在果蠅（D. melanogaster）中，已知mir-100 會在果蠅發育時的前蛹期 開始表現，先前研究發現在Canton S 品系中的mir-100 表現量較其他品系果 蠅來的低，且蛹期存活率遠低於其他品系的果蠅，而且該品系基因組中mir- 100 下游有一段flea 跳躍因子的存在，推測其可能影響了mir-100 的表現 量。本論文研究延續前人研究結果，測試了mir-100 primary transcript 的轉 錄，在RT-PCR 的實驗結果中發現帶有flea 跳躍因子的果蠅，其mir-100 所 在的let-7 cluster 在primary transcript 的過程中會被分成兩個或以上的片段。 接著利用遺傳背景控制與miRNA sponge 的方法檢測mir-100 對蛹期存活率 的影響。在置換過染色體且具有flea 跳躍因子的果蠅，其蛹期存活率顯著地 低於其他品系，但是利用抑制mir-100 表現量之品系的果蠅測試其蛹期存活 率，結果發現其蛹期存活率並無明顯差異。此兩種方法所測得mir-100 對於 果蠅蛹期存活率的影響不同，需更進一步的實驗來驗證。;In Drosophila melanogaster, it is known that the expression of mir-100 starts at the pre-pupal stage. The expression level of mir-100 in a strain isolated from Canton S strain, named CS-UCI, is lower than that of other strains and the survival rate of this strain at the pupal stage is much lower than that of other strains, as found in the previous studies. The previous study revealed the presence of a flea transposon insertion in the downstream of mir-100, presumably affecting the expression level of mir-100. In this study, the primary transcript of mir-100 was examined by RTPCR. Based on the results of three RT-PCR experiments, the let-7 cluster, including mir-100, was transcribed into more than two primary transcripts in CSUCI flies. Next, the chromosome replacement of X and 3rd chromosomes in CSUCI and control strains was carried out to control the genetic background and the pupal survival rate was tested at 25°C . The results showed that flies carrying flea insertion exhibited lower survival rate at the pupal stage in comparison of other strains. However, the pupal survival rate did not change when the miR-100 expression level was decreased by mir-100 sponge. Further experiments on measuring mir-100 expression level in genetic background controlled flies and mir-100 sponge flies are needed to resolve the contradictory results in pupal survival rate.
