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標題: | 過度活化的Tem1 GTPase對酵母菌孢子生成的影響 Studies of the Effect of Hyperactivated Tem1 GTPase on Yeast Sporulation |
作者: | Chia-Jou Lin 林佳柔 |
指導教授: | 董桂書(Kuei-Shu Tung) |
關鍵字: | Hsp26,Tem1,Bfa1,GTP酶,GTP,紡錘絲檢控點,孢子形成過程, Hsp26,Tem1,Bfa1,GTPase,GTP,spindle checkpoint,sporulation, |
出版年 : | 2020 |
學位: | 碩士 |
摘要: | 當環境缺乏養分時,會使二倍體出芽酵母菌細胞進行減數分裂並產生孢子。對於出芽酵母菌來說這是一個營養缺乏的逆境反應,因此會誘導出一些逆境蛋白,包括Hsp26蛋白。我們實驗室先前已經發現一個與Hsp26相關的紡錘絲檢控點,其會監控第二次減數分裂過程中的紡錘絲是否適合形成孢子。之前研究也發現Tem1參與在這個檢控點中。我們想了解Tem1是如何參與在此Hsp26相關紡錘絲檢控點。因為Tem1是GTP水解酶會受GAP複合物加速GTP進行水解,我們使用兩種方法將Tem1維持在GTP狀態並探討其效應。第一,是將GAP相關基因BFA1剔除以阻止GTP水解。第二,建構TEM1-Q79L突變株,組成持續與GTP結合的Tem1。我們發現若維持Tem1-GTP狀態,會使檢控點失去功能。透過pCLB2-TEM1突變細胞關閉減數分裂中Tem1表現也會使此一檢控點失效,據此我們提出兩種可能的模型來解釋此現象,一、Tem1-GDP可以主動阻擋的方式干擾孢子形成;二、Tem1必須存在才能活化Hsp26紡錘絲檢控點,接著此檢控點會反過來調控Tem1在孢子形成中的功能。 In the budding yeast Saccharomyces cerevisiae, absence of nitrogen and presence of nonfermentable carbon source lead diploid cells to enter meiosis and spore formation, which called sporulation. It is a starvation-stress response to the yeast. During sporulation, several stress proteins are induced, including Hsp26. Our laboratory has discovered that there is a Hsp26-dependent spindle checkpoint to monitor spindle assembly at meiosis II and regulates spore formation. Tem1, a component of the mitotic spindle checkpoint, is also involved in this checkpoint. We would like to know how Tem1 is involved in this Hsp26-dependent spindle checkpoint. Because Tem1 is a GTPase, which switches between GTP and GDP status, we adopted two approaches to keep Tem1 in the GTP-bound form. One was to delete the GAP-related gene, BFA1, and to block GTP hydrolysis. The other one was to construct TEM1-Q79L mutant that keeps Tem1 in the GTP-bound form. We found that Tem1-GTP may inactivates this checkpoint. pCLB2-TEM1 mutants, which shut down Tem1 during meiosis, also inactivate this checkpoint. We propose two models to explain these results. First, Tem1-GDP may actively block spore formation. Alternatively, Tem1 is required to activate the Hsp26-dependent spindle checkpoint that in turn regulates Tem1 function in spore formation. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/18265 |
DOI: | 10.6342/NTU202003206 |
全文授權: | 未授權 |
顯示於系所單位: | 分子與細胞生物學研究所 |
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