Grimes H D, Boss W F
Department of Botany, North Carolina State University, Raleigh, North Carolina 27695-7612.
Plant Physiol. 1985 Sep;79(1):253-8. doi: 10.1104/pp.79.1.253.
(45)Ca(2+) uptake was compared between fusogenic and nonfusogenic Daucus carota L. protoplasts. Fusogenic protoplasts took 10 minutes to reach calcium equilibrium compared to 5 minutes in the nonfusogenic protoplasts. Intracellular stores of calcium were manipulated by isolating protoplasts in different calcium regimes. Lowering of intracellular calcium lowered fusion potential, while raising intracellular stores of calcium enhanced fusion potential. Regardless of the amount of calcium sequestered in a store, mobilization with A23187 increased fusion levels within 10 minutes. Calmodulin antagonists were potent inhibitors of protoplast fusion. This inhibition was obtained by treating cells with the calmodulin antagonists during protoplast isolation. A23187, however, only allowed a partial recovery from this inhibition, indicating that calcium flux alone was not sufficient for maximum fusion potential. On the basis of the evidence presented, we propose that calcium fluxes during protoplast isolation activate a calmodulin-mediated biochemical process that is necessary for the formation or maintenance of a fusion permissive state.
比较了融合性和非融合性胡萝卜原生质体对(45)Ca(2+)的摄取情况。融合性原生质体达到钙平衡需要10分钟，而非融合性原生质体则需要5分钟。通过在不同钙环境中分离原生质体来调控细胞内钙储存。降低细胞内钙会降低融合潜能，而提高细胞内钙储存则会增强融合潜能。无论储存在细胞内的钙量如何，用A23187进行动员可在10分钟内提高融合水平。钙调蛋白拮抗剂是原生质体融合的有效抑制剂。这种抑制作用是通过在原生质体分离过程中用钙调蛋白拮抗剂处理细胞而获得的。然而，A23187只能使这种抑制作用部分恢复，这表明仅钙通量不足以实现最大融合潜能。根据所提供的证据，我们提出，原生质体分离过程中的钙通量激活了一个钙调蛋白介导的生化过程，这一过程对于形成或维持融合允许状态是必需的。
