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.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alanine
  • Amino Acid Sequence
  • Apolipoprotein C-III
  • Apolipoproteins C / genetics*
  • Base Sequence
  • Cloning, Molecular*
  • DNA / analysis
  • Glycosylation
  • Humans
  • Lipoproteins, VLDL / blood
  • Molecular Sequence Data
  • Mutation
  • Threonine


  • Apolipoprotein C-III
  • Apolipoproteins C
  • Lipoproteins, VLDL
  • Threonine
  • DNA
  • Alanine