DUAL INITIATION SITES OF PROTEIN-SYNTHESIS ON FOOT-AND-MOUTH-DISEASE VIRUS-RNA ARE SELECTED FOLLOWING INTERNAL ENTRY AND SCANNING OF RIBOSOMES INVIVO
DUAL INITIATION SITES OF PROTEIN-SYNTHESIS ON FOOT-AND-MOUTH-DISEASE VIRUS-RNA ARE SELECTED FOLLOWING INTERNAL ENTRY AND SCANNING OF RIBOSOMES INVIVO
复制标题
DOI：
10.1002/j.1460-2075.1992.tb05150.x
复制
发表时间：
1992-03-01
期刊：
影响因子：
11.4
通讯作者：
BELSHAM, GJ
中科院分区：
文献类型：
--
作者：
BELSHAM, GJ
口蹄疫病毒RNA上蛋白质合成的起始发生在相隔84个核苷酸的两个位点。紧邻这些位点中的第一个的上游是内部核糖体进入位点（IRES），其指导该RNA的翻译为帽非依赖性的。这两个起始位点的利用已经在多种条件下使用人工融合基因在体内进行了检查。在这两个真正的起始位点之间引入了额外的符合读框的AUG密码子，以确定核糖体识别第二个起始位点的机制。结果表明，在第一个起始密码子5'侧的核糖体内部进入后，许多核糖体未能在该位置启动蛋白质合成，并沿着RNA扫描到第二个起始位点。在存在或不存在IRES的情况下，两个起始位点都被有效地利用，但IRES对这两个位点的利用略微偏向于第二个起始位点。此外，在IRES的存在下，蛋白质合成在两个位点独立于帽结合复合物的活性而启动。
The initiation of protein synthesis on foot-and-mouth disease virus RNA occurs at two sites separated by 84 nucleotides. Immediately upstream from the first of these sites is the internal ribosome entry site (IRES), which directs the translation of this RNA to be cap-independent. The utilization of these two initiation sites has been examined using artificial fusion genes in vivo under a variety of conditions. Additional in-frame AUG codons have been introduced between these two authentic start sites to determine the mechanism by which ribosomes recognize the second start site. The results indicate that following internal entry of ribosomes on the 5' side of the first initiation codon, many fail to initiate protein synthesis at this position and scan along the RNA to the second initiation site. In the presence or absence of the IRES both initiation sites are efficiently used but the utilization of the two sites is slightly biased towards the second initiation site by the IRES. Furthermore, in the presence of the IRES, protein synthesis initiates at both sites independently of the activity of the cap-binding complex.