Cloning and expression of a cDNA AAPT3 encoding aminoalcoholphosphotransferase Isoform from Chinese Cabbage

Aminoalcoholphosphotransferase catalyzes the synthesis of phosphatidylcholine and phosphatidylethanolamine from diacylglycerol plus a CDP‐aminoalcohol such as CDP‐choline or CDP‐ethanolamine. Previously we suggested the presence of possible isoforms of this enzyme from Chinese cabbage roots and now report the cDNA cloning and expression analysis of AAPT3 encoding a third isoform of aminoalcoholphosphotransferase (AAPT3). AAPT3 contains an open reading frame of 1,176 bp coding for a protein of 392 amino acids. It shares 96 and 95% identity with Chinese cabbage AAPT1 and AAPT2, respectively, at the deduced amino acid level. The results from reverse transcriptase‐polymerase chain reaction analysis indicate that expression of AAPT3 is up‐regulated by low temperature as well as AAPT1 and AAPT2.