title: Molecular and functional analyses of COPT/Ctr-type copper transporter-like gene family in rice.
abstract: BACKGROUND
  The copper (Cu) transporter (COPT/Ctr) gene family has an important role in the maintenance of Cu homeostasis in different species. The rice COPT-type gene family consists of seven members (COPT1 to COPT7). However, only two, COPT1 and COPT5, have been characterized for their functions in Cu transport.
  
  
  RESULTS
  Here we report the molecular and functional characterization of the other five members of the rice COPT gene family (COPT2, COPT3, COPT4, COPT6, and COPT7). All members of the rice COPT family have the conserved features of known COPT/Ctr-type Cu transporter genes. Among the proteins encoded by rice COPTs, COPT2, COPT3, and COPT4 physically interacted with COPT6, respectively, except for the known interaction between COPT1 and COPT5. COPT2, COPT3, or COPT4 cooperating with COPT6 mediated a high-affinity Cu uptake in the yeast Saccharomyces cerevisiae mutant that lacked the functions of ScCtr1 and ScCtr3 for Cu uptake. COPT7 alone could mediate a high-affinity Cu uptake in the yeast mutant. None of the seven COPTs alone or in cooperation could complement the phenotypes of S. cerevisiae mutants that lacked the transporter genes either for iron uptake or for zinc uptake. However, these COPT genes, which showed different tissue-specific expression patterns and Cu level-regulated expression patterns, were also transcriptionally influenced by deficiency of iron, manganese, or zinc.
  
  
  CONCLUSIONS
  These results suggest that COPT2, COPT3, and COPT4 may cooperate with COPT6, respectively, and COPT7 acts alone for Cu transport in different rice tissues. The endogenous concentrations of iron, manganese, or zinc may influence Cu homeostasis by influencing the expression of COPTs in rice.
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Meng
authors.initials: M
authors.lastname: Yuan
authors.forename: Xianghua
authors.initials: X
authors.lastname: Li
authors.forename: Jinghua
authors.initials: J
authors.lastname: Xiao
authors.forename: Shiping
authors.initials: S
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D001692:Biological Transport; D027682:Cation Transport Proteins / Q000235:genetics* / Q000378:metabolism*; D002874:Chromosome Mapping; D003300:Copper / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D006706:Homeostasis; D007501:Iron / Q000378:metabolism; D008969:Molecular Sequence Data; D012275:Oryza / Q000235:genetics* / Q000378:metabolism*; D010802:Phylogeny; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D015032:Zinc / Q000378:metabolism
chemical_list: D027682:Cation Transport Proteins; D003300:Copper; D007501:Iron; D015032:Zinc