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Distinct subclades of Aux/IAA genes are direct targets of ARF 5/ MP transcriptional regulation
Author(s) -
Krogan Naden T.,
Yin Xiaojun,
Ckurshumova Wenzislava,
Berleth Thomas
Publication year - 2014
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.12994
Subject(s) - auxin , biology , gene , repressor , chromatin immunoprecipitation , signal transduction , microbiology and biotechnology , transcriptional regulation , regulation of gene expression , genetics , gene expression , trans acting , transcription factor , promoter , mutant
Summary The regulatory interactions between AUXIN RESPONSE FACTORS ( ARF s) and Aux/ IAA repressors play a central role in auxin signal transduction. Yet, the systems properties of this regulatory network are not well established. We generated a steroid‐inducible ARF 5/ MONOPTEROS ( MP ) transgenic background to survey the involvement of this factor in the transcriptional regulation of the entire Aux/ IAA family in A rabidopsis thaliana . Target genes of ARF 5/ MP identified by this approach were confirmed by chromatin immunoprecipitation, in vitro gel retardation assays and gene expression analyses. Our study shows that ARF 5/ MP is indispensable for the correct regulation of nearly one‐half of all Aux/ IAA genes, and that these targets coincide with distinct subclades. Further, genetic analyses demonstrate that the protein products of multiple Aux/ IAA targets negatively feed back onto ARF 5/ MP activity. This work indicates that ARF 5/ MP broadly influences the expression of the Aux/ IAA gene family, and suggests that such regulation involves the activation of specific subsets of redundantly functioning factors. These groups of factors may then act together to control various processes within the plant through negative feedback on ARF 5. Similar detailed analyses of other Aux/ IAA – ARF regulatory modules will be required to fully understand how auxin signal transduction influences virtually every aspect of plant growth and development.