Activation of CYP11A and CYP11B gene promoters by the steroidogenic cell-specific transcription factor, Ad4BP.
Activation of CYP11A and CYP11B gene promoters by the steroidogenic cell-specific transcription factor, Ad4BP.
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DOI：
10.1210/mend.7.9.8247022
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发表时间：
1993-09
影响因子：
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通讯作者：
K. Morohashi;U. Zanger;S. Honda;M. Hara;M. Waterman;T. Omura
中科院分区：
文献类型：
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作者：
K. Morohashi;U. Zanger;S. Honda;M. Hara;M. Waterman;T. Omura
我们已经研究了四个顺式元件，广告1（CRE），广告2，广告3，和广告4，这是目前在牛CYP 11 B（11 β-羟化酶P-450）基因的启动子使用β-珠蛋白报告基因构建体和瞬时转染类固醇和nonsteroidogenic细胞类型的转录活性。只有Ad 1（CRE），CRE同源物，在肾上腺肿瘤Y-1细胞中表现出毛喉素依赖的转录活性，而其他元件本身不能刺激转录。由于Ad 3和Ad 4先前已被鉴定为该基因完全cAMP依赖性转录所需的顺式元件，我们研究了不同顺式元件组合对报告基因转录的影响。在Y-1细胞中，Ad 1（CRE）和其他顺式元件中的任何一个的四个串联拷贝在毛喉素处理后显著激活转录。携带Ad 1（CRE）和Ad 4的模板在睾丸Leydig细胞I-10中也有活性，而在非类固醇生成PC-12细胞中无活性。4xAd 4/Ad 1（CRE）组合的转录激活可能依赖于Ad 4结合蛋白（Ad 4 BP）的存在，这在PC-12细胞中是不存在的，如免疫印迹分析所示。通过将Ad 4 BP的表达载体共转染到PC-12细胞中，这导致毛喉素依赖性转录与表达载体的量成比例地增加，证实了这一点。在Y-1细胞中，通过共转染蛋白激酶A催化亚基的表达载体来模拟毛喉素的转录激活。（250字处删节）
We have examined the transcriptional activity of four cis-elements, Ad1(CRE), Ad2, Ad3, and Ad4, that are present in the promoter of the bovine CYP11B (11 beta-hydroxylase P-450) gene using beta-globin reporter gene constructs and transient transfection into steroidogenic and nonsteroidogenic cell types. Only Ad1(CRE), a CRE homolog, showed forskolin-dependent transcriptional activity in adrenal tumor Y-1 cells, whereas the other elements were not able to stimulate transcription by themselves. As Ad3 and Ad4 had previously been identified as the cis-elements required for full cAMP-dependent transcription of this gene, we examined the effect of combinations of different cis-elements on the transcription of the reporter gene. In Y-1 cells, Ad1(CRE) and four tandem copies of any one of the other cis-elements substantially activated transcription in response to forskolin treatment. The template carrying Ad1(CRE) and Ad4 was also active in testicular Leydig cells, I-10, whereas it was inactive in nonsteroidogenic PC-12 cells. Transcriptional activation by the 4xAd4/Ad1(CRE) combination presumably depended on the presence of Ad4-binding protein (Ad4BP), which is absent in PC-12 cells, as shown by immunoblot analysis. This was confirmed by cotransfecting an expression vector for Ad4BP into PC-12 cells, which caused forskolin-dependent transcription to increase in proportion to the amount of expression vector. In Y-1 cells, transcriptional activation by forskolin was mimicked by cotransfection of an expression vector for the catalytic subunit of protein kinase-A.(ABSTRACT TRUNCATED AT 250 WORDS)