A Strong Loss-of-Function Mutation in RAN1 Results in Constitutive Activation of the Ethylene Response Pathway as Well as a Rosette-Lethal Phenotype

• Published in: The Plant cell Vol. 12; no. 3; pp. 443 - 455
• Main Authors: Woeste, Keith E., Kieber, Joseph J.
• Format: Journal Article
• Language: English
• Published: Legacy CDMS American Society of Plant Physiologists 01.03.2000; American Society of Plant Biologists
• Subjects: Adenosine triphosphatases; Alleles; Amino Acid Sequence; Arabidopsis - cytology; Arabidopsis - drug effects; Arabidopsis - genetics; Arabidopsis Proteins; Cation Transport Proteins; Cell Size - genetics; Cloning; Cloning, Molecular; Copper; Copper - pharmacology; Epidermal cells; Ethylenes - pharmacology; Gene Expression Regulation, Plant - drug effects; Genes, Lethal; Genetic mutation; Genotype; Life Sciences (General); Molecular Sequence Data; Mutation; Phenotype; Phenotypes; Plant cells; Plant Growth Regulators - pharmacology; Plant Proteins - genetics; Plants; Plants - drug effects; Plants - genetics; Protein Kinases - genetics; Protein Kinases - physiology; Receptors; Receptors, Cell Surface - genetics; Seedlings; Sequence Homology, Amino Acid; Yeasts; Nasa Discipline Plant Biology; Non-Nasa Center; Nasa Program Fundamental Space Biology; NASA Program Fundamental Space Biology; NASA Discipline Plant Biology; Non-NASA Center
• ISSN: 1040-4651; 1532-298X
• DOI: 10.1105/tpc.12.3.443

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.