Zhou Jianwei, Wang Yuexia, Qiu Yonghui, Wang Yongxia, Yang Xiaoyu, Liu Changzhe, Shi Yongyan, Feng Xufei, Hou Lei, Liu Jue
College of Veterinary Medicine, Yangzhou University, Yangzhou, China.
Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China.
Front Microbiol. 2022 Feb 25;13:802740. doi: 10.3389/fmicb.2022.802740. eCollection 2022.
Porcine circovirus type 4 (PCV4) is a newly emerging pathogen which might be associated with diverse clinical signs, including respiratory and gastrointestinal distress, dermatitis, and various systemic inflammations. The host cellular proteins binding to PCV4 capsid (Cap) protein are still not clear. Herein, we found that the PCV4 Cap mediated translocation of DEAD-box RNA helicase 21 (DDX21) to the cytoplasm from the nucleolus and further verified that the nucleolar localization signal (NoLS) of the PCV4 Cap bound directly to the DDX21. The NoLS of PCV4 Cap and GSRSNRFQNK residues at the C-terminal domain (CTD) of DDX21 were required for this PCV4 Cap/DDX21 interaction. Further studies indicated that the PCV4 Cap NoLS exploited DDX21 to facilitate its nucleolar localization. In summary, our results firstly demonstrated that DDX21 binds directly to the NoLS of the PCV4 Cap thereby contributing to the nucleolar localization of the PCV4 Cap protein.
猪圆环病毒4型（PCV4）是一种新出现的病原体，可能与多种临床症状有关，包括呼吸和胃肠道不适、皮炎以及各种全身性炎症。与PCV4衣壳（Cap）蛋白结合的宿主细胞蛋白仍不清楚。在此，我们发现PCV4 Cap介导了DEAD盒RNA解旋酶21（DDX21）从核仁向细胞质的转运，并进一步证实PCV4 Cap的核仁定位信号（NoLS）直接与DDX21结合。这种PCV4 Cap/DDX21相互作用需要PCV4 Cap的NoLS和DDX21 C末端结构域（CTD）的GSRSNRFQNK残基。进一步研究表明，PCV4 Cap NoLS利用DDX21促进其核仁定位。总之，我们的结果首次证明DDX21直接与PCV4 Cap的NoLS结合，从而有助于PCV4 Cap蛋白的核仁定位。
