Théveniau M, Durbec P, Gennarini G, Wood J N, Rougon G
Laboratoire de Biologie de la Différenciation Cellulaire, URA179 CNRS, Université de Luminy, Marseille, France.
J Cell Biochem. 1992 Jan;48(1):61-72. doi: 10.1002/jcb.240480110.
Early postnatal mouse dorsal root ganglion neurons were found to express several glycosylphosphatidylinositol-anchored (GPI) molecules from the immunoglobulin superfamily (neural cell adhesion molecule 120 kD isoform, F3, Thy1) whose expression is developmentally regulated. A hybrid cell line (ND26), made by fusing postmitotic rat dorsal root ganglion (DRG) neurons with the mouse neuroblastoma N18Tg2, could be induced to differentiate by manipulating the composition of the culture medium and expressed similar GPI molecules to DRG neurons. We used this model system to investigate the metabolism of GPI-anchored molecules. We found that neural cell adhesion molecule 120 Kd isoform expression decreased upon differentiation, whereas the level of F3 and Thy1 increased, suggesting a role in neurite outgrowth processes. The ratio of molecules cleavable by exogenous phosphatidylinositol phospholipase C (PI-PLC) was similar for all the GPI-anchored molecules, which could mean that cell-specific modifications of the basic anchoring structure determine the level of potentially releasable molecules. Measurements of spontaneous release indicated that this reflected the overall level of expression of these molecules by the ND26 cell line. Finally, we observed an effect of dibutyryl cAMP on the level of expression of F3 and Thy1 but not of N-CAM. However, we could not detect any significant effect of nerve growth factor (NGF) either on the level of expression or on the amount of spontaneously released molecules.
研究发现，出生后早期的小鼠背根神经节神经元表达免疫球蛋白超家族中几种糖基磷脂酰肌醇锚定（GPI）分子（神经细胞黏附分子120kD异构体、F3、Thy1），其表达受发育调控。通过将有丝分裂后的大鼠背根神经节（DRG）神经元与小鼠神经母细胞瘤N18Tg2融合构建的杂交细胞系（ND26），可通过调控培养基成分诱导分化，并表达与DRG神经元相似的GPI分子。我们利用这个模型系统研究GPI锚定分子的代谢。我们发现，分化后神经细胞黏附分子120Kd异构体的表达降低，而F3和Thy1的水平升高，提示其在神经突生长过程中发挥作用。所有GPI锚定分子可被外源性磷脂酰肌醇磷脂酶C（PI-PLC）切割的分子比例相似，这可能意味着基本锚定结构的细胞特异性修饰决定了潜在可释放分子的水平。自发释放的测量结果表明，这反映了ND26细胞系中这些分子的总体表达水平。最后，我们观察到二丁酰环磷腺苷（dibutyryl cAMP）对F3和Thy1的表达水平有影响，但对N-CAM没有影响。然而，我们未检测到神经生长因子（NGF）对表达水平或自发释放分子数量有任何显著影响。
