Abstract
We present evidence that oestrogen receptor activity in human MCF-7 breast cancer cells is reduced by over-expression of c-Jun or c-Fos proteins and to a lesser extent by Jun B overexpression. In contrast, overexpression of Jun D protein does not affect the activity of the oestrogen receptor. A region of c-Jun found to be required for repression of oestrogen receptor activity is located outside the DNA binding domain and is not conserved among the three Jun proteins. Finally, we suggest that c-Jun and c-Fos act independently to inactivate the oestrogen receptor.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Base Sequence
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Blotting, Western
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Breast Neoplasms / metabolism*
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DNA-Binding Proteins / genetics*
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Estrogens / metabolism
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Fluorescent Antibody Technique
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Gene Expression Regulation*
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Humans
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Molecular Sequence Data
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Plasmids
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Proto-Oncogene Proteins / genetics*
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Proto-Oncogene Proteins c-fos
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Proto-Oncogene Proteins c-jun
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Receptors, Estrogen / antagonists & inhibitors
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Receptors, Estrogen / metabolism*
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Tetradecanoylphorbol Acetate / pharmacology
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Transcription Factors / genetics*
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Transcription, Genetic
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Tumor Cells, Cultured
Substances
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DNA-Binding Proteins
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Estrogens
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Proto-Oncogene Proteins
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Proto-Oncogene Proteins c-fos
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Proto-Oncogene Proteins c-jun
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Receptors, Estrogen
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Transcription Factors
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Tetradecanoylphorbol Acetate