HCMV挟持WDR5至病毒装配中心调控病毒复制的机制

Congenital human cytomegalovirus (HCMV) infection is the leading cause of birth defects in children, and HCMV infection is also the most common cause of failure in patients following hematopoietic stem cell transplantation. The HCMV structure is sophisticated and the replication mechanism has not been fully clarified so far. We have previously found that the host factor WDR5 regulates HCMV replication and participates in capsids nuclear egress. The preliminary experiment of this project showed that HCMV specifically hijacked WDR5 to the virus assembly center (vAC) during its infection. Other DNA viruses (e.g. herpes simplex virus type I, varicella zoster virus, adenovirus and baculovirus) have no such phenomenon. What’s more, WDR5 may be packaged into virus particles during virus packaging. How HCMV regulates WDR5 and controls virus replication remains to be clarified. In order to solve this, we will screen the viral factors that regulate WDR5 via mass spectrometry and validate by co-immunoprecipitation and mutant recombinant viruses. On the other hand, WDR5 will be knocked down to clarify the impact of WDR5 on the formation of vAC and the assembly of viral particles, and further illuminate the molecular mechanism of HCMV to affect its own packaging by hijacking WDR5 to vAC. This project will provide new insights into HCMV's use of host factors to complete its own life cycle, and may provide candidate target molecules for the development of new methods to prevent and treat HCMV infections.

人巨细胞病毒（HCMV）感染是引起出生缺陷的主要病因，也是骨髓移植失败的最常见病因。HCMV结构复杂，迄今复制机制未完全阐明。我们前期发现宿主因子WDR5参与衣壳出核过程。进一步预实验发现：HCMV感染过程中特异性地挟持WDR5并聚集于病毒的装配中心，而其他DNA病毒（单纯疱疹病毒I型、水痘带状疱疹病毒、腺病毒和杆状病毒）感染无此现象；在病毒包装过程中WDR5可能被包装入病毒粒子。HCMV如何挟持WDR5进而调控病毒复制有待阐明。本项目将通过质谱分析筛选调控WDR5的病毒蛋白，经免疫共沉淀证实其相互作用；进一步通过构建重组突变病毒鉴定调控WDR5的病毒因子；通过敲降WDR5的表达，明确WDR5对病毒的装配中心（vAC）形成以及病毒粒子装配的影响，阐明HCMV挟持WDR5至vAC影响病毒包装的分子机制。本项目将为揭示HCMV利用宿主因子完成自身复制提供新的知识，为干预HCMV感染提供新靶标。

人巨细胞病毒（HCMV）感染是引起出生缺陷的最主要病因，也是骨髓移植失败的最常见病因。HCMV基因组全长大约235kb包含超过170个开放阅读框。HCMV在复制过程中利用多种宿主因子帮助自身复制。在病毒感染的晚期时像，胞膜发生重组形成病毒的装配中心（vAC）从而帮助子代病毒粒子的高效组装与成熟。我们课题组之前报道了宿主因子WDR5参与HCMV核衣壳出核过程。在本项目执行期间，我们主要开展了以下工作：.(1)通过研究WDR5在不同病毒感染成纤维细胞中的定位发现CMV感染过程中特异性地挟持WDR5并聚集于近核区；HCMV感染导致WDR5积聚在病毒的装配中心（vAC），该过程依赖病毒的复制与微管结构的运输；WDR5参与vAC的形成与子代病毒粒子的包装与成熟；通过质谱分析筛选调控WDR5的病毒蛋白，经免疫共沉淀证实病毒结构蛋白MCP，pp150，pp65，pIRS1与pTRS1与WDR5有相互作用；通过免疫印迹法检测密度梯度离心纯化的病毒，证实WDR5被包裹在病毒粒子中。.(2)我们发现HCMV感染过程中上调WDR11的表达。在感染的晚期WDR11被挟持至vAC。敲除WDR11影响HCMV招募高尔基体定位至vAC的过程，从而影响vAC的形成，进而导致大量未带包膜的病毒粒子产生。本项目将为揭示了WDR11被HCMV利用并促进其病毒粒子包装的机制。