Graduate Institute of Microbiology and Public Health, National Chung Hsing University, Taichung, Taiwan.
WHO Collaborating Centre for Reference and Research on Influenza, VIDRL, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Australia.
FEBS Lett. 2021 Jun;595(12):1721-1733. doi: 10.1002/1873-3468.14099. Epub 2021 May 27.
The OV20.0 virulence factor of orf virus antagonizes host antiviral responses. One mechanism through which it functions is by inhibiting activation of the dsRNA-activated protein kinase R (PKR) by sequestering dsRNA and by physically interacting with PKR. Sequence alignment indicated that several key residues critical for dsRNA binding were conserved in OV20.0, and their contribution to OV20.O function was investigated in this study. We found that residues F141, K160, and R164 were responsible for the dsRNA-binding ability of OV20.0. Interestingly, mutation at K160 (K160A) diminished the OV20.0-PKR interaction and further reduced the inhibitory effect of OV20.0 on PKR activation. Nevertheless, OV20.0 homodimerization was not influenced by K160A. The contribution of the dsRNA-binding domain and K160 to the suppression of RNA interference by OV20.0 was further demonstrated in plants. In summary, K160 is essential for the function of OV20.0, particularly its interaction with dsRNA and PKR that ultimately contributes to the suppression of PKR activation.
ORF 病毒的 OV20.0 毒力因子拮抗宿主抗病毒反应。其作用机制之一是通过隔离 dsRNA 并与 PKR 物理相互作用来抑制双链 RNA 激活蛋白激酶 R (PKR)的激活。序列比对表明，OV20.0 中几个关键残基对于 dsRNA 结合至关重要，本研究探讨了它们对 OV20.O 功能的贡献。我们发现残基 F141、K160 和 R164 负责 OV20.0 的 dsRNA 结合能力。有趣的是，K160 处的突变 (K160A) 削弱了 OV20.0-PKR 相互作用，进一步降低了 OV20.0 对 PKR 激活的抑制作用。然而，K160A 不影响 OV20.0 同源二聚化。dsRNA 结合域和 K160 对 OV20.0 抑制 RNA 干扰的贡献在植物中进一步得到证实。总之，K160 对 OV20.0 的功能至关重要，特别是它与 dsRNA 和 PKR 的相互作用，最终有助于抑制 PKR 的激活。
