Arabidopsis (Arabidopsis thaliana) Short Hypocotyl in White Light1 (SHW1) encodes a Ser-Arg-Asp-rich protein that acts as a negative regulator of photomorphogenesis. SHW1 and Constitutive Photomorphogenic1 (COP1) genetically interact in an additive manner to suppress photomorphogenesis. Elongated Hypocotyl5 (HY5) is a photomorphogenesis promoting a basic leucine zipper transcription factor that...

Arabidopsis seedlings display contrasting developmental patterns depending on the light environment, e.g. photomorphogenesis in the light and skotomorphogenesis (etiolation) in darkness. Recent studies have implicated protein degradation as a means of regulating this developmental switch (Osterlund et al., 2000). For example, HY5, a positive photomorphogenic regulator that acts to promote the l...

ELONGATED HYPOCOTYL5 (HY5) is a basic domain/leucine zipper (bZIP) transcription factor, central for the regulation of seedling photomorphogenesis. Here, we identified a B-BOX (BBX)-containing protein, BBX25/SALT TOLERANCE HOMOLOG, as an interacting partner of HY5, which has been previously found to physically interact with CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1). BBX25 physically interacts with ...

Several transcription factors (TFs) coordinate to regulate expression of specific genes at the transcriptional level. In Arabidopsis thaliana it is estimated that approximately 10% of all genes encode TFs or TF-like proteins. It is important to identify target genes that are directly regulated by TFs in order to understand the complete picture of a plant's transcriptome profile. Here, we invest...

Arabidopsis bZIP transcription factor, GBF1, acts as a differential regulator of cryptochrome-mediated blue light signaling. Whereas the bZIP proteins, HY5 (elongated hypocotyl 5) and HYH (HY5 homologue), are degraded by COP1-mediated proteasomal pathways, GBF1 is degraded by a proteasomal pathway independent of COP1. In this study, we have investigated the functional interrelations of GBF1 wit...

LONG HYPOCOTYL5 (HY5) is a bZIP (basic leucine zipper) transcription factor that activates photomorphogenesis and root development in Arabidopsis (Arabidopsis thaliana). Previously, STF1 (soybean [Glycine max] TGACG-motif binding factor 1), a homologous legume protein with a RING-finger motif and a bZIP domain, was reported in soybean. To investigate the role of STF1, the phenotypes of transgen...

Plant developmental processes are controlled by both endogenous programs and environmental stimuli. As a photomorphogenetic mutant, hy5 of Arabidopsis has been isolated and characterized. Our detailed characterization has revealed that the mutant is deficient in a variety of stimulus responses, including gravitropic response and waving growth of roots, as well as light-dependent hypocotyl elong...

Grapevine (Vitis vinifera L.) is a species well known for its adaptation to radiation. However, photomorphogenic factors related to UV-B responses have not been molecularly characterized. We cloned and studied the role of UV-B RECEPTOR (UVR1), ELONGATED HYPOCOTYL 5 (HY5), and HY5 HOMOLOGUE (HYH) from V. vinifera We performed gene functional characterizations, generated co-expression networks, a...

The Arabidopsis HY5 gene has been defined genetically as a positive regulator of photomorphogenesis and recently has been shown to encode a basic leucine zipper type of transcription factor. Here, we report that HY5 is constitutively nuclear localized and is involved in light regulation of transcriptional activity of the promoters containing the G-box, a well-characterized light-responsive elem...

Coordination of shoot photosynthetic carbon fixation with root inorganic nitrogen uptake optimizes plant performance in a fluctuating environment [1]. However, the molecular basis of this long-distance shoot-root coordination is little understood. Here we show that Arabidopsis ELONGATED HYPOCOTYL5 (HY5), a bZIP transcription factor that regulates growth in response to light [2, 3], is a shoot-t...