IRES-dependent second gene expression is significantly lower than cap-dependent first gene expression in a bicistronic vector
IRES-dependent second gene expression is significantly lower than cap-dependent first gene expression in a bicistronic vector
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DOI：
10.1006/mthe.2000.0050
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发表时间：
2000-04-01
影响因子：
12.4
通讯作者：
Hayakawa, T
中科院分区：
文献类型：
--
作者：
Mizuguchi, H;Xu, ZL;Hayakawa, T
内部核糖体进入位点（IRES）已被广泛用于通过单个启动子的信息来共表达异种基因产物。然而，ires依赖性第二基因表达的效率与第一基因表达的效率相比尚不清楚。本研究的目的是表征ires依赖性第二基因在脑心肌炎病毒（EMCV） 5'非翻译区双链载体中的相对表达。在几种体外培养细胞系和小鼠肝脏中比较了ires依赖性第二基因与cap依赖性第一基因的表达。ires依赖性第二基因的表达量为第一基因的6 - 100%（大多数情况下为20 - 50%）。在没有IRES的质粒中，第二个基因的表达量为第一个基因的0.1-0.8%（有例外）。这些发现对IRES的使用具有重要意义，即应注意IRES依赖性下游基因表达能力的下降，以及确定哪个基因应定位为双电载体中的第一或第二基因。
The internal ribosome entry site (IRES) has been widely used to coexpress heterologous gene products by a message from a single promoter. However, little is known about the efficiency of IRES-dependent second gene expression in comparison with that of first gene expression. This study was undertaken to characterize the relative expression of IRES-dependent second gene in a bicistronic vector, which was derived from the 5' untranslated regions of the encephalomyocarditis virus (EMCV). IRES-dependent second gene expression was compared with cap-dependent first gene expression in several cultured cell lines and in mouse liver in vivo. The expression of the IRES-dependent second gene ranged from 6 to 100% (in most cases between 20 and 50%) that of the first gene. Second gene expression in a plasmid without the IRES was 0.1-0.8% (with some exceptions) that of the first gene. These findings have important implications for the use of IRES, i.e., care should be taken regarding the decreased capacity of IRES-dependent downstream gene expression as well as in determining which gene should be positioned as the first or second gene in a bicistronic vector.