核衣壳(nucleocapsid, N)蛋白是病毒必不可少的结构蛋白，具有保护病毒基因组和调控病毒复制进程的重要作用。作为冠状病毒的经典模型，鼠肝炎病毒(mouse hepatitis virus, MHV) N蛋白的磷酸化调控病毒RNA复制转录和装配已有报道。本研究发现MHV-A59感染鼠neuro-2a细胞后期表达的N蛋白呈现明显的电荷不均一性，其中只有小部分发生磷酸化并被装配至病毒颗粒中；等电聚焦电泳显示N蛋白的电荷呈连续分布。用蛋白脂酰化抑制剂2-溴棕榈酸(2-BP)和蛋白酶体抑制剂MG-132处理后显示病毒复制水平不但与N蛋白电负性相关，而且与细胞的PKCα S657磷酸化和内质网蛋白水平相关。结果提示磷酸化修饰与鼠冠状病毒N蛋白电荷不均一性及稳定性密切相关。

The nucleocapsid (N) protein is an essential structural protein of the virus and plays an important role in protecting the viral genome and regulating the process of viral replication. The phosphorylation of N protein of mouse hepatitis virus (MHV), has been proved to be associated with viral transcription, replication and assembly. We found that N protein expressed at late stage rather than early stage in neuro-2a cells infected with MHV-A59 showed a significant charge heterogeneity. Isoelectric focusing electrophoresis showed that the charge of N protein was continuously distributed. Treatment with the protein S-palmitoylation inhibitor 2-BP and the proteasome inhibitor MG-132 showed that viral replication levels were not only associated with N protein electronegativity, but also with the PKCα phosphorylation at S657 and the maintenance of some endoplasmic reticulum components involved in protein modification and degradation. These results suggest that phosphorylation is a factor associated to the heterogeneity and stability of the murine coronavirus N protein.