Characterization of the sequence element directing translation reinitiation in RNA of the calicivirus, rabbit hemorrhagic disease virus
Characterization of the sequence element directing translation reinitiation in RNA of the calicivirus, rabbit hemorrhagic disease virus
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DOI：
10.1128/jvi.00771-07
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发表时间：
2007-09-01
影响因子：
5.4
通讯作者：
Meyers, Gregor
中科院分区：
文献类型：
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作者：
Meyers, Gregor
杯状病毒次要衣壳蛋白VP2通过在前一个VP1基因翻译终止后重新启动蛋白质合成来表达。约80个核苷酸的序列元件表示为“终止上游核糖体结合位点”（TURBS）（25），对于再起始至关重要。兔杯状病毒TURBS中的缺失作图确定了两个对VP2表达至关重要的短序列基序。基序1在杯状病毒中是保守的，并且与18S rRNA中的序列互补。单残基交换在这个基序严重损害重新启动时，他们影响了假定的rRNA结合，而交换保留互补性只有轻微的影响。基序2的单交换耐受性相当好，但引入双交换几乎阻断了VP2的表达。相反，缺失分析表明，两个基序之间的RNA是次要的。基序2和起始位点之间的距离被认为是重要的，因为在该序列中增加长度的缺失或起始密码子的上游定位逐步降低VP2表达至低水平，而在该区域中的多核苷酸交换是耐受的。TURBS基序2和起始密码子的排列的低灵活性与关于前面的VP1基因的终止密码子的位置的要求形成鲜明对比，所述终止密码子可以被移动到下游很远的地方，同时连续减少但不损失VP2翻译。序列定位导致了导致VP2表达的再起始机制的精细模型。
The calicivirus minor capsid protein VP2 is expressed via reinitiation of protein synthesis after termination of translation of the preceding VP1 gene. A sequence element of about 80 nucleotides denoted "termination upstream ribosomal binding site" (TURBS) (25) is crucial for reinitiation. Deletion mapping in the TURBS of a rabbit calicivirus identified two short sequence motifs that were crucial for VP2 expression. Motif 1 is conserved among caliciviruses and is complementary to a sequence in the 18S rRNA. Single-residue exchanges in this motif severely impaired reinitiation when they affected the putative rRNA binding, whereas an exchange preserving complementarity had only a minor effect. Single exchanges in motif 2 were rather well tolerated, but the introduction of double exchanges almost blocked VP2 expression. In contrast, the deletion analyses showed that the RNA between the two motifs is of minor importance. The distance between motif 2 and the start site was,found to be important, since deletions of increasing length in this sequence or upstream positioning of the start codon reduced VP2 expression stepwise to low levels, whereas multiple-nucleotide exchanges in this region were tolerated. The low flexibility of the arrangement of TURBS motif 2 and the start codon stand in marked contrast to the requirements with regard to the location of the stop codon of the preceding VP1 gene, which could be moved far downstream with continuous reduction, but without loss, of VP2 translation. The sequence mapping resulted in a refined model of the reinitiation mechanism leading to VP2 expression.