Research Centre, Agriculture and Agri-Food Canada, Lethbridge, Alberta, Canada.
Virology. 2013 Apr 10;438(2):61-9. doi: 10.1016/j.virol.2012.12.012. Epub 2013 Feb 21.
Potato leafroll virus (PLRV) is a positive-strand RNA virus that generates subgenomic RNAs (sgRNA) for expression of 3' proximal genes. Small RNA (sRNA) sequencing and mapping of the PLRV-derived sRNAs revealed coverage of the entire viral genome with the exception of four distinctive gaps. Remarkably, these gaps mapped to areas of PLRV genome with extensive secondary structures, such as the internal ribosome entry site and 5' transcriptional start site of sgRNA1 and sgRNA2. The last gap mapped to ∼500 nt from the 3' terminus of PLRV genome and suggested the possible presence of an additional sgRNA for PLRV. Quantitative real-time PCR and northern blot analysis confirmed the expression of sgRNA3 and subsequent analyses placed its 5' transcriptional start site at position 5347 of PLRV genome. A regulatory role is proposed for the PLRV sgRNA3 as it encodes for an RNA-binding protein with specificity to the 5' of PLRV genomic RNA.
马铃薯卷叶病毒（PLRV）是一种正链 RNA 病毒，可生成亚基因组 RNA（sgRNA）以表达 3'近端基因。PLRV 衍生的小 RNA（sRNA）的测序和映射显示，除了四个独特的缺口外，整个病毒基因组都有覆盖。值得注意的是，这些缺口映射到 PLRV 基因组中具有广泛二级结构的区域，例如 sgRNA1 和 sgRNA2 的内部核糖体进入位点和 5'转录起始位点。最后一个缺口映射到 PLRV 基因组 3'末端约 500 个核苷酸处，表明可能存在额外的 PLRV sgRNA。定量实时 PCR 和 northern blot 分析证实了 sgRNA3 的表达，随后的分析将其 5'转录起始位点置于 PLRV 基因组位置 5347。PLRV sgRNA3 可能具有调节作用，因为它编码一种 RNA 结合蛋白，对 PLRV 基因组 RNA 的 5'具有特异性。
