109 Morrison Life Science Research Center, 4240 Fair Street, East Campus, University of Nebraska-Lincoln, Lincoln, NE 68583-0900, USA.
J Virol. 2011 Sep;85(18):9459-71. doi: 10.1128/JVI.05179-11. Epub 2011 Jul 13.
Immunoprecipitation and subsequent mass spectrometry analysis of the cellular proteins from cells expressing the vesicular stomatitis virus (VSV) P protein identified the poly(C) binding protein 2 (PCBP2) as one of the P protein-interacting proteins. To investigate the role of PCBP2 in the viral life cycle, we examined the effects of depletion or overexpression of this protein on VSV growth. Small interfering RNA-mediated silencing of PCBP2 promoted VSV replication. Conversely, overexpression of PCBP2 in transfected cells suppressed VSV growth. Further studies revealed that PCBP2 negatively regulates overall viral mRNA accumulation and subsequent genome replication. Coimmunoprecipitation and immunofluorescence microscopic studies showed that PCBP2 interacts and colocalizes with VSV P protein in virus-infected cells. The P-PCBP2 interaction did not result in reduced levels of protein complex formation with the viral N and L proteins, nor did it induce degradation of the P protein. In addition, PCBP1, another member of the poly(C) binding protein family with homology to PCBP2, was also found to interact with the P protein and inhibit the viral mRNA synthesis at the level of primary transcription without affecting secondary transcription or genome replication. The inhibitory effects of PCBP1 on VSV replication were less pronounced than those of PCBP2. Overall, the results presented here suggest that cellular PCBP2 and PCBP1 antagonize VSV growth by affecting viral gene expression and highlight the importance of these two cellular proteins in restricting virus infections.
免疫沉淀和随后对表达水疱性口炎病毒 (VSV) P 蛋白的细胞中的细胞蛋白进行的质谱分析鉴定出多聚 (C) 结合蛋白 2 (PCBP2) 是 P 蛋白相互作用蛋白之一。为了研究 PCBP2 在病毒生命周期中的作用，我们研究了耗尽或过表达这种蛋白对 VSV 生长的影响。小干扰 RNA 介导的 PCBP2 沉默促进了 VSV 的复制。相反，转染细胞中 PCBP2 的过表达抑制了 VSV 的生长。进一步的研究表明，PCBP2 负调控病毒 mRNA 的总体积累和随后的基因组复制。共免疫沉淀和免疫荧光显微镜研究表明，PCBP2 在病毒感染的细胞中与 VSV P 蛋白相互作用并共定位。P-PCBP2 相互作用不会导致与病毒 N 和 L 蛋白的蛋白复合物形成水平降低，也不会诱导 P 蛋白降解。此外，还发现多聚 (C) 结合蛋白家族的另一个成员 PCBP1 与 P 蛋白相互作用，并在不影响次级转录或基因组复制的情况下抑制病毒 mRNA 合成的初级转录。PCBP1 对 VSV 复制的抑制作用不如 PCBP2 明显。总体而言，这里提出的结果表明，细胞 PCBP2 和 PCBP1 通过影响病毒基因表达来拮抗 VSV 的生长，并强调了这两种细胞蛋白在限制病毒感染方面的重要性。
