Ramsey-Ewing A, Moss B
Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892-0445, USA.
Virology. 1998 Mar 1;242(1):138-49. doi: 10.1006/viro.1997.8985.
Unlike most cell types examined, nonpermissive Chinese hamster ovary (CHO) cells readily underwent apoptosis upon infection with vaccinia virus (VV). Apoptosis was observed as early as 3 h postinfection with an electrophoretic assay of DNA fragmentation and by 8 h using an in situ (TUNEL) assay. The CHO hr gene from cowpox virus, which overcomes host range restriction of VV in CHO cells, merely delayed the onset of apoptosis by approximately 3 h. Intermediate and late viral protein synthesis were not necessary for apoptosis since these events do not proceed under nonpermissive conditions. Apoptosis also occurred in the presence of cytosine arabinoside or cycloheximide, which inhibits DNA or protein synthesis, respectively, and after infection with a mutant virus that is blocked in early transcription. We also demonstrated that viral early transcription was not required for induction of apoptosis by infecting CHO cells with psoralen/UV-inactivated virus. On the other hand, apoptosis was inhibited by a neutralizing antibody to the virion L1R protein added either before or after virus attachment to cells. These results indicate that a postbinding step associated with cell entry is sufficient and required for induction of apoptosis in CHO cells. Recent progress on apoptotic signaling pathways raises the possibility that a cellular receptor for VV may be involved in apoptosis.
与大多数已检测的细胞类型不同，非允许性中国仓鼠卵巢（CHO）细胞在感染痘苗病毒（VV）后很容易发生凋亡。早在感染后3小时，通过DNA片段化的电泳分析就可观察到凋亡，而使用原位（TUNEL）分析在8小时后可观察到凋亡。来自牛痘病毒的CHO hr基因可克服VV在CHO细胞中的宿主范围限制，它只是将凋亡的起始延迟了约3小时。由于在非允许条件下这些事件不会发生，因此凋亡不需要病毒中期和晚期蛋白质的合成。在分别抑制DNA或蛋白质合成的阿糖胞苷或环己酰亚胺存在的情况下，以及在用早期转录受阻的突变病毒感染后，凋亡也会发生。我们还通过用补骨脂素/紫外线灭活的病毒感染CHO细胞证明，病毒早期转录不是诱导凋亡所必需的。另一方面，在病毒附着于细胞之前或之后添加的针对病毒粒子L1R蛋白的中和抗体可抑制凋亡。这些结果表明，与细胞进入相关的结合后步骤足以并引发CHO细胞的凋亡。凋亡信号通路的最新进展增加了一种可能性，即VV的细胞受体可能参与凋亡。
