Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
Virology. 2015 Sep;483:209-17. doi: 10.1016/j.virol.2015.04.014. Epub 2015 May 15.
Most poxvirus proteins are either highly conserved and essential for basic steps in replication or less conserved and involved in host interactions. Homologs of the CPXV219 protein, encoded by cowpox virus, are present in nearly all chordopoxvirus genera and some species have multiple copies. The CPXV219 homologs have estimated masses of greater than 200 kDa, making them the largest known poxvirus proteins. We showed that CPXV219 was expressed early in infection and cleaved into N- and C-terminal fragments that remained associated. The protein has a signal peptide and transited the secretory pathway where extensive glycosylation and proteolytic cleavage occurred. CPXV219 was located by immunofluorescence microscopy in association with the endoplasmic reticulum, Golgi apparatus and plasma membrane. In non-permeabilized cells, CPXV219 was accessible to external antibody and biotinylation. Mutants that did not express CPXV219 replicated normally in cell culture and retained virulence in a mouse respiratory infection model.
大多数痘病毒蛋白要么高度保守，是复制基本步骤所必需的，要么保守性较低，参与宿主相互作用。牛痘病毒编码的 CPXV219 蛋白的同源物存在于几乎所有的正痘病毒属和一些物种中，它们具有多个拷贝。CPXV219 同源物的估计质量大于 200 kDa，使其成为已知最大的痘病毒蛋白。我们表明 CPXV219 在感染早期表达，并被切割成 N-和 C-末端片段，这些片段仍然保持关联。该蛋白具有信号肽，并通过分泌途径运输，在此过程中发生了广泛的糖基化和蛋白水解切割。通过免疫荧光显微镜观察，CPXV219 与内质网、高尔基体和质膜相关联。在非通透细胞中，CPXV219 可被外部抗体和生物素化。不能表达 CPXV219 的突变体在细胞培养中正常复制，并在小鼠呼吸道感染模型中保留了毒力。
