Molecular cloning of a human apoC-III variant: Thr 74----Ala 74 mutation prevents O-glycosylation.
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Maeda H, Hashimoto RK, Ogura T, Hiraga S, Uzawa H
Molecular cloning of a human apoC-III variant: Thr 74----Ala 74 mutation prevents O-glycosylation.
J Lipid Res. 1987 Dec;28(12):1405-9.
- PubMed ID
- 3123586 [ View in PubMed]
- Abstract
Apolipoprotein C-III (apoC-III) is a major protein of very low density lipoprotein (VLDL). The apoC-III polypeptide contains a carbohydrate chain containing galactosamine, galactose, and sialic acid attached in O-linkage to a threonine residue at position 74. We have cloned the apoC-III gene from a subject whose serum contained unusually high amounts of apoC-III lacking the carbohydrate moiety (C-III-0). DNA sequence analysis of the cloned gene revealed a single nucleotide substitution (A----G) that encodes an alanine at position 74 instead of the normal threonine. As a result of this amino acid replacement, the mutant apoC-III polypeptide is not glycosylated. The mutation in the apoC-III gene creates a novel AluI site that permits diagnosis of the change by Southern blotting of genomic DNA.