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Analysis on the transcriptional regulation mechanism of aromatase gene

芳香酶基因转录调控机制分析

基本信息

批准号：
02680163
负责人：
HARADA Nobuhiro
金额：
$ 1.34万
依托单位：
Fujita Health University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

项目摘要

Aromatase has been known to be widely distributed in various extra-gonadal tissues as well as gonadal tissues and to take part in various physiological functions. The expression of aromatase in these tissues was regulated by tissuespecific factors and tissue-dependent mechanisms. In this study, we used Bewo cells derived from choriocarcinoma for such analyses and analyzed on these complicated regulation mechanisms in the transcription level of aromatase gene. We observed only one promoter site at the approximately 500 base pairs (bp) upstream within 2.8 kb from the transcriptional initiation site of aromatase gene. Unexpectedly, the promoter activity in this site was not responsive to the induction by CAMP or TPA as transcriptional inducers of aromatase gene. The 13 kb fragment of 5'-flanking region of aromatase gene was furhter isolated and the screening of promoter sites in the region was carried out. However, there were not any detectable promoter activities in this region. Then, we used JEG-3 cells derived from choriocarcinoma as more suitable culture cells for analysis of aromatase induction. It was observed in the levels of aromatase activity and mRNA that JEG-3 cells expressed aromatase so much and its expression was regulated by the same factors as human placenta. By using JEG-3 cells, the promoter activity of 5'-flanking region (13 kb) of aromatase gene was examined. Consequently, two promoter sites was newly found in addition to 500 bp upstream site described above. They were located at about 2 kb and 1 kb upstream from the transcriptional initiation site and had promoter activities with positive and negative regulatory actions, respectively. However, in the case of JEG-3 cells, we could not also find any CAMP- or TPA-responsive promoter sites in this region of aromatase gene. Further screening is now being in progress.

芳香化酶广泛分布于性腺和性腺外的各种组织中，参与多种生理功能。芳香化酶在这些组织中的表达受组织特异性因子和组织依赖性机制的调节。本研究以绒毛膜癌Bewo细胞为研究对象，从芳香化酶基因的转录水平分析了芳香化酶基因复杂的调控机制。在芳香化酶基因转录起始位点上游约500个碱基对（bp）的2.8kb内，我们只观察到一个启动子位点。出乎意料的是，该位点的启动子活性对作为芳香化酶基因转录诱导剂的CAMP或TPA的诱导没有响应。进一步分离了芳香化酶基因5 ′侧翼区的13 kb片段，并对该区域的启动子位点进行了筛选。然而，在该区域中没有任何可检测的启动子活性。然后，我们使用来自绒毛膜癌的JEG-3细胞作为更适合用于分析芳香化酶诱导的培养细胞。从芳香化酶活性和mRNA水平观察，JEG-3细胞大量表达芳香化酶，其表达受与人胎盘相同的因子调控。用JEG-3细胞检测芳香化酶基因5 ′侧翼区（13 kb）的启动子活性。因此，除了上述500 bp上游位点之外，新发现了两个启动子位点。它们分别位于转录起始位点上游约2kb和1 kb处，具有启动子活性，分别具有正调控和负调控作用。然而，在JEG-3细胞的情况下，我们也不能找到任何CAMP或TPA响应启动子位点在芳香化酶基因的这一区域。目前正在进行进一步筛查。