Regulation of Estrogen Receptor Transcription in Breast Carcinoma.
Annual rept. 1 Oct 94-30 Sep 95,
STANFORD UNIV CA
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An important transcriptional regulatory element of the estrogen receptor ER gene has been identified that binds a protein expressed in ER-positive breast carcinoma. Using a transient expression assay, a seventy-five base pair region of the 5 untranslated leader of the ER gene was identified which augments expression from the ER promoter.This region contains two binding sites for a protein, estrogen receptor factor-1 ERF-1, which is expressed in ER-positive breast carcinomas. A concentrated ERF-1 binding site probe identified a 30,000 dalton protein. Low level ERF-1 expression was detected in normal human mammary epithelial cells. Abundant ERF-l expression was also found in endometrial carcinoma cell lines that express the ER-positive phenotype. These results indicate that ERF- 1 expression represents a common mechanism of ER regulation in hormonally responsive carcinomas.
- Medicine and Medical Research
- Anatomy and Physiology