THE RIBOSOMAL FRACTION MEDIATES THE TRANSLATIONAL ENHANCEMENT ASSOCIATED WITH THE 5'-LEADER OF TOBACCO MOSAIC-VIRUS
THE RIBOSOMAL FRACTION MEDIATES THE TRANSLATIONAL ENHANCEMENT ASSOCIATED WITH THE 5'-LEADER OF TOBACCO MOSAIC-VIRUS
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DOI：
10.1093/nar/16.17.8675
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发表时间：
1988-09-12
影响因子：
14.9
通讯作者：
HERSHEY, JWB
中科院分区：
文献类型：
--
作者：
GALLIE, DR;WALBOT, V;HERSHEY, JWB
.OMEGA。烟草花叶病毒 (TMV) RNA 5'' 末端的序列充当翻译增强子。利用源自小麦胚芽(WG)和兔网织红细胞(MDL)的体外翻译系统之间与.OMEGA.相关的翻译增强的差异来鉴定负责裂解物对.OMEGA.的特征性反应的裂解物成分。使用以各种组合重构的分级分离的MDL和WG裂解物，确定高盐洗涤的核糖体级分是响应性的裂解物中的元素。对.OMEGA.增强翻译的能力的分析在低mRNA和高核糖体浓度下是最大的，并且发生在体外翻译测定的早期阶段。与不含.OMEGA.的CAT mRNA相比，含有.OMEGA.的CAT mRNA的翻译对微球菌核酸酶的存在更敏感。在替代实验中，WG核糖体在MDL中的作用效率大大降低，正如MDL核糖体在WG裂解物中的作用一样。 作为一个整体，一个系统中含有起始因子的部分不能在功能上替代另一个系统的部分，并且实际上起到抑制异源系统中翻译的作用。
The .OMEGA. sequence at the 5''-terminus of tobacco mosaic virus (TMV) RNA acts as a translational enhancer. The differential in .OMEGA.-associated translational enhancement between the in vitro translation system derived from wheat germ (WG) and that from rabbit reticulocytes (MDL) was exploited to identify that lysate component which was responsbile for a lysate''s characteristic response to .OMEGA.. Using fractionated MDL and WG lysates, which were reconstituted in various combinations, the high salt-washed ribosomal fraction was determined to be the responsive element in a lysate. Analysis of .OMEGA.''s ability to enhance translation was greatest at low mRNA and high ribosomal concentrations and to occur in the early phase of an in vitro translation assay. Translation of .OMEGA.-containing CAT mRNA was more sensitive to the presence of micrococcal nuclease than CAT mRNA without an .OMEGA.. In substitution experiments, WG ribosomes functioned at much reduced efficiency in MDL as did MDL ribosomes in WG lysate. The initiation factor-containing fraction of one system could not, as a whole, functionally replace that of the other and actually acted to inhibit translation in the heterologous system.