Department of Pediatrics, The University of Texas Medical Branch, Galveston, TX 77555, USA.
Department of Chemistry, The University of Houston Clear Lake, Clear Lake, TX 77058, USA.
Int J Mol Sci. 2020 Nov 20;21(22):8766. doi: 10.3390/ijms21228766.
Respiratory syncytial virus (RSV) is the most common cause of lower respiratory tract infection in infants, the elderly, and immune-compromised patients. It is also a significant contributor to upper respiratory tract infection in the pediatric population. However, its disease mechanisms are still largely unknown. We have recently shown that a tRNA-derived RNA fragment () from the 5'-end of mature tRNA encoding (tRF5-GluCTC), a recently discovered non-coding RNA, is functionally important for RSV replication and host gene regulation at the post-transcriptional level. However, how tRF5-GluCTC carries out the gene regulation is not fully known. In this study, we found that tRF5-GluCTC has impaired gene -silencing function in cells deficient of AGO1 or 4, while AGO2 and 3 seem not involved in tRF5-GluCTC-mediated gene regulation. By pulling down individual AGO protein, we discovered that tRF5-GluCTC is detectable only in the AGO4 complex, confirming the essential role of AGO4 in gene regulation and also suggesting that AGO1 contributes to the gene -silencing activity of tRF5-GluCTC in an atypical way. We also found that the P protein of RSV is associated with both AGO1 and 4 and AGO4 deficiency leads to reduced infectious viral particles. In summary, this study demonstrates the importance of AGO1 and 4 in mediating the gene -silencing function of tRF5-GluCTC.
呼吸道合胞病毒（RSV）是婴儿、老年人和免疫功能低下患者下呼吸道感染的最常见原因。它也是儿科人群上呼吸道感染的重要原因。然而，其发病机制在很大程度上仍不清楚。我们最近表明，来自成熟 tRNA 编码 （tRF5-GluCTC）的 5'-端的 tRNA 衍生的 RNA 片段（），是一种最近发现的非编码 RNA，在 RSV 复制和宿主基因调控方面具有重要的功能，这种功能是在转录后水平上实现的。然而，tRF5-GluCTC 如何进行基因调控还不完全清楚。在这项研究中，我们发现 tRF5-GluCTC 在 AGO1 或 4 缺失的细胞中基因沉默功能受损，而 AGO2 和 3 似乎不参与 tRF5-GluCTC 介导的基因调控。通过下拉单个 AGO 蛋白，我们发现 tRF5-GluCTC 仅在 AGO4 复合物中可检测到，这证实了 AGO4 在基因调控中的重要作用，也表明 AGO1 以非典型的方式有助于 tRF5-GluCTC 的基因沉默活性。我们还发现 RSV 的 P 蛋白与 AGO1 和 4 都有关联，并且 AGO4 缺失会导致感染性病毒颗粒减少。总之，这项研究表明了 AGO1 和 4 在介导 tRF5-GluCTC 的基因沉默功能中的重要性。
