2016-08-012024-05-14https://scholars.lib.ntu.edu.tw/handle/123456789/658621摘要：在細胞分裂中，正確將染色體分配到子細胞對於發展及細胞功能有關鍵影響。在精子減數分裂過程，需要將複製後的染色體經兩次對稱分裂形成四個單倍體精子。由於只發生在雄性生殖器官中，精子減數分裂需靠特殊的調節。我們團隊過去的研究已成功建立線蟲做為探討精子減數分裂機制的模式。在本計畫中，我們的研究將聚焦在兩個廣泛表現的PP1 去磷酸酶，GSP-1 和GSP-2，對精子減數分裂的影響。在線蟲卵子減數分裂及體細胞分裂中，GSP-1 和GSP-2 被發現會拮抗激酶Aurora B kinase 的功能，以避免染色體在還未排列好前提早分開。在其他物種有絲分裂的系統中，PP1 去磷酸酶也被發現與分裂前期染色體的移動及排列有關。我們初步研究發現在線蟲精子減數分裂中，GSP-2 對於兩次的染色體分配事件都很重要，而GSP-1 可能不具影響。我們計畫就這些初步發現做深入分子機制的探討。我們會先探討是否GSP-1 在精子減數分裂中和GSP-2 其實具有互補作用而非不具功能。進一步，利用遺傳學方法，我們會探討GSP-1 和GSP-2 在精子減數分裂中亦會抑制配對染色體的提前分離。利用免疫螢光染色及活體攝影，我們計畫深入檢視GSP-1 和GSP-2 對染色體的轉向及排列具影響。最後，我們計畫以Yeast two hybrid篩選方式找出GSP-1 和GSP-2 在精原細胞中的標的及調節分子。本計畫將會是第一個以細胞生物學方式探討精子減數分裂的研究，其成果將對生殖生物學有深遠影響。<br> Abstract: Faithful chromosome segregation is crucial for development and cellular function. In malemeiosis, however, distinct strategies have to be implemented to achieve two consecutivesymmetric partitioning of the chromosomes. Our previous works have established thenematode C. elegans as a model for investigating the molecular mechanisms that regulatechromosome segregation events during male meiosis. In this proposed study, we focus on theroles of two ubiquitously expressed PP1 phosphatases, GSP-1 and GSP-2, in male meioticdivisions. It has been shown in that, during C. elegans mitosis and oocyte meiosis, PP1phosphatases prevents premature separation of sister chromatids by antagonizing Aurora Bkinase activities. Studies from other mitotic systems also show that PP1 phosphatases arerequired for proper chromosome orientation and movement. We have conducted preliminarystudies to evaluate if loss of PP1 phosphatases would perturb the progression of male meioticdivisions. We found that GSP-2 is required for chromosome segregation during both malemeiosis I and meiosis II, while GSP-1 might be dispensable from male meiosis. We propose tofurther our discovery and explore possible mechanisms that GSP-1 and GSP-2 involve in. Wewill first investigate if GSP-1 and GSP-2 are partially redundant for male meiosis. Geneticapproaches will be used to analyze if GSP-1 and GSP-2 are part of the cohesin removalpathway as shown in oocyte meiosis. Furthermore, cytological and live imaging analyses willbe employed to investigate the roles of GSP-1 and GSP-2 in chromosomal congression andbi-orientation. Finally, in order to understand how GSP-2 regulates variety aspects of malemeiosis, we will identify potential GSP-2 regulators and substrates by yeast two hybrid screen.Our proposed study will be the first to explore the molecular mechanisms of chromosomesegregation events using modern cell biology techniques.