title: Parallel structural evolution of auxin response factors in the angiosperms.
abstract: Here we analyze the structural evolution of the paralogous transcription factors ETTIN (ETT/ARF3) and AUXIN RESPONSE FACTOR 4 (ARF4), which control the development of floral organs and leaves in the model angiosperm Arabidopsis. ETT is truncated at its C terminus, and consequently lacks two regulatory domains present in most other ARFs, including ARF4. Our analysis indicates ETT and ARF4 to have been generated by the duplication of a non-truncated ARF gene prior to the radiation of the extant angiosperms. We furthermore show that either ETT or ARF4 orthologs have become modified to encode truncated ARF proteins, lacking C-terminal regulatory domains, in representatives of three groups that separated early in angiosperm evolution: Amborellales, Nymphaeales and the remaining angiosperm clade. Interestingly, the production of truncated ARF4 transcripts in Amborellales occurs through an alternative splicing mechanism, rather than through a permanent truncation, as in the other groups studied. To gain insight into the potential functional significance of truncations to ETT and ARF4, we tested the capacity of native, truncated and chimeric coding sequences of these genes to restore a wild-type phenotype to Arabidopsis ett mutants. We discuss the results of this analysis in the context of the structural evolution of ARF genes in the angiosperms.
authors.affiliation: Laboratoire de Reproduction et Développement des Plantes (UMR 5667 - CNRS, INRA, Université de Lyon) Ecole Normale Supérieure de Lyon, 46, allée d'Italie, 69364 Lyon Cedex 07, France.
authors.forename: Cédric
authors.initials: C
authors.lastname: Finet
authors.forename: Chloé
authors.initials: C
authors.lastname: Fourquin
authors.forename: Marion
authors.initials: M
authors.lastname: Vinauger
authors.forename: Annick
authors.initials: A
authors.lastname: Berne-Dedieu
authors.forename: Pierre
authors.initials: P
authors.lastname: Chambrier
authors.forename: Sandrine
authors.initials: S
authors.lastname: Paindavoine
authors.forename: Charles P
authors.initials: CP
authors.lastname: Scutt
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D029789:Ephedra / Q000235:genetics / Q000378:metabolism; D019143:Evolution, Molecular; D019684:Magnoliopsida / Q000145:classification* / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism; D010802:Phylogeny; D010940:Plant Proteins / Q000145:classification* / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000145:classification / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000145:classification* / Q000235:genetics / Q000378:metabolism*
chemical_list: D009687:Nuclear Proteins; D010940:Plant Proteins; D014157:Transcription Factors