
<ArticleTitle>Over-expression of <prot>beta-1,4-galactosyltransferase I</prot>, II, and V in human astrocytoma.</ArticleTitle>
<AbstractText>PURPOSE: <prot>beta-1,4-Galactosyltransferase (<prot>beta-1,4-GalT</prot>) I</prot>, II, and V are the enzymes responsible for the biosynthesis of N-acetyllactosamine on N-glycans by transferring UDP-galactose to the terminal N-acetylglucosamine (N-GlcNAc) residues with the formation of a beta-1,4-linkage. Neoplasms undergo various changes in the carbohydrate of their glycoconjugates, indicating the possible changes in glycosyltransferases themselves. METHOD: Therefore, we compared the expression of <prot>beta-1,4-GalT</prot>s between astrocytoma and normal brain tissues. RESULTS: Our reverse-transcription polymerase chain reaction (RT-PCR) results showed that <prot>beta-1,4-GalT I</prot> transcript was absent in normal adult brain but detectable in grade II, III, and IV astrocytomas; the level of <prot>beta-1,4-GalT II</prot> transcript was increased in grade II, III, and IV astrocytomas while only a trace amount was found in normal brain; <prot>beta-1,4-GalT V</prot> transcript existed in normal brain and increased in the process of astrocytoma progress, with the highest level in grade IV astrocytoma. By <prot>Ricinus communis agglutinin-1 (<prot>RCA-1</prot>)</prot> lectin blot assay, we also found the more extensive galactosylated bands in astrocytomas compared with normal brain. A major 61kD protein was galactosylated in astrocytoma but not in normal brain tissues. CONCLUSION: These results indicate that the increase of galactosylation in astrocytomas may be caused by the alterations of gene expression of <prot>beta-1,4-GalT I</prot>, II, and V and that the malignant degree of astrocytoma is correlated with the expression of <prot>beta-1,4-GalT V</prot>.</AbstractText>
