Wehrenberg U, Ivell R, Jansen M, von Goedecke S, Walther N
Institute for Hormone and Fertility Research, University of Hamburg, Germany.
Proc Natl Acad Sci U S A. 1994 Feb 15;91(4):1440-4. doi: 10.1073/pnas.91.4.1440.
The peptide hormone oxytocin is highly expressed in the hypothalamus within only a small number of magnocellular neurons. However, it is also expressed in a much larger number of cells in the bovine corpus luteum at high levels in an estrous cycle-dependent manner. By using nuclear extracts from this tissue for in vitro binding studies, two protein complexes have been shown to bind to a common site in the bovine oxytocin promoter. One of these proteins has been identified as the bovine homologue of the chicken ovalbumin upstream promoter transcription factor (COUP-TF). The second protein is here characterized as the bovine homologue of a tissue-specific transcription factor, steroidogenic factor 1 (SF-1). The relative expression of these two factors during luteal development correlates with the level of luteal oxytocin gene expression, with SF-1 being the factor binding to the promoter of the oxytocin gene when this promoter is activated. Cotransfection experiments using the murine testicular cell line TM4 show that SF-1 can stimulate the expression of a transfected oxytocin gene, suggesting that SF-1 may be involved in upregulation of the oxytocin gene in vivo, possibly by transducing a stimulatory signal to the RNA polymerase.
肽激素催产素仅在少数大细胞神经元的下丘脑中有高表达。然而，它也以发情周期依赖性方式在牛黄体中大量细胞中高水平表达。通过使用该组织的核提取物进行体外结合研究，已显示两种蛋白质复合物与牛催产素启动子中的一个共同位点结合。其中一种蛋白质已被鉴定为鸡卵清蛋白上游启动子转录因子（COUP-TF）的牛同源物。第二种蛋白质在此被表征为组织特异性转录因子类固醇生成因子1（SF-1）的牛同源物。这两种因子在黄体发育过程中的相对表达与黄体催产素基因表达水平相关，当该启动子被激活时，SF-1是与催产素基因启动子结合的因子。使用小鼠睾丸细胞系TM4进行的共转染实验表明，SF-1可以刺激转染的催产素基因的表达，这表明SF-1可能参与体内催产素基因的上调，可能是通过向RNA聚合酶转导刺激信号来实现的。
