Lv Dong-Wen, Zhong Jun, Zhang Kun, Pandey Akhilesh, Li Renfeng
1 Philips Institute for Oral Health Research, VCU School of Dentistry, Virginia Commonwealth University , Richmond, Virginia.
2 McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine , Baltimore, Maryland.
OMICS. 2017 Jan;21(1):27-37. doi: 10.1089/omi.2016.0158.
Epstein-Barr virus (EBV) is a human γ-herpesvirus associated with cancer, including Burkitt lymphoma, nasopharyngeal, and gastric carcinoma. EBV reactivation in latently infected B cells is essential for persistent infection whereby B cell receptor (BCR) activation is a physiologically relevant stimulus. Yet, a global view of BCR activation-regulated protein ubiquitination is lacking when EBV is actively replicating. We report here, for the first time, the long-term effects of IgG cross-linking-regulated protein ubiquitination and offer a basis for dissecting the cellular environment during the course of EBV lytic replication. Using the Akata-BX1 (EBV) and Akata-4E3 (EBV) Burkitt lymphoma cells, we monitored the dynamic changes in protein ubiquitination using quantitative proteomics. We observed temporal alterations in the level of ubiquitination at ∼150 sites in both EBV and EBV B cells post-IgG cross-linking, compared with controls with no cross-linking. The majority of protein ubiquitination was downregulated. The upregulated ubiquitination events were associated with proteins involved in RNA processing. Among the downregulated ubiquitination events were proteins involved in apoptosis, ubiquitination, and DNA repair. These comparative and quantitative proteomic observations represent the first analysis on the effects of IgG cross-linking at later time points when the majority of EBV genes are expressed and the viral genome is actively being replicated. In all, these data enhance our understanding of mechanistic linkages connecting protein ubiquitination, RNA processing, apoptosis, and the EBV life cycle.
爱泼斯坦-巴尔病毒（EBV）是一种与癌症相关的人类γ-疱疹病毒，包括伯基特淋巴瘤、鼻咽癌和胃癌。潜伏感染的B细胞中EBV的重新激活对于持续感染至关重要，其中B细胞受体（BCR）激活是一种生理相关刺激。然而，当EBV活跃复制时，缺乏对BCR激活调节的蛋白质泛素化的全局认识。我们在此首次报告了IgG交联调节的蛋白质泛素化的长期影响，并为剖析EBV裂解复制过程中的细胞环境提供了基础。使用Akata-BX1（EBV）和Akata-4E3（EBV）伯基特淋巴瘤细胞，我们通过定量蛋白质组学监测了蛋白质泛素化的动态变化。与未交联的对照相比，我们观察到在IgG交联后，EBV和EBV B细胞中约150个位点的泛素化水平发生了时间变化。大多数蛋白质泛素化被下调。上调的泛素化事件与参与RNA加工的蛋白质相关。下调的泛素化事件中包括参与凋亡、泛素化和DNA修复的蛋白质。这些比较和定量蛋白质组学观察结果代表了在大多数EBV基因表达且病毒基因组活跃复制的后期时间点对IgG交联影响的首次分析。总之，这些数据加深了我们对连接蛋白质泛素化、RNA加工、凋亡和EBV生命周期的机制联系的理解。
