High-Mobility Group (HMG) Protein HMG-1 and TATA-Binding Protein-Associated Factor TAFII30 Affect Estrogen Receptor-Mediated Transcriptional Activation
Autor: | M. Bustin, R. A. Jensen, C. J. Yee, C. S. Verrier, F. F. Parl, L. R. Bailey, N. Roodi |
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Rok vydání: | 1997 |
Předmět: |
Transcription
Genetic Oligonucleotides Estrogen receptor Endocrinology Animals Humans Electrophoretic mobility shift assay HMGB1 Protein Molecular Biology Estrogen receptor beta Hormone response element TATA-Binding Protein Associated Factors biology High Mobility Group Proteins Estrogens General Medicine Hmg protein Molecular biology Recombinant Proteins DNA-Binding Proteins High-mobility group Receptors Estrogen biology.protein Transcription Factor TFIID TATA-binding protein Carrier Proteins Estrogen receptor alpha hormones hormone substitutes and hormone antagonists Transcription Factors |
Zdroj: | Molecular Endocrinology. 11:1009-1019 |
ISSN: | 1944-9917 0888-8809 |
Popis: | The estrogen receptor (ER) belongs to a family of ligand-inducible nuclear receptors that exert their effects by binding to cis-acting DNA elements in the regulatory region of target genes. The detailed mechanisms by which ER interacts with the estrogen response element (ERE) and affects transcription still remain to be elucidated. To study the ER-ERE interaction and transcription initiation, we employed purified recombinant ER expressed in both the baculovirus-Sf9 and his-tagged bacterial systems. The effect of high-mobility group (HMG) protein HMG-1 and purified recombinant TATA-binding protein-associated factor TAF(II)30 on ER-ERE binding and transcription initiation were assessed by electrophoretic mobility shift assay and in vitro transcription from an ERE-containing template (pERE2LovTATA), respectively. We find that purified, recombinant ER fails to bind to ERE in spite of high ligand-binding activity and electrophoretic and immunological properties identical to ER in MCF-7 breast cancer cells. HMG-1 interacts with ER and promotes ER-ERE binding in a concentration- and time-dependent manner. The effectiveness of HMG-1 to stimulate ER-ERE binding in the electrophoretic mobility shift assay depends on the sequence flanking the ERE consensus as well as the position of the latter in the oligonucleotide. We find that TAF(II)30 has no effect on ER-ERE binding either alone or in combination with ER and HMG-1. Although HMG-1 promotes ER-ERE binding, it fails to stimulate transcription initiation either in the presence or absence of hormone. In contrast, TAF(II)30, while not affecting ER-ERE binding, stimulates transcription initiation 20-fold in the presence of HMG-1. These results indicate that HMG-1 and TAF(II)30 act in sequence, the former acting to promote ER-ERE binding followed by the latter to stimulate transcription initiation. |
Databáze: | OpenAIRE |
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