- 學位論文
人類與老鼠基因體序列中ESE分布的比較研究
Comparative analysis of the distribution of exonic splicing enhancers in human and mouse genomes
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摘要
Pre-mRNA之剪接過程中，絲胺酸/精胺酸蛋白質(Ser/Arg-rich protein,SR protein)可以與外顯子剪接增強子(exonic splicing enhancer, ESE)相結合，達到聚集剪接體(spliceosome)並辨識外顯子(exon)的目的。本研究分析人類與老鼠的pre-mRNA序列當中ESE motif之出現頻率。我們發現ESE motif在外顯子的密度遠高於內含子(intron)，而有部份的SR protein其ESE motif的密度在UTR序列當中較高，在5`端的外顯子序列也有較高密度的ESE motif。ESE motif密度亦會隨外顯子與內含子的長度而有所不同。我們考慮不同剪接事件之外顯子中ESE motif頻率，結果發現exon skipping之類型有著較低之ESE motif密度，相較之下AA型選擇性剪接則有較高的ESE motif密度。此外，外顯子兩側符合剪接位置GT-AG規則者有著較高的ESE motif頻率。人類與老鼠同源基因之ESE motif的分布亦極為相似，具有顯著的正相關。
並列摘要
In pre-mRNA splicing, the SR(Serine Argenine rich) proteins bind to the exonic splicing enhancers(ESEs) and interact with the components of spliceosome. Since ESEs play an important role in splice site recognition, we characterized the distribution of ESE in human and mouse pre-mRNAs. It was found that ESEs present at a higher density within exons compared with introns. A significant higher ESE density was observed in UTR for three of the SR proteins. Additionally the exons have a higher ESE density in the vicinity of acceptor splice site. There are relations between ESE density, length of introns and length of exons. In different type of alternative splicing events, we observed a higher ESE density in AA-type exons and a lower ESE density in skipped exons. Besides, higher frequency of ESE was observed in exons flanked by splicing sites that follow the GT-AG rule. Finally, there is a similar distribution and significant posititve correlation of ESE density in human and mouse orthologous genes.
參考文獻
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