Topology of mRNA chain in isolated eukaryotic double-row polyribosomes
Topology of mRNA chain in isolated eukaryotic double-row polyribosomes
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DOI：
10.1134/s0006297913050027
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发表时间：
2013-05-01
影响因子：
2.8
通讯作者：
Spirin, A. S.
中科院分区：
文献类型：
--
作者：
Afonina, Zh. A.;Myasnikov, A. G.;Spirin, A. S.
在蛋白质合成过程中，真核细胞的翻译核糖体形成多聚核糖体，这些多聚核糖体被发现是具有有序空间组织元件的多重功能复合物。正如许多电子显微镜研究所揭示的那样，真核生物多聚核糖体的主要可见构型是圆形（环状多聚核糖体）和双链构型（所谓的双排多聚核糖体）。“长”（即重负载的）多聚核糖体通常由双排结构表示，其可以被解释为拓扑圆形（“塌陷环”）或拓扑线性（双标签或螺旋）。在目前的工作中，我们分析了真核多聚核糖体内的mRNA路径，从小麦胚芽无细胞翻译系统中分离，通过整合两种方法：通过用金纳米颗粒（3 '-末端）标记多聚核糖体中的mRNA末端和启动40 S亚基（5'-末端）以及通过冷冻电子断层扫描来可视化多聚核糖体中的mRNA末端。对mRNA标记物在多聚核糖体中的位置和核糖体在其中的相互取向的检查表明，同一样品的双排多聚核糖体可以具有其mRNA的圆形和线性排列。
In the process of protein synthesis, the translating ribosomes of eukaryotic cells form polyribosomes that are found to be multiplex functional complexes possessing elements of ordered spatial organization. As revealed by a number of electron microscopy studies, the predominant visible configurations of the eukaryotic polyribosomes are circles (circular polyribosomes) and two-stranded formations (so-called double-row polyribosomes). The "long" (i.e. heavy loaded) polyribosomes are usually represented by double-row structures, which can be interpreted as either topologically circular ("col-lapsed rings"), or topologically linear (zigzags or helices). In the present work we have analyzed the mRNA path within the eukaryotic polyribosomes, isolated from a wheat germ cell-free translation system, by integrating two approaches: the visualization of mRNA ends in polyribosomes by marking them with gold nanoparticles (3'-end) and initiating 40S subunits (5'-end), as well as by the cryoelectron tomography. Examination of the location of the mRNA markers in polyribosomes and mutual orientation of ribosomes in them has shown that the double-row polyribosomes of the same sample can have both circular and linear arrangements of their mRNA.