Laboratory of Virology, Department of Plant Sciences, Wageningen University and Research, Droevendaalsesteeg 1, 6708PB Wageningen, The Netherlands.
Laboratory of Bioinformatics, Department of Plant Sciences, Wageningen University and Research, Droevendaalsesteeg 1, 6708PB Wageningen, The Netherlands.
J Gen Virol. 2022 Aug;103(8). doi: 10.1099/jgv.0.001763.
Cap-snatching is a mechanism applied by segmented, negative strand (-) RNA viruses (NSVs) to initiate genome transcription. So far, the cap donor source of cytoplasmic-replicating NSVs has remained elusive. Recently, studies pointed to processing body (P body, PB) as the potential source for providing capped RNAs but conclusive evidence is still lacking. To attempt identifying these sources, here the 5' non-viral leader sequences of Tomato spotted wilt virus (TSWV) N mRNAs were analysed by high-throughput sequencing (HTS) from plants subjected to normal and heat-stress conditions, and subsequently mapped on host donor transcripts. The majority of non-viral heterogenous, host-derived leader sequences ranged in size between ~10-20 nt and contained A or AG residues at the cleavage site and the presence of certain sequence motifs. Mapping the capped-leader sequences to the 5' UTR region of genes encoded by the genome, identified 348 donor genes and which were specifically enriched in cellular photosynthesis pathway. Nineteen of those were clearly expressed differentially at normal condition versus heat-stress conditions. Although the results did not point towards snatching of capped-RNA leader sequences from certain cytoplasmic RNA granules in particular, they indicated photosynthesis downregulation (and development of disease symptoms) partially result from cap-snatching.
帽抢夺是分段的负链 RNA 病毒 (NSV) 用于启动基因组转录的一种机制。到目前为止，细胞质复制 NSV 的帽供体来源仍然难以捉摸。最近的研究指出，处理体 (P 体，PB) 可能是提供加帽 RNA 的潜在来源，但仍缺乏确凿的证据。为了尝试确定这些来源，本研究通过高通量测序 (HTS) 分析了受正常和热应激条件影响的植物中番茄斑萎病毒 (TSWV) N mRNAs 的 5'非病毒前导序列，并随后将其映射到宿主供体转录本上。大多数非病毒异质、宿主衍生的前导序列大小在 10-20nt 之间，在切割位点含有 A 或 AG 残基，并存在某些序列基序。将加帽前导序列映射到基因组编码基因的 5'UTR 区域，鉴定出 348 个供体基因，这些基因特异性富集在细胞光合作用途径中。其中 19 个基因在正常条件与热应激条件下的表达差异明显。尽管这些结果并没有指向从特定细胞质 RNA 颗粒中抢夺加帽 RNA 前导序列，但它们表明，光合作用的下调（以及疾病症状的发展）部分是由帽抢夺引起的。
