摘要或動機

去氧核糖核酸水解?，(deoxyribonuclease,簡稱DNase)為一種核酸內切?。目前研究得最透徹的去氧核糖核酸水解?為牛胰臟的DNase I，有四種以上的同功?存在。而牛和雞的DNA序列有極高的相似度，由之前的研究中在等電點焦集電泳法顯示雞胰臟DNase I 具A、B 兩種同功?，本實驗則希望能進一步了解兩種同功?的差異原因。在抽取RNA 後，以RT-PCR 方法合成cDNA，將其以限制?切割，再以大腸桿菌作為載體進行轉殖及繁殖培養，最後將其DNA 定序後進行分析比較。目前已完成第一次定序，但因引子接合過程中有部分位置錯亂造成殖體無法進行表現。另外在此次所得之序列中有發現一個胺基酸的轉變，而其是否為多型性之表現則有待進一步的實驗證實。The most advanced research on deoxyribonuclease in current states is on the bovine pancreatic DNase I, more than four of which isoforms have been found. It is shown that the DNA sequences of chicken and bovine have relatively high similarity. In addition, according to the result of isoelectric focusing from previous researches, chicken pancreatic DNaseI has two isoforms (A and B.) In this research, the author expects to establish more knowledge on the differences on the isoforms and the causes. After receiving the RNA, the RT-PCR is preformed to incorporate the cDNA, which is later cleaved by restriction enzyme and inserted into the plasmid DNA of the E. coli host cell to be cloned. So far a polynucleotide sequence has been deduced from clones of the cDNA, but it cannot be expressed successfully in E.coli due to few random mistaken splicing. There is an alternation of one amino acid, and whether it is the actual state of isoform or not still requires further proof.