Molecular cloning and characterization of an α1,3 fucosyltransferase, CEFT-1, frm Caenorhabditis elegans

We report on the identification, molecular cloning, and characterization of an α1,3 fucosyltransferase (α1,3FT) expressed by the nematode, Caenorhabditis elegans. Although C. elegans glycoconjugates do not express the Lewis x antigen Galβ1→4[Fucα1→3]GlcNAcβ→R, detergent extracts of adult C. elegans contain an α1,3FT that can fucosylate both nonsialylated and sialylated acceptor glycans to generate the Le(x) and sialyl Le(x) antigens, as well as the lacdiNAc-containing acceptor GalNAcβ1→R to generate Gal-NAcβ1→4[Fucα1→3]GlcNAcβ1→R. A search of the C. elegans genome database revealed the existence of a gene with 20-23% overall identity to al five cloned human α1,3FTs. The putative cDNA for the C. elegans α1,3FT (CEFT-1) was amplified by PCR from a cDNA λZAP library, cloned, and sequenced. COS7 cells transiently transfected with cDNA encoding CEFT-1 express the Le(x), but not sLe(x) antigen. The CEFT-1 in the transfected cell extracts can synthesize Le(x), but not sialyl Le(x), using exogenous acceptors. A second fucosyl-transferase activity was detected in extracts of C. elegans that transfers Fuc in α1,2 linkage to Gal specifically on type-1 chains. The discovery of α-fucosyltransferases in C. elegans opens the possibility of using this well-characterized nematode as a model system for studying the role of fucosylated glycans in the development and survival of C. elegans and possibly other helminths.