CAP-INDEPENDENT TRANSLATION OF ENCEPHALOMYOCARDITIS VIRUS-RNA - STRUCTURAL ELEMENTS OF THE INTERNAL RIBOSOMAL ENTRY SITE AND INVOLVEMENT OF A CELLULAR 57-KD RNA-BINDING PROTEIN
CAP-INDEPENDENT TRANSLATION OF ENCEPHALOMYOCARDITIS VIRUS-RNA - STRUCTURAL ELEMENTS OF THE INTERNAL RIBOSOMAL ENTRY SITE AND INVOLVEMENT OF A CELLULAR 57-KD RNA-BINDING PROTEIN
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DOI：
10.1101/gad.4.9.1560
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发表时间：
1990-09-01
影响因子：
10.5
通讯作者：
WIMMER, E
中科院分区：
文献类型：
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作者：
JANG, SK;WIMMER, E
脑心肌炎病毒（EMCV）mRNA的翻译是通过核糖体内部进入5''非翻译区（5'' NTR）而不是通过核糖体扫描进行的。EMCV 5“NTR中的内部核糖体进入位点（IRES）通过体外翻译确定，RNA通过体外转录含有EMCV 5”NTR的5“或3”末端连续缺失的EMCV cDNA产生。EMCV的核苷酸403下游和核苷酸811上游的区域是有效翻译所必需的。定点突变显示，茎环结构（起始密码子上游400个核苷酸）是IRES功能所必需的。我们发现了一个57 kD的细胞蛋白，其特定的相互作用，这个茎环似乎是IRES功能的先决条件。一个富含嘧啶的延伸近端的起始密码子也是至关重要的EMCV mRNA的有效翻译。我们建议，核糖体直接绑定到启动AUG没有扫描。
Translation of encephalomyocarditis virus (EMCV) mRNA occurs by ribosomal internal entry into the 5''-nontranslated region (5'' NTR) rather than by ribosomal scanning. The internal ribosomal entry site (IRES) in the EMCV 5'' NTR was determined by in vitro translation with RNAs that were generated by in vitro transcription of EMCV cDNAs containing serial deletions from either the 5'' or 3'' end of the EMCV 5'' NTR. Regions downstream of nucleotide 403 and upstream of nucleotide 811 of EMCV were required for efficient translation. Site-directed mutagenesis revealed that a stem-loop structure (400 nucleotides upstream of the initiation codon) was essential for IRES function. We discovered a 57-kD cellular protein whose specific interaction which this stem-loop appears to be prerequisite for IRES function. A pyrimidine-rich stretch proximal to the initiation codon was also crucial for efficient translation of EMCV mRNA. We propose that ribosomes bind directly to the initiating AUG without scanning.