EXPRESSION OF THE GENE FOR THE POU DOMAIN TRANSCRIPTION FACTOR TST-1 OCT6 IS REGULATED BY AN ESTROGEN-DEPENDENT ENHANCER/

Expression of the POU domain protein Tst-1/Oct6 during development of glia and neurons is subject to a tight multifactorial control, Here we show that 17 beta-estradiol increases the level of endogenous Tst-1/O ct6 in glial cells. This effect was mediated at the level of gene expr ession by an enhancer present in the 5' flanking region of the mouse g ene for Tst1/Oct6, similar to 5 kb upstream of the transcriptional sta rt site, The enhancer contained as the functional element a sequence m otif that closely resembled a classical estrogen response element, It consisted of an imperfect palindrome with a spacing of 3 bp, and was b ound in vitro by activated estrogen receptor, Furthermore, this elemen t was able to confer estrogen responsiveness when introduced into a he terologous promoter, In the Tst-1/Oct6 gene enhancer, a TPA response e lement was found in close proximity to the estrogen receptor binding s ite, As a consequence, TPA and estrogen activated transcription of the Tst-1/Oct6 gene in a synergistic manner.