Department of Cell Biology and Molecular Genetics, University of Maryland College Park, College Park, MD 20742, USA.
Virology. 2011 Oct 10;419(1):10-6. doi: 10.1016/j.virol.2011.07.019.
SatC is a noncoding subviral RNA associated with Turnip crinkle virus (TCV). A 100-nt stretch in the 3' UTR of TCV contains three hairpins and two pseudoknots that fold into a tRNA-shaped structure (TSS) that binds 80S ribosomes. The 3' half of satC is derived from TCV and contains 6-nt differences in the TSS-analogous region. SatC binds poorly to 80S ribosomes, and molecular modeling that predicted the 3D structure of the TSS did not predict a similar structure for satC. When the satC TSS region was step-wise converted to the original TCV TSS bases, ribosome binding increased to TCV TSS levels without significantly affecting satC replication. However, mutant satC was less fit when accumulating in plants and gave rise to numerous second site changes that weakened one of two satC conformations. These results suggest that minor changes from the original TCV sequence in satC reflect requirements other than elimination of ribosome binding.
SatC 是一种与芜菁皱缩病毒（TCV）相关的非编码亚病毒 RNA。TCV 的 3'UTR 中有一段 100 个核苷酸，包含三个发夹结构和两个假结，折叠成一个与 tRNA 相似的结构（TSS），可以结合 80S 核糖体。SatC 的 3' 端来源于 TCV，在 TSS 类似区域有 6 个核苷酸的差异。SatC 与 80S 核糖体结合不良，预测 TSS 三维结构的分子建模并未预测出 SatC 的类似结构。当 SatC 的 TSS 区域逐步转换为原始 TCV TSS 碱基时，核糖体结合增加到 TCV TSS 水平，而不会显著影响 SatC 的复制。然而，在植物中积累时，突变 SatC 的适应性较差，导致许多第二位置的变化，削弱了 SatC 的两种构象之一。这些结果表明，SatC 中与原始 TCV 序列的微小差异反映了除了消除核糖体结合之外的其他要求。
