果蠅胚胎發育的過程中，骨骼肌由中胚層細胞特化而來的。先前的研究指出，轉錄因子Twist和Mef2 (Myocyte enhancer factor 2)在骨骼肌的發育過程中扮演了相當重要的角色。他們藉由調控其下游相關基因的轉錄作用，進而影響整個肌肉發育分化。近年來有數個研究以Chip-on-chip或是ChIP-Seq的方式有系統地建立了整個果蠅基因體中胚層和其下游發育過程包括骨骼肌發育的基因調控網絡 (gene regulatory network)。但大多數經由功能基因體學方法找出的Twist或Mef2所結合的DNA區域和其所相關聯的下游基因在果蠅骨骼肌發育過程有無功能則尚未被釐清。為了驗證這些下游基因在果蠅骨骼肌發育過程中的角色並篩選出新的基因來增進對果蠅骨骼肌發育過程的了解，我首先分析整理了Twist和Mef2在整個果蠅基因體的結合位點資料，並結合現有的基因表現資料庫 BDGP in situ database選出受Twist和Mef2結合的區域和其所相關聯的可能候選基因，再以原位雜合染色實驗並利用RNAi果蠅株在果蠅胚胎中胚層細胞抑制基因的表現，找到9個表現在中胚層以及骨骼肌細胞中且其在中胚層細胞的表現量下降時會影響果蠅骨骼肌的正常發育的基因，證實了這些受Twist和Mef2結合的DNA區域其所相關聯的下游基因在果蠅骨骼肌發育過程有所作用。

During Drosophila embryogenesis, somatic muscle is derived from the mesoderm. Transcription factors Twist and Mef2 (Myocyte enhancer factor 2) have been shown playing critical roles in regulating Drosophila mesoderm and somatic muscle development. Several studies have established the gene regulatory network of Drosophila mesoderm development by using ChIP-on-chip or ChIP-seq against key mesoderm transcriptional regulators, including Twist and Mef2. However, it is not clear whether most of the identified bound regions of Twist and Mef2 and their associated target genes play roles in Drosophila somatic muscle development. In order to understand functions of these target genes associated with the Twist- and Mef2- bound regions and identify novel genes involved in Drosophila somatic muscle development, I selected several genes for further studies based on the Twist- and Mef2- binding profiles and information of expression patterns from BDGP in situ database to select Twist- and Mef2- bound regions and their associated target genes. I then performed-1) in situ hybridization experiments to examine the expression patterns of the selected genes, 2) tissue-specific RNAi experiments to understand the functions of the selected genes for somatic muscle development, and 3) ectopic expression of transcription factor Mef2 to know the regulatory relationships between Mef2 and the selected genes. In total, I found 9 genes that were expressed in the mesoderm or the somatic muscles, and showed malformation of somatic musculature when the expression levels of the selected genes were reduced in the mesoderm. These preliminary results suggest these Twist- and Mef2- bound regions and their associated genes play roles in Drosophila somatic muscle development.

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