title: ARF-Aux/IAA interactions through domain III/IV are not strictly required for auxin-responsive gene expression.
abstract: Auxin response factors (ARFs), together with auxin/indole acetic acid proteins (Aux/IAAs), are transcription factors that play key roles in regulating auxin-responsive transcription in plants. Current models for auxin signaling predict that auxin response is dependent on ARF-Aux/IAA interactions mediated by the related protein-protein interaction domain (i.e., referred to as the CTD) found in the ARF and Aux/IAA C-terminal regions. When auxin concentrations in a cell are low, ARF activators residing on the promoters of auxin response genes are thought to be inactive because of the association with dominant Aux/IAA repressors. When auxin concentrations are elevated, the Aux/IAA repressors are recruited to auxin receptors and degraded via the ubiquitin-proteasome pathway. Destruction of the Aux/IAA repressors allows the ARF activators to function in derepressing/activating auxin response genes. While this auxin signaling pathway is simple and attractive, it is unclear whether auxin-regulated gene expression is solely dependent on ARF-Aux/IAA interactions. Here we show that auxin can affect the expression of auxin response genes in a manner that is independent of the ARF activator CTD.
authors.affiliation: Current affiliation: Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics & Cytology; Northeast Normal University; Changchun, PR China.
authors.forename: Shucai
authors.initials: S
authors.lastname: Wang
authors.forename: Gretchen
authors.initials: G
authors.lastname: Hagen
authors.forename: Tom J
authors.initials: TJ
authors.lastname: Guilfoyle
mesh_terms: D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D007210:Indoleacetic Acids / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D010940:Plant Proteins; D011956:Receptors, Cell Surface; D014157:Transcription Factors; C046131:auxin receptor, plant
keywords: DNA-binding domain; activation domain; auxin; auxin response factors; auxin response gene; carboxyl terminal domain; protoplast transfection