Cooperative binding of steroid hormone receptors contributes to transcriptional synergism at target enhancer elements.
We demonstrated previously that two molecules of steroid hormone receptor bound efficiently to a single hormone response element (GRE/PRE) of the tyrosine aminotransferase gene (Tsai et al., 1988). Here, we show that two tandemly linked GRE/PREs conferred progesterone inducibility synergistically to a heterologous TK-CAT fusion gene. Binding studies demonstrated that occupation of one GRE/PRE site by a progesterone receptor dimer increased the binding affinity of receptors for the second GRE/PRE site 100-fold. Thus, the observed synergistic induction of TK-CAT may result from cooperative binding of receptor dimers to the two GRE/PRE sites.
Tsai
S Y
SY
Department of Cell Biology, Baylor College of Medicine, Houston, Texas 77030.
Tsai
M J
MJ
O'Malley
B W
BW
D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002645:Chickens; D004247:DNA / Q000032:analysis; D004742:Enhancer Elements, Genetic; D005938:Glucocorticoids / Q000378:metabolism*; D010957:Plasmids; D011374:Progesterone / Q000378:metabolism* / Q000494:pharmacology; D011401:Promoter Regions, Genetic / Q000187:drug effects; D011980:Receptors, Progesterone / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D014162:Transfection; D014444:Tyrosine Transaminase / Q000235:genetics
D005938:Glucocorticoids; D011980:Receptors, Progesterone; D011374:Progesterone; D004247:DNA; D014444:Tyrosine Transaminase