Comparison of expression systems for human fucosyltransferase IX

Human fucosyltransferase IX (hFucT-IX) is a highly conserved alpha1,3 fucosyltransferase with a distinct acceptor and site specificity. hFucT-IX catalyses the transfer of activated fucose to a sugar acceptor, thereby forming the Lewis x epitope. This epitope is responsible for recognition phenomena throughout the body e.g. in tumour growth. Detailed characterisation of hFucT-IX structure-function relationships by kinetic and X-ray structure analysis is prerequisite to the development of enzyme inhibitors for clinical applications such as the suppression of tumour metastasis. For these analyses substantial amounts of hFucT-IX are desirable. Since hFucT-IX is not present in considerable amounts in common cells an overproduction of recombinant hFucT-IX is appropriate. To evaluate the best system for this overproduction we compared different strategies employing prokaryotes (Escherichia coli), mammalian cells and insect cells. Insect cells were tested using stable and baculoviral expression strategies. Current results favour the use of the baculoviral expression system for further experiments.