Ahkong Q F, Baldwin J M, O'Reilly R, Lucy J A
Department of Medicine, University of British Columbia, Vancouver, Canada.
Mol Membr Biol. 1994 Jul-Sep;11(3):171-9. doi: 10.3109/09687689409162236.
Diffusion of the fluorescent membrane probe, Dil-C16 (3), from labelled to unlabelled human erythrocytes has been employed to monitor hemi-fusion (membrane fusion) in monolayers of cells exposed to poly(ethylene glycol) (PEG). Diffusion of the cytoplasmic probe, 6-carboxyfluorescein, was used similarly to monitor cell fusion (cytoplasmic mixing). Hemi-fusion, which is normally seen when erythrocytes are exposed to dehydrating concentrations of commercial PEG 6000, did not occur when the PEG was pretreated with Chelex 100 resin to remove metal ions. Cytoplasmic mixing, which is normally observed when the dehydrated erythrocytes are substantially rehydrated, also failed to occur when both PEG 6000 and the rehydrating buffer had been treated with Chelex 100. The re-addition to Chelex-treated PEG of components removed by the resin, and the addition of 10 mu mM concentrations of La3+ or Al3+, restored its ability to induce hemi-fusion and cell fusion. Higher concentrations of several other metals, including Ca2+, were also effective. These observations show that metal ions are required for hemi-fusion with erythrocytes in the presence of PEG, and that dehydration alone is insufficient to induce hemi-fusion. Phosphatidylserine was apparently not accessible in erythrocytes treated with PEG 6000 until the cells were rehydrated. This indicates that metal ions do not assist the hemi-fusion of erythrocytes by forming trans complexes with surface phosphatidylserine when the cells are dehydrated by PEG.(ABSTRACT TRUNCATED AT 250 WORDS)
已利用荧光膜探针Dil-C16(3)从标记的人红细胞扩散至未标记的人红细胞，来监测暴露于聚乙二醇(PEG)的细胞单层中的半融合(膜融合)。类似地，利用细胞质探针6-羧基荧光素的扩散来监测细胞融合(细胞质混合)。当红细胞暴露于商业PEG 6000的脱水浓度时通常会出现的半融合，在用Chelex 100树脂预处理PEG以去除金属离子后未发生。当脱水的红细胞大量再水化时通常观察到的细胞质混合，在PEG 6000和再水化缓冲液均用Chelex 100处理后也未发生。向经Chelex处理的PEG中重新添加被树脂去除的成分，以及添加10 μM浓度的La3+或Al3+，恢复了其诱导半融合和细胞融合的能力。包括Ca2+在内的其他几种金属的较高浓度也有效。这些观察结果表明，在PEG存在的情况下，金属离子是红细胞半融合所必需的，仅脱水不足以诱导半融合。在用PEG 6000处理的红细胞中，直到细胞再水化时磷脂酰丝氨酸显然才是可及的。这表明当细胞被PEG脱水时，金属离子不会通过与表面磷脂酰丝氨酸形成反式复合物来协助红细胞的半融合。(摘要截短于250字)
