| Glycoconjugates have important biological functions such as cell adhesion, cell signaling, and correct folding and targeting of glycoproteins. The biological functions associated with glycoconjugates are often associated with terminal elements at the non-reducing ends. Fucosylation is probably the most general terminal modification; fucosyltransferases that synthesize them have been found in mammals, insects, helminthes, prokaryotes, and plants. Fucosylated glycans participate in a wide variety of cellular recognition events such as the recruitment of leukocytes to sites of infection and their homing to lymph nodes, tumor metastasis, neural development, angiogenesis, fertilization, signal transduction, and bacterial adhesion. The functions and detailed interactions of most fucosylated glycans remain largely unknown. Because of the many important biological roles associated with fucosylated glycans and the fact that fucosylated glycan expression is developmentally-regulated in higher animals, it is hypothesized that fucosylated glycans are important in development and differentiation. The identification and characterization of the fucosyltransferases is the first step in understanding their function and role in development.; The Caenorhabditis elegans model system offers the opportunity to study these potential functions because of its well-defined development and physiology, as well as its fully defined genomic sequence. In addition, C. elegans is amenable to experimental manipulation, mutagenesis, and genetic analysis. C. elegans shares many of the biological and biochemical pathways with higher organisms, and its genome revealed coding sequences for many known glycosyltransferases. The genome of C. elegans encodes five genes with homology to known alpha1,3 fucosyltransferases (alpha1,3Fuc-Ts), but the expression and functions of these enzymes are not known. Here we report on the molecular cloning and characterization of these alpha1,3Fuc-Ts termed CEFT-1 through -5. We prepared a recombinant epitope-tagged form of each CEFT and demonstrated that they exhibited unique acceptor specificity, cation requirement, and sensitivity to temperature. The expression pattern of CEFT-1 by promoter analysis shows that its expression is limited to a few cells. C. elegans deletion mutants were generated for each yme for phenotypic analysis. Taken together, the results show that each member of the alpha1,3-fucosyltransferase family in C. elegans has unique acceptor specificities and expression, which may reflect their various biological roles. |
