Hoff H S, Donis R O
Department of Veterinary and Biomedical Sciences, University of Nebraska, Lincoln 68583-0905, USA.
Virus Res. 1997 May;49(1):101-13. doi: 10.1016/s0168-1702(97)01460-3.
The Pestivirus bovine viral diarrhea virus (BVDV) causes the fatal diarrheal syndrome, mucosal disease, because of mutations in the viral genome which convert the common noncytopathic (ncp) BVDV into a cytopathic (cp) biotype. We examined the nature of the cytopathic effect of cp-BVDV in cultured bovine cells in order to accurately describe the process and to gain insight into the mechanism of cp-BVDV-induced cell death. The findings demonstrate that cells infected with cp-BVDV in vitro die by apoptosis, but cells infected with ncp-BVDV do not. Analysis of nuclear morphology by staining with fluorescent DNA dye and cpi-fluorescence microscopy showed chromatin condensation and margination in cells infected with cp-BVDV. Transmission electron microscopy (TEM) confirmed the condensation of chromatin, as well as cell shrinkage and generation of apoptotic bodies. The chromosomal DNA of cells infected with cp-BVDV undergoes fragmentation, generating the typical oligonucleosomal fragments commonly noted during apoptosis. The fragmented DNA was released from the nucleus to the cytoplasm, and eventually to the culture supernatant. Infection with cp-BVDV activates cellular proteases of the ICE family leading to cleavage of poly(ADP-ribose) polymerase (PARP), a nuclear enzyme implicated in genome maintenance. This demonstration that cp-BVDV kills cells by triggering apoptosis suggests the possibility that cp-BVDV is associated with a fatal disease by the acquisition of a new apoptosis-inducing activity. We consider BVDV to be an excellent model system for studies of the biological and medical relevance of apoptosis in viral infections.
瘟病毒属的牛病毒性腹泻病毒（BVDV）会引发致命的腹泻综合征——黏膜病，这是由于病毒基因组发生突变，将常见的非致细胞病变（ncp）BVDV转变为致细胞病变（cp）生物型所致。我们研究了cp - BVDV在培养的牛细胞中致细胞病变效应的本质，以便准确描述这一过程，并深入了解cp - BVDV诱导细胞死亡的机制。研究结果表明，体外感染cp - BVDV的细胞通过凋亡死亡，但感染ncp - BVDV的细胞则不会。用荧光DNA染料染色并通过共聚焦荧光显微镜分析细胞核形态，结果显示感染cp - BVDV的细胞中染色质浓缩并边缘化。透射电子显微镜（TEM）证实了染色质的浓缩，以及细胞收缩和凋亡小体的形成。感染cp - BVDV的细胞的染色体DNA发生片段化，产生凋亡过程中常见的典型寡核小体片段。片段化的DNA从细胞核释放到细胞质，最终释放到培养上清液中。感染cp - BVDV会激活ICE家族的细胞蛋白酶，导致聚（ADP - 核糖）聚合酶（PARP）的裂解，PARP是一种参与基因组维持的核酶。这一结果表明cp - BVDV通过触发凋亡杀死细胞，提示cp - BVDV可能通过获得新的凋亡诱导活性而与一种致命疾病相关。我们认为BVDV是研究病毒感染中凋亡的生物学和医学相关性的优秀模型系统。
