Delos S E, Montross L, Moreland R B, Garcea R L
Division of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115.
Virology. 1993 May;194(1):393-8. doi: 10.1006/viro.1993.1274.
During polyomavirus infection the capsid proteins are synthesized in the cytoplasm and transported into the nucleus were virion assembly occurs. Expression of the major capsid protein VP1 in Sf9 insect cells results in the accumulation of capsid-like particles in the nucleus, independent of the presence of the minor capsid proteins VP2 and VP3 or the viral DNA (Montross et al., J. Virol. 65, 4991-4998, 1991). Sf9 cells infected with baculovirus vectors expressing the polyomavirus minor capsid proteins VP2 and VP3 were examined. VP2 was myristylated in Sf9 cells, as seen during polyomavirus infection of mouse cells. Immunoprecipitation of lysates from co-infected cells demonstrated an association between VP1 and VP2. As determined by immunogold electron microscopy, when expressed alone VP2 was associated with membrane structures in the cytoplasm and VP3 was diffusely localized in the cytoplasm. When co-infected with a VP1 expressing baculovirus, both VP2 and VP3 became predominantly localized to the nucleus in association with capsid-like structures. Thus, the polyomavirus capsid proteins interact in vivo and alter their subcellular localization as a consequence.
在多瘤病毒感染期间，衣壳蛋白在细胞质中合成并转运到发生病毒体组装的细胞核中。在 Sf9 昆虫细胞中主要衣壳蛋白 VP1 的表达导致细胞核中衣壳样颗粒的积累，这与次要衣壳蛋白 VP2 和 VP3 或病毒 DNA 的存在无关（Montross 等人，《病毒学杂志》65，4991 - 4998，1991）。对感染了表达多瘤病毒次要衣壳蛋白 VP2 和 VP3 的杆状病毒载体的 Sf9 细胞进行了检查。VP2 在 Sf9 细胞中被肉豆蔻酰化，这在多瘤病毒感染小鼠细胞时也可见。对共感染细胞的裂解物进行免疫沉淀表明 VP1 和 VP2 之间存在关联。通过免疫金电子显微镜确定，当单独表达时，VP2 与细胞质中的膜结构相关，而 VP3 则分散地定位于细胞质中。当与表达 VP1 的杆状病毒共感染时，VP2 和 VP3 都主要定位于细胞核并与衣壳样结构相关。因此，多瘤病毒衣壳蛋白在体内相互作用并因此改变它们的亚细胞定位。
