Agutter P S
Department of Biological Sciences, Napier University, Edinburgh, U.K.
Cell Biol Int. 1994 Sep;18(9):849-58. doi: 10.1006/cbir.1994.1121.
This paper explores the idea that mRNAs are transported between their transcription and processing sites in the nucleus, and their translation and degradation sites in the cytoplasm, by a 'solid-state' process. The underlying assumption is that negligible quantities of mRNA and of mRNA precursors are in solution in vivo. Therefore, mRNA transport cannot be considered as movement in the aqueous phase of the cell. The main lines of experimental evidence supporting this 'solid-state' concept are summarized and related controversies are outlined. Three possible models for a solid-state transport mechanism are discussed: a direct transfer model, with receptors organized analogously to the components of a multienzyme complex; a motor-driven model, analogous to synaptic vesicle transport in axons; and an assembly-driven model which assumes net movement along a fibril resulting from differential activities at the poles. Qualitative evaluation indicates that each of these models has characteristic advantages and disadvantages. The possibility that other nucleocytoplasmic transport processes might operate by solid-state mechanisms is briefly discussed.
本文探讨了这样一种观点，即信使核糖核酸（mRNAs）通过一种“固态”过程在细胞核内的转录和加工位点与细胞质中的翻译和降解位点之间进行转运。其基本假设是，在体内可忽略不计数量的信使核糖核酸及其前体处于溶液状态。因此，信使核糖核酸的转运不能被视为在细胞水相中的移动。总结了支持这一“固态”概念的主要实验证据，并概述了相关争议。讨论了固态转运机制的三种可能模型：一种直接转移模型，其受体的组织方式类似于多酶复合体的组分；一种马达驱动模型，类似于轴突中突触小泡的转运；以及一种组装驱动模型，该模型假定沿着原纤维的净移动是由两极的差异活性导致的。定性评估表明，这些模型中的每一个都有其独特的优缺点。简要讨论了其他核质转运过程可能通过固态机制运行的可能性。
