title: COP1 E3 ligase protects HYL1 to retain microRNA biogenesis.
abstract: Constitutive photomorphogenic 1 (COP1) is a RING-finger E3 ligase that plays a central role in photomorphogenesis by destabilizing many light-regulated transcription factors and photoreceptors. Here, we reveal a novel function for COP1 E3 ligase in controlling global miRNA biogenesis in Arabidopsis thaliana. In cop1 mutants, the level of miRNAs is dramatically reduced because of the diminution of HYPONASTIC LEAVES 1 (HYL1), an RNA-binding protein required for precise miRNA processing. HYL1 is destabilized by an unidentified protease, which we tentatively call protease X, that specifically cleaves the N-terminal region from HYL1, thus neutralizing its function. Our results further show that the cytoplasmic partitioning of COP1 under light is essential to protect HYL1 against protease X. Taken together, we suggest a novel regulatory network involving HYL1, protease X, COP1 and light signalling that is indispensable for miRNA biogenesis in Arabidopsis thaliana.
authors.affiliation: Laboratory of Plant Biochemistry, Department of Plant and Environmental Sciences, Center for UNIK Synthetic Biology, Faculty of Science, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Copenhagen, Denmark.
authors.forename: Seok Keun
authors.initials: SK
authors.lastname: Cho
authors.affiliation: Laboratory of Plant Biochemistry, Department of Plant and Environmental Sciences, Center for UNIK Synthetic Biology, Faculty of Science, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Copenhagen, Denmark.
authors.forename: Samir
authors.initials: S
authors.lastname: Ben Chaabane
authors.affiliation: Laboratory of Plant Biochemistry, Department of Plant and Environmental Sciences, Center for UNIK Synthetic Biology, Faculty of Science, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Copenhagen, Denmark.
authors.forename: Pratik
authors.initials: P
authors.lastname: Shah
authors.affiliation: Laboratory of Plant Biochemistry, Department of Plant and Environmental Sciences, Center for UNIK Synthetic Biology, Faculty of Science, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Copenhagen, Denmark.
authors.forename: Christian Peter
authors.initials: CP
authors.lastname: Poulsen
authors.affiliation: Laboratory of Plant Biochemistry, Department of Plant and Environmental Sciences, Center for UNIK Synthetic Biology, Faculty of Science, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Copenhagen, Denmark.
authors.forename: Seong Wook
authors.initials: SW
authors.lastname: Yang
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects; D008027:Light; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000235:genetics / Q000378:metabolism; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D012323:RNA Processing, Post-Transcriptional; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; C420966:HYL1 protein, Arabidopsis; D035683:MicroRNAs; D018749:RNA, Plant; D016601:RNA-Binding Proteins; C471983:AT2G32950 protein, Arabidopsis; D044767:Ubiquitin-Protein Ligases; D010447:Peptide Hydrolases