臺灣博碩士論文加值系統

以老鼠脂肪細胞(3T3-L1 adipocyte)為材料，細胞在受到Glucose, insulin,ET-1, Iso, ET-1+Iso, Dex, TNF-?刺激下，造成細胞內某些基因的表現量改變。利用抑制性雜合扣除法找到這些基因後，從這些基因中，針對一個目前功能未知但會在isoproterenol作用下而增加其表現量的基因作為研究目標。本論文即在探討此基因的性質及其蛋白可能的功能。
此基因在NCBI的accession number 為XM_128090。 藉由生物資訊的方法，將XM_128090在蛋白質資料庫中比對從序列的結構上發現此基因具有兩個重要的功能區，分別是LA domain 及RRM (RNA recognition motif) 。從資料庫中比對發現在其他物種具有同源性的基因，包括人類在內。實驗結果發現此基因普遍存在於老鼠各組織以及人類乳癌細胞 MCF-7中。
有報告指出乳癌細胞在isoproterenol處理後會抑制DNA合成而造成細胞數目減少。而XM_128090又是一個在 isoproterenol的刺激下增加表現量的基因，因此我們進一步探討isoproterenol對乳癌細胞的生長抑制可能是透過這個LA-RRM protein的可能性。
比起正常細胞，癌細胞的生存更需要大量地攝取及代謝葡萄糖，之前有報告指出抑制癌細胞葡萄糖代謝會促使細胞走向apoptosis。而MCF-7乳癌細胞主要利用Glucose transporter-1來攝取葡萄糖，從實驗結果發現此基因的產物LA-RRM protein能抑制 MCF-7乳癌細胞 Glucose transporter-1 的轉錄。由以上的資料與實驗結果，我們認為在癌細胞中此基因的表現可能跟癌細胞的生存有關。

In 3T3-L1 adipocyte, under treatments of glucose, isoproterenol, ET-1, ET-1+Iso, dexamethasone, TNF-α, many genes were up-regulated or down-regulated. By the method of subtractive suppression hybridization (SSH), we found 561 genes were influenced by treatment as mentioned above. Thus these genes might play important roles in the regulation of cell function. Using bioinformatics, we examined these genes, and we focused on one gene, which accession number in NCBI is XM_128090. XM_128090 is up-regulated by isoproterenol. The gene product is XP_128090 and the function of this protein is still unknown.
Analyzing the protein sequence of XP_128090, two important conserved domains were found. These domains are LA domain and RRM (RNA recognition motif). Using BLAST (basic local alignment search tool) to compare XM_128090 sequence in a sequence database, we found homologues genes in many species, including human. The result showed that various mouse tissues contain this gene. Human MCF-7 cells also contain the homologues gene.
Due to the requirement of energy to feed uncontrolled proliferation, cancer cells strongly rely on glucose as energy source. Inhibition of glucose metabolism sensitizes tumor cells for apoptosis. Our result indicated that the LA-RRM binding protein might inhibit glucose transporter-1 expression in MCF-7 cells. Since glucose uptake into MCF-7 cells is mediated mainly by GLUT-1, we speculate that this protein might be involved in the regulation of growth of breast tumor cells.

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