Department of Biology, Dickinson College, Carlisle, PA 17013, USA.
Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA.
Virology. 2015 Sep;483:149-62. doi: 10.1016/j.virol.2015.04.002. Epub 2015 May 15.
The 356 nt noncoding satellite RNA C (satC) of Turnip crinkle virus (TCV) is composed of 5' sequences from a second TCV satRNA (satD) and 3' sequences derived from TCV. SHAPE structure mapping revealed that 76 nt in the poorly-characterized satD-derived region form an extended hairpin (H2). Pools of satC in which H2 was replaced with 76, 38, or 19 random nt were co-inoculated with TCV helper virus onto plants and satC fitness assessed using in vivo functional selection (SELEX). The most functional progeny satCs, including one as fit as wild-type, contained a 38-39 nt H2 region that adopted a hairpin structure and exhibited an increased ratio of dimeric to monomeric molecules. Some progeny of satC with H2 deleted featured a duplication of 38 nt, partially rebuilding the deletion. Therefore, H2 can be replaced by a 38-39 nt hairpin, sufficient for overall structural stability of the 5' end of satC.
芜菁黄花叶病毒的 356 个核苷酸非编码卫星 RNA C（satC）由第二个芜菁黄花叶病毒 satRNA（satD）的 5'序列和源自芜菁黄花叶病毒的 3'序列组成。形状分析表明，在特征不明显的 satD 衍生区的 76 个核苷酸形成一个扩展的发夹（H2）。将 H2 替换为 76、38 或 19 个随机核苷酸的 satC 池与芜菁黄花叶病毒辅助病毒共同接种到植物上，并通过体内功能选择（SELEX）评估 satC 的适应性。最具功能的后代 satC，包括一种与野生型一样适应的 satC，包含一个 38-39 个核苷酸的 H2 区，采用发夹结构，并表现出二聚体与单体分子的比例增加。一些 H2 缺失的 satC 后代具有 38 个核苷酸的重复，部分重建了缺失。因此，H2 可以被一个 38-39 个核苷酸的发夹取代，足以维持 satC 5'端的整体结构稳定性。
