糖皮質素受體及其共同活化因子核受體交互作用蛋白質在人類子宮頸瘤病毒十六型轉錄調控區域之角色

The Roles of Glucocorticoid Receptor and Its Coactivator NRIP in the Regulation of Human Papillomavirus Type 16 Long Control Region

呂培瑜(Pei-Yu Lu)

指導教授 ： 陳小梨

國立臺灣大學/醫學院/微生物學研究所/碩士(2008年)

https://doi.org/10.6342/NTU.2008.00543

摘要

人類乳突瘤病毒十六型 (HPV-16) 感染是造成子宮頸癌的主因，而且此癌症的發生與體內的糖皮質激素濃度相關。在前人的研究中指出糖皮質素 (glucocorticoid) 會藉由位於 HPV-16 之 long control region (LCR) 中的三個糖皮質素反應序列 (glucocorticoid response element, GRE) 來增強 HPV-16 的轉錄能力，以提升其下游的主要致癌蛋白質 E6 及 E7 之表現，因而促成細胞轉形及癌症發展。此外，GR 屬於細胞核受體家族的一員，具有轉錄因子的功能，在受到配體刺激的情況之下，會結合至目標基因上游的 GRE，並招募其他共同活化因子或共同抑制因子前來進行調控，顯示 GR 的轉錄共同因子在 HPV-16 的調控中，必定也扮演重要角色。其中，本實驗室先前發現之細胞核受體交互作用蛋白質 (nuclear receptor interaction protein, NRIP) 已被證明能夠增強 GR 的轉錄活性，可作為 GR 之共同活化因子。因此，本論文針對 GR 及其共同活化因子 NRIP 在 HPV-16 LCR 之調控中所扮演的角色進行研究。首先，我們以染色質免疫沉澱法 (chromatin immunoprecipitation, ChIP) 證明 GR 在受到配體 dexamethosome (Dex) 的刺激後，會結合至 HPV-16 LCR 上的 GRE。啟動子活性分析的結果除了證實 HPV-16 LCR 上的三個已知 GREs 都能被 GR 所增進，序列刪除突變株的結果更指出第四個具有功能的 GRE 之存在。在細胞受到配體刺激的情形下，我們以 ChIP 證實共同活化因子 NRIP 會藉由 GR 共同結合至 HPV-16 LCR。以核酸干擾技術降低 NRIP 的表現量後，HPV-16 的 E6 及 E7 的 mRNA 表現量也隨之降低，子宮頸癌細胞株受 GR 配體促進而提升的生長速率也隨之減緩。
本篇結果顯示 GR 藉由結合 HPV-16 LCR 上的四個 GREs 來促進其轉錄活性，而共同活化因子 NRIP 又對 GR 的調控功能扮演著舉足輕重的角色。

關鍵字

子宮頸癌 ； 人類乳突瘤病毒 ； 糖皮質素受體 ； 核受體交互作用蛋白質 ； 轉錄調控

並列摘要

The major cause of cervical cancer is infection of human papillomavirus type 16 (HPV-16), which pathogenicity and oncogenicity are correlated with the hormone glucocorticoid. Previous studies have shown that glucocorticoid upregulates the transcription activity through the three glucocorticoid response elements (GREs) in HPV-16 long control region (LCR), enhancing the expression of the two major oncogenes E6 and E7 downstream, resulting in cell transformation and oncogenesis.
Moreover, GR belongs to Type I nuclear receptor family and serves as transcription factor. When treated with ligand, GR binds to the GREs upstream of its target genes and recruits other coregulators to exert its function, implicating that the cofactors of GR may play roles in the regulation of HPV-16. Previously, our lab found a novel cofactor of GR, named NRIP, which was demonstrated to upregulate the transactivity of GR. Hence, we investigate the roles of GR and its coactivator NRIP in the regulation of HPV-16. First, we demonstrated that GR bound to the GRE(s) in HPV-16 LCR upon ligand dexamethosome (Dex) treatment by chromatin immunoprecipitation (ChIP). The results of luciferase activity assays not only proved the three unknown GREs were separately functional, but also revealed the existence of the fourth GRE. We also proved that NRIP bound HPV-16 LCR through GR in the presence of Dex. Knockdown of NRIP downregulated the mRNA expression of HPV-16 E6 and E7, and also decreased the cell proliferation promoted by Dex.
These results indicate that GR enhances the transcription activity of HPV-16 LCR by binding to the four GREs, and cofactor NRIP also plays an important role in GR-mediated regulation.

並列關鍵字

cervical cancer ； HPV-16 LCR ； glucocorticoid receptor (GR) ； nuclear receptor interaction protein (NRIP)

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