Differential contribution of the m7G-cap to the 5' end-dependent translation initiation of mammalian mRNAs.
Differential contribution of the m7G-cap to the 5' end-dependent translation initiation of mammalian mRNAs.
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DOI：
10.1093/nar/gkp665
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发表时间：
2009-10
影响因子：
14.9
通讯作者：
Shatsky IN
中科院分区：
文献类型：
--
作者：
Andreev DE;Dmitriev SE;Terenin IM;Prassolov VS;Merrick WC;Shatsky IN
许多哺乳动物的mRNA具有长的5′ UTR和许多茎环结构。对于其中一些，内部核糖体进入位点（IRES）的存在被认为是解释其显著活性的原因，特别是当帽依赖性翻译受损时。为了验证这一假设，我们比较了RNA转染细胞和无细胞系统中一些具有IRES活性的细胞5′ UTR与缺乏IRES元件的细胞5′ UTR的翻译起始效率。与病毒IRES不同，具有所谓“细胞IRES”的测试的5′ UTR在置于双顺反子RNA的顺反子间位置时仅显示背景活性。相比之下，它们在单顺反子背景下非常活跃，并且帽对于它们的活动是不可或缺的。令人惊讶的是，在培养的细胞或细胞质提取物中，帽的刺激水平和总体翻译活性与测试的5′ UTR的二级结构的累积能量不相关。在使用eIF 4 E-BP 1对翻译进行深度抑制的情况下，仍然观察到帽正效应，但其幅度因单个5′ UTR而异，与其二级结构的累积能量无关。因此，这不是强制性的调用IRES假说，至少对于一些mRNA，以解释其优先翻译时，eIF 4 E部分失活。
Many mammalian mRNAs possess long 5′ UTRs with numerous stem-loop structures. For some of them, the presence of Internal Ribosome Entry Sites (IRESes) was suggested to explain their significant activity, especially when cap-dependent translation is compromised. To test this hypothesis, we have compared the translation initiation efficiencies of some cellular 5′ UTRs reported to have IRES-activity with those lacking IRES-elements in RNA-transfected cells and cell-free systems. Unlike viral IRESes, the tested 5′ UTRs with so-called ‘cellular IRESes’ demonstrate only background activities when placed in the intercistronic position of dicistronic RNAs. In contrast, they are very active in the monocistronic context and the cap is indispensable for their activities. Surprisingly, in cultured cells or cytoplasmic extracts both the level of stimulation with the cap and the overall translation activity do not correlate with the cumulative energy of the secondary structure of the tested 5′ UTRs. The cap positive effect is still observed under profound inhibition of translation with eIF4E-BP1 but its magnitude varies for individual 5′ UTRs irrespective of the cumulative energy of their secondary structures. Thus, it is not mandatory to invoke the IRES hypothesis, at least for some mRNAs, to explain their preferential translation when eIF4E is partially inactivated.
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DOI：
10.1083/jcb.108.2.229
发表时间：
1989-02
期刊：
The Journal of cell biology
影响因子：
--
作者：
Kozak M
通讯作者：
Kozak M
Polycomb蛋白和E3泛素连接酶环1b在其高度保守的5'UTR中具有IRES。
影响因子：
3.7
作者：
Boutsma, Erwin;Noback, Sonja;van Lohuizen, Maarten
通讯作者：
van Lohuizen, Maarten
影响因子：
5.3
作者：
Dmitriev, Sergey E.;Andreev, Dmitri E.;Shatsky, Ivan N.
通讯作者：
Shatsky, Ivan N.
DOI：
10.1073/pnas.0710650105
发表时间：
2008-03-25
影响因子：
11.1
作者：
Baranick, Brian T.;Lemp, Nathan A.;Logg, Christopher R.
通讯作者：
Logg, Christopher R.
影响因子：
4.5
作者：
Holcik, M;Graber, T;Baird, S
通讯作者：
Baird, S