Interaction between estrogen receptor and Pit-1 protein is influenced by estrogen in pituitary cells.
The estrogen responsiveness of the rat prolactin gene expression requires the presence of both the estrogen receptor (ER) and the tissue-specific transcription factor, Pit-1 protein. We performed protein interaction assays using anti-rat Pit-1 antiserum (a-rPit-1) to investigate the physical interactions which occur between ER and Pit-1 proteins following estrogen treatment. After fusing maltose binding protein (MBP) and Pit-1 protein, we used the resulting MBP Pit-1 fusion protein to prepare a-rPit-1. Our results show that the estrogen receptor readily co-precipitated with the Pit-1 protein drawn from the lysates of two prolactin-expressing pituitary cell lines GH3 and PR1. The rate of precipitation appears to be both estrogen- and time-dependent. Cellular levels of estrogen receptors and Pit-1 proteins did not show significant changes during the time of estrogen treatment. We therefore suggest that an estrogen-dependent physical interaction between ER and Pit-1 protein exists in vivo, and that this interaction may play an important role in the regulation of prolactin gene expression.
Ying
C
C
Department of Microbiology, Soochow University, Taipei, Taiwan, ROC. cying@mbm1.scu.edu.tw
Lin
D H
DH
Sarkar
D K
DK
Chen
T T
TT
D000818:Animals; D002460:Cell Line; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004054:Diethylstilbestrol / Q000494:pharmacology; D004926:Escherichia coli; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology; D004965:Estrogen Antagonists / Q000494:pharmacology*; D004967:Estrogens / Q000494:pharmacology*; D000431:Ethanol / Q000494:pharmacology; D000077267:Fulvestrant; D005786:Gene Expression Regulation / Q000187:drug effects; D010902:Pituitary Gland / Q000166:cytology / Q000378:metabolism; D010911:Pituitary Neoplasms; D011388:Prolactin / Q000235:genetics; D051381:Rats; D011960:Receptors, Estrogen / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D050817:Transcription Factor Pit-1; D014157:Transcription Factors / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D004268:DNA-Binding Proteins; D004965:Estrogen Antagonists; D004967:Estrogens; C494186:Pou1f1 protein, rat; D011960:Receptors, Estrogen; D011993:Recombinant Fusion Proteins; D050817:Transcription Factor Pit-1; D014157:Transcription Factors; D000077267:Fulvestrant; D000431:Ethanol; D004958:Estradiol; D004054:Diethylstilbestrol; D011388:Prolactin