title: Genetic separation of third and fourth whorl functions of AGAMOUS.
abstract: AGAMOUS (AG) is an Arabidopsis MADS box gene required for normal development of the third and fourth whorls of the flower. In previously described ag mutants, the third whorl stamens are replaced by petals, and the fourth whorl is replaced by another (mutant) flower. We describe two new ag alleles, ag-4 and AG-Met205, retaining partial AG activity. Both produce flowers with stamens in the third whorl and indeterminate floral meristems; however, ag-4 flowers contain sepals in the fourth whorl, and AG-Met205 produces carpels. The ag-4 mutation results in partial loss of the C terminus of the K domain, a putative coiled coil, and AG-Met205 contains a site-directed mutation that causes a single amino acid change in this same region of the K box. Two models that might explain how these changes in AG result in the separation of different AG activities are discussed.
authors.affiliation: Department of Biology, California Institute of Technology, Pasadena 91125, USA.
authors.forename: L E
authors.initials: LE
authors.lastname: Sieburth
authors.forename: M P
authors.initials: MP
authors.lastname: Running
authors.forename: E M
authors.initials: EM
authors.lastname: Meyerowitz
mesh_terms: D026342:AGAMOUS Protein, Arabidopsis; D000483:Alleles; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics*; D017343:Genes, Plant / Q000235:genetics*; D018398:Homeodomain Proteins / Q000235:genetics; D007091:Image Processing, Computer-Assisted; D017403:In Situ Hybridization; D026161:MADS Domain Proteins; D008855:Microscopy, Electron, Scanning; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009024:Morphogenesis / Q000235:genetics; D016296:Mutagenesis; D009687:Nuclear Proteins / Q000235:genetics; D010641:Phenotype; D010940:Plant Proteins / Q000096:biosynthesis / Q000235:genetics*; D018520:Plant Shoots / Q000235:genetics* / Q000254:growth & development; D030821:Plants, Genetically Modified; D017433:Protein Structure, Secondary; D012326:RNA Splicing / Q000235:genetics; D017386:Sequence Homology, Amino Acid
chemical_list: D026342:AGAMOUS Protein, Arabidopsis; C091535:AP1 protein, Arabidopsis; C499534:APETALA2 protein, Arabidopsis; D029681:Arabidopsis Proteins; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D026161:MADS Domain Proteins; D009687:Nuclear Proteins; D010940:Plant Proteins