title: Arabidopsis CONSTANS-LIKE3 is a positive regulator of red light signaling and root growth.
abstract: CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1) is an E3 ubiquitin ligase that represses photomorphogenesis in the dark. Therefore, proteins interacting with COP1 could be important regulators of light-dependent development. Here, we identify CONSTANS-LIKE3 (COL3) as a novel interaction partner of COP1. A green fluorescent protein-COL3 fusion protein colocalizes with COP1 to nuclear speckles when transiently expressed in plant cells. This localization requires the B-box domains in COL3, indicating a novel function of this domain. A loss-of-function col3 mutant has longer hypocotyls in red light and in short days. Unlike constans, the col3 mutant flowers early and shows a reduced number of lateral branches in short days. The mutant also exhibits reduced formation of lateral roots. The col3 mutation partially suppresses the cop1 and deetiolated1 (det1) mutations in the dark, suggesting that COL3 acts downstream of both of these repressors. However, the col3 mutation exerts opposing effects on cop1 and det1 in terms of lateral roots and anthocyanin accumulation, suggesting that COL3 also has activities that are independent of COP1 and DET1. In conclusion, we have identified COL3 as a positive regulator of photomorphogenesis that acts downstream of COP1 but can promote lateral root development independently of COP1 and also function as a daylength-sensitive regulator of shoot branching.
authors.affiliation: Department of Cell and Molecular Biology, Gothenburg University, Sweden.
authors.forename: Sourav
authors.initials: S
authors.lastname: Datta
authors.forename: G H C M
authors.initials: GH
authors.lastname: Hettiarachchi
authors.forename: Xing-Wang
authors.initials: XW
authors.lastname: Deng
authors.forename: Magnus
authors.initials: M
authors.lastname: Holm
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000033:anatomy & histology* / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D035264:Flowers / Q000033:anatomy & histology / Q000502:physiology; D018506:Gene Expression Regulation, Plant; D018546:Hypocotyl / Q000033:anatomy & histology / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D008027:Light; D008969:Molecular Sequence Data; D009024:Morphogenesis / Q000502:physiology; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D017440:Photoperiod; D018517:Plant Roots / Q000033:anatomy & histology / Q000254:growth & development*; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D015398:Signal Transduction / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C509520:COL3 protein, Arabidopsis; C092776:CONSTANS protein, Arabidopsis; D002352:Carrier Proteins; C088435:DET1 protein, Arabidopsis; D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D020033:Protein Isoforms; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; C471983:AT2G32950 protein, Arabidopsis; D044767:Ubiquitin-Protein Ligases