Chemello Maria Elena, Aristimuño Olga Carolina, Michelangeli Fabián, Ruiz Marie-Christine
Laboratorio de Fisiología Gastrointestinal, Instituto Venezolano de Investigaciones Científicas (IVIC), 1020A Caracas, Venezuela.
J Virol. 2002 Dec;76(24):13083-7. doi: 10.1128/jvi.76.24.13083-13087.2002.
The mechanism by which rotavirus and other nonenveloped viruses enter the cell is still not clear. We have proposed an endocytosis model where the critical step for virus uncoating and membrane permeabilization is the decrease in Ca(2+) concentration in the endosome. In this paper, we monitored rotavirus entry by measuring alpha-sarcin-rotavirus coentry and infectivity in MA104 cells. The participation of endocytosis, acidification, and endosomal Ca(2+) concentration on virus entry was studied by inhibiting the endosomal H(+)-ATPase with bafilomycin A1 and/or increasing the extracellular calcium reservoir by addition of 10 mM CaEGTA. Rotavirus-alpha-sarcin coentry was inhibited by bafilomycin A1 and by addition of 10 mM CaEGTA. These effects were additive. These substances induced a significant inhibition of infectivity without affecting virus binding and postentry steps. These results are compatible with the interpretation that bafilomycin A1 and CaEGTA block rotavirus penetration from the endosome into the cytoplasm and support our hypothesis of a Ca(2+)-dependent endocytosis model.
轮状病毒和其他无包膜病毒进入细胞的机制仍不清楚。我们提出了一种内吞作用模型，其中病毒脱壳和膜通透化的关键步骤是内体中Ca(2+)浓度的降低。在本文中，我们通过测量α-肌动蛋白-轮状病毒共进入和在MA104细胞中的感染性来监测轮状病毒的进入。通过用巴弗洛霉素A1抑制内体H(+)-ATP酶和/或通过添加10 mM CaEGTA增加细胞外钙库，研究了内吞作用、酸化和内体Ca(2+)浓度对病毒进入的影响。巴弗洛霉素A1和添加10 mM CaEGTA可抑制轮状病毒-α-肌动蛋白共进入。这些作用是相加的。这些物质可显著抑制感染性，而不影响病毒结合和进入后步骤。这些结果与巴弗洛霉素A1和CaEGTA阻断轮状病毒从内体进入细胞质的解释一致，并支持我们关于Ca(2+)依赖性内吞作用模型的假设。
