CSN ( COP9 signalosome)包含八個單體，為生物體中高度保留的蛋白質複合體，與泛素所參與的蛋白質裂解相關。Jun-activation domain binding protein 1 (Jab1)為組成CSN 的第五個成員，分子量大小為38 kDa；先前研究證據亦顯示，人類許多癌症中Jab1 皆有高度表現的情形，但仍無法直接證實Jab1 對癌症惡性轉移的影響。Bcr-Abl 是一個不正常的融合性致癌基因，起因於人類第9 與第22 對染色體轉位的費城染色體，而百分之九十以上的慢性骨髓性白血病患者即源自於此。最近的研究發現Jab1/COP9 signalosome subcomplex 屬於Bcr-Abl 的下游且接受其調控細胞週期前進。在我們的實驗中發現，利用抑制Bcr-Abl kinase 的藥物STI-571 處理可降低約百分之五十的人類Jab1 啟動子活性及蛋白質表現。接著測試不同片段順序的啟動子活性後發現，真正接受Bcr-Abl 調控的Jab1 啟動子，主要介於 pJab-405/-223 區域。處理了PI3K 的抑制劑LY294002 後，發現同時降低了pJab-405/-223 活性與蛋白質表現。最後利用promoter mutagenesis assay 與Chromatin immunoprecipitation assay 發現，Bcr-Abl 藉由ß-catenin/TCF complex 與STAT1 結合位共同調控
pJab-405/-223 啟動子。統合結果後推測，Bcr-Abl 經由PI3K/AKT 的訊息傳導路徑及ß-catenin/TCF 與STAT1 轉錄因子而調控Jab1 表現。

The COP9 signalosome (CSN) contains eight-subunits and is a highly conserved protein complex implicated in ubiquitin-mediated proteolysis. Jun activation domain-binding protein 1 (Jab1) is the fifth component of CSN (CSN5) with a molecular weight of 38 kDa. Jab1 overexpression is observed in many human cancers, but there is no clear evidence how Jab1 contributes to malignant transformation in human cancers. Bcr-Abl is a cytoplasmic chimeric oncoprotein produced by Philadelphia chromosome
translocation and found in more than 90% of patients with chronic myelogenous leukemia (CML). Recent studies have shown that the Jab1/COP9 signalosome subcomplex is a downstream mediator of Bcr-Abl kinase and may facilitate cell-cycle progression. In this study, we found that inhibition of Bcr-Abl kinase by STI-571 downregulated 50% of full length human Jab1 promoter activity and gene expression. Promoter deletion assay indicated that the responsive element for Bcr-Abl is located between -405/-223 region of human Jab1 promoter. Treatment of LY294002 also reduced Jab-405/-223 promoter activity and Jab1
expression. Promoter mutagenesis assay and ChIP assay suggest that Bcr-Abl stimulated both β-catenin /TCF complex and STAT1 bind to the consensus binding sites of Jab-405/-223 promoter. Taken together, Bcr-Abl oncogene may regulate Jab1 via PI3K/AKT signal pathway, β-catenin /TCF and STAT1 transcription factors.

中文摘要 3
英文摘要 4
縮寫語 5
前言 6
研究方向 10
實驗材料與方法 11
實驗結果 28
討論 32
實驗結果之圖表 36
參考文獻 48
附圖 51

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