Ras 能將外在的訊息傳遞到細胞之中，進而引導許多不同的功能，在細胞中扮演一個很重要的角色。Ras相關下游不同的訊息傳導路徑以及其活化的相關基因可以調控細胞的存活、週期以及死亡。本研究主要探討兩個會受到ras誘導活化的基因，分別是 Bcl-2/E1B Nineteen kDa Interacting Protein-3 (BNIP3)和Retinoblastoma binding protein-7 (RBBP7)。BNIP3 是一個會促進細胞凋亡的蛋白質，並會和促進細胞存活的蛋白質Bcl-2結合，至於兩者結合的生物學意義仍在積極探討中。 本研究顯示當Ras 過度表現時會正向調控BNIP3 啟動子(promoter)；且Ras和BNIP3會在粒腺體(mitochondria)中相結合。另一個基因RBBP7 最早被發現能與Rb蛋白質相結合。此外，RBBP7也參與在histone deacetylase (HDAC) complexes中；而許多報導更指出細胞 histone的調控和腫瘤的形成與轉移有關。也因此RBBP7 很可能在調控細胞週期與腫瘤形成過程中扮演重要角色。而我們證實了RBBP7是一個會被Ras正向調控的基因。RECK (reversion-inducing-cysteine-rich protein with Kazal motifs) 是細胞膜上的醣蛋白，可以經由matrix metalloproteinases (MMPs)抑制腫瘤轉移和血管新生。最近有研究指出Ras活化會增強HDAC1結合在RECK 啟動子上的Sp1結合位置以抑制RECK表現量。本研究利用小鼠RECK啟動子luciferase assay和RBBP7 特異性的小片段干擾性RNA( siRNA)進一步發現當Ras過度表現時，細胞中的RBBP7和HDAC1會有明顯的結合，證實Ras過量表現會造成RBBP7大量表現並與HDAC1連結，一起結合至RECK 啟動子上的Sp1結合位置以抑制RECK表現量。總言之，當Ras蛋白質過量表現時，會活化各類功能特異的基因。本研究證實Ras與促使細胞死亡有的BNIP3密切關係；並可利用RBBP7去負向調控像RECK腫瘤抑制基因，.這些發現對於Ras過度表現活化下游相關的基因及其與腫瘤形成之關係都有莫大的助益。

　　Ras is an essential component in the transduction of extracellular signals that can cause multiple functions in the cell. Multiple signaling pathways downstream of Ras are responsible for survival, cell cycle progression, and cell death. We have identified two ras-upregulated genes, Bcl-2/E1B Nineteen kDa Interacting Protein-3 (BNIP3) and Retinoblastoma binding protein-7 (RBBP7), using PCR cDNA substration analysis and DNA microarray analysis, respectively. BNIP3 has been reported as an ras-upregulate gene and it is a pro-apoptotic protein that interacts with survival promoting protein Bcl-2. We demonstrated that Ras overexpression can up-regulate BNIP3 promoter and found that Ras binds to BNIP3 on the mitochondria by immunoprecipitation. As for the biological functions of this binding effect is still under investigation. Another gene, RBBP7 was first identified as a protein that binds to an Rb affinity column. It has been reported that RBBP7 involves many histone deacetylase (HDAC) complexes. Numerous studies support an important role for histone modification in tumor formation and in the metastatic spread of cancer. Therefore, RBBP7 may have an essential role in cell cycle control and tumorigenesis. We confirmed that RBBP7 was an ras-upregulate gene using the inducible Ras cell lines. RECK is a membrane –anchored glycoprotein that negatively regulates matrix metalloproteinases (MMPs) and inhibits tumor metastasis and angiogenesis. Recently, it is reported that Ras activation increased the binding between HDAC1 and the Sp1 site on RECK promoter. We discovered a strong interaction between RBBP7 and HDAC1 under Ras overexpression. Therefore, it is possible that Ras activation stimulates RBBP7 expression and recruits HDAC1 to the Sp1 site on the RECK promoter and represses it. We confirmed this speculation using mouse RECK promoter luciferase assays and RBBP7 RNA interference. In summary, we prove that Ras binds to BNIP3 in the mitochondria fraction and uses RBBP7 to down-regulate RECK.

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