title: Arabidopsis SHY2/IAA3 inhibits auxin-regulated gene expression.
abstract: In Arabidopsis, SHY2 encodes IAA3, a member of the auxin-induced Aux/IAA family. Gain-of-function mutations in SHY2/IAA3 cause enlarged cotyledons, short hypocotyls, and altered auxin-regulated root development. Here we show that the gain-of-function mutation shy2-2 decreases both the induction and repression of auxin-regulated genes, suggesting that SHY2/IAA3 acts as a negative regulator in auxin signaling. shy2-2 affects auxin induction of many previously characterized primary response genes, implying that it might repress primary auxin responses. In addition, shy2-2 also affects expression of multiple auxin-nonresponsive genes. Light regulates expression of SHY2/IAA3, suggesting a possible link between light and auxin response pathways.
authors.affiliation: Department of Biology, University of North Carolina at Chapel Hill, North Carolina 27599-3280, USA.
authors.forename: Qing
authors.initials: Q
authors.lastname: Tian
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Uhlir
authors.forename: Jason W
authors.initials: JW
authors.lastname: Reed
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics*; D029681:Arabidopsis Proteins; D015152:Blotting, Northern; D003066:Coenzyme A Ligases / Q000235:genetics; D018548:Cotyledon / Q000187:drug effects / Q000254:growth & development; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000528:radiation effects; D018546:Hypocotyl / Q000187:drug effects / Q000254:growth & development; D007210:Indoleacetic Acids / Q000494:pharmacology*; D008027:Light; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics*; D010937:Plant Growth Regulators / Q000494:pharmacology*; D010940:Plant Proteins / Q000235:genetics; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development; D015398:Signal Transduction; D030262:Soybean Proteins
chemical_list: D029681:Arabidopsis Proteins; C070797:GH3 protein, soybean; D007210:Indoleacetic Acids; D009687:Nuclear Proteins; D010937:Plant Growth Regulators; D010940:Plant Proteins; C401721:SAUR protein, Raphanus sativus; C117994:SHY2 protein, Arabidopsis; D030262:Soybean Proteins; C030737:indoleacetic acid; C445074:ACS6 protein, Brassica napus; D003066:Coenzyme A Ligases