Formation of circular polyribosomes on eukaryotic mRNA without cap-structure and poly(A)-tail: a cryo electron tomography study.
Formation of circular polyribosomes on eukaryotic mRNA without cap-structure and poly(A)-tail: a cryo electron tomography study.
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DOI：
10.1093/nar/gku599
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发表时间：
2014-08
影响因子：
14.9
通讯作者：
Spirin AS
中科院分区：
文献类型：
--
作者：
Afonina ZA;Myasnikov AG;Shirokov VA;Klaholz BP;Spirin AS
新形成的多聚核糖体的重组绿色荧光蛋白编码的mRNA在小麦胚芽无细胞翻译系统进行了分析，使用冷冻电子断层扫描，亚断层平均的多聚核糖体和重建的三维结构的个别多聚核糖体。在重建的多聚核糖体中实现的分辨率水平允许通过连接每个多聚核糖体内的核糖体处的相邻出口和入口位点来推断mRNA路径。以这种方式，在加帽的聚（A）尾mRNA的情况下证明了翻译多聚核糖体的显著部分（约50%）的环化，这与通过帽结合的起始因子eIF 4F与聚（A）结合蛋白的相互作用的环化的现有范例一致。然而，不含poly（A）尾，但具有来自非编码质粒序列的非特异性3′-UTR的加帽mRNA构建体的翻译也导致类似比例（40%）的环状多聚核糖体的形成。此外，在具有非协同性5′-和3′-UTR的未加帽的非多聚腺苷酸化mRNA上形成的多聚核糖体也被证明是环状的，并且出现的比例与先前的情况相同。因此，发现环状多聚核糖体的形成实际上不依赖于mRNA中帽结构和poly（A）尾的存在，这与该领域的长期范例相反。
The polyribosomes newly formed on recombinant GFP-encoding mRNAs in a wheat germ cell-free translation system were analyzed using cryo-electron tomography, with sub-tomogram averaging of polysomal ribosomes and reconstruction of 3D structures of individual polyribosomes. The achieved level of resolution in the reconstructed polyribosomes allowed deducing the mRNA path by connecting adjacent exit and entry sites at the ribosomes inside each polyribosome. In this way, the circularity of a significant fraction (about 50%) of translating polyribosomes was proved in the case of the capped poly(A)-tailed mRNA, in agreement with the existing paradigm of the circularization via interaction of cap-bound initiation factor eIF4F with poly(A)-binding protein. However, translation of the capped mRNA construct without poly(A) tail, but with unspecific 3′-UTR derived from non-coding plasmid sequence, also led to the formation of circular polyribosomes in similar proportion (40%). Moreover, the polyribosomes formed on the uncapped non-polyadenylated mRNA with non-synergistic 5′- and 3′-UTRs proved to be circular as well, and appeared in the same proportion as in the previous cases. Thus, the formation of circular polyribosomes was found to be virtually independent of the presence of cap structure and poly(A) tail in mRNA, in contrast to the longstanding paradigm in the field.
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影响因子：
3
作者：
Sorzano, COS;Marabini, R;Pascual-Montano, A
通讯作者：
Pascual-Montano, A
影响因子：
5.6
作者：
SHELTON, E;KUFF, EL
通讯作者：
KUFF, EL
影响因子：
14.9
作者：
Kopeina, Gelina S.;Afonina, Zhanna A.;Spirin, Alexander S.
通讯作者：
Spirin, Alexander S.
DOI：
10.1083/jcb.1.1.59
发表时间：
1955-01
期刊：
The Journal of biophysical and biochemical cytology
影响因子：
--
作者：
PALADE GE
通讯作者：
PALADE GE
影响因子：
3
作者：
Pettersen, EF;Goddard, TD;Ferrin, TE
通讯作者：
Ferrin, TE