Submitted to: Animal Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/18/1998
Publication Date: N/A
Interpretive Summary: Apolipoproteins are involved in the transport and metabolism of cholesterol and lipids. As such they help to regulate the levels of phospholipids and triglycerides in the body and serum. Changes in apolipoproteins can cause heart disease, hyperlipoproteineimia and atherosclerosis. Analyses of alleles at apolipoprotein genes in pigs can help indicate causes of differences in lean to fat ratios in pigs and in consumers' pork products. Additionally these studies could help delineate potential causes of heart disease, using the pig as a model for humans. This study describes the isolation, sequencing and genetic characterization of the porcine apolipoprotein E gene. We report the identification of a genetic polymorphism, a microsatellite marker within the noncoding intron three, that enabled the exact map position to be established on the genetic linkage map of chromosome 6. This position was confirmed by fluorescent staining of pig chromosome 6. Because of the similarity of pigs to humans, studies of the genetics of apolipoproteins can lead to important new information on normal fat physiology and on the effects of different alleles, or specifically designed mutants, of apoprotein genes on the progression of cardiovascular disease.
Technical Abstract: This report describes the isolation and genetic characterization of the porcine apolipoprotein E gene. A single positive recombinant phage clone containing a 10.7-kb insert was isolated from a porcine genomic library and a 4.2-kb fragment was subcloned and sequenced. The 4.2-kb fragment contained the entire apo-E gene in addition to upstream and downstream sequences (GenBank accession number 470240). The porcine apo-E gene is made up of four exons and three introns and encodes a preapo-E protein comprised of a signal peptide of 18 amino acids and a mature protein of 299 amino acids. The porcine apo-E gene contains a (CG)13 microsatellite marker within intron three. This microsatellite is moderately polymorphic and at least four alleles were evident at this locus among 10 animals from each of the Yorkshire, Hampshire, Landrace and Duroc breeds. Finally, localization of the porcine apo-E gene to chromosome 6 band q2.1 was determined by fluorescent in situ hybridzation and confirmed by genetic linkage analysis.