title: A polymorphism in a region with enhancer activity in the second intron of the human apolipoprotein B gene.
abstract: A 443-base pair fragment (+622 to +1064) from the second intron of the human apolipoprotein B gene was shown to contain a tissue-specific enhancer when placed in front of an apolipoprotein B promoter-chloramphenicol acetyltransferase construct in transfection experiments. To identify potential regulatory mutations in this region of the gene, DNA from various subjects was examined for the presence of point mutations by means of chemical cleavage of mismatched heteroduplexes. An A----G substitution within the second intron of the gene at position +722 was identified in three unrelated subjects and confirmed by DNA sequencing. Although the base substitution was contained within a nuclear protein-binding site, as determined by DNase I footprinting, it did not appear to affect the protein/DNA interaction in its vicinity, as shown by gel retardation experiments. The single base substitution at position +722 abolishes a StyI restriction site, thus creating a StyI polymorphism. Using allele-specific oligonucleotides, we screened the DNA of 172 subjects for the presence of this polymorphism: two other subjects carrying the polymorphism were found. In each of the five unrelated subjects, the polymorphism was associated with the same haplotype.
authors.affiliation: Gladstone Foundation Laboratories for Cardiovascular Disease, Department of Pharmaceutical Chemistry, University of California, San Francisco 94140-0608.
authors.forename: B
authors.initials: B
authors.lastname: Levy-Wilson
authors.forename: L
authors.initials: L
authors.lastname: Soria
authors.forename: E H
authors.initials: EH
authors.lastname: Ludwig
authors.forename: M
authors.initials: M
authors.lastname: Argyres
authors.forename: A R
authors.initials: AR
authors.lastname: Brooks
authors.forename: B D
authors.initials: BD
authors.lastname: Blackhart
authors.forename: W
authors.initials: W
authors.lastname: Friedl
authors.forename: B J
authors.initials: BJ
authors.lastname: McCarthy
mesh_terms: D001055:Apolipoproteins B / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA / Q000378:metabolism; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins / Q000378:metabolism; D015252:Deoxyribonucleases, Type II Site-Specific; D004742:Enhancer Elements, Genetic; D005260:Female; D006239:Haplotypes; D006801:Humans; D006938:Hyperlipoproteinemia Type II / Q000235:genetics; D007438:Introns; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D010375:Pedigree; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D015183:Restriction Mapping; D014162:Transfection
chemical_list: D001055:Apolipoproteins B; D004268:DNA-Binding Proteins; D004247:DNA; C045874:endodeoxyribonuclease StyI; D015252:Deoxyribonucleases, Type II Site-Specific