Iwanaga M, Kang W K, Kobayashi M, Maeda S
Laboratory of Molecular Entomology and Baculovirology, RIKEN, Wako, Japan.
Arch Virol. 2000;145(9):1763-71. doi: 10.1007/s007050070054.
The effect of baculovirus infection into silkworm pupa particularly on programmed fat body degradation during metamorphosis was investigated. Pupal fat body degradation did not occur following infection with Bombyx mori nucleopolyhedrovirus (BmNPV). There were no histolytic differences between the fat body tissues of mock and BmNPV infected papae until 48 h postinfection (p.i.). Between 48 and 72 h p.i., significant differences were observed. In order to determine whether the histolysis of fat body was due to apoptosis, genomic DNAs were purified at various p.i. times and analyzed. Rapid genomic DNA fragmentation was observed at 24 and 48 h after pupation in both mock and BmNPV infected pupae. However, BmNPV infection clearly inhibited DNA fragmentation and ladder formation at 72 h and later times p.i. Furthermore, pulse-labeling analysis showed that BmNPV infection restored protein synthesis in fat body cells. These results suggested that fat body degradation during pupal-adult development was due to apoptosis, and that BmNPV was able to evoke a cellular response in these cells.
研究了杆状病毒感染家蚕蛹，特别是对变态过程中脂肪体程序性降解的影响。感染家蚕核型多角体病毒（BmNPV）后，蛹脂肪体未发生降解。在感染后48小时（p.i.）之前， mock和BmNPV感染的蛹的脂肪体组织之间没有组织溶解差异。在感染后48至72小时之间，观察到显著差异。为了确定脂肪体的组织溶解是否是由于凋亡引起的，在不同的感染后时间点纯化基因组DNA并进行分析。在化蛹后24小时和48小时，mock和BmNPV感染的蛹中均观察到快速的基因组DNA片段化。然而，BmNPV感染在感染后72小时及以后的时间明显抑制了DNA片段化和梯状条带的形成。此外，脉冲标记分析表明，BmNPV感染恢复了脂肪体细胞中的蛋白质合成。这些结果表明，蛹-成虫发育过程中的脂肪体降解是由于凋亡引起的，并且BmNPV能够在这些细胞中引发细胞反应。
