THE HUMAN ASTROVIRUS RNA-DEPENDENT RNA-POLYMERASE CODING REGION IS EXPRESSED BY RIBOSOMAL FRAMESHIFTING
THE HUMAN ASTROVIRUS RNA-DEPENDENT RNA-POLYMERASE CODING REGION IS EXPRESSED BY RIBOSOMAL FRAMESHIFTING
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DOI：
10.1128/jvi.68.9.5588-5595.1994
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发表时间：
1994-09-01
影响因子：
5.4
通讯作者：
BRIERLEY, I
中科院分区：
文献类型：
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作者：
MARCZINKE, B;BLOYS, AJ;BRIERLEY, I
人星状病毒血清型1（HAst-1）的基因组RNA含有三个开放阅读框（ORF），1a、1b和2。ORF 1b位于1a的下游，并与1a重叠，并且基于序列分析已经表明ORF 1b的表达通过-1核糖体移码介导。为了检验这种可能性，将含有1a-1b重叠区的cDNA片段克隆到报告基因内，并置于重组质粒中噬菌体SP 6启动子的控制下。当在兔网织红细胞裂解物无细胞系统中翻译时，源自该质粒的合成转录物指定多肽的合成，所述多肽的大小和抗体反应性与重叠区的有效-1核糖体移码事件一致。HAst-1移码信号有两个基本组成部分，一个七核苷酸滑动序列A（6）C和RNA中的茎环结构。通过互补和补偿突变分析以及通过用单链和双链RNA特异性试剂直接结构探测来证实这种结构的存在。HAst-1移码信号，如存在于逆转录病毒人T细胞嗜淋巴细胞病毒II型的gag和pro基因重叠处的信号，不涉及RNA假结的形成。
The genomic RNA of human astrovirus serotype 1 (HAst-1) contains three open reading frames (ORFs), 1a, 1b, and 2. ORF 1b is located downstream of, and overlaps, 1a, and it has been suggested on the basis of sequence analysis that expression of ORF 1b is mediated through -1 ribosomal frameshifting. To examine this possibility, a cDNA fragment containing the 1a-1b overlap region was cloned within a reporter gene and placed under the control of the bacteriophage SP6 promoter in a recombinant plasmid. Synthetic transcripts derived from this plasmid, when translated in the rabbit reticulocyte lysate cell-free system, specified the synthesis of polypeptides whose size and antibody reactivity were consistent with an efficient -1 ribosomal frameshift event at the overlap region. The HAst-1 frameshift signal has two essential components, a heptanucleotide slippery sequence, A(6)C, and a stem-loop structure in the RNA. The presence of this structure was confirmed by complementary and compensatory mutation analysis and by direct structure probing with single- and double-stranded RNA-specific reagents. The HAst-1 frameshift signal, like that present at the overlap of the gag and pro genes of the retrovirus human T-cell lymphotrophic virus type II, does not involve the formation of an RNA pseudoknot.