title: OsPUB15, an E3 ubiquitin ligase, functions to reduce cellular oxidative stress during seedling establishment.
abstract: The plant U-box (PUB) protein functions as an E3 ligase to poly-ubiquitinate a target protein for its degradation or post-translational modification. Here, we report functional roles for OsPUB15, which encodes a cytosolic U-box protein in the class-II PUB family. Self-ubiquitination assays showed that bacterially expressed MBP-OsPUB15 protein has E3 ubiquitin ligase activity. A T-DNA insertional mutation in OsPUB15 caused severe growth retardation and a seedling-lethal phenotype. Mutant seeds did not produce primary roots, and their shoot development was significantly delayed. Transgenic plants expressing the OsPUB15 antisense transcript phenocopied these mutant characters. The abnormal phenotypes were partially rescued by two antioxidants, catechin and ascorbic acid. Germinating seeds in the dark also recovered the rootless defect. Levels of H2O2 and oxidized proteins were higher in the knock-out mutant compared with the wild type. OsPUB15 transcript levels were increased upon H2O2, salt and drought stresses; plants overexpressing the gene grew better than the wild type under high salinity. These results indicate that PUB15 is a regulator that reduces reactive oxygen species (ROS) stress and cell death.
authors.affiliation: Department of Life Science, Pohang University of Science and Technology (POSTECH), Pohang 790-784, Korea.
authors.forename: Jong-Jin
authors.initials: JJ
authors.lastname: Park
authors.forename: Jakyung
authors.initials: J
authors.lastname: Yi
authors.forename: Jinmi
authors.initials: J
authors.lastname: Yoon
authors.forename: Lae-Hyeon
authors.initials: LH
authors.lastname: Cho
authors.forename: Jin
authors.initials: J
authors.lastname: Ping
authors.forename: Hee Joong
authors.initials: HJ
authors.lastname: Jeong
authors.forename: Seok Keun
authors.initials: SK
authors.lastname: Cho
authors.forename: Woo Taek
authors.initials: WT
authors.lastname: Kim
authors.forename: Gynheung
authors.initials: G
authors.lastname: An
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics / Q000502:physiology; D001483:Base Sequence; D016923:Cell Death; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D006861:Hydrogen Peroxide / Q000378:metabolism; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D012275:Oryza / Q000201:enzymology / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology*; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000201:enzymology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D030821:Plants, Genetically Modified; D055049:Salt Tolerance / Q000502:physiology; D036226:Seedlings / Q000201:enzymology / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D012639:Seeds / Q000201:enzymology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*
chemical_list: D010940:Plant Proteins; D006861:Hydrogen Peroxide; D044767:Ubiquitin-Protein Ligases