An N-Terminal Deletion Mutant of Estrogen Receptor Exhibits Increased Synergism with Upstream Activators and Enhanced Binding to the Estrogen Response Element

Hong Xing, Sandra Mattick, David J. Shapiro, Denise Lew

Research output: Contribution to journalArticlepeer-review

Abstract

To study the role of the N-terminal region of the estrogen receptor (ER) in transcription activation and in DNA binding, we constructed a mutant of the Xenopus laevis ER which lacks amino acids 1-159 (XER160/586). In transient transfections, XER160/586 exhibited <10% of the activity of wild-type XER on a synthetic promoter containing two estrogen response elements (EREs). To examine transcriptional synergism by XER and by XER160/586, we determined the activity of promoters containing EREs and binding sites for either the vitellogenin activator, NF1, or API upstream activator protein. For the three promoters transcription by XER was 2.8-fold greater than expected for additive activities, and transcription by XER160/586 was 6.2-fold greater. These data demonstrate that an upstream activator protein bound near the promoter can partially compensate for the loss of the internal N-terminal (AF1) transactivation domain in XER160/586. Using a promoter interference assay to study the intracellular interaction between ER and the estrogen response element, we found that XER160/586 exhibited a significant increase in affinity for the ERE. Its low basal activity and enhanced affinity for the ERE make XER160/586 an effective dominant negative mutant. When co-expressed with wild-type XER at 1:1 and 5:1 ratios, XER160/586 suppressed the activity of wild-type XER by 57% and >80%, respectively.

Original languageEnglish (US)
Pages (from-to)3956-3963
Number of pages8
JournalBiochemistry
Volume34
Issue number12
DOIs
StatePublished - Sep 1 1995

ASJC Scopus subject areas

  • Biochemistry

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