Molecular cloning and characterization of estrogen, androgen, and progesterone nuclear receptors from a freshwater turtle (Pseudemys nelsoni).
Molecular cloning and characterization of estrogen, androgen, and progesterone nuclear receptors from a freshwater turtle (Pseudemys nelsoni).
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DOI：
10.1210/en.2007-0938
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发表时间：
2008
期刊：
影响因子：
4.8
通讯作者：
Y. Katsu;R. Ichikawa;T. Ikeuchi;S. Kohno;L. Guillette;T. Iguchi
中科院分区：
文献类型：
--
作者：
Y. Katsu;R. Ichikawa;T. Ikeuchi;S. Kohno;L. Guillette;T. Iguchi
类固醇激素是脊椎动物许多器官系统的正常功能所必需的。雌性和雄性的生殖活动，如生殖系统的分化、生长和维持，都需要性类固醇的信号。虽然在哺乳动物和一些鱼类、两栖动物和鸟类中进行了广泛的研究，但爬行动物中性类固醇激素(雌激素、雄激素和孕激素)作用的分子机制却知之甚少。在这里，我们研究了一种淡水龟--红腹龟的激素受体配体之间的相互作用，在分离出编码雌激素受体α(ERα)、雄激素受体(AR)和孕激素受体(PR)的cDNA之后。通过5‘和3’端的快速扩增获得了赤腹龟(T)ERpha、TAR和TPR的全长cDNAs。推导的氨基酸序列与鸡的同源基因有很高的同源性(tERpha，90%；TAR，71%；TPR，71%)。利用哺乳动物细胞的瞬时转染试验，tERpha蛋白显示出雌激素依赖的转录激活，该转录来自含有雌激素反应元件的启动子。其他受体蛋白TAR和TPR也表现出雄激素或孕激素依赖的转录激活，这些转录来自雄激素和孕激素反应的小鼠乳腺肿瘤病毒启动子。我们进一步使用改进的GAL4反式激活系统研究了配体对TERα、TAR和TPR的反式激活。我们发现GAL4反式激活系统不适合于TAR和TPR反式激活的测量。这是首次报道爬行动物AR和PR的完整编码区以及类固醇激素对其反式激活的研究。
Steroid hormones are essential for the normal function of many organ systems in vertebrates. Reproductive activity in females and males, such as the differentiation, growth, and maintenance of the reproductive system, requires signaling by the sex steroids. Although extensively studied in mammals and a few fish, amphibians, and bird species, the molecular mechanisms of sex steroid hormone (estrogens, androgens, and progestins) action are poorly understood in reptiles. Here we evaluate hormone receptor ligand interactions in a freshwater turtle, the red-belly slider (Pseudemys nelsoni), after the isolation of cDNAs encoding an estrogen receptor alpha (ERalpha), an androgen receptor (AR), and a progesterone receptor (PR). The full-length red-belly slider turtle (t)ERalpha, tAR, and tPR cDNAs were obtained using 5' and 3' rapid amplification cDNA ends. The deduced amino acid sequences showed high identity to the chicken orthologs (tERalpha, 90%; tAR, 71%; tPR, 71%). Using transient transfection assays of mammalian cells, tERalpha protein displayed estrogen-dependent activation of transcription from an estrogen-responsive element-containing promoter. The other receptor proteins, tAR and tPR, also displayed androgen- or progestin-dependent activation of transcription from androgen- and progestin-responsive murine mammary tumor virus promoters. We further examined the transactivation of tERalpha, tAR and tPR by ligands using a modified GAL4-transactivation system. We found that the GAL4-transactivation system was not suitable for the measurement of tAR and tPR transactivations. This is the first report of the full coding regions of a reptilian AR and PR and the examination of their transactivation by steroid hormones.