Epel B L
Botany Department, Tel Aviv University, George S. Wise Faculty of Life Sciences, Tel Aviv University, Israel.
Plant Mol Biol. 1994 Dec;26(5):1343-56. doi: 10.1007/BF00016479.
Plasmodesmata are highly specialized gatable trans-wall channels that interconnect contiguous cells and function in direct cytoplasm-to-cytoplasm intercellular transport. Computer-enhanced digital imaging analysis of electron micrographs of plasmodesmata has provided new information on plasmodesmatal fine structure. It is now becoming clear that plasmodesmata are dynamic quasi-organelles whose conductivity can be regulated by environmental and developmental signals. New findings suggest that signalling mechanisms exist which allow the plasmodesmatal pore to dilate to allow macromolecular transport. Plant viruses spread from cell to cell via plasmodesmata. Two distinct movement mechanisms have been elucidated. One movement mechanism involves the movement of the complete virus particle along virus-induced tubular structures within a modified plasmodesma. Apparently two virus-coded movement proteins are involved. A second movement mechanism involves the movement of a non-virion form through existing plasmodesmata. In this mechanism, the viral movement protein causes a rapid dilation of existing plasmodesmata to facilitate protein and nucleic acid movement. Techniques for the isolation of plasmodesmata have been developed and information on plasmodesma-associated proteins is now becoming available. New evidence is reviewed which suggests that plasmodesmatal composition and regulation may differ in different cells and tissues.
胞间连丝是高度特化的可调控跨壁通道，它连接相邻细胞，在细胞间直接的细胞质到细胞质的运输中发挥作用。对胞间连丝电子显微照片进行计算机增强数字成像分析，为胞间连丝的精细结构提供了新信息。现在越来越清楚的是，胞间连丝是动态的准细胞器，其传导性可受环境和发育信号调控。新发现表明存在信号传导机制，可使胞间连丝孔道扩张以允许大分子运输。植物病毒通过胞间连丝在细胞间传播。已阐明两种不同的移动机制。一种移动机制涉及完整病毒粒子沿着修饰胞间连丝内病毒诱导的管状结构移动。显然有两种病毒编码的移动蛋白参与其中。第二种移动机制涉及非病毒粒子形式通过现有的胞间连丝移动。在这种机制中，病毒移动蛋白使现有的胞间连丝迅速扩张，以促进蛋白质和核酸的移动。已开发出分离胞间连丝的技术，现在有关胞间连丝相关蛋白的信息也已可得。本文综述了新证据，这些证据表明胞间连丝的组成和调控在不同细胞和组织中可能有所不同。
