細胞中的後轉錄調控是經由調節核醣核酸穩定度、轉譯效率、訊息核醣核酸的運輸與位移以及多聚腺核苷酸的選擇與長度來調節基因的表現量。主要是藉由非轉譯序列和其特定之調控蛋白交互作用來調控。其中，三端非轉譯的區域已在先前的研究中被指出，是決定發育時期細胞不同蛋白質表現分佈的重要調控序列。第九纖維母細胞生長因子在先前的動物研究中被發現是一個對胚胎發育、器官形成、性別發育和維持生命機能都十分重要的內分泌物質；然而目前對於人類第九纖維母細胞生長因子基因調控的研究所知有限。本實驗室先前之研究指出此基因的三端非轉譯序列上之微衛星序列具有調控基因表現的能力；進一步的生物資訊分析發現，此區域有富含腺核苷酸及尿核苷酸的序列存在，可能參與基因調控，並在表達序列標籤資料庫中，亦發現此基因有數種不同長度的三端非轉譯序列。這些結果都指出人類第九纖維母細胞生長因子的三端非轉譯序列研究之重要性。因此，這個實驗的主要目的在於找出此區域中具調控功能的序列及相互作用之蛋白質。我們利用快速放大基因末端片段的方法，發現在人類胚胎腎細胞株(HEK293)中有五種不同的三端非轉譯序列存在。此五種不同的片段包含微衛星序列及富含腺核苷酸及尿核苷酸序列之各種組合。進而利用冷光報導基因系統來研究此兩種調控序列和不同的三端非轉譯片段對此生長因子表現的調控，實驗結果顯示此兩種調控序列的突變皆會增加蛋白質的表現量，而不同的三端非轉譯片段也有不同的調控能力。進一步的實驗也發現，此兩種調控序列是經由與特定調控蛋白的結合來增加核醣核酸的不穩定度。綜合以上結果顯示，在人類第九纖維母細胞生長因子的三端非轉譯序列上，微衛星序列及富含腺核苷酸及尿核苷酸序列，可經由讓核醣核酸較不穩定的負調控方式來改變人類第九纖維母細胞生長因子在細胞中的表現程度。

　Post-transcriptional control, which includes determining transcript stability, level of translation, mRNA targeting, poly (A) shortening and alternative polyadenylation, has been shown to regulate protein expression via interaction of untranslated regions (5’ and 3’UTR) with regulatory proteins. Recent studies reveal the power of 3’UTR in controlling cell–fate determination, location and timing of cell division, and shaping the expression pattern during development. Fibroblast growth factor 9 (FGF9) is an autocrine/paracrine growth factor that plays important roles in embryonic development, organ development, sexual development and physiologic maintenances. Limited studies have reported the expression control of human FGF9. Our previous study has demonstrated the microsatellite (MS) motif of FGF9 3’UTR can influence gene expression in a reporter gene system. Additional sequence analysis using bioinformatics tools suggested the AU-rich element (ARE) of FGF9 3’UTR may also participate in regulating FGF9 mRNAs. Furthermore, information from searching EST database showed several FGF9 transcripts with different length in 3’UTR. These data suggested the potential regulatory role of FGF9 3’UTR on FGF9 protein expression. This study aims to identify all possible functional cis-elements of FGF9 3’UTR and its associated proteins. We have identified five FGF9 transcripts with different lengths in 3’end by 3’RACE in HEK293 cells. The varied lengths of 614-, 549-, 194-, 73-, and 50-bp from the stop codon of FGF9 transcript are containing both MS and ARE motifs, MS motif only, or none of the motifs. The role of each element and varied FGF9 transcripts in regulating FGF9 protein expression is investigated using luciferase assay. The data showed either a point mutation within the AUUUA motif or deletion of FGF9 3’UTR MS motif significantly increased reporter gene activity in HEK293 cells, besides; the different FGF9 transcripts have various expression level of reporter gene. Additional mRNA turnover and RNA-protein interaction studies suggested both ARE and MS motif of FGF9 3’UTR may destabilize FGF9 mRNA through the interactions and RNA-binding proteins. In conclusion, results from this study indicate ARE and MS motifs of FGF9 3’UTR can modulate FGF9 protein expression by destabilizing FGF9 mRNA stability.

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