In vivo translation and stability of trans-spliced mRNAs in nematode embryos
In vivo translation and stability of trans-spliced mRNAs in nematode embryos
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DOI：
10.1016/j.molbiopara.2007.02.003
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发表时间：
2007-06-01
影响因子：
1.5
通讯作者：
Davis, Richard E.
中科院分区：
文献类型：
--
作者：
Cheng, Guofeng;Cohen, Leah;Davis, Richard E.
剪接前导序列反式剪接将短外显子，剪接前导序列（SL），添加到前体mRNA以产生mRNA的5 '末端。在后生动物中加入SL也为mRNA增加了一个新的帽，一个三甲基鸟苷（M（3）（2，2，7）GpppN）（TMG）取代了典型的真核生物单甲基鸟苷（m（7）GpppN）（m（7）G）帽。反式剪接（M（3）（2，2，7）GpppN-SL-RNA）和非反式剪接（m（7）GpppN-RNA）mRNA均存在于相同细胞中。以前的研究使用无细胞系统来比较反式剪接与非反式剪接RNA的整体翻译，得出了不同的结论。在这里，我们研究了m（3）（2，2，7）GpppG-cap和SL序列和其他RNA元件对线虫胚胎体内mRNA翻译和稳定性的贡献。尽管70 - 90%的线虫mRNA都有TMG帽，但TMG帽并不像m（7）G帽那样支持翻译。然而，当TMG帽和SL一起存在时，它们协同地相互作用并且翻译增强，表明两个反式剪接元件对于促进有效翻译是必需的。SL本身并不充当帽独立的翻译增强子。poly（A）-尾与mRNA帽协同相互作用，增强翻译，并在促进TMG-SL mRNA的翻译中发挥更大的作用。一般来说，SL和AUG之间的受体mRNA序列和3'UTR对反式剪接mRNA的翻译没有显著贡献。总的来说，TMG帽和SL的组合以真核m（7）G-cap和5'UTR的典型方式有助于mRNA翻译和稳定性，但与没有反式剪接元件的RNA相比，它们没有差异地增强mRNA翻译或稳定性。(c)2007 Elsevier B.V.保留所有权利。
Spliced leader trans-splicing adds a short exon, the spliced leader (SL), to pre-mRNAs to generate 5' ends of mRNAs. Addition of the SL in metazoa also adds a new cap to the mRNA, a trimethy1guanosine (M(3)(2,2,7)GpppN) (TMG) that replaces the typical eukaryotic monomethylguanosine (m(7)GpppN)(m(7)G) cap. Both trans-spliced (M(3)(2,2,7)GpppN-SL-RNA) and not trans-spliced (m(7)GpppN-RNA) mRNAs are present in the same cells. Previous studies using cell-free systems to compare the overall translation of trans-spliced versus non-trans-spliced RNAs led to different conclusions. Here, we examine the contribution of m(3)(2,2,7)GpppG-cap and SL sequence and other RNA elements to in vivo mRNA translation and stability in nematode embryos. Although 70-90% of all nematode mRNAs have a TMG-cap, the TMG cap does not support translation as well as an m(7)G-cap. However, when the TMG cap and SL are present together, they synergistically interact and translation is enhanced, indicating both trans-spliced elements are necessary to promote efficient translation. The SL by itself does not act as a cap-independent enhancer of translation. The poly(A)-tail synergistically interacts with the mRNA cap enhancing translation and plays a greater role in facilitating translation of TMG-SL mRNAs. In general, recipient mRNA sequences between the SL and AUG and the 3' UTR do not significantly contribute to the translation of trans-spliced mRNAs. Overall, the combination of TMG cap and SL contribute to mRNA translation and stability in a manner typical of a eukaryotic m(7)G-cap and 5'UTRs, but they do not differentially enhance mRNA translation or stability compared to RNAs without the trans-spliced elements. (c) 2007 Elsevier B.V. All rights reserved.