Abstract
EIN2 is one of the central players in the ethylene response pathway. The amino-terminal portion of EIN2 consists of twelve putative membrane-spanning domains with similarity to Nramp metal-ion-transporters. Ion transporter activity of EIN2, however, has not been reported. By contrast, overexpression of the carboxyl-terminal portion was sufficient to constitutively activate ethylene responses, suggesting that this portion plays a crucial role in the ethylene response pathway. However, its molecular mechanism is unknown, either. Most ein2 mutants are null-type, making it difficult to identify the functional domains.
In order to identify the functional domains of EIN2, we randomly introduced a 15 bp insertion (translated to five amino acids in any frame) into the EIN2cDNA. Mutated EIN2cDNA was introduced into the ein2-5 plants, to identify the functional domains by examining the ability to complement the ein2-5 mutation. Currently, we are obtaining transgenic plants. Coming results will be discussed.
