title: A strong loss-of-function mutation in RAN1 results in constitutive activation of the ethylene response pathway as well as a rosette-lethal phenotype.
abstract: A recessive mutation was identified that constitutively activated the ethylene response pathway in Arabidopsis and resulted in a rosette-lethal phenotype. Positional cloning of the gene corresponding to this mutation revealed that it was allelic to responsive to antagonist1 (ran1), a mutation that causes seedlings to respond in a positive manner to what is normally a competitive inhibitor of ethylene binding. In contrast to the previously identified ran1-1 and ran1-2 alleles that are morphologically indistinguishable from wild-type plants, this ran1-3 allele results in a rosette-lethal phenotype. The predicted protein encoded by the RAN1 gene is similar to the Wilson and Menkes disease proteins and yeast Ccc2 protein, which are integral membrane cation-transporting P-type ATPases involved in copper trafficking. Genetic epistasis analysis indicated that RAN1 acts upstream of mutations in the ethylene receptor gene family. However, the rosette-lethal phenotype of ran1-3 was not suppressed by ethylene-insensitive mutants, suggesting that this mutation also affects a non-ethylene-dependent pathway regulating cell expansion. The phenotype of ran1-3 mutants is similar to loss-of-function ethylene receptor mutants, suggesting that RAN1 may be required to form functional ethylene receptors. Furthermore, these results suggest that copper is required not only for ethylene binding but also for the signaling function of the ethylene receptors.
authors.affiliation: Department of Biological Sciences, Laboratory for Molecular Biology, University of Illinois at Chicago, Chicago, Illinois 60607, USA.
authors.forename: K E
authors.initials: KE
authors.lastname: Woeste
authors.forename: J J
authors.initials: JJ
authors.lastname: Kieber
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000166:cytology / Q000187:drug effects / Q000235:genetics; D029681:Arabidopsis Proteins; D027682:Cation Transport Proteins; D048429:Cell Size / Q000235:genetics; D003001:Cloning, Molecular; D003300:Copper / Q000494:pharmacology; D000079922:Copper Transport Proteins; D005030:Ethylenes / Q000494:pharmacology*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005804:Genes, Lethal; D005838:Genotype; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D010937:Plant Growth Regulators / Q000494:pharmacology*; D010940:Plant Proteins / Q000235:genetics; D010944:Plants / Q000187:drug effects / Q000235:genetics; D011494:Protein Kinases / Q000235:genetics* / Q000502:physiology; D016601:RNA-Binding Proteins; D011956:Receptors, Cell Surface / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D020931:ran GTP-Binding Protein
chemical_list: D029681:Arabidopsis Proteins; C490178:At5g20010 protein, Arabidopsis; D027682:Cation Transport Proteins; D000079922:Copper Transport Proteins; C119963:EIN2 protein, Arabidopsis; D005030:Ethylenes; D010937:Plant Growth Regulators; D010940:Plant Proteins; D016601:RNA-Binding Proteins; D011956:Receptors, Cell Surface; C083750:ethylene receptors, plant; D003300:Copper; C036216:ethylene; D011494:Protein Kinases; D020931:ran GTP-Binding Protein