Tilo Schwientek

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Enzymatic glycosylation of proteins and lipids is an abundant and important biological process. A great diversity of oligosaccharide structures and types of glycoconjugates is found in nature, and these are synthesized by a large number of glycosyltransferases. Glycosyltransferases have high donor and acceptor substrate specificities and are in general(More)
The completed fruit fly genome was found to contain up to 15 putative UDP-N-acetyl-alpha-d-galactosamine:polypeptide N-acetylgalactosaminyltransferase (GalNAc-transferase) genes. Phylogenetic analysis of the putative catalytic domains of the large GalNAc-transferase enzyme families of Drosophila melanogaster (13 available), Caenorhabditis elegans (9 genes),(More)
The MUC1 mucin represents a prime target antigen for cancer immunotherapy because it is abundantly expressed and aberrantly glycosylated in carcinomas. Attempts to generate strong humoral immunity to MUC1 by immunization with peptides have generally failed partly because of tolerance. In this study, we have developed chemoenzymatic synthesis of extended(More)
In breast cancer, the O-glycans added to the MUC1 mucin are core 1- rather than core 2-based. We have analyzed whether competition by the glycosyltransferase, ST3Gal-I, which transfers sialic acid to galactose in the core 1 substrate, is key to this switch in MUC1 glycosylation that results in the expression of the cancer-associated SM3 epitope. Of the(More)
BLAST analysis of expressed sequence tags (ESTs) using the coding sequence of a human UDP-galactose:beta-N-acetyl-glucosamine beta-1, 3-galactosyltransferase, designated beta3Gal-T1, revealed no ESTs with identical sequences but a large number with similarity. Three different sets of overlapping ESTs with sequence similarities to beta3Gal-T1 were compiled,(More)
A seventh member of the human beta4-galactosyltransferase family, beta4Gal-T7, was identified by BLAST analysis of expressed sequence tags. The coding region of beta4Gal-T7 depicts a type II transmembrane protein with sequence similarity to beta4-galactosyltransferases, but the sequence was distinct in known motifs and did not contain the cysteine residues(More)
The neurogenic Drosophila genes brainiac and egghead are essential for epithelial development in the embryo and in oogenesis. Analysis of egghead and brainiac mutants has led to the suggestion that the two genes function in a common signaling pathway. Recently, brainiac was shown to encode a UDP-N-acetylglucosamine:beta Man beta(More)
A novel human UDP-GlcNAc:Gal/GlcNAcbeta1-3GalNAcalpha beta1, 6GlcNAc-transferase, designated C2/4GnT, was identified by BLAST analysis of expressed sequence tags. The sequence of C2/4GnT encoded a putative type II transmembrane protein with significant sequence similarity to human C2GnT and IGnT. Expression of the secreted form of C2/4GnT in insect cells(More)
MUC1 is a glycoprotein overexpressed in breast cancer and other adenocarcinomas, and is known to elicit cellular and humoral immunity directed against unglycosylated peptide epitopes in the repeat domain. Based on immunological evidence that O-linked glycans on repeat peptides remain intact during processing by dendritic cells (DC), we used MUC1 as a model(More)
To investigate the function of the membrane anchor region of a mammalian glycosyltransferase in yeast we constructed a fusion gene that encodes the 34 amino-terminal residues of rat liver beta-galactoside alpha-2,6-sialyl-transferase (EC 2.4.99.1) (ST) fused to the mature form of yeast invertase. Transformants of Saccharomyces cerevisiae expressing the(More)