title: Ethylene promotes hypocotyl growth and HY5 degradation by enhancing the movement of COP1 to the nucleus in the light.
abstract: In the dark, etiolated seedlings display a long hypocotyl, the growth of which is rapidly inhibited when the seedlings are exposed to light. In contrast, the phytohormone ethylene prevents hypocotyl elongation in the dark but enhances its growth in the light. However, the mechanism by which light and ethylene signalling oppositely affect this process at the protein level is unclear. Here, we report that ethylene enhances the movement of constitutive photomorphogenesis 1 (COP1) to the nucleus where it mediates the degradation of long hypocotyl 5 (HY5), contributing to hypocotyl growth in the light. Our results indicate that HY5 is required for ethylene-promoted hypocotyl growth in the light, but not in the dark. Using genetic and biochemical analyses, we found that HY5 functions downstream of ethylene insensitive 3 (EIN3) for ethylene-promoted hypocotyl growth. Furthermore, the upstream regulation of HY5 stability by ethylene is COP1-dependent, and COP1 is genetically located downstream of EIN3, indicating that the COP1-HY5 complex integrates light and ethylene signalling downstream of EIN3. Importantly, the ethylene precursor 1-aminocyclopropane-1-carboxylate (ACC) enriched the nuclear localisation of COP1; however, this effect was dependent on EIN3 only in the presence of light, strongly suggesting that ethylene promotes the effects of light on the movement of COP1 from the cytoplasm to the nucleus. Thus, our investigation demonstrates that the COP1-HY5 complex is a novel integrator that plays an essential role in ethylene-promoted hypocotyl growth in the light.
authors.affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China ; National Key Facility of Crop Gene Resources and Genetic Improvement, Beijing, China.
authors.forename: Yanwen
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China ; National Key Facility of Crop Gene Resources and Genetic Improvement, Beijing, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Wang
authors.affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China ; National Key Facility of Crop Gene Resources and Genetic Improvement, Beijing, China.
authors.forename: Zhijin
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China ; National Key Facility of Crop Gene Resources and Genetic Improvement, Beijing, China.
authors.forename: Ruidang
authors.initials: R
authors.lastname: Quan
authors.affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China ; National Key Facility of Crop Gene Resources and Genetic Improvement, Beijing, China.
authors.forename: Haiwen
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut, United States of America.
authors.forename: Xing Wang
authors.initials: XW
authors.lastname: Deng
authors.affiliation: College of Life Science, Capital Normal University, Beijing, China.
authors.forename: Ligeng
authors.initials: L
authors.lastname: Ma
authors.affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China ; National Key Facility of Crop Gene Resources and Genetic Improvement, Beijing, China.
authors.forename: Rongfeng
authors.initials: R
authors.lastname: Huang
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D050976:Basic-Leucine Zipper Transcription Factors / Q000235:genetics* / Q000378:metabolism; D002467:Cell Nucleus / Q000235:genetics; D004268:DNA-Binding Proteins; D003624:Darkness; D005030:Ethylenes / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant; D018546:Hypocotyl / Q000187:drug effects / Q000254:growth & development*; D008027:Light; D009024:Morphogenesis / Q000187:drug effects / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D010937:Plant Growth Regulators / Q000235:genetics; D059748:Proteolysis / Q000187:drug effects; D036226:Seedlings; D014157:Transcription Factors / Q000235:genetics; D044767:Ubiquitin-Protein Ligases
chemical_list: D029681:Arabidopsis Proteins; D050976:Basic-Leucine Zipper Transcription Factors; D004268:DNA-Binding Proteins; C106987:EIN3 protein, Arabidopsis; D005030:Ethylenes; C109254:HY5 protein, Arabidopsis; D009687:Nuclear Proteins; D010937:Plant Growth Regulators; D014157:Transcription Factors; C036216:ethylene; C471983:AT2G32950 protein, Arabidopsis; D044767:Ubiquitin-Protein Ligases