title: The seirena B class floral homeotic mutant of California Poppy (Eschscholzia californica) reveals a function of the enigmatic PI motif in the formation of specific multimeric MADS domain protein complexes.
abstract: The products of B class floral homeotic genes specify petal and stamen identity, and loss of B function results in homeotic conversions of petals into sepals and stamens into carpels. Here, we describe the molecular characterization of seirena-1 (sei-1), a mutant from the basal eudicot California poppy (Eschscholzia californica) that shows homeotic changes characteristic of floral homeotic B class mutants. SEI has been previously described as EScaGLO, one of four B class-related MADS box genes in California poppy. The C terminus of SEI, including the highly conserved PI motif, is truncated in sei-1 proteins. Nevertheless, like the wild-type SEI protein, the sei-1 mutant protein is able to bind CArG-boxes and can form homodimers, heterodimers, and several higher order complexes with other MADS domain proteins. However, unlike the wild type, the mutant protein is not able to mediate higher order complexes consisting of specific B, C, and putative E class related proteins likely involved in specifying stamen identity. Within the PI motif, five highly conserved N-terminal amino acids are specifically required for this interaction. Several families lack this short conserved sequence, including the Brassicaceae, and we propose an evolutionary scenario to explain these functional differences.
authors: Evolutionary Developmental Genetics Group, Zentrum für Umweltforschung und nachhaltige Technologien, University of Bremen, D-28359 Bremen, Germany.
authors: Matthias
authors: M
authors: Lange
authors: Svetlana
authors: S
authors: Orashakova
authors: Sabrina
authors: S
authors: Lange
authors: Rainer
authors: R
authors: Melzer
authors: Günter
authors: G
authors: Theißen
authors: David R
authors: DR
authors: Smyth
authors: Annette
authors: A
authors: Becker
mesh_terms: D020816:Amino Acid Motifs; D029681:Arabidopsis Proteins / Q000235:genetics; D001483:Base Sequence; D017124:Conserved Sequence; D031675:Eschscholzia / Q000235:genetics*; D019143:Evolution, Molecular; D035264:Flowers / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D005801:Genes, Homeobox; D026161:MADS Domain Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization
chemical_list: D029681:Arabidopsis Proteins; D026161:MADS Domain Proteins; C090225:PISTILLATA protein, Arabidopsis; D010940:Plant Proteins