DNA修復系統在維持基因完整度上是極為重要的，真核細胞發展出兩個主要的機制進行修補斷裂的雙股DNA：同源性重組(homologous recombination)和非同源末端結合(non-homologous end-joining)。在植物體中，目前大多認為主要是利用非同源末端結合的途徑去修補斷裂的雙股DNA。古氏蛋白異二聚體(Ku heterodimer protein)為非同源末端結合途徑的一種修復蛋白複合體，其包含分子量分別為70和80 kDa的兩個次單元體，此蛋白已經在許多植物中被證明出來(例如：綠豆、稻米、阿拉伯芥)，且其功能與哺乳動物中的Ku蛋白有不少相似之處。在本實驗中，我們利用酵母菌雙雜合系統(yeast two-hybrid system)和GST融合蛋白沉澱實驗(GST pull-down assay)證明阿拉伯芥橢圓家族一號蛋白(Arabidopsis thaliana ovate family protein 1)與古氏蛋白有交互的作用。此橢圓家族基因最早是從蕃茄中證明而得，當時發現此基因的單點突變會造成番茄果實的外觀由圓形轉變成梨形。我們想要進一步瞭解橢圓家族一號蛋白與古氏蛋白在植物中所扮演的生理意義，因此將阿拉伯芥古氏蛋白70 (AtKu70)區分成不同的片段，結果發現古氏蛋白是利用其C端與橢圓家族一號蛋白進行相互作用。此外我們也利用電泳移動率變動分析(electrophoretic mobility shift assay)證明橢圓家族一號蛋白亦為DNA結合蛋白，主要是藉由其N端的區域與DNA結合。我們更發現在三週大的阿拉伯芥植株中，橢圓家族一號基因會受到造成DNA損傷的藥劑(例如：甲烷磺酸甲酯(methyl methanesulfonate；MMS)及亞硫酸氫鈉甲(2-methyl-1,4- naphthoquinone；menadione))刺激而隨著時間增加其基因的表現量。另一方面，將橢圓家族一號蛋白缺失的突變株與野生型植株相比，其在生長過程中對於這些藥劑的處理更加敏感而易凋零。此外在in vivo實驗中，橢圓家族一號蛋白缺失的細胞其非同源末端結合的活性也相對的降低，此結果類似於古氏蛋白70和80缺失的細胞。綜合以上結果，我們推測橢圓家族一號蛋白或許與古氏蛋白一同透過非同源末端結合的途徑參與在DNA修復機制中。

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