Vilain E, Guo W, Zhang Y H, McCabe E R
Department of Pediatrics, University of California Los Angeles School of Medicine 90095-1752, USA.
Biochem Mol Med. 1997 Jun;61(1):1-8. doi: 10.1006/bmme.1997.2601.
Two nuclear hormone receptor superfamily members, DAX1 and SF1, are required for normal adrenal cortical development. Mutations in DAX1 are responsible for X-linked adrenal hypoplasia congenita (AHC) and hypogonadotropic hypogonadism. Steroidogenic Factor 1 (SF1) regulates the expression of a number of steroidogenic genes and a putative SF1 response element (SF1-RE) in the DAX1 promoter which binds SF1 specifically. Therefore, we examined deletions in the DAX1 promoter driving expression of beta-galactosidase, with and without coexpression of SF1, in the human adrenocortical carcinoma cell line NCI-H295. We defined the DAX initiation start site and localized the putative SF1-RE at -135 to -143 bp. Loss of the putative SF1-RE region or specific removal of the 9-bp SF1 site resulted in decreased transcriptional activity by 2.3-to 2.5-fold. When cotransfected with 1550 bp of the DAX1 promoter, an SF1-containing expression vector increased the transcriptional activity of the DAX1 promoter by 4-fold. No significant change above baseline occurred when the cells were cotransfected with the 1541-bp fragment containing the entire 1550-bp promoter region minus the 9-bp SF1-RE. We conclude that the SF1-RE is an enhancer element within the DAX1 promoter and speculate that SF1 may be a transcription factor that acts, at least in part, through DAX1 for normal adrenal cortical development.
两个核激素受体超家族成员，DAX1和SF1，是正常肾上腺皮质发育所必需的。DAX1突变导致X连锁先天性肾上腺发育不全（AHC）和低促性腺激素性性腺功能减退。类固醇生成因子1（SF1）调节许多类固醇生成基因的表达以及DAX1启动子中一个假定的SF1反应元件（SF1-RE），该元件能特异性结合SF1。因此，我们在人肾上腺皮质癌细胞系NCI-H295中检测了驱动β-半乳糖苷酶表达的DAX1启动子的缺失情况，有无共表达SF1。我们确定了DAX起始位点，并将假定的SF1-RE定位在-135至-143 bp处。假定的SF1-RE区域缺失或9 bp的SF1位点特异性去除导致转录活性降低2.3至2.5倍。当与1550 bp的DAX1启动子共转染时，一个含SF1的表达载体使DAX1启动子的转录活性增加了4倍。当细胞与包含整个1550 bp启动子区域减去9 bp SF1-RE的1541 bp片段共转染时，未观察到高于基线的显著变化。我们得出结论，SF1-RE是DAX1启动子内的一个增强子元件，并推测SF1可能是一种转录因子，至少部分通过DAX1发挥作用以实现正常肾上腺皮质发育。
