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標題: | 剪接蛋白RBM4在神經分化中選擇性剪接之調控 RBM4-mediated splicing regulation in neuronal cell differentiation |
作者: | Hung-Che Kuo 郭宏哲 |
指導教授: | 譚婉玉(Woan-Yuh Tarn) |
關鍵字: | 選擇性剪接,神經分化,RBM4,Numb,Kif1B, Alternative splicing,Neuron differentiation,RBM4,Numb,Kif1B, |
出版年 : | 2014 |
學位: | 碩士 |
摘要: | 剪接蛋白RBM4在有多種不同功能在調控訊息核糖核酸(mRNA)包含選擇性剪接(alternative splicing)與轉錄調控(translational control),RBM4在先前的研究中被發現透過調控特定基因之選擇性剪接促進在肌肉與胰臟細胞之分化。在我們的研究當中,我們利用一株胚胎幹細胞(P19 cells)來做為研究RBM4在神經分化的模式。我們發現在P19 cells分化成為神經的過程中,RBM4蛋白質及核糖核酸表現量同時上升,意味著RBM4在神經分化上有著特殊的意義。利用shRNA我們可以成功的降低RBM4 在細胞中的表現量,並發現異常Numb的選擇性剪接是受到RBM4缺乏的影響。而Numb是一個adaptor protein,已知有非常多樣化的功能包含參與細胞分化(cell differentiation)、非對稱性細胞分裂(asymmetric cell division)、胞吞作用(endocytosis)、細胞附著(cell adhesion)、細胞遷移(cell migration)、發育(developmental process)及決定細胞命運(cell fate determination)。哺乳類動物的Numb帶有phospoh-tyrosine binding(PTB)及proline-rich region(PRR)的蛋白質片段,這兩個片段剛好會受到選擇性剪接的影響。上述提到在未分化P19 cells中降低RBM4表現量會影響Numb的選擇性剪接,更進一步我們製造出穩定的細胞株(stable cells)會穩定下降RBM4表現量,利用穩定細胞株我們也發現在神經分化過程中Numb的選擇性剪接也受到影響。此外除了Numb的選擇性剪接受RBM4 調控,我們亦發現Kif1B這個motor protein同樣的受到影響。接著利用minigene reporter assay,我們也證明Numb與Kif1B皆直接受到RBM4的調控。在神經突觸生長方面,在降低RBM4表現量會同時減短神經突觸的長度,因此也證明RBM4在延長神經突觸的功能。最後我們也嘗試著找出RBM4剔除鼠當中有任何的腦部異常,我們發現在小腦中第六與第七腦葉之凹陷較不明顯,同時Purkinje cells在小腦中的排列也有些許的異常。總結我們的發現,我們推測RBM4會透過調控Numb與Kif1B的選擇性剪接影響神經分化與神經突觸之延長進而影響小腦之發育。 The RNA-binding motif 4 (RBM4) has multiple roles in mRNA metabolism including alternative splicing and translational control. RBM4 is also known to promote muscle and pancreas cell differentiation through regulating tissue specific alternative splicing. Using P19 cells as an in vitro neuronal differentiation model, we found that RBM4 was up-regulated in retinoic acid treated cells, which led us to investigate the role of RBM4 in neuron specific splicing. Numb displays multiple functions during differentiation, such as the control of asymmetric cell division, endocytosis, cell adhesion, cell migration, developmental processes, and cell fate determination. Mammalian Numb contains a phospho-tyrosine binding (PTB) and proline-rich region (PRR) domain, which are differentially affected by alternative splicing. In undifferentiated P19 cells, knockdown of RBM4 decreased exon-9 skipping, which is known for promoting neuronal differentiation and neurite growth. Moreover, RBM4 stable-knockdown P19 cells had a misregulated Numb and Kif1B alternative splicing and accordingly exhibited delayed neuronal differentiation. We next demonstrated that RBM4 directly promoted exon-3 inclusion and exon-9 exclusion by the mini-gene reporter assay. We also found that knockdown of Rbm4 shortened the neurite length in cortical neurons. In vitro experiment had demonstrated RBM4 would regulate several important targets like Numb and Kif1B, therefore exhibit delayed neuronal differentiation and shortened neurite length. In vivo cerebellum section, surprisingly show the same phenotype as Numb knock out mice, displaying shallow VI-VII fissure. Taken together, our findings suggested that RBM4 might play an important role in neuronal differentiation and neurite growth via regulating alternative splicing of Numb. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/56814 |
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顯示於系所單位: | 分子醫學研究所 |
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