Functional analyses of the EBNAl origin DNA binding protein of Epstein-Barr virus
Functional analyses of the EBNAl origin DNA binding protein of Epstein-Barr virus
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DOI：
10.1128/jvi.74.11.4939-4948.2000
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发表时间：
2000-06-01
影响因子：
5.4
通讯作者：
Frappier, L
中科院分区：
文献类型：
--
作者：
Ceccarelli, DFJ;Frappier, L
EB 病毒 (EBV) 的 EBNA1 蛋白控制潜伏感染细胞中病毒附加体的复制和分离，并通过与 EBV 潜伏复制起点 oriP 中的 DNA 序列直接相互作用反式激活其他 EBV 潜伏蛋白的表达。为了更好地了解 EBNA1 如何控制这些过程，我们评估了各种 EBNA1 序列对其复制、分离和反式激活功能的贡献。在这里，我们表明 EBNA1 残基 325 至 376 负责 EBNA1 的反式激活活性。该区域与先前显示的 DNA 环结构域一致，可介导 DNA 结合的 EBNA1 分子之间一定距离的相互作用。相同的残基介导DNA分离，但在DNA复制中没有明显作用，表明EBNA1的复制和转录激活活性是不同的。未发现 EBNA1 的酸性 C 末端尾巴有助于复制、反式激活或分离。我们还研究了 EBNA1 的 DNA 结合和二聚化结构域内两个结构基序（脯氨酸环和 WF 基序）的功能意义。尽管这些基序中的氨基酸不直接接触 DNA，但这两个基序都被发现通过增加 EBNA1 的 DNA 结合能力来促进 EBNA1 功能。讨论了这些基序刺激 DNA 结合的机制。
The EBNA1 protein of Epstein-Barr virus (EBV) governs the replication and segregation of the viral episomes in latently infected cells and transactivates the expression of other EBV latency proteins through direct interactions with DNA sequences in the EBV latent origin of replication, oriP. To better understand how EBNA1 controls these processes, we have assessed the contribution of various EBNA1 sequences to its replication, segregation, and transactivation functions. Here we show that EBNA1 residues 325 to 376 are responsible for the transactivation activity of EBNA1. This region coincides with the DNA looping domain previously shown to mediate interactions at a distance between DNA-bound EBNA1 molecules. The same residues mediate DNA segregation but have no apparent role in DNA replication, indicating that the replication and transcription activation activities of EBNA1 are distinct. The acidic C-terminal tail of EBNA1 was not found to contribute to replication, transactivation, or segregation. We have also investigated the functional significance of two structural motifs within the DNA binding and dimerization domains of EBNA1, the proline loop and the WF motif. Although the amino acids in these motifs do not directly contact the DNA, both of these motifs were found to contribute to EBNA1 functions by increasing the DNA-binding ability of EBNA1. Mechanisms by which DNA binding is stimulated by these motifs are discussed.