Small RNA sequencing of flavivirus-infected Huh7 cells

RNA interference is an important component of innate antiviral defense in invertebrates and facilitated through production of viral-derived short interfering RNAs (siRNAs). There remains lack of evidence for siRNA production in vertebrate cells--specifically, mammalian somatic cells; however, these cells do express cellular microRNAs (miRNAs) with inhibitory function. Additionally, a number of DNA viruses express viral miRNAs with roles in the viral life cycles. Flaviviruses, such as Dengue virus (DENV4) or West Nile virus (WNV), can infect both invertebrate and mammalian cells. To examine whether these viruses express either siRNAs or viral miRNAs in infected mammalian cells, we analyzed Huh7 cells infected with DENV subtype 4 (DENV4) or with WNV strain TX-IC7. We identified a large number of cellular miRNAs; however, only 1% of the small RNAs were of viral origin and none of them exhibited characteristics of viral miRNAs or siRNAs.

RNA干扰（RNA interference）是无脊椎动物先天抗病毒防御的重要组成部分，其发挥功能依赖于病毒源性短干扰RNA（siRNAs）的产生。目前尚无证据表明脊椎动物细胞——尤其是哺乳动物体细胞——可产生siRNAs，但此类细胞确实表达具有抑制功能的细胞微小RNA（miRNAs）。此外，多种DNA病毒会编码病毒miRNAs，在病毒生命周期中发挥作用。黄病毒属（Flaviviruses）如登革病毒（Dengue virus, DENV4）或西尼罗病毒（West Nile virus, WNV），可同时感染无脊椎动物与哺乳动物细胞。为探究此类病毒在感染的哺乳动物细胞中是否会表达siRNAs或病毒miRNAs，我们对感染了登革病毒4型（DENV4）或西尼罗病毒毒株TX-IC7的Huh7细胞进行了分析。结果我们鉴定出了大量细胞miRNAs，但仅有1%的小RNA来源于病毒，且这些病毒源性小RNA均未表现出病毒miRNAs或siRNAs的特征。