show that dimers of the UVR8 protein perceive UV-B, probably by a tryptophan-based mechanism. Absorption of UV-B induces instant(More)
The light environment is a key factor that governs a multitude of developmental processes during the entire life cycle of plants. An important and increasing part of the incident sunlight encompasses a segment of the UV-B region (280-320 nm) that is not entirely absorbed by the ozone layer in the stratosphere of the earth. This portion of the solar(More)
Light and gibberellins (GAs) mediate many essential and partially overlapping plant developmental processes. DELLA proteins are GA-signalling repressors that block GA-induced development. GA induces degradation of DELLA proteins via the ubiquitin/proteasome pathway, but light promotes accumulation of DELLA proteins by reducing GA levels. It was proposed(More)
CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1) is a negative regulator of photomorphogenesis in Arabidopsis thaliana. COP1 functions as an E3 ubiquitin ligase, targeting select proteins for proteasomal degradation in plants as well as in mammals. Among its substrates is the basic domain/leucine zipper (bZIP) transcription factor ELONGATED HYPOCOTYL5 (HY5), one of(More)
Following light-induced nuclear translocation, specific members of the phytochrome (phy) photoreceptor family (phyA to phyE) interact with bHLH transcription factors, such as PIF3, and induce changes in target-gene expression. The biochemical mechanism comprising signal transfer from phy to PIF3 has remained undefined but results in rapid degradation of(More)
In plants, light perception by photoreceptors leads to differential expression of an enormous number of genes. An important step for differential gene expression is the regulation of transcription factor activities. To understand these processes in light signal transduction we analyzed the three well-known members of the common plant regulatory factor(More)
Plants monitor changes in the ambient light environment using sensory photoreceptor families: the phototropins and cryptochromes, which absorb UV-A or blue light; the phytochromes, which sense red/far-red light; and the UV-B photoreceptors, which have not yet been identified. Recent advances suggest that photoreceptor-induced signalling cascades regulate(More)