title: Constitutive auxin response in Physcomitrella reveals complex interactions between Aux/IAA and ARF proteins.
abstract: The coordinated action of the auxin-sensitive Aux/IAA transcriptional repressors and ARF transcription factors produces complex gene-regulatory networks in plants. Despite their importance, our knowledge of these two protein families is largely based on analysis of stabilized forms of the Aux/IAAs, and studies of a subgroup of ARFs that function as transcriptional activators. To understand how auxin regulates gene expression we generated a Physcomitrella patens line that completely lacks Aux/IAAs. Loss of the repressors causes massive changes in transcription with misregulation of over a third of the annotated genes. Further, we find that the aux/iaa mutant is blind to auxin indicating that auxin regulation of transcription occurs exclusively through Aux/IAA function. We used the aux/iaa mutant as a simplified platform for studies of ARF function and demonstrate that repressing ARFs regulate auxin-induced genes and fine-tune their expression. Further the repressing ARFs coordinate gene induction jointly with activating ARFs and the Aux/IAAs.
authors.affiliation: Section of Cell and Developmental Biology, Howard Hughes Medical Institute, University of California, San Diego, San Diego, United States.
authors.forename: Meirav
authors.initials: M
authors.lastname: Lavy
authors.affiliation: Section of Cell and Developmental Biology, Howard Hughes Medical Institute, University of California, San Diego, San Diego, United States.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Prigge
authors.affiliation: Section of Cell and Developmental Biology, Howard Hughes Medical Institute, University of California, San Diego, San Diego, United States.
authors.forename: Sibo
authors.initials: S
authors.lastname: Tao
authors.affiliation: Section of Cell and Developmental Biology, Howard Hughes Medical Institute, University of California, San Diego, San Diego, United States.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Shain
authors.affiliation: Section of Cell and Developmental Biology, Howard Hughes Medical Institute, University of California, San Diego, San Diego, United States.
authors.forename: April
authors.initials: A
authors.lastname: Kuo
authors.affiliation: Section of Cell and Developmental Biology, Howard Hughes Medical Institute, University of California, San Diego, San Diego, United States.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Kirchsteiger
authors.affiliation: Section of Cell and Developmental Biology, Howard Hughes Medical Institute, University of California, San Diego, San Diego, United States.
authors.forename: Mark
authors.identifier: 0000-0002-2613-8652
authors.initials: M
authors.lastname: Estelle
mesh_terms: D019068:Bryopsida / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D007210:Indoleacetic Acids / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D010940:Plant Proteins; D014157:Transcription Factors
keywords: ARFs; Aux/IAAs; Physcomitrella patens; auxin; chromosomes; genes; plant biology; plant development