Human apolipoprotein B: Chromosomal mapping and DNA polymorphisms of hepatic and intestinal species

Publisher Website
Google Scholar
Abstract
Apolipoprotein B (apoB) is the major protein component of low-density and very-low-density lipoproteins. We have recently isolated nonoverlapping cDNA clones for apoB and confirmed their identity by sequence comparisons. We now report the mapping of the human apoB gene (APOB)to the p23–p24 region of chromosome 2 by examination of human-mouse somatic cell hybrids and by in situ hybridization to human chromosomes. Thus, APOBis unlinked to members of the dispersed gene family encoding other apolipoprotein species or to the gene encoding the low-density lipoprotein receptor. Hybridization analysis with genomic DNA and liver and intestinal mRNA suggests that APOBencodes both the high-molecular-weight form of apoB (apoB100) incorporated into very-low-density lipoproteins in liver and the lower-molecular-weight form (apoB48) incorporated into chylomicrons in intestine. Restriction fragment length polymorphisms of APOBhave been identified and should prove useful in examining the possibility that genetic variations of APOBare involved in dyslipoproteinemias and atherosclerosis.