Feederle R, Shannon-Lowe C, Baldwin G, Delecluse H J
German Cancer Research Center, Department of Virus-Associated Tumours, Im Neuenheimer Feld 242, 69120 Heidelberg, Germany.
J Virol. 2005 Jun;79(12):7641-7. doi: 10.1128/JVI.79.12.7641-7647.2005.
The Epstein-Barr virus (EBV) lytic program includes lytic viral DNA replication and the production of a viral particle into which the replicated viral DNA is packaged. The terminal repeats (TRs) located at the end of the linear viral DNA have been identified as the packaging signals. A TR-negative (TR(-)) mutant therefore provides an appropriate tool to analyze the relationships between EBV DNA packaging and virus production. Here, we show that supernatants from lytically induced 293 cells carrying TR mutant EBV genomes (293/TR(-)) contain large amounts of viral particles devoid of viral DNA which are nevertheless able to bind to EBV target cells. This shows that viral DNA packaging is not a prerequisite for virion formation and egress. Rather surprisingly, supernatants from lytically induced 293/TR(-) cells also contained rare infectious viruses carrying the viral mutant DNA. This observation indicates that the TRs are important but not absolutely essential for virus encapsidation.
爱泼斯坦-巴尔病毒（EBV）的裂解程序包括裂解性病毒DNA复制以及产生一个将复制的病毒DNA包装其中的病毒颗粒。位于线性病毒DNA末端的末端重复序列（TRs）已被确定为包装信号。因此，TR阴性（TR(-)）突变体为分析EBV DNA包装与病毒产生之间的关系提供了一个合适的工具。在这里，我们发现，携带TR突变EBV基因组的裂解诱导293细胞（293/TR(-)）的上清液中含有大量不含病毒DNA的病毒颗粒，但这些病毒颗粒仍能与EBV靶细胞结合。这表明病毒DNA包装不是病毒粒子形成和释放的先决条件。相当令人惊讶的是，裂解诱导的293/TR(-)细胞的上清液中还含有携带病毒突变DNA的罕见感染性病毒。这一观察结果表明，TRs对于病毒衣壳化很重要，但不是绝对必需的。
