Henis Y I, Herman-Barhom Y, Aroeti B, Gutman O
Department of Biochemistry, George S. Wise Faculty of Life Sciences, Tel Aviv University, Israel.
J Biol Chem. 1989 Oct 15;264(29):17119-25.
Fluorescence photobleaching recovery was employed to study the effects of specific immobilization of Sendai virus envelope glycoproteins (F, the fusion protein, and HN, the hemagglutinin-neuraminidase) on the virally mediated fusion of human erythrocytes. Lateral immobilization of varying fractions of F and/or HN (after virus adsorption and hemagglutination, but before fusion) was achieved by cross-linking them with succinyl concanavalin A (inhibiting both F and HN) or with specific rabbit IgG directed against either F or HN. Alternatively, agglutinated cells were treated with low concentrations of the above proteins (inducing only minor inhibition of either mobility or fusion), and immobilization of F and/or HN was induced by cross-linking with a secondary antibody; this protocol ensured a minimal contribution of direct binding to the viral proteins to the inhibition of fusion. Our results demonstrate that lateral immobilization of either F or HN results in a strong inhibition of cell-cell fusion and a much weaker inhibition of virus-cell fusion. The level of cell-cell fusion was directly correlated with the level of laterally mobile viral glycoproteins in the cell membrane (either F or HN). We conclude that lateral mobility of both F and HN in the red cell membrane is essential for cell-cell fusion and that not only F but also HN has a role in this fusion event. The possible reasons for the different dependence of cell-cell and virus-cell fusion on viral glycoprotein mobility are discussed.
采用荧光光漂白恢复技术来研究仙台病毒包膜糖蛋白（F，融合蛋白；HN，血凝素神经氨酸酶）的特异性固定对病毒介导的人红细胞融合的影响。通过用琥珀酰伴刀豆球蛋白A（抑制F和HN）或针对F或HN的特异性兔IgG交联，实现了不同比例的F和/或HN在病毒吸附和血凝后但在融合前的侧向固定。或者，用低浓度的上述蛋白质处理凝集细胞（仅对迁移率或融合产生轻微抑制），并通过与二抗交联诱导F和/或HN的固定；该方案确保了病毒蛋白的直接结合对融合抑制的贡献最小。我们的结果表明，F或HN的侧向固定均会强烈抑制细胞间融合，而对病毒 - 细胞融合的抑制作用则弱得多。细胞间融合水平与细胞膜中侧向移动的病毒糖蛋白（F或HN）水平直接相关。我们得出结论，红细胞膜中F和HN的侧向移动对于细胞间融合至关重要，并且不仅F而且HN在这一融合事件中都发挥作用。讨论了细胞间融合和病毒 - 细胞融合对病毒糖蛋白移动性不同依赖性的可能原因。
