title: Central role for ferritin in the day/night regulation of iron homeostasis in marine phytoplankton.
abstract: In large regions of the open ocean, iron is a limiting resource for phytoplankton. The reduction of iron quota and the recycling of internal iron pools are among the diverse strategies that phytoplankton have evolved to allow them to grow under chronically low ambient iron levels. Phytoplankton species also have evolved strategies to cope with sporadic iron supply such as long-term storage of iron in ferritin. In the picophytoplanktonic species Ostreococcus we report evidence from observations both in the field and in laboratory cultures that ferritin and the main iron-binding proteins involved in photosynthesis and nitrate assimilation pathways show opposite diurnal expression patterns, with ferritin being maximally expressed during the night. Biochemical and physiological experiments using a ferritin knock-out line subsequently revealed that this protein plays a central role in the diel regulation of iron uptake and recycling and that this regulation of iron homeostasis is essential for cell survival under iron limitation.
authors.affiliation: Sorbonne Universités, University Pierre et Marie Curie, University of Paris VI, CNRS, Laboratoire d'Océanographie Microbienne, Observatoire Océanologique, F-66650, Banyuls-sur-Mer, France;
authors.forename: Hugo
authors.initials: H
authors.lastname: Botebol
authors.affiliation: Université Paris Diderot-Paris 7, CNRS, Institut Jacques Monod, F-75013 Paris, France;
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Lesuisse
authors.affiliation: Department of Parasitology, Faculty of Science, Charles University, 12844 Prague, Czech Republic;
authors.forename: Robert
authors.initials: R
authors.lastname: Šuták
authors.affiliation: Sorbonne Universités, University Pierre et Marie Curie, University of Paris VI, CNRS UMR 7144 Adaptation et Diversité en Milieux Marins, Marine Phototrophic Prokaryotes Group, Roscoff Biological Station, CS 90074, 29688 Roscoff cedex, France;
authors.forename: Christophe
authors.initials: C
authors.lastname: Six
authors.affiliation: Sorbonne Universités, University Pierre et Marie Curie, University of Paris VI, CNRS, Laboratoire d'Océanographie Microbienne, Observatoire Océanologique, F-66650, Banyuls-sur-Mer, France;
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Lozano
authors.affiliation: Sorbonne Universités, University Pierre et Marie Curie, University of Paris VI, CNRS, Laboratoire d'Océanographie Microbienne, Observatoire Océanologique, F-66650, Banyuls-sur-Mer, France;
authors.forename: Philippe
authors.initials: P
authors.lastname: Schatt
authors.affiliation: Unité Mixte de Service, UMS2348, F-66651, Banyuls-sur-Mer, France;
authors.forename: Valérie
authors.initials: V
authors.lastname: Vergé
authors.affiliation: Institut de Biologie de l'Ecole Normale Supérieure, CNRS UMR8197 Inserm U1024, 75005 Paris, France.
authors.forename: Amos
authors.initials: A
authors.lastname: Kirilovsky
authors.affiliation: Institut de Biologie de l'Ecole Normale Supérieure, CNRS UMR8197 Inserm U1024, 75005 Paris, France.
authors.forename: Joe
authors.initials: J
authors.lastname: Morrissey
authors.affiliation: Université Paris Diderot-Paris 7, CNRS, Institut Jacques Monod, F-75013 Paris, France;
authors.forename: Thibaut
authors.initials: T
authors.lastname: Léger
authors.affiliation: Université Paris Diderot-Paris 7, CNRS, Institut Jacques Monod, F-75013 Paris, France;
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Camadro
authors.affiliation: Sorbonne Universités, University Pierre et Marie Curie, University of Paris VI, CNRS, Laboratoire d'Océanographie Microbienne, Observatoire Océanologique, F-66650, Banyuls-sur-Mer, France;
authors.forename: Audrey
authors.initials: A
authors.lastname: Gueneugues
authors.affiliation: Institut de Biologie de l'Ecole Normale Supérieure, CNRS UMR8197 Inserm U1024, 75005 Paris, France.
authors.forename: Chris
authors.initials: C
authors.lastname: Bowler
authors.affiliation: Sorbonne Universités, University Pierre et Marie Curie, University of Paris VI, CNRS, Laboratoire d'Océanographie Microbienne, Observatoire Océanologique, F-66650, Banyuls-sur-Mer, France; blain@obs-banyuls.fr fy.bouget@obs-banyuls.fr.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Blain
authors.affiliation: Sorbonne Universités, University Pierre et Marie Curie, University of Paris VI, CNRS, Laboratoire d'Océanographie Microbienne, Observatoire Océanologique, F-66650, Banyuls-sur-Mer, France; blain@obs-banyuls.fr fy.bouget@obs-banyuls.fr.
authors.forename: François-Yves
authors.initials: FY
authors.lastname: Bouget
mesh_terms: D015153:Blotting, Western; D011232:Chemical Precipitation; D002940:Circadian Rhythm / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D005293:Ferritins / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000528:radiation effects; D006706:Homeostasis / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D007501:Iron / Q000378:metabolism* / Q000494:pharmacology; D033862:Iron-Binding Proteins / Q000378:metabolism; D007700:Kinetics; D008027:Light; D013058:Mass Spectrometry; D050296:Microbial Viability / Q000187:drug effects / Q000528:radiation effects; D010839:Phytoplankton / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D012623:Seawater / Q000382:microbiology*; D059467:Transcriptome / Q000235:genetics
chemical_list: D033862:Iron-Binding Proteins; D005293:Ferritins; D007501:Iron
keywords: Ostreococcus; circadian; ferritin; iron; phytoplankton