Karpel R, Sternfeld M, Ginzberg D, Guhl E, Graessmann A, Soreq H
Department of Biological Chemistry, Hebrew University, Jerusalem, Israel.
J Neurochem. 1996 Jan;66(1):114-23. doi: 10.1046/j.1471-4159.1996.66010114.x.
In addition to its well-known synaptic function, acetylcholinesterase was recently shown to stimulate neurite outgrowth from cultured chick neurons in a manner unrelated to its catalytic activity. It remained unclear, however, whether each of the variant acetylcholinesterase enzyme forms can promote such process extension and whether this effect of acetylcholinesterase was limited to neurite outgrowth. Using DNA microinjections and stable transfections of cultured glioma cells, we explored the possibility that specific acetylcholinesterase isoforms affect cellular development and morphology of CNS astrocytes. Cells microinjected with human ACHEDNA constructs that differ in their exon-intron composition displayed rapid yet stable induction of cell body enlargement and process extensions. Cells transfected with ACHEDNA carrying the neuronal-characteristic 3'-E6 domain also displayed stable process extensions. However, stable transfections with ACHEDNAs including the 3'-alternative 14/E5 region induced the appearance of small, round cells in a dominant manner. This was associated with expression of 14/E5-ACHEmRNA transcripts and the production of soluble acetylcholinesterase monomers that were catalytically indistinguishable from the 3'-E6 enzyme but displayed higher electrophoretic mobility than that of the 3'-E6 form. Thus, variable expression levels and alternative splicing modes of the ACHE gene correlated in these experiments with glial development in a manner that was apparently unrelated to catalysis.
除了其众所周知的突触功能外，最近研究表明，乙酰胆碱酯酶能以一种与其催化活性无关的方式刺激培养的鸡神经元的神经突生长。然而，尚不清楚每种变异的乙酰胆碱酯酶形式是否都能促进这种神经突生长过程，以及乙酰胆碱酯酶的这种作用是否仅限于神经突生长。我们通过对培养的胶质瘤细胞进行DNA显微注射和稳定转染，探讨了特定的乙酰胆碱酯酶同工型影响中枢神经系统星形胶质细胞的细胞发育和形态的可能性。显微注射了外显子-内含子组成不同的人乙酰胆碱酯酶DNA构建体的细胞，表现出细胞体迅速且稳定的增大以及神经突的延伸。用携带神经元特征性3'-E6结构域的乙酰胆碱酯酶DNA转染的细胞也表现出稳定的神经突延伸。然而，用包含3'-可变14/E5区域的乙酰胆碱酯酶DNA进行稳定转染，以显性方式诱导出现小的圆形细胞。这与14/E5-乙酰胆碱酯酶mRNA转录本的表达以及可溶性乙酰胆碱酯酶单体的产生有关，这些单体在催化作用上与3'-E6酶无法区分，但电泳迁移率高于3'-E6形式。因此，在这些实验中，乙酰胆碱酯酶基因的可变表达水平和可变剪接模式与神经胶质细胞发育相关，而这种相关性显然与催化作用无关。
