PMID: 3123586

 

    Legend: Sugar

Title : Molecular cloning of a human apoC-III variant : Thr 74---- Ala 74 mutation prevents O-glycosylation

Abstract :
  1. Apolipoprotein C-III ( apoC-III ) is a major protein of very low density lipoprotein ( VLDL )
  2. 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
  3. 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)
  4. 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
  5. As a result of this amino acid replacement, the mutant apoC-III polypeptide is not glycosylated
  6. The mutation in the apoC-III gene creates a novel AluI site that permits diagnosis of the change by Southern blotting of genomic DNA