title: Functional genomic analysis of the AUXIN RESPONSE FACTOR gene family members in Arabidopsis thaliana: unique and overlapping functions of ARF7 and ARF19.
abstract: The AUXIN RESPONSE FACTOR (ARF) gene family products, together with the AUXIN/INDOLE-3-ACETIC ACID proteins, regulate auxin-mediated transcriptional activation/repression. The biological function(s) of most ARFs is poorly understood. Here, we report the identification and characterization of T-DNA insertion lines for 18 of the 23 ARF gene family members in Arabidopsis thaliana. Most of the lines fail to show an obvious growth phenotype except of the previously identified arf2/hss, arf3/ett, arf5/mp, and arf7/nph4 mutants, suggesting that there are functional redundancies among the ARF proteins. Subsequently, we generated double mutants. arf7 arf19 has a strong auxin-related phenotype not observed in the arf7 and arf19 single mutants, including severely impaired lateral root formation and abnormal gravitropism in both hypocotyl and root. Global gene expression analysis revealed that auxin-induced gene expression is severely impaired in the arf7 single and arf7 arf19 double mutants. For example, the expression of several genes, such as those encoding members of LATERAL ORGAN BOUNDARIES domain proteins and AUXIN-REGULATED GENE INVOLVED IN ORGAN SIZE, are disrupted in the double mutant. The data suggest that the ARF7 and ARF19 proteins play essential roles in auxin-mediated plant development by regulating both unique and partially overlapping sets of target genes. These observations provide molecular insight into the unique and overlapping functions of ARF gene family members in Arabidopsis.
authors.affiliation: Plant Gene Expression Center, Albany, California 94710, USA.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Okushima
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Overvoorde
authors.forename: Kazunari
authors.initials: K
authors.lastname: Arima
authors.forename: Jose M
authors.initials: JM
authors.lastname: Alonso
authors.forename: April
authors.initials: A
authors.lastname: Chan
authors.forename: Charlie
authors.initials: C
authors.lastname: Chang
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Ecker
authors.forename: Beth
authors.initials: B
authors.lastname: Hughes
authors.forename: Amy
authors.initials: A
authors.lastname: Lui
authors.forename: Diana
authors.initials: D
authors.lastname: Nguyen
authors.forename: Courtney
authors.initials: C
authors.lastname: Onodera
authors.forename: Hong
authors.initials: H
authors.lastname: Quach
authors.forename: Alison
authors.initials: A
authors.lastname: Smith
authors.forename: Guixia
authors.initials: G
authors.lastname: Yu
authors.forename: Athanasios
authors.initials: A
authors.lastname: Theologis
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D018546:Hypocotyl / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D007210:Indoleacetic Acids / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D010802:Phylogeny; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: C503426:ARF19 protein, Arabidopsis; C503425:ARF7 protein, Arabidopsis; D029681:Arabidopsis Proteins; D004269:DNA, Bacterial; D007210:Indoleacetic Acids; C036483:T-DNA; D015534:Trans-Activators; D014157:Transcription Factors; C517136:auxin response factor 6, Arabidopsis