Faculty Collaboration Database

Retinoid X receptor and peroxisome proliferator-activated receptor activate an estrogen responsive gene independent of the estrogen receptor. Mol Cell Endocrinol 1997 Mar 14;127(1):27-40

Date

03/14/1997

Pubmed ID

9099898

DOI

10.1016/s0303-7207(96)03980-9

Scopus ID

2-s2.0-0343742625 (requires institutional sign-in at Scopus site)   93 Citations

Abstract

Estrogen receptors regulate transcription of genes essential for sexual development and reproductive function. Since the retinoid X receptor (RXR) is able to modulate estrogen responsive genes and both 9-cis RA and fatty acids influenced development of estrogen responsive tumors, we hypothesized that estrogen responsive genes might be modulated by RXR and the fatty acid receptor (peroxisome proliferator-activated receptor, PPAR). To test this hypothesis, transfection assays in CV-1 cells were performed with an estrogen response element (ERE) coupled to a luciferase reporter construct. Addition of expression vectors for RXR and PPAR resulted in an 11-fold increase in luciferase activity in the presence of 9-cis RA. Furthermore, mobility shift assays demonstrated binding of RXR and PPAR to the vitellogenin A2-ERE and an ERE in the oxytocin promoter. Methylation interference assays demonstrated that specific guanine residues required for RXR/PPAR binding to the ERE were similar to residues required for ER binding. Moreover, RXR domain-deleted constructs in transfection assays showed that activation required RXR since an RXR delta AF-2 mutant completely abrogated reporter activity. Oligoprecipitation binding studies with biotinylated ERE and (35)S-labeled in vitro translated RXR constructs confirmed binding of delta AF-2 RXR mutant to the ERE in the presence of baculovirus-expressed PPAR. Finally, in situ hybridization confirmed RXR and PPAR mRNA expression in estrogen responsive tissues. Collectively, these data suggest that RXR and PPAR are present in reproductive tissues, are capable of activating estrogen responsive genes and suggest that the mechanism of activation may involve direct binding of the receptors to estrogen response elements.

Author List

Nuñez SB, Medin JA, Braissant O, Kemp L, Wahli W, Ozato K, Segars JH

Author

Jeffrey A. Medin PhD Professor in the Pediatrics department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Cell Culture Techniques
Estrogens
Gene Expression Regulation
Genes, Regulator
Genes, Reporter
Genetic Vectors
In Situ Hybridization, Fluorescence
Luciferases
RNA, Messenger
Receptors, Cytoplasmic and Nuclear
Receptors, Estrogen
Receptors, Retinoic Acid
Retinoid X Receptors
Transcription Factors
Transfection