Isolation and characterization of cDNA clones corresponding to two different human apoC-III alleles.
We have recently reported that the human apolipoprotein A-I (apoA-I) and apolipoprotein C-III (apoC-III) genes are physically linked and that the presence of a DNA insertion in the apoA-I gene is correlated with apoA-I-apoC-III deficiency in patients with premature atherosclerosis. In addition, the presence of a polymorphic restriction endonuclease site (SacI) in the 3' noncoding region of apoC-III mRNA has been correlated with hypertriglyceridemia in humans. In this study, we report the isolation and characterization of cDNA clones containing the entire apoC-III mRNA coding sequence. The nucleotide-derived apoC-III amino acid sequence indicates that the apoC-III primary translational product contains a 20 amino acid N-terminal extension, which conforms with the general properties of known signal peptides, and is highly homologous to the recently reported rat apoC-III signal peptide. The DNA-derived apoC-III amino acid sequence differs from the previously reported apoC-III amino acid sequence at four amino acid residues. More specifically, at positions +32, +33, +37, +39, the DNA sequence predicts Glu, Ser, Gln, Ala, respectively, while the previously reported sequence specifies Ser, Gln, Ala, Gln, respectively. Finally, isolation and characterization of apoC-III cDNA clones, with or without the polymorphic SacI restriction site, indicated that the apoC-III nucleotide sequence corresponding to the Sac+ and Sac- clones differs at three nucleotide sites; however, the amino acid sequence specified by the Sac+ and Sac- alleles is identical.
Karathanasis
S K
SK
Zannis
V I
VI
Breslow
J L
JL
D000483:Alleles; D000595:Amino Acid Sequence; D053305:Apolipoprotein C-III; D001056:Apolipoproteins C / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA / Q000302:isolation & purification*; D004262:DNA Restriction Enzymes; D005796:Genes; D006801:Humans; D006953:Hyperlipoproteinemia Type IV / Q000235:genetics; D008099:Liver / Q000378:metabolism; D010957:Plasmids; D012016:Reference Values
D053305:Apolipoprotein C-III; D001056:Apolipoproteins C; D004247:DNA; D004262:DNA Restriction Enzymes