title: Transcriptional regulation of the apolipoprotein B-100 gene: identification of cis-acting elements in the first nontranslated exon of the human apolipoprotein B-100 gene.
abstract: Apolipoprotein B-100, produced primarily in the human liver, is the sole protein component of low-density lipoprotein and serves as a ligand for the LDL receptor. Two cis-acting positive elements between -128 and -70 control hepatic cell-specific expression of the human apoB gene (H. K. Das, T. Leff, and J. L. Breslow, J. Biol. Chem. 263: 11452-11458, 1988). In this study, two apoB cis-acting elements (+20 to +40; +43 to +53) have been identified using DNase I footprint analysis. Through in vitro mutagenesis and transient transfection experiments in Hep G2 and HeLa cells, the element (+20 to +40) was observed to have a negative effect on transcription of the apoB gene. The element (+43 to +53) was found to have a strong positive effect on apoB gene transcription in Hep G2 cells and mild positive effect in HeLa cells. Therefore these two cis-acting elements mediate hepatic-cell specific expression of the apolipoprotein gene by interacting with trans-acting protein factors.
authors.affiliation: Department of Pharmacology, University of North Texas, Fort Worth 76107, USA.
authors.forename: S S
authors.initials: SS
authors.lastname: Chuang
authors.forename: H
authors.initials: H
authors.lastname: Zhuang
authors.forename: S R
authors.initials: SR
authors.lastname: Reisher
authors.forename: S I
authors.initials: SI
authors.lastname: Feinstein
authors.forename: H K
authors.initials: HK
authors.lastname: Das
mesh_terms: D053299:Apolipoprotein B-100; D001055:Apolipoproteins B / Q000235:genetics*; D001483:Base Sequence; D018983:DNA Footprinting; D003850:Deoxyribonuclease I; D005091:Exons; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D008099:Liver / Q000378:metabolism; D008969:Molecular Sequence Data; D016296:Mutagenesis; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid; D014158:Transcription, Genetic; D014162:Transfection
chemical_list: D053299:Apolipoprotein B-100; D001055:Apolipoproteins B; D003850:Deoxyribonuclease I