Powerful dominant negative mutants of the human estrogen receptor

B. A. Ince, Y. Zhuang, C. K. Wrenn, D. J. Shapiro, B. S. Katzenellenbogen

Research output: Contribution to journalArticle

Abstract

We have identified and characterized three human estrogen receptor (ER) mutants, which, at low concentrations, are capable of blocking the intracellular activity of wild type ER. The mutants, a truncated ER (ER1- 530), a point mutant (L540Q), and a frameshift (S554fs), were generated by random chemical mutagenesis of the ER hormone binding domain and screened first for low activity in a yeast selection system. In transient co- transfection assays using ER-deficient Chinese hamster ovary cells, all three mutants exhibited less than 10% of the transcription activation activity of wild type ER, and when co-expressed with wild type ER, each of the mutants effectively suppressed the ability of wild type ER to activate transcription of an estrogen-regulated reporter plasmid. When equal amounts of plasmid encoding the ER mutants and wild type ER were used, S554fs, ER1-530, and L540Q suppressed the activity of wild type ER by 80, 55, and 75%, respectively. At a ratio of 1 part S554fs to 10 parts wild type ER, transcription was still inhibited by 40%. Western blot analysis showed that all three mutants were expressed at approximately the same level as wild type ER. Suppression of transcription was specific for ER, since the mutants did not inhibit progesterone receptor-mediated transcription. Not all mutations leading to inactive ER confer the dominant negative phenotype, as five ER mutants rendered transcriptionally inactive by point mutations between residues 516 and 524 of the ER hormone binding domain were poor inhibitors of wild type ER activity. Binding studies showed that the L540Q and S554fs dominant negative mutants bound 17β-estradiol with wild type affinity (K(d) = 0.3-0.5 nM), whereas ER1-530 exhibited a 15-fold reduction in affinity for estradiol. The three dominant negative ERs showed significant ability to interact with the estrogen response element (ERE) in promoter interference assays, but ER1-530 and S554fs displayed little or no binding to the ERE in gel mobility shift assays where higher affinity for the DNA may be required for the receptor-ERE complex to remain associated during the electrophoresis. These data support the idea that, in all three mutants, it is loss of function of the COOH-terminal transactivation domain which leads to the dominant negative phenotype. S554fs, a powerful dominant negative mutant, is a good candidate for further studies aimed at suppressing the estrogen- dependent growth of human breast cancer cells.

Original languageEnglish (US)
Pages (from-to)14026-14032
Number of pages7
JournalJournal of Biological Chemistry
Volume268
Issue number19
StatePublished - Jan 1 1993

Fingerprint

Estrogen Receptors
Transcription
Estrogens
Response Elements
Assays
Transcriptional Activation
Estradiol
Plasmids
Cells
Hormones
Phenotype
Mutagenesis
Electrophoretic Mobility Shift Assay
Progesterone Receptors
Cricetulus
Electrophoresis
Point Mutation
Yeast

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

Powerful dominant negative mutants of the human estrogen receptor. / Ince, B. A.; Zhuang, Y.; Wrenn, C. K.; Shapiro, D. J.; Katzenellenbogen, B. S.

In: Journal of Biological Chemistry, Vol. 268, No. 19, 01.01.1993, p. 14026-14032.

Research output: Contribution to journalArticle

@article{db2cce1b16dd4d67857898c5c0811188,
title = "Powerful dominant negative mutants of the human estrogen receptor",
abstract = "We have identified and characterized three human estrogen receptor (ER) mutants, which, at low concentrations, are capable of blocking the intracellular activity of wild type ER. The mutants, a truncated ER (ER1- 530), a point mutant (L540Q), and a frameshift (S554fs), were generated by random chemical mutagenesis of the ER hormone binding domain and screened first for low activity in a yeast selection system. In transient co- transfection assays using ER-deficient Chinese hamster ovary cells, all three mutants exhibited less than 10{\%} of the transcription activation activity of wild type ER, and when co-expressed with wild type ER, each of the mutants effectively suppressed the ability of wild type ER to activate transcription of an estrogen-regulated reporter plasmid. When equal amounts of plasmid encoding the ER mutants and wild type ER were used, S554fs, ER1-530, and L540Q suppressed the activity of wild type ER by 80, 55, and 75{\%}, respectively. At a ratio of 1 part S554fs to 10 parts wild type ER, transcription was still inhibited by 40{\%}. Western blot analysis showed that all three mutants were expressed at approximately the same level as wild type ER. Suppression of transcription was specific for ER, since the mutants did not inhibit progesterone receptor-mediated transcription. Not all mutations leading to inactive ER confer the dominant negative phenotype, as five ER mutants rendered transcriptionally inactive by point mutations between residues 516 and 524 of the ER hormone binding domain were poor inhibitors of wild type ER activity. Binding studies showed that the L540Q and S554fs dominant negative mutants bound 17β-estradiol with wild type affinity (K(d) = 0.3-0.5 nM), whereas ER1-530 exhibited a 15-fold reduction in affinity for estradiol. The three dominant negative ERs showed significant ability to interact with the estrogen response element (ERE) in promoter interference assays, but ER1-530 and S554fs displayed little or no binding to the ERE in gel mobility shift assays where higher affinity for the DNA may be required for the receptor-ERE complex to remain associated during the electrophoresis. These data support the idea that, in all three mutants, it is loss of function of the COOH-terminal transactivation domain which leads to the dominant negative phenotype. S554fs, a powerful dominant negative mutant, is a good candidate for further studies aimed at suppressing the estrogen- dependent growth of human breast cancer cells.",
author = "Ince, {B. A.} and Y. Zhuang and Wrenn, {C. K.} and Shapiro, {D. J.} and Katzenellenbogen, {B. S.}",
year = "1993",
month = "1",
day = "1",
language = "English (US)",
volume = "268",
pages = "14026--14032",
journal = "Journal of Biological Chemistry",
issn = "0021-9258",
publisher = "American Society for Biochemistry and Molecular Biology Inc.",
number = "19",

}

TY - JOUR

T1 - Powerful dominant negative mutants of the human estrogen receptor

AU - Ince, B. A.

