3',5'-cyclic adenosine monophosphate-dependent transcription of the CYP11A (cholesterol side chain cleavage cytochrome P450) gene involves a DNA response element containing a putative binding site for transcription factor Sp1.
3',5'-cyclic adenosine monophosphate-dependent transcription of the CYP11A (cholesterol side chain cleavage cytochrome P450) gene involves a DNA response element containing a putative binding site for transcription factor Sp1.
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DOI：
10.1210/mend.6.10.1333053
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发表时间：
1992-10
影响因子：
--
通讯作者：
K. Momoi;M. Waterman;E. Simpson;U. Zanger
中科院分区：
文献类型：
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作者：
K. Momoi;M. Waterman;E. Simpson;U. Zanger
CYP11A基因的产物，胆固醇侧链切割细胞色素P450，催化甾体生成的第一步。肾上腺皮质调节类固醇羟化酶基因转录的主要机制需要垂体肽激素ACTH，它通过cAMP起作用。我们之前已经在牛CYP11A基因的5'侧序列[-183到-83碱基对（bp）]中发现了一个转录增强子，它在瞬时转染的小鼠Y1肾上腺皮质肿瘤细胞中激活β -珠蛋白启动子/报告基因的转录，以响应腺苷酸环化酶激活剂forskolin。进一步的缺失分析确定了最小camp响应序列（CRS）在-118到-100 bp之间。利用Y1细胞的核提取物对dna -蛋白相互作用进行分析，发现了两个蛋白结合位点，通过竞争分析表明，这两个蛋白结合位点与之前在人类CYP21基因的CRS中发现的两个蛋白结合位点密切相关。也就是说，在cAMP响应片段-118 ~ -100 bp内，存在一个与普遍存在的转录因子Sp1的一致结合序列高度相似的序列，并且由于与过量的GC盒寡核苷酸竞争，蛋白质与该位点的结合被取消。第二个部分重叠的位点位于假定的sp1结合位点的3'处，与假定的肾上腺特异性蛋白相同或密切相关的蛋白结合。尽管先前已证明CYP21 CRS的肾上腺特异性蛋白结合位点足以赋予camp应答性转录激活，但CYP11A CRS内的同源位点似乎对转录具有减弱作用。（摘要删节250字）
The product of the CYP11A gene, cholesterol side chain cleavage cytochrome P450, catalyzes the initial step of steroidogenesis. A major mechanism whereby steroid hydroxylase gene transcription is regulated in the adrenal cortex requires the pituitary peptide hormone, ACTH, which acts via cAMP. We have previously identified a transcriptional enhancer in the 5'-flanking sequence [-183 to -83 base pairs (bp)] of the bovine CYP11A gene, which activates transcription of a beta-globin promoter/reporter gene in transiently transfected mouse Y1 adrenocortical tumor cells in response to the activator of adenylate cyclase, forskolin. Further deletion analysis has located the minimal cAMP-responsive sequence (CRS) to -118 to -100 bp. Analysis of DNA-protein interactions using nuclear extracts from Y1 cells revealed two protein binding sites, which were shown by competition analysis to be closely related to the two protein binding sites identified previously in the CRS of the human CYP21 gene. Namely, within the cAMP responsive fragment -118 to -100 bp, a sequence with a high degree of similarity to the consensus binding sequence for the ubiquitous transcription factor Sp1 is present, and binding of protein to this site was abolished by competition with excess GC box oligonucleotide. The second partially overlapping site is located 3' of the putative Sp1-binding site and binds to a protein identical or closely related to a putative adrenal-specific protein. Whereas the adrenal-specific protein binding site of the CYP21 CRS was previously shown to be sufficient to confer cAMP-responsive activation of transcription, the homologous site within the CYP11A CRS appears to have an attenuating effect on transcription.(ABSTRACT TRUNCATED AT 250 WORDS)