Formation of Bombyx mori nucleopolyhedrovirus IE2 nuclear foci is regulated by the functional domains for oligomerization and ubiquitin ligase activity.
Formation of Bombyx mori nucleopolyhedrovirus IE2 nuclear foci is regulated by the functional domains for oligomerization and ubiquitin ligase activity.
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DOI：
10.1099/vir.0.80523-0
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发表时间：
2005-03
期刊：
影响因子：
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通讯作者：
N. Imai;S. Matsumoto;W. Kang
中科院分区：
文献类型：
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作者：
N. Imai;S. Matsumoto;W. Kang
杆状病毒IE2作为一种转调控因子，也参与病毒DNA复制。然而，这些功能的机制尚不清楚。以前有报道称家蚕核多角体病毒（BmNPV） IE2具有依赖环指结构域的泛素连接酶活性，并且IE2可以通过其c端卷曲区进行寡聚。共聚焦显微镜分析显示，IE2仅在感染早期（感染后2-6小时）形成核灶。因此，确定上述IE2功能区是否会影响这一特征分布。ie2的瞬时表达也出现了病灶形成，表明ie2不需要任何其他病毒因子。缺乏c -末端线圈区的IE2突变体不形成焦点，而RING finger结构域突变体的核焦点比野生型IE2更大、更亮。此外，用蛋白酶体抑制剂处理后，IE2在感染细胞中表现出扩大的灶，这表明由于泛素-蛋白酶体途径的抑制，IE2的积累导致灶扩大。这些结果表明，BmNPV IE2寡聚化和泛素连接酶活性功能域调控着核病灶的形成。
Baculovirus IE2 functions as a transregulator and is also involved in viral DNA replication. However, the mechanism for these functions remains unknown. It has previously been reported that Bombyx mori nucleopolyhedrovirus (BmNPV) IE2 has a ubiquitin ligase activity that is dependent on the RING finger domain and that IE2 can oligomerize through its C-terminal coiled-coil region. Here, confocal microscopy analysis demonstrated that IE2 formed nuclear foci only during the early phase of infection (2-6 h post-infection). Therefore, it was determined whether the IE2 functional regions described above could affect this characteristic distribution. Transient expression of ie2 also showed focus formation, suggesting that IE2 does not require any other viral factors. IE2 mutants lacking the C-terminal coiled-coil region did not form foci, while a mutant of the RING finger domain showed nuclear foci that appeared larger and brighter than those formed by wild-type IE2. In addition, IE2 exhibited enlarged foci in infected cells following treatment with a proteasome inhibitor, suggesting that foci enlargement resulted from accumulation of IE2 due to inhibition of the ubiquitin-proteasome pathway. These results suggest that BmNPV IE2 oligomerization and ubiquitin ligase activity functional domains regulate nuclear foci formation.