The major low molecular weight apolipoprotein from normal and hyperlipidemia atherosclerosis-prone (LAP) Japanese quail

The low molecular weight (LMW) apolipoprotein of apo C plays an important role in the metabolism of triglyceride-rich lipoproteins. This study aimed at a characterization of the major LMW apolipoproteins from normal quail strain, and also from LAP (hyperlipidemia atherosclerosis-prone) strain to identify its genetic disorder. The major LMW apoprotein cDNA clone from normal quail comprised of approximately 500 bp, and encoded polypeptide of 78 amino acid residues containing 57 amino acids as a mature apolipoprotein. Although the quail LMW apoprotein showed a low homology to either apo C-I, C-II, or C-III of other animals, it retained a well-developed amphipathic alpha-helix structure. There was no difference in the deduced primary structure of the quail LMW apoprotein between LAP and normal strain. An analysis of the mRNA expression showed that the quail LMW apoprotein was only expressed in the liver of both LAP and normal Japanese quail. No difference was noted in the hepatic expression of the quail LMW apoprotein mRNA between normal and LAP strains with neither normal nor atherogenic dietary conditions. The structure and expression of the major LMW apoprotein thus had no relevance to higher susceptibility of LAP strain to the experimental atherosclerosis.