Involvement of NRAMP1 from Arabidopsis thaliana in iron transport.
Nramp genes code for a widely distributed class of proteins involved in a variety of processes, ranging from the control of susceptibility to bacterial infection in mammalian cells and taste behaviour in Drosophila to manganese uptake in yeast. Some of the NRAMP proteins in mammals and in yeast are capable of transporting metal ions, including iron. In plants, iron transport was shown to require a reduction/Fe(II) transport system. In Arabidopsis thaliana this process involves the IRT1 and Fro2 genes. Here we report the sequence of five NRAMP proteins from A. thaliana. Sequence comparison suggests that there are two classes of NRAMP proteins in plants: A. thaliana (At) NRAMP1 and Oriza sativa (Os) NRAMP1 and 3 (two rice isologues) represent one class, and AtNRAMP2-5 and OsNRAMP2 the other. AtNramp1 and OsNramp1 are able to complement the fet3fet4 yeast mutant defective both in low- and high-affinity iron transports, whereas AtNramp2 and OsNramp2 fail to do so. In addition, AtNramp1 transcript, but not AtNramp2 transcript, accumulates in response to iron deficiency in roots but not in leaves. Finally, overexpression of AtNramp1 in transgenic A. thaliana plants leads to an increase in plant resistance to toxic iron concentration. Taken together, these results demonstrate that AtNramp1 participates in the control of iron homoeostasis in plants.
Curie
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Laboratoire de Biochimie et Physiologie Moléculaire des Plantes, CNRS/INRA/ENSAM/Université Montpellier 2. Place Viala, F-34060 Montpellier CEDEX 1, France. curie@ensam.inra.fr
Alonso
J M
JM
Le Jean
M
M
Ecker
J R
JR
Briat
J F
JF
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D001692:Biological Transport / Q000187:drug effects; D002352:Carrier Proteins / Q000737:chemistry / Q000145:classification / Q000235:genetics* / Q000378:metabolism*; D027682:Cation Transport Proteins; D003001:Cloning, Molecular; D017124:Conserved Sequence / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005800:Genes, Fungal / Q000235:genetics; D017343:Genes, Plant / Q000235:genetics / Q000502:physiology; D005816:Genetic Complementation Test; D006706:Homeostasis; D007501:Iron / Q000378:metabolism* / Q000494:pharmacology; D033862:Iron-Binding Proteins; D008565:Membrane Proteins / Q000737:chemistry / Q000145:classification / Q000235:genetics* / Q000378:metabolism*; D026901:Membrane Transport Proteins; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics; D009154:Mutation / Q000235:genetics; D012275:Oryza / Q000235:genetics; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D016415:Sequence Alignment; D000099173:Natural Resistance-associated Macrophage Protein 1; D000099236:Solute Carrier Family 11, Member 2
D002352:Carrier Proteins; D027682:Cation Transport Proteins; D007501:Iron; D033862:Iron-Binding Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D010940:Plant Proteins; D012333:RNA, Messenger; D018749:RNA, Plant; D000099173:Natural Resistance-associated Macrophage Protein 1; D000099236:Solute Carrier Family 11, Member 2; C106214:OsNramp1 protein, Oryza sativa; C499536:OsNramp2 protein, Oryza sativa; C499537:OsNramp3 protein, Oryza sativa