Involvement of NF-κB subunit p65 and retinoic acid receptors, RARα and RXRα, in transcriptional regulation of the human GnRH II gene
Involvement of NF-κB subunit p65 and retinoic acid receptors, RARα and RXRα, in transcriptional regulation of the human GnRH II gene
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DOI：
10.1111/j.1742-4658.2007.05804.x
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发表时间：
2007-06-01
期刊：
影响因子：
5.4
通讯作者：
Chow, Billy K. C.
中科院分区：
文献类型：
--
作者：
Hoo, Ruby L. C.;Chan, Kathy Y. Y.;Chow, Billy K. C.
促性腺激素释放激素（GnRH）I和II是下丘脑的十肽，在生殖能力的发育和生殖事件的调节中起关键作用。在这项研究中，人类GnRH II基因的转录调控进行了研究。通过扫描突变分析结合瞬时启动子测定，-641/-636处的基序（CATGCC，命名为GII-Sil）被鉴定为阻遏物元件。该基序的突变导致TE 671髓母细胞瘤和JEG-3胎盘绒毛膜癌细胞中启动子活性的完全恢复。Supershift和染色质免疫沉淀分析显示NF-κ B亚基p65和视黄酸受体RAR α和RXR α与启动子序列的体外和体内结合。这些蛋白因子的过度表达表明p65是一种有效的阻遏物，RAR α/RXR α异源二聚体参与神经元和胎盘细胞中GnRH II基因的差异调节。这通过定量实时PCR证实。用RAR α/RXR α配体全反式视黄酸和9-顺式视黄酸处理细胞，分别降低和增加TE 671和JEG-3细胞中GnRH II基因的表达。总之，这些数据证明了NF-κ B p65和RAR α/RXR α的不同作用，它们与人GnRH II基因启动子中的相同序列相互作用，以细胞特异性方式影响基因表达。
Gonadotropin-releasing hormone (GnRH) I and II are hypothalamic decapeptides with pivotal roles in the development of reproductive competence and regulation of reproductive events. In this study, transcriptional regulation of the human GnRH II gene was investigated. By scanning mutation analysis coupled with transient promoter assays, the motif at -641/-636 (CATGCC, designated GII-Sil) was identified as a repressor element. Mutation of this motif led to full restoration of promoter activity in TE671 medulloblastoma and JEG-3 placenta choriocarcinoma cells. Supershift and chromatin immunoprecipitation assays showed in vitro and in vivo binding of NF-kappa B subunit p65 and the retinoic acid receptors, RAR alpha and RXR alpha, to the promoter sequences. Over-expression of these protein factors indicated that p65 is a potent repressor, and the RAR alpha/RXR alpha heterodimer is involved in the differential regulation of the GnRH II gene in neuronal and placental cells. This was confirmed by quantitative real-time PCR. Treatment of cells with the RAR alpha/RXR alpha ligands, all-trans retinoic acid and 9-cis-retinoic acid, reduced and increased GnRH II gene expression in TE671 and JEG-3 cells, respectively. Taken together, these data demonstrate the differential roles of NF-kappa B p65 and RAR alpha/RXR alpha, interacting with the same sequence in the promoter of the human GnRH II gene to influence gene expression in a cell-specific manner.