Characterization of specific antigenic epitopes and the nuclear export signal of the Porcine circovirus 2 ORF3 protein
Characterization of specific antigenic epitopes and the nuclear export signal of the Porcine circovirus 2 ORF3 protein
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猪圆环病毒 2 ORF3 蛋白的特异性抗原表位和核输出信号的表征。
DOI：
10.1016/j.vetmic.2016.01.006
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发表时间：
2016-02-29
影响因子：
3.3
通讯作者：
Zhou, Jiyong
中科院分区：
文献类型：
--
作者：
Gu, Jinyan;Wang, Lun;Zhou, Jiyong
猪圆环病毒2 （PCV2）是断奶后多系统消耗综合征的病原。PCV2 ORF3蛋白是一种已知的诱导细胞凋亡的非结构蛋白，但对其生物学功能知之甚少。因此，我们进行了这项研究，绘制了一组单克隆抗体（mab）识别的ORF3蛋白表位，并表征了ORF3中假定的核定位（NLS）和核输出（NES）序列。两个先前发表的单克隆抗体3B1和1H3以及一个新的小鼠单克隆抗体3C3靶向的线性表位是使用重叠肽池定义的。本研究发现，在PCV2感染的细胞中，ORF3含有一个被抗体3C3靶向的构象表位，这与重组ORF3蛋白中被抗体3B1和1H3识别的线性表位不同。这些结果表明，被3B1和1H3识别的线性表位在PCV2感染的细胞中被掩盖，并且构象表位是PCV2感染所特有的。此外，我们发现ORF3蛋白在PCV2感染早期在细胞质中表达，然后随着时间的推移在细胞核中积累。此外，我们在ORF3的n端（残基1-35aa）定位了一个NES，它在核出口活动中起着关键作用。这些发现提供了新的见解，加深了我们对PCV2 ORF3生物学功能的理解。(C) 2016 Elsevier B.V.版权所有
Porcine circovirus 2 (PCV2) is the etiological agent of postweaning multisystemic wasting syndrome. PCV2 ORF3 protein is a nonstructural protein known to induce apoptosis, but little is known about the biological function of ORF3 protein. Therefore, we undertook this study to map ORF3 protein epitopes recognized by a panel of monoclonal antibodies (mAbs) and to characterize putative nuclear localization (NLS) and nuclear export (NES) sequences in ORF3. The linear epitopes targeted by two previously published mAbs 3B1 and 1H3 and a novel mouse mAb 3C3 were defined using overlapping pools of peptides. Here, we find that ORF3 in PCV2 infected cells contains a conformational epitope targeted by the antibody 3C3, which is distinct from linear epitopes recognized by the antibodies 3B1 and 1H3 in recombinant ORF3 protein. These results suggest that the linear epitope recognized by 3B1 and 1H3 is masked in PCV2 infected cells, and that the conformational epitope is unique to PCV2 infection. Furthermore, we find that ORF3 protein expressed in cytoplasm in early stages of PCV2 infection and then accumulated in nucleus over time. Moreover, we localize a NES at the N-terminus (residues 1-35aa) of ORF3 which plays critical role in nuclear export activity. These findings provide a novel insight that deepens our understanding of the biological function of PCV2 ORF3. (C) 2016 Elsevier B.V. All rights reserved.