Molecular cloning and characterization of human estrogen receptor betacx: a potential inhibitor ofestrogen action in human.
Molecular cloning and characterization of human estrogen receptor betacx: a potential inhibitor ofestrogen action in human.
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人雌激素受体 betacx 的分子克隆和表征：人类雌激素作用的潜在抑制剂。
DOI：
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发表时间：
1998
影响因子：
14.9
通讯作者：
M. Muramatsu
中科院分区：
文献类型：
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作者：
S. Ogawa;S. Inoue;T. Watanabe;A. Orimo;T. Hosoi;Y. Ouchi;M. Muramatsu
我们已经鉴定并鉴定了一种新的人类雌激素受体(ER)β亚型ERbetacx，它在C-末端被截断，但由于选择性剪接而多了26个氨基酸。ERbetacx转录本在睾丸、卵巢、胸腺和前列腺以及人类培养细胞系如HEC-1、HOS-TE85和Saos-2细胞中表达。ERbetacx蛋白在这些人类细胞中也可以免疫检测到。生化分析表明，ERα和ERβ对17β-雌二醇(E_2)的平均解离常数(Kd)分别为0.2和0.6 nM，而ERbetacx不具有配体结合能力。ERpha和ERbeta蛋白与雌激素反应元件结合，而ERbetacx在凝胶移位分析中不形成任何移位的复合体。在瞬时表达实验中，ERbetacx不显示基本启动子的配体依赖的反式激活能力，也不能在存在或不存在E2的情况下与辅因子TIF1α相互作用。ERbetacx优先与ERpha而不是ERbeta形成异源二聚体，从而抑制ERpha与DNA的结合。然而，有趣的是，它只对ERAlpha反式激活表现出显著的显性负活性。因此，这项研究表明，ERbetacx可能抑制ERα介导的雌激素作用，C末端区域的选择性剪接及其抑制特性是核受体亚型的几个成员的特征。
We have identified and characterized a novel human estrogen receptor (ER) beta isoform, ERbetacx, which is truncated at the C-terminal region but has an extra 26 amino acids due to alternative splicing. The ERbetacx transcript is expressed in testis, ovary, thymus and prostate as well as in human cultured cell lines such as HEC-1, HOS-TE85 and Saos-2 cells. ERbetacx protein is also immunodetectable in these human cells. Biochemical analysis reveals that the average dissociation constants ( K d) of ERalpha and ERbeta for 17beta-estradiol (E2) are 0.2 and 0.6 nM respectively, but ERbetacx has no ligand binding ability. ERalpha and ERbeta proteins bind to the estrogen response element, whereas ERbetacx does not form any shifted complex in gel shift assays. In a transient expression assay, ERbetacx shows no ligand-dependent transactivation ability of a basal promoter and also cannot interact with a cofactor, TIF1alpha, in the presence or absence of E2. ERbetacx preferentially forms a heterodimer with ERalpha rather than that with ERbeta, inhibiting DNA binding by ERalpha. Interestingly, however, it shows a significant dominant negative activity only against ERalpha transactivation. Thus, this study indicates that ERbetacx potentially inhibits ERalpha-mediated estrogen action and that alternative splicing of the C-terminal region and its inhibitory properties are characteristic of several members of nuclear receptor isoforms.