Cloning and expression of cDNAs encoding alpha 1,3-fucosyltransferase homologues from Arabidopsis thaliana

The core alpha1.3-fucosyltransferases are involved in the synthesis of glyc ans specific to plants and invertebrates which are known to be immunogenic and allergenic. We report the identification. isolation and characterisatio n of the cDNAs of three genes (FucTA. FucTB and FucTC) encoding proteins si milar to alpha1.3-fucosyltransferases in Arabidopis thaliana. Reverse trans cription-polymerase chain reaction was used to amplify the full length codi ng sequence of FucTA. The FucTA gene. which consists of seven exons, encode s a presumptive protein of 501 amino acids showing an overall sequence iden tity of 66% to the protein encoded by the recently isolated mung bean Fuc-T C3 cDNA. FucTA was expressed in Pichia pastoris under the control of the A OX1 gene promoter. The soluble enzyme was found to catalyse the same reacti on as mung bean core alpha1.3-fucosyltransferase as judged by analyses of t he products by MALDI-TOF and high-performance liquid chromatography. The Fu cTB cDNA was isolated from a A-ZAP library, but the clone used an alternati ve splicing site between the second and third exon resulting in a premature stop codon. The FucTC gene encodes a protein with less than 40% identity t o FucTA across 115 amino acids of a total of 401 amino acids and is a membe r of a new sub-family of plant alpha1.3/4-fucosyltransferase homologues. (C ) 2001 Published by Elsevier Science B.V.