AU - Zhuang, Y.

AU - Wrenn, C. K.

AU - Shapiro, D. J.

AU - Katzenellenbogen, B. S.

PY - 1993/1/1

Y1 - 1993/1/1

N2 - We have identified and characterized three human estrogen receptor (ER) mutants, which, at low concentrations, are capable of blocking the intracellular activity of wild type ER. The mutants, a truncated ER (ER1- 530), a point mutant (L540Q), and a frameshift (S554fs), were generated by random chemical mutagenesis of the ER hormone binding domain and screened first for low activity in a yeast selection system. In transient co- transfection assays using ER-deficient Chinese hamster ovary cells, all three mutants exhibited less than 10% of the transcription activation activity of wild type ER, and when co-expressed with wild type ER, each of the mutants effectively suppressed the ability of wild type ER to activate transcription of an estrogen-regulated reporter plasmid. When equal amounts of plasmid encoding the ER mutants and wild type ER were used, S554fs, ER1-530, and L540Q suppressed the activity of wild type ER by 80, 55, and 75%, respectively. At a ratio of 1 part S554fs to 10 parts wild type ER, transcription was still inhibited by 40%. Western blot analysis showed that all three mutants were expressed at approximately the same level as wild type ER. Suppression of transcription was specific for ER, since the mutants did not inhibit progesterone receptor-mediated transcription. Not all mutations leading to inactive ER confer the dominant negative phenotype, as five ER mutants rendered transcriptionally inactive by point mutations between residues 516 and 524 of the ER hormone binding domain were poor inhibitors of wild type ER activity. Binding studies showed that the L540Q and S554fs dominant negative mutants bound 17β-estradiol with wild type affinity (K(d) = 0.3-0.5 nM), whereas ER1-530 exhibited a 15-fold reduction in affinity for estradiol. The three dominant negative ERs showed significant ability to interact with the estrogen response element (ERE) in promoter interference assays, but ER1-530 and S554fs displayed little or no binding to the ERE in gel mobility shift assays where higher affinity for the DNA may be required for the receptor-ERE complex to remain associated during the electrophoresis. These data support the idea that, in all three mutants, it is loss of function of the COOH-terminal transactivation domain which leads to the dominant negative phenotype. S554fs, a powerful dominant negative mutant, is a good candidate for further studies aimed at suppressing the estrogen- dependent growth of human breast cancer cells.

AB - We have identified and characterized three human estrogen receptor (ER) mutants, which, at low concentrations, are capable of blocking the intracellular activity of wild type ER. The mutants, a truncated ER (ER1- 530), a point mutant (L540Q), and a frameshift (S554fs), were generated by random chemical mutagenesis of the ER hormone binding domain and screened first for low activity in a yeast selection system. In transient co- transfection assays using ER-deficient Chinese hamster ovary cells, all three mutants exhibited less than 10% of the transcription activation activity of wild type ER, and when co-expressed with wild type ER, each of the mutants effectively suppressed the ability of wild type ER to activate transcription of an estrogen-regulated reporter plasmid. When equal amounts of plasmid encoding the ER mutants and wild type ER were used, S554fs, ER1-530, and L540Q suppressed the activity of wild type ER by 80, 55, and 75%, respectively. At a ratio of 1 part S554fs to 10 parts wild type ER, transcription was still inhibited by 40%. Western blot analysis showed that all three mutants were expressed at approximately the same level as wild type ER. Suppression of transcription was specific for ER, since the mutants did not inhibit progesterone receptor-mediated transcription. Not all mutations leading to inactive ER confer the dominant negative phenotype, as five ER mutants rendered transcriptionally inactive by point mutations between residues 516 and 524 of the ER hormone binding domain were poor inhibitors of wild type ER activity. Binding studies showed that the L540Q and S554fs dominant negative mutants bound 17β-estradiol with wild type affinity (K(d) = 0.3-0.5 nM), whereas ER1-530 exhibited a 15-fold reduction in affinity for estradiol. The three dominant negative ERs showed significant ability to interact with the estrogen response element (ERE) in promoter interference assays, but ER1-530 and S554fs displayed little or no binding to the ERE in gel mobility shift assays where higher affinity for the DNA may be required for the receptor-ERE complex to remain associated during the electrophoresis. These data support the idea that, in all three mutants, it is loss of function of the COOH-terminal transactivation domain which leads to the dominant negative phenotype. S554fs, a powerful dominant negative mutant, is a good candidate for further studies aimed at suppressing the estrogen- dependent growth of human breast cancer cells.

UR - http://www.scopus.com/inward/record.url?scp=0027252955&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0027252955&partnerID=8YFLogxK

M3 - Article

C2 - 8314770

AN - SCOPUS:0027252955

VL - 268

SP - 14026

EP - 14032

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 19

ER -