Binding of nuclear proteins to the enhancer elements of the rat apolipoprotein A-I gene.
To determine the cis- and trans-regulatory elements which control the expression of the apolipoprotein (apo) A-I gene, several DNA-protein binding assays, namely, gel mobility shift, exonuclease III protection, and exonuclease III footprinting assays, were employed to identify these elements. It is demonstrated that nuclear proteins of Hep G2 cells bind to five regions of DNA sequences between 252 and 149 base pairs upstream from the transcription initiation site of the rat apo A-I gene. Using South-Western blot analysis, it is determined that DNA-binding protein has a molecular mass of approximately 90 kDa. It is also shown that the DNA-binding protein was present in Hep G2 cells and rat livers but absent in rabbit livers. The results suggest that the lack of expression of the apo A-I gene in rabbit livers is due to the absence of this DNA-binding protein.
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Merck Sharp & Dohme Research Laboratories, Rahway, New Jersey 07065-0900.
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Ding
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Chao
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D000818:Animals; D016632:Apolipoprotein A-I; D001054:Apolipoproteins A / Q000032:analysis / Q000235:genetics*; D001483:Base Sequence; D015153:Blotting, Western; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000378:metabolism* / Q000502:physiology; D004742:Enhancer Elements, Genetic; D005786:Gene Expression Regulation; D008099:Liver / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism*; D011817:Rabbits; D051381:Rats; D014158:Transcription, Genetic
D016632:Apolipoprotein A-I; D001054:Apolipoproteins A; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins