Oestrogen facilitates the binding of ubiquitous and liver-enriched nuclear proteins to the apoVLDL II promoter in vivo.
Using genomic and in vitro DNasel footprinting, we have analyzed protein-DNA interactions within the promoter region of the oestrogen-inducible gene encoding chicken apoVLDL II. The footprints coincide with previously detected guanosine-protein contacts in vivo. All footprints identified are present in the apoVLDL II-expressing liver exclusively and absent in hormone-naive liver, spleen and oviduct. They comprise recognition sites for the oestrogen receptor, the ubiquitous COUP-transcription factor, the liver-enriched C/EBP and/or DBP and the liver-specific LF-A1. In vitro, binding of protein to the oestrogen response element (ERE) is excluded by the prior binding of a protein, possibly C/EBP or DBP, to an adjacent element. The recognition sequence of the COUP-TF is also a target for LF-A1. The results suggests that oestrogen-dependent liver specific activation of the apoVLDL II promoter is established by the binding of the oestrogen receptor to EREs and multiple liver-enriched factors (C/EBP, DBP and LF-A1) to their nearby recognition sequences. Apparently, several DNA binding nuclear proteins cooperate to keep the promoter in a state that is accessible for the RNA polymerase complex.
Wijnholds
J
J
Department of Biochemistry, University of Groningen, The Netherlands.
Muller
E
E
Ab
G
G
D000818:Animals; D001053:Apolipoproteins / Q000235:genetics*; D001483:Base Sequence; D051838:COUP Transcription Factor I; D002645:Chickens; D004247:DNA; D004268:DNA-Binding Proteins; D003850:Deoxyribonuclease I / Q000378:metabolism; D004967:Estrogens / Q000502:physiology*; D005260:Female; D008079:Lipoproteins, VLDL / Q000235:genetics*; D008099:Liver / Q000378:metabolism*; D008297:Male; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism*; D009841:Oligonucleotides / Q000138:chemical synthesis / Q000235:genetics; D009928:Organ Specificity / Q000235:genetics; D010047:Ovalbumin / Q000235:genetics; D011401:Promoter Regions, Genetic; D013696:Temperature; D014157:Transcription Factors / Q000378:metabolism*
D001053:Apolipoproteins; D051838:COUP Transcription Factor I; D004268:DNA-Binding Proteins; D004967:Estrogens; D008079:Lipoproteins, VLDL; D009687:Nuclear Proteins; D009841:Oligonucleotides; D014157:Transcription Factors; C027610:apolipoprotein VLDL II; D010047:Ovalbumin; D004247:DNA; D003850:Deoxyribonuclease I