title: Zinc triggers a complex transcriptional and post-transcriptional regulation of the metal homeostasis gene FRD3 in Arabidopsis relatives.
abstract: In Arabidopsis thaliana, FRD3 (FERRIC CHELATE REDUCTASE DEFECTIVE 3) plays a central role in metal homeostasis. FRD3 is among a set of metal homeostasis genes that are constitutively highly expressed in roots and shoots of Arabidopsis halleri, a zinc hyperaccumulating and hypertolerant species. Here, we examined the regulation of FRD3 by zinc in both species to shed light on the evolutionary processes underlying the evolution of hyperaccumulation in A. halleri. We combined gene expression studies with the use of β-glucuronidase and green fluorescent protein reporter constructs to compare the expression profile and transcriptional and post-transcriptional regulation of FRD3 in both species. The AtFRD3 and AhFRD3 genes displayed a conserved expression profile. In A. thaliana, alternative transcription initiation sites from two promoters determined transcript variants that were differentially regulated by zinc supply in roots and shoots to favour the most highly translated variant under zinc-excess conditions. In A. halleri, a single transcript variant with higher transcript stability and enhanced translation has been maintained. The FRD3 gene thus undergoes complex transcriptional and post-transcriptional regulation in Arabidopsis relatives. Our study reveals that a diverse set of mechanisms underlie increased gene dosage in the A. halleri lineage and illustrates how an environmental challenge can alter gene regulation.
authors.affiliation: Functional Genomics and Plant Molecular Imaging, Center for Protein Engineering (CIP), Department of Life Sciences, University of Liège, B-4000 Liège, Belgium.
authors.forename: Jean-Benoit
authors.initials: JB
authors.lastname: Charlier
authors.affiliation: Functional Genomics and Plant Molecular Imaging, Center for Protein Engineering (CIP), Department of Life Sciences, University of Liège, B-4000 Liège, Belgium.
authors.forename: Catherine
authors.initials: C
authors.lastname: Polese
authors.affiliation: Functional Genomics and Plant Molecular Imaging, Center for Protein Engineering (CIP), Department of Life Sciences, University of Liège, B-4000 Liège, Belgium.
authors.forename: Cécile
authors.initials: C
authors.lastname: Nouet
authors.affiliation: Laboratory of Plant and Microbial Ecology, Department of Biology, Ecology, Evolution, University of Liège, B-4000 Liège, Belgium.
authors.forename: Monique
authors.initials: M
authors.lastname: Carnol
authors.affiliation: Laboratory of Plant and Microbial Ecology, Department of Biology, Ecology, Evolution, University of Liège, B-4000 Liège, Belgium.
authors.forename: Bernard
authors.initials: B
authors.lastname: Bosman
authors.affiliation: Department of Plant Physiology, Ruhr University Bochum, D-44801 Bochum, Germany.
authors.forename: Ute
authors.initials: U
authors.lastname: Krämer
authors.affiliation: Functional Genomics and Plant Molecular Imaging, Center for Protein Engineering (CIP), Department of Life Sciences, University of Liège, B-4000 Liège, Belgium PhytoSYSTEMS, University of Liège, B-4000 Liège, Belgium.
authors.forename: Patrick
authors.initials: P
authors.lastname: Motte
authors.affiliation: Functional Genomics and Plant Molecular Imaging, Center for Protein Engineering (CIP), Department of Life Sciences, University of Liège, B-4000 Liège, Belgium PhytoSYSTEMS, University of Liège, B-4000 Liège, Belgium marc.hanikenne@ulg.ac.be.
authors.forename: Marc
authors.initials: M
authors.lastname: Hanikenne
mesh_terms: D020121:5' Untranslated Regions / Q000235:genetics; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D017343:Genes, Plant; D005838:Genotype; D006706:Homeostasis / Q000187:drug effects / Q000235:genetics*; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D014176:Protein Biosynthesis / Q000187:drug effects; D020871:RNA Stability / Q000187:drug effects / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D024363:Transcription Initiation Site; D014158:Transcription, Genetic / Q000187:drug effects*; D015032:Zinc / Q000494:pharmacology*
chemical_list: D020121:5' Untranslated Regions; D029681:Arabidopsis Proteins; C469252:FRD3 protein, Arabidopsis; D026901:Membrane Transport Proteins; D012333:RNA, Messenger; D015032:Zinc
keywords: Alternative promoter; Arabidopsis halleri; gene regulation; transcript stability; translation; zinc homeostasis.