Determinants of vitellogenin B1 promoter architecture. HNF3 and estrogen responsive transcription within chromatin.
The liver-specific vitellogenin B1 promoter is efficiently activated by estrogen within a nucleosomal environment after microinjection into Xenopus laevis oocytes, consistent with the hypothesis that significant nucleosome remodeling over this promoter is not a prerequisite for the activation by the estrogen receptor (ERalpha). This observation lead us to investigate determinants other than ERalpha of chromatin structure and transcriptional activation of the vitellogenin B1 promoter in this system and in vitro. We find that the liver-enriched transcription factor HNF3 has an important organizational role for chromatin structure as demonstrated by DNase I-hypersensitive site mapping. Both HNF3 and the estrogen receptor activate transcription synergistically and are able to interact with chromatin reconstituted in vitro with three positioned nucleosomes. We propose that HNF3 is the cellular determinant which establishes a promoter environment favorable to a rapid transcriptional activation by the estrogen receptor.
Robyr
D
D
Institut de Biologie animale, Université de Lausanne, Bâtiment de Biologie, CH-1015 Lausanne, Switzerland.
Gegonne
A
A
Wolffe
A P
AP
Wahli
W
W
D000818:Animals; D002843:Chromatin / Q000187:drug effects / Q000235:genetics*; D018983:DNA Footprinting; D004268:DNA-Binding Proteins / Q000378:metabolism*; D003850:Deoxyribonuclease I; D047628:Estrogen Receptor alpha; D005260:Female; D005786:Gene Expression Regulation; D051541:Hepatocyte Nuclear Factor 3-alpha; D008099:Liver / Q000378:metabolism*; D008836:Micrococcal Nuclease; D008845:Microinjections; D016297:Mutagenesis, Site-Directed; D009687:Nuclear Proteins / Q000378:metabolism*; D009707:Nucleosomes / Q000502:physiology; D009865:Oocytes / Q000502:physiology; D017354:Point Mutation; D011401:Promoter Regions, Genetic; D011960:Receptors, Estrogen / Q000502:physiology; D011994:Recombinant Proteins / Q000096:biosynthesis; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic / Q000187:drug effects / Q000502:physiology*; D014819:Vitellogenins / Q000235:genetics* / Q000502:physiology; D014982:Xenopus laevis
D002843:Chromatin; D004268:DNA-Binding Proteins; D047628:Estrogen Receptor alpha; D051541:Hepatocyte Nuclear Factor 3-alpha; D009687:Nuclear Proteins; D009707:Nucleosomes; D011960:Receptors, Estrogen; D011994:Recombinant Proteins; D014157:Transcription Factors; D014819:Vitellogenins; D003850:Deoxyribonuclease I; D008836:Micrococcal Nuclease