title: The homeodomain-leucine zipper ATHB23, a phytochrome B-interacting protein, is important for phytochrome B-mediated red light signaling.
abstract: Phytochromes are red (R)/far-red (FR) photoreceptors that are central to the regulation of plant growth and development. Although it is well known that photoactivated phytochromes are translocated into the nucleus where they interact with a variety of nuclear proteins and ultimately regulate genome-wide transcription, the mechanisms by which these photoreceptors function are not completely understood. In an effort to enhance our understanding of phytochrome-mediated light signaling networks, we attempted to identify novel proteins interacting with phytochrome B (phyB). Using affinity purification in Arabidopsis phyB overexpressor, coupled with mass spectrometry analysis, 16 proteins that interact with phyB in vivo were identified. Interactions between phyB and six putative phyB-interacting proteins were confirmed by bimolecular fluorescence complementation (BiFC) analysis. Involvement of these proteins in phyB-mediated signaling pathways was also revealed by physiological analysis of the mutants defective in each phyB-interacting protein. We further characterized the athb23 mutant impaired in the homeobox protein 23 (ATHB23) gene. The athb23 mutant displayed altered hypocotyl growth under R light, as well as defects in phyB-dependent seed germination and phyB-mediated cotyledon expansion. Taken together, these results suggest that the ATHB23 transcription factor is a novel component of the phyB-mediated R light signaling pathway.
authors: Academy of New Biology for Plant Senescence and Life History, Institute for Basic Science, DGIST, Daegu, Republic of Korea; Department of Life Sciences, POSTECH, Pohang, Republic of Korea.
authors: Hyunmo
authors: H
authors: Choi
authors: Suyeong
authors: S
authors: Jeong
authors: Dong Su
authors: DS
authors: Kim
authors: Hyung Jin
authors: HJ
authors: Na
authors: Jong Sang
authors: JS
authors: Ryu
authors: Seung Sik
authors: SS
authors: Lee
authors: Hong Gil
authors: HG
authors: Nam
authors: Pyung Ok
authors: PO
authors: Lim
authors: Hye Ryun
authors: HR
authors: Woo
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism* / Q000528:radiation effects*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D018548:Cotyledon / Q000254:growth & development / Q000528:radiation effects; D005453:Fluorescence; D018525:Germination / Q000528:radiation effects; D049452:Green Fluorescent Proteins / Q000378:metabolism; D018398:Homeodomain Proteins / Q000378:metabolism*; D018546:Hypocotyl / Q000254:growth & development / Q000528:radiation effects; D016350:Leucine Zippers; D008027:Light; D055537:Light Signal Transduction / Q000528:radiation effects*; D009154:Mutation / Q000235:genetics; D051939:Phytochrome B / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011485:Protein Binding / Q000528:radiation effects; D036226:Seedlings / Q000235:genetics / Q000528:radiation effects; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: C523746:ATHB23 protein, Arabidopsis; D029681:Arabidopsis Proteins; D018398:Homeodomain Proteins; C497952:PHYB protein, Arabidopsis; D051939:Phytochrome B; D049452:Green Fluorescent Proteins