Glycoconjugates are important in cell recognition/adhesion and protein targeting/folding. Although the expression of glycoconjugates is altered during embryonic development, differentiation and tumorigenesis, their functions in these processes are poorly understood. A valuable model system that offers the opportunity to use genetic approaches to study these potential functions is the common soil nematode Caenorhabditis elegans. C. elegans is an hermaphroditic roundworm with a well-defined developmental plan and is amenable to experimental manipulation, mutagenesis, and genetic analysis. In initial attempts to define the potential of C. elegans as a model system for studies into developmental glycobiology, several glycosyltransferase activities were identified in C. elegans that are also present in mammalian cells. For example, both alpha1,3-fucosyltransferase (alpha1,3FT) and alpha1,2- fucosyltransferase (alpha1,2FT) activities were found that have specificities similar to enzymes in human cells and in human parasitic helminths. In preliminary studies the cDNA encoding one of the alpha1,3FTs was isolated and is termed CEFT-1. Genomic analysis suggests that two other alpha1,3FTs may also exist (termed CEFT-2 and CEFT-3). Because of the important roles fucosylated glycoconjugates play in cellular recognition, it is hypothesized that alpha1,3- and alpha1,2-fucosylated glycans in C. elegans are important in worm development and differentiation. To explore this hypothesis, the following 4 specific aims are proposed.
Aim 1 - Complete the cloning of CEFT-1, -2 and -3 and the alpha1,2FT and examine the acceptor specificity of recombinant enzymes.
Aim 2 - Define the developmental expression of the enzymes by immunofluorescence, promoter analysis and in situ hybridization and examine their developmental roles by mutagenesis.
Aim 3 - Initiate structural studies on the N- and 0- glycans in glycoproteins from adult C. elegans, with an emphasis on those glycans containing terminal alpha1,3- and alpha 1,2-linked fucose residues.
Aim 4 - Prepare monoclonal antibodies that recognize the fucosylated N- and/or O-linked glycans from C. elegans to assist in studying developmental expression of the glycans and their biological roles. These studies should provide new information about glycoconjugate functions in development and differentiation of C. elegans and establish this organism as a model system for developmental glycobiology. Since C. elegans and vertebrates express many similar glycosyltransferases, these studies may also provide important insights into glycan function in vertebrate development, differentiation and acquisition of the malignant phenotype.
| Zheng, Qinlong; Van Die, Irma; Cummings, Richard D (2002) Molecular cloning and characterization of a novel alpha 1,2-fucosyltransferase (CE2FT-1) from Caenorhabditis elegans. J Biol Chem 277:39823-32 |
