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標題: | p53 及 ΔNp63α 對 CTEN 基因表現的調控 Regulation of CTEN expression by p53 and ΔNp63α |
作者: | Ya-chi Chen 陳雅琪 |
指導教授: | 廖憶純(Yi-Chun Liao) |
關鍵字: | CTEN,p53,DNp63alpha, |
出版年 : | 2016 |
學位: | 碩士 |
摘要: | p53 蛋白質,有基因組守護員之稱,當細胞面臨壓力時, p53 致使細胞週期暫停和細胞凋亡等機制以維持基因的穩定性。p63 蛋白質為 p53 家族成員之一,對於上皮細胞的生長以及恆定扮演重要角色,其isoform ΔNp63α 蛋白質主要為維持上皮細胞的貼附能力。我們先前研究已發現 ΔNp63α 會與 CTEN 啟動子結合並調控其基因表現,參與細胞貼附的機制,以及隨著前列腺癌惡化程度提高,CTEN 與p63 的 mRNA 也會隨之下降。因此本論文假設 ΔNp63α 促進 CTEN 表現增加,能降低前列腺癌細胞惡化程度。本論文研究發現,在前列腺癌細胞中過量表現 ΔNp63α 蛋白質會促進CTEN mRNA及蛋白質表現量增加,然而增加的幅度並不大,我們認為除了外源表現的 ΔNp63α之外,在前列腺癌細胞中亦有其他的轉錄因子或 co-activator 共同參與調控 CTEN 的表現機制。另一方面,我們發現無論 p63 存在與否, p53 均抑制 CTEN promoter 轉錄活性,而在人類正常前列腺細胞株 RWPE-1 中,過量表現 p53 會造成 CTEN mRNA 及蛋白質表現量下降,我們以染色質免疫沉澱 (ChIP) 方式,證明了 p53 蛋白質會結合至 CTEN 啟動子上 -81~+25的 p53 預測結合位置上。此外,我們發現以 cisplatin 造成 DNA 損傷使細胞面臨生存壓力時,會促進 p53 表現量增加,並造成 CTEN mRNA 以及蛋白質表現量均下降之結果。本論文證實 p53 會結合在 ΔNp63α 亦辨識結合之 CTEN 啟動子位置上,抑制 CTEN 基因表現,並可能參與在細胞 DNA 損傷壓力的機制中。 p53, the guardian of genome, is involved in cell cycle arrest and apoptosis to maintain the stability of genome in cellular stress. p63, a member of the p53 transcriptional factor family, is a master of regulation of epithelial homeostasis and development. ΔNp63α, one of p63 isoforms, enhances the ability of cell adhesion. Our previous study revealed that ΔNp63α binds to putative p53 binding sites present in CTEN promoter and transcriptionally regulates CTEN expression involved in prostate cell adhesion. Furthermore, CTEN and p63 down-regulation correlates with prostate cancer progression from primary tumors to metastatic lesions. Therefore, we hypothesize that overexpression of ΔNp63α might enhance CTEN expression and hamper prostate cancer cell progression. In our study, overexpression of ΔNp63α in prostate cancer cells induced the mRNA and protein levels of CTEN. However the increases are slight. We assume that there might be other transcription factors or co-activators involved in the regulation of CTEN gene expression in prostate cancer cells in addition to exogenously expressed ΔNp63α. On the other hand, we found that p53 down-regulates CTEN promoter activity whether ΔNp63α exists or not. Also, overexpression of p53 decreased CTEN mRNA and protein in non-malignant prostate cell line, RWPE-1. By using the chromatin immunoprecipitation (ChIP) assay, we demonstrated that p53 binds to CTEN promoter within the region between -80 to +25. Moreover, by using cisplatin to induce DNA damage and celluar stress, we discovered that cisplatin exposure caused increased p53 and decreased the mRNA and protein levels of CTEN. In conclusion, our findings reveal that p53 binds to the CTEN promoter region which also recognized by ΔNp63α. p53 repressed the expression of CTEN in response to DNA damage stress. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/19049 |
DOI: | 10.6342/NTU201602524 |
全文授權: | 未授權 |
顯示於系所單位: | 生化科技學系 |
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