title: ETTIN patterns the Arabidopsis floral meristem and reproductive organs.
abstract: ettin (ett) mutations have pleiotropic effects on Arabidopsis flower development, causing increases in perianth organ number, decreases in stamen number and anther formation, and apical-basal patterning defects in the gynoecium. The ETTIN gene was cloned and encodes a protein with homology to DNA binding proteins which bind to auxin response elements. ETT transcript is expressed throughout stage 1 floral meristems and subsequently resolves to a complex pattern within petal, stamen and carpel primordia. The data suggest that ETT functions to impart regional identity in floral meristems that affects perianth organ number spacing, stamen formation, and regional differentiation in stamens and the gynoecium. During stage 5, ETT expression appears in a ring at the top of the floral meristem before morphological appearance of the gynoecium, consistent with the proposal that ETT is involved in prepatterning apical and basal boundaries in the gynoecium primordium. Double mutant analyses and expression studies show that although ETT transcriptional activation occurs independently of the meristem and organ identity genes LEAFY, APETELA1, APETELA2 and AGAMOUS, the functioning of these genes is necessary for ETT activity. Double mutant analyses also demonstrate that ETT functions independently of the 'b' class genes APETELA3 and PISTILLATA. Lastly, double mutant analyses suggest that ETT control of floral organ number acts independently of CLAVATA loci and redundantly with PERIANTHIA.
authors.affiliation: Department of Plant and Microbiology, University of California at Berkeley, 94720, USA.
authors.forename: A
authors.initials: A
authors.lastname: Sessions
authors.forename: J L
authors.initials: JL
authors.lastname: Nemhauser
authors.forename: A
authors.initials: A
authors.lastname: McColl
authors.forename: J L
authors.initials: JL
authors.lastname: Roe
authors.forename: K A
authors.initials: KA
authors.lastname: Feldmann
authors.forename: P C
authors.initials: PC
authors.lastname: Zambryski
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development*; D029681:Arabidopsis Proteins; D001483:Base Sequence; D018076:DNA, Complementary / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D018398:Homeodomain Proteins / Q000235:genetics; D017403:In Situ Hybridization; D026161:MADS Domain Proteins; D018519:Meristem / Q000254:growth & development; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics; D009928:Organ Specificity; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics; D014157:Transcription Factors; D015533:Transcriptional Activation
chemical_list: C091535:AP1 protein, Arabidopsis; C499534:APETALA2 protein, Arabidopsis; D029681:Arabidopsis Proteins; D018076:DNA, Complementary; D018744:DNA, Plant; D004268:DNA-Binding Proteins; C109765:ETT protein, Arabidopsis; D018398:Homeodomain Proteins; C074747:LFY protein, Arabidopsis; D026161:MADS Domain Proteins; D009687:Nuclear Proteins; D010940:Plant Proteins; D014157:Transcription Factors