Abstract：
Minute virus of canines (MVC) belongs to the genus Bocaparvovirus (formerly Bocavirus) within the Parvoviridae family and causes serious respiratory and gastrointestinal symptoms in neonatal canines worldwide. A productive viral infection relies on the successful recruitment of host factors for various stages of the viral life cycle. However, little is known about the MVC-host cell interactions. In this study, we identified that two cellular proteins (Hsc70 and Hsp70) interacted with NS1 and VP2 proteins of MVC, and both two domains of Hsc70/Hsp70 were mediated for their interactions. Functional studies revealed that Hsp70 was induced by MVC infection, knockdown of Hsc70 considerably suppressed MVC replication, whereas the replication was dramatically promoted by Hsp70 knockdown. It is interesting that low amounts of overexpressed Hsp70 enhanced viral protein expression and virus production, but high amounts of Hsp70 overexpression weakened them. Upon Hsp70 overexpressing, we observed that the ubiquitination of viral proteins changed with Hsp70 overexpression, and proteasome inhibitor (MG132) restored an accumulation of viral proteins. In addition, we verified that Hsp70 family inhibitors remarkably decreased MVC replication. Overall, we identified Hsc70 and Hsp70 as interactors of MVC NS1 and VP2 proteins and were involved in MVC replication, which may provide novel targets for anti-MVC approach.
摘要：
犬微小病毒（MVC）属于细小病毒科中的Bocapavovirus属（以前称为Bocavirus），在全球范围内的新生犬中引起严重的呼吸道和胃肠道症状。生产性病毒感染依赖于病毒生命周期各个阶段的宿主因子的成功募集。然而,对MVC与宿主细胞的相互作用知之甚少。在这项研究中,我们发现两种细胞蛋白（Hsc70和Hsp70）与MVC的NS1和VP2蛋白相互作用，Hsc70/Hsp70的两个结构域均介导了它们的相互作用。功能研究表明，Hsp70是由MVC感染诱导的，HSC70的击倒大大抑制了MVC复制，而Hsp70敲低显著促进了复制。有趣的是，少量过表达的Hsp70增强了病毒蛋白表达和病毒生产，但是大量的Hsp70过度表达削弱了它们。在Hsp70过度表达时，我们观察到病毒蛋白的泛素化随着Hsp70的过表达而改变，和蛋白酶体抑制剂（MG132）恢复了病毒蛋白的积累。此外,我们证实Hsp70家族抑制剂显著降低MVC复制。总的来说,我们确定Hsc70和Hsp70是MVCNS1和VP2蛋白的相互作用者，并且参与MVC复制，这可能为反MVC方法提供新的目标。
