Small interfering RNAs (siRNAs) can efficiently inhibit gene expression by sequence-specific RNA interference (RNAi). A common 5' leader sequence exists in the genomic RNA and all subgenomic RNAs of SARS-CoV, and is well conserved among various SARS-CoV strains, thus providing a preferable target for RNAi of SARS-CoV replication. Here efficient depletion of the SARS-CoV mRNAs by either a synthetic siRNA or DNA vector-derived short hairpin RNAs (shRNAs) targeting the leader sequence in mammalian cell lines were reported. The siRNA or shRNAs efficiently suppressed the expression of an EGFP reporter gene which contains the leader sequence at the 5' end. Both the siRNA and shRNAs efficiently knocked down the levels of leader-containing transcripts of three SARS-CoV genes encoding the spike protein, membrane protein and nucleocapsid protein were demonstrated. The results suggest that RNAi targeting the leader sequence is a potential efficient strategy for anti-SARS-CoV therapy.%小干扰RNAs(siRNAs)能够有效降解具有互补序列的RNA.在SARS-CoV的基因组RNA和所有亚基因组RNA的5'端均有一段共同的leader序列,而且该leader序列在不同的病毒分离物中高度保守,因此leader序列可作为一个用于抑制SARS-CoV复制的有效靶点.研究表明,针对leader序列化学合成的siRNA和DNA载体表达的shRNA都可以有效抑制SARS-CoV mRNA的表达.Leader序列特异的siRNA或shRNA不仅可以有效抑制leader与报告基因EGFP融合基因的表达,而且还可以有效抑制leader与刺突蛋白(spike protein)、膜蛋白(membrane protein)和核衣壳蛋白(nucleocapsid protein)基因的融合转录产物的表达.结果表明,针对leader序列的RNA干扰可以发展成为一种抗SARS-CoV治疗的有效策略.
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