Please use this identifier to cite or link to this item:
Liver-Specific Overexpression of igf-2 Leads to Liver hypertrophy
|Publication Year :||2005|
第二形類胰島素因子 (IGF-II)，是刺激細胞分裂分化的一個重要的原素，且在胚胎發育上扮演一個重要的角色。大部分的IGFs由肝臟生產藉由與類胰島素因子結合蛋白(IGFBPs)構成一個複合蛋白然後釋放到血液中在生物體內循環。在先前的研究中指出，IGF-2通常會被基因印痕(genomic imprinting)抑制其表現。但是，IGF-2經常由腫瘤和腫瘤細胞株所分泌，尤其是在肝癌中，在肝臟硬化的早期機制中，通常會伴隨著IGF-2表現量的增加，特別是在由HBV和HCV引起的慢性肝癌。由於IGF-2的大量表現與肝癌的發生有著相當密切的關係，所以本篇論文嘗試設計在斑馬魚的肝臟中過量表現IGF-2，並針對其下游因子以及受到過量表現IGF-2影響的肝臟的型態加以分析。 在結果中發現，過量表現IGF-2 將引起肝臟異常肥大，而且細胞的型態也與對照組不同，在分析其下游基因後發現，抗細胞凋亡基因群及促細胞週期基因群都會受到IGF-2的正調控，從這些的結果中指出，在肝臟中過量表現IGF-2極有可能可以發展成肝癌。在將來的實驗上可以利用這樣的轉殖基因魚，使其成為一個易於誘發肝癌的疾病模式。
Insulin-like growth factor-2 (IGF-II), mainly synthesized in liver then transport to target tissues through endocrine system, is an important factor that stimulate cell proliferation, differentiation and division, promote organ development and play as a survival factor in apoptosis. However, the functional role of liver-derived IGF-II before partum still remains unclear. In this study, we use liver fatty acid binding protein (L-FABP) promoter to drive IGF-II expression in a liver-specific manner. To facilitate the direct imaging of liver development, constructs containing expression cascade were introduced to one-cell stage embryo of transgenic zebrafish lines bearing liver-specific GFP expression. Exogenous IGF-2 expression is first detected at 34hpf under the control of LFABP promoter. Obvious liver enlargement was observed at 10dpf and continues to grow; gut tube was pushed up by the enlarged liver but appears un-disrupted morphologically. At 17dpf, the volume of IGF-2 over-expressed liver is 1.5 times bigger statistically than the wild-type control using confocal microscopy. The increased number and enlarged hepatocyte cell shape were also observed under confocal microscopy examination. We further use PT-PCR to monitor molecular, which may involve in this phenomena. IGF-binding protein, IGFBP1 and IGFBP3 were down-regulated; Cell cycle related gene such as c-myc, cyclin-D1, gankyrin; anti-apoptosis genes such as bcl-xl and liver-enriched transcription factors such as HNF4αand HNF1αwere up-regulated suggesting the rapid cell division leading to increase cell number were controlled by hepatic program and anti-apoptosis genes.
|Appears in Collections:||漁業科學研究所|
Files in This Item:
|1.59 MB||Adobe PDF|
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.