title: Arabidopsis ferritin 1 (AtFer1) gene regulation by the phosphate starvation response 1 (AtPHR1) transcription factor reveals a direct molecular link between iron and phosphate homeostasis.
abstract: A yeast one-hybrid screening allowed the selection of PHR1 as a factor that interacted with the AtFer1 ferritin gene promoter. In mobility shift assays, PHR1 and its close homologue PHL1 (PHR1-like 1) interact with Element 2 of the AtFer1 promoter, containing a P1BS (PHR1 binding site). In a loss of function mutant for genes encoding PHR1 and PHL1 (phr1 phl1 mutant), the response of AtFer1 to phosphate starvation was completely lost, showing that the two transcription factors regulate AtFer1 expression upon phosphate starvation. This regulation does not involve the IDRS (iron-dependent regulatory sequence) present in the AtFer1 promoter and involved in the iron-dependent regulation. The phosphate starvation response of AtFer1 is not linked to the iron status of plants and is specifically initiated by phosphate deficiency. Histochemical localization of iron, visualized by Perls DAB staining, was strongly altered in a phr1 phl1 mutant, revealing that both PHR1 and PHL1 are major factors involved in the regulation of iron homeostasis.
authors.affiliation: Laboratoire de Biochimie et Physiologie Moleculaire des Plantes, UMR 5004, Agro-M/CNRS/Institut National de la Recherche Agronomique/Universite Montpelier II, 34060 Montpellier Cedex 1, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Bournier
authors.forename: Nicolas
authors.initials: N
authors.lastname: Tissot
authors.forename: Stéphane
authors.initials: S
authors.lastname: Mari
authors.forename: Jossia
authors.initials: J
authors.lastname: Boucherez
authors.forename: Eric
authors.initials: E
authors.lastname: Lacombe
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Briat
authors.forename: Frédéric
authors.initials: F
authors.lastname: Gaymard
mesh_terms: D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000502:physiology*; D005293:Ferritins / Q000235:genetics*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D006706:Homeostasis; D007501:Iron / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D015398:Signal Transduction; D014157:Transcription Factors / Q000502:physiology*
chemical_list: D029681:Arabidopsis Proteins; C514695:PHR1 protein, Arabidopsis; D010710:Phosphates; D014157:Transcription Factors; D005293:Ferritins; D007501:Iron
keywords: Iron; Iron Metabolism; Metal Homeostasis; Plant; Redox