2017-01-012024-05-17https://scholars.lib.ntu.edu.tw/handle/123456789/678172摘要：減數分裂的重組反應 (Meiotic Recombination)，能使同源染色體彼此連結形成聯會 (Crossover)，這對於在減數分裂時，將染色體能正確的分配到子細胞的過程中，扮演不可或缺的角色。至今在所有已分析的物種得知，減數分裂的重組反應，通常是由去氧核醣核酸雙股的斷裂，所誘導而啟始整個反應的進行。遺傳學的研究已充份的証明，類拓樸異構酵素 Spo11，是主要的酵素造成去氧核醣核酸雙股的斷裂，進而啟始減數分裂的重組反應進行。但是在過去20年的研究，科學家對於Spo11 如何造成去氧核醣核酸雙股斷裂的分子機制，和Spo11的酵素活性如何被其相互作用的蛋白質所調控影響，至今仍不得而知。之所以Spo11酵素的分子機制研究無法能夠順利進行，主要是因為科學家無法純化出 Spo11的重組蛋白質，來進行其生化功能和蛋白質結構的分析。最近我們實驗室克服了這個難題，我們成功的建構了一套實驗流程，能夠得到高純度的Spo11重組蛋白質。因此在這份研究計畫書，我們主要的目標在探討：Spo11在減數分裂的過程中，造成去氧核醣核酸雙股斷裂的機制，和其酵素活性如何被其相互作用的蛋白質所調控。最重要的是我們的研究成果，不僅能闡釋這在演化上高度保留的Spo11酵素的基礎蛋白質分子特性，並且能夠提供有用的資訊，來和已知的第二構型的拓樸異構酵素做機制上的相互比擬。<br> Abstract: Meiotic recombination establishes physical connections between homologous chromosomes to generate chromosomal crossover, which is pivotal to ensure proper chromosome segregation during meiosis. In every organism that has been examined to date, meiotic recombination is often induced via the formation of double-strand breaks (DSBs). Genetic studies have well documented that Spo11, a topoisomerase II-like enzyme, makes DSBs to initiate meiotic recombination. However, in the past two decades, it still remains enigma regarding the molecular mechanism of Spo11-mediated DNA cleavage and its regulation by its associated partners. The mechanistic study of Spo11 has been hampered by difficulties in obtaining the native purified Spo11 protein for their functional and structural analyses. Recently, we have overcome this hurdle and successfully established an experimental protocol to obtain Spo11 recombinant protein. Thus, in this proposal we aim to delineate the mechanism of Spo11-mediated DNA cleavage and its regulation by its interacting partners during meiotic recombination. Importantly, our findings will not only shield light on the fundamental features of evolutionarily conserved Spo11, but also provide the insightful mechanistic analogy with known type II topoisomerase.減數分裂同源重組類拓樸異構酵素 Spo11DNA雙股斷裂MeiosisHomologous recombinationSPO11DNA double-strand break