caa a22 4500 467894639 CHVBK 20180406152759.0 cr unu---uuuuu 170328e20060501xx s 000 0 eng 10.1007/s11103-006-0010-2 doi (NATIONALLICENCE)springer-10.1007/s11103-006-0010-2 KIDARI , Encoding a Non-DNA Binding bHLH Protein, Represses Light Signal Transduction in Arabidopsis thaliana [Elektronische Daten] [Youbong Hyun, Ilha Lee] Through activation tagging mutagenesis, we isolated a kidari-D (kdr-D) mutant, which exhibited a defect in blue and far-red light mediated photomorphogenesis. Under continuous blue light, the kdr-D mutant showed long hypocotyl phenotype, whereas it showed normal cotyledon opening and expansion. In addition, the kdr-D showed slightly longer hypocotyl under continuous far-red light, suggesting that KDR functions in a branch of cry signaling and mediates a cross-talk between cry and phyA. In the kdr-D mutant, a gene encoding a putative basic/Helix-Loop-Helix (bHLH) protein was overexpressed by the insertion of 35S enhancer into 10kb upstream of the gene. Consistently, overexpression of this gene recapitulated the phenotype of kdr-D. KDR is composed of 94 amino acids with non-DNA binding HLH domain, a structure found in human Inhibitor of DNA binding 1 (Id-1) which functions as a negative regulator of bHLH proteins through heterodimerization with them. The KDR specifically interacted with HFR1, a bHLH protein regulating photomorphogenesis, in yeast two hybrid assay and the kdr-D was epistatic to 35S::HFR1 in the hypocotyl phenotype. Thus, it shows that KDR functions as a negative regulator of HFR1, similar to Id-1 in human. The KDR exhibited circadian expression pattern with an increase during the day. Taken together, our results suggest that KDR attenuates light mediated responses in day light condition through inhibition of the activity of bHLH proteins involved in light signaling. Springer, 2006 bHLH nationallicence cryptochrome nationallicence light signaling nationallicence non-DNA binding photomorphogenesis nationallicence Hyun Youbong Laboratory of Plant Developmental Genetics, Department of Biological Sciences, Seoul National University, 151-742, Seoul, Korea aut Lee Ilha Laboratory of Plant Developmental Genetics, Department of Biological Sciences, Seoul National University, 151-742, Seoul, Korea aut Plant Molecular Biology Kluwer Academic Publishers 61/1-2(2006-05-01), 283-296 0167-4412 61:1-2<283 2006 61 11103 https://doi.org/10.1007/s11103-006-0010-2 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11103-006-0010-2 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Hyun Youbong Laboratory of Plant Developmental Genetics, Department of Biological Sciences, Seoul National University, 151-742, Seoul, Korea aut NATIONALLICENCE 700 1- Lee Ilha Laboratory of Plant Developmental Genetics, Department of Biological Sciences, Seoul National University, 151-742, Seoul, Korea aut NATIONALLICENCE 773 0- Plant Molecular Biology Kluwer Academic Publishers 61/1-2(2006-05-01), 283-296 0167-4412 61:1-2<283 2006 61 11103 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer