title: OsARF1, an auxin response factor from rice, is auxin-regulated and classifies as a primary auxin responsive gene.
abstract: We screened for auxin-induced genes with an expression correlated to the auxin-induced growth response from rice coleoptiles by fluorescent differential display. A rice homologue of the auxin response factor (ARF) family of transcriptional regulators, OsARF1, was identified. An OsARF1:GFP fusion protein was localized to the nucleus. Steady-state levels of OsARF1 mRNA correlated positively with auxin-dependent differential growth: gravitropic stimulation enhanced the amount of OsARF1 transcript in the lower, faster-growing flank accompanied by a decrease in the upper flank of gravitropically stimulated rice coleoptiles. Exogenous auxin up-regulated the steady-state level of OsARF1 mRNA within 15-30 min. This up-regulation is independent of de novo protein synthesis. Thus, OsARF1 is the first ARF that classifies as an early auxin-responsive gene. The observed auxin-dependent regulation comprises a new level of regulation in auxin-induced gene expression and is discussed as a possible feedback mechanism in plant growth control.
mesh_terms: D000595:Amino Acid Sequence; D002467:Cell Nucleus / Q000378:metabolism; D018548:Cotyledon / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D018522:Gravitropism / Q000187:drug effects; D049452:Green Fluorescent Proteins; D007210:Indoleacetic Acids / Q000494:pharmacology*; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D012275:Oryza / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development; D010940:Plant Proteins; D012333:RNA, Messenger / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014026:Nicotiana / Q000166:cytology / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D007210:Indoleacetic Acids; D008164:Luminescent Proteins; D009687:Nuclear Proteins; D010940:Plant Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D049452:Green Fluorescent Proteins