title: AtMRP6/AtABCC6, an ATP-binding cassette transporter gene expressed during early steps of seedling development and up-regulated by cadmium in Arabidopsis thaliana.
abstract: BACKGROUND
  ABC proteins constitute one of the largest families of transporters found in all living organisms. In Arabidopsis thaliana, 120 genes encoding ABC transporters have been identified. Here, the characterization of one member of the MRP subclass, AtMRP6, is described.
  
  
  RESULTS
  This gene, located on chromosome 3, is bordered by AtMRP3 and AtMRP7. Using real-time quantitative PCR (RT-Q-PCR) and the GUS reporter gene, we found that this gene is essentially expressed during early seedling development, in the apical meristem and at initiation point of secondary roots, especially in xylem-opposite pericycle cells where lateral roots initiate. The level of expression of AtMRP6 in response to various stresses was explored and a significant up-regulation after cadmium (Cd) treatment was detected. Among the three T-DNA insertion lines available from the Salk Institute library, two knock-out mutants, Atmrp6.1 and Atmrp6.2 were invalidated for the AtMRP6 gene. In the presence of Cd, development of leaves was more affected in the mutants than wild-type plants, whereas root elongation and ramification was comparable.
  
  
  CONCLUSIONS
  The position of AtMRP6 on chromosome 3, flanked by two other MRP genes, (all of which being induced by Cd) suggests that AtMRP6 is part of a cluster involved in metal tolerance, although additional functions in planta cannot be discarded.
authors.affiliation: CEA, DSV, IBEB, Lab Echanges Membranaires & Signalisation, Saint-Paul-lez-Durance, F-13108, France. sgaillard@ibdml.univ-mrs.fr
authors.forename: Stéphane
authors.initials: S
authors.lastname: Gaillard
authors.forename: Hélène
authors.initials: H
authors.lastname: Jacquet
authors.forename: Alain
authors.initials: A
authors.lastname: Vavasseur
authors.forename: Nathalie
authors.initials: N
authors.lastname: Leonhardt
authors.forename: Cyrille
authors.initials: C
authors.lastname: Forestier
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics*; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D002104:Cadmium / Q000494:pharmacology*; D002460:Cell Line; D018076:DNA, Complementary; D018744:DNA, Plant; D017353:Gene Deletion; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D006801:Humans; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics / Q000378:metabolism*; D005810:Multigene Family; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D036226:Seedlings / Q000235:genetics / Q000254:growth & development*; D015854:Up-Regulation / Q000187:drug effects*
chemical_list: D018528:ATP-Binding Cassette Transporters; D029681:Arabidopsis Proteins; D002104:Cadmium; D018076:DNA, Complementary; D018744:DNA, Plant; D027425:ATP-Binding Cassette, Sub-Family C Proteins; C531576:MRP6 protein, Arabidopsis