Expression of UDP-N-acetylgalactosamine: beta-galactose beta 1,4-N-acetylgalactosaminyltransferase in functionally defined T-cell clones.
To measure UDP-N-acetylgalactosamine: beta-galactose beta 1,4-N-acetylgalactosaminyltransferase (beta 1,4-GalNActransferase) in crude cell and tissue extracts we designed an assay containing UDP-[3H]N-acetylgalactosamine as donor and biotinylated human glycophorin A as an acceptor. After incubation the labelled acceptor was separated by the use of avidin-agarose from extract-derived endogenous acceptors. This assay permitted one to measure specifically the beta 1,4-GalNActransferase in crude extracts. This glycosyltransferase has previously been shown to be involved in the biosynthesis of Vicia villosa (hairy winter vetch)-lectin (VV)-binding sites of the murine cytotoxic T-cell line B6.1. Since VV-binding sites are a distinct marker for the cytotoxic subclass of murine T-lymphocytes, we used this assay to determine enzyme levels in a panel of functionally defined murine T-cell clones. Non-cytolytic T-cell lines generally have low activity, whereas most cytotoxic lines have high levels of activity. However, one cytotoxic T-cell line does not express the enzyme, although it has large numbers of VV-binding sites. This suggests the existence of another type of VV-binding sites which is independent of the beta 1,4-GalNActransferase in some cytotoxic-T-lymphocyte lines. The enzyme was also assayed in a variety of other tissues and found to have a very high activity in the intestine but a low activity in most other tissues. This was in considerable contrast with the ubiquitously high expression of UDP-GalNAc:peptide alpha 1-GalNActransferase. Therefore, the beta 1,4-GalNActransferase seems to be regulated during differentiation.
D000818:Animals; D002460:Cell Line; D002999:Clone Cells; D003208:Concanavalin A / Q000494:pharmacology; D005700:Galactosyltransferases / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D051379:Mice; D017350:N-Acetylgalactosaminyltransferases; D009844:Oligosaccharides / Q000032:analysis; D013601:T-Lymphocytes / Q000187:drug effects / Q000201:enzymology*; D014018:Tissue Distribution; D000097763:Polypeptide N-acetylgalactosaminyltransferase
D003208:Concanavalin A; D005700:Galactosyltransferases; D008070:Lipopolysaccharides; D017350:N-Acetylgalactosaminyltransferases; D009844:Oligosaccharides; D000097763:Polypeptide N-acetylgalactosaminyltransferase