Characterization of apolipoproteins B-100, AI and C from plasma lipoprotein in the goose, Anser anser. Evidence for a genetic polymorphism in ApoC-like apolipoproteins.

Abstract

In this study we have characterized four of the principle goose apolipoproteins and compared their physicochemical properties with human and avian counterparts. Goose ApoB-100 and ApoAI amino acid compositions were very similar to their chicken and human homologous proteins. The partial N-terminal sequence from goose ApoAI was 91% and 82% similar to the corresponding duck and chicken proteins, respectively. Most of the observed amino acid changes detected between the ApoAI sequences were amino acid replacements having the same characteristics and could be the result of a single base mutation. The N-terminal portion of two ApoC-like apolipoproteins were also studied. Goose ApoCa had an electrophoretic mobility of 0.31 and exhibited a nine-residue motif that was well conserved between ApoCIII sequences from different species. We therefore suggest that ApoCa is the equivalent of mammalian ApoCIII. The N-terminal portion of goose ApoCb, the second major ApoC in high-density apolipoprotein, showed no similarity to proteins previously described in the literature. This protein displayed two isomorphs in alkaline urea gel electrophoresis called ApoCb1 and ApoCb2 with Rf values of 0.36 and 0.39, respectively. A genetic polymorphism was detected in the population whereby 25% of the animals carried only one isomorph and 50% exhibited both ApoCb isomorphs. These frequencies were similar in females and males. The transmission mode of these ApoCb isomorphs was consistent with two segregating alleles from a single codominantly expressed gene.