Bonfanti L, Theodosis D T
Dipartimento di Morfofisiologia Veterinaria, University of Turin, Italy.
Neuroscience. 1994 Sep;62(1):291-305. doi: 10.1016/0306-4522(94)90333-6.
The highly sialylated isoform of the neural cell adhesion molecule is thought to be expressed predominantly in the developing nervous system, where it is implicated in a variety of dynamic events linked to neural morphogenesis. It has become increasingly evident, however, that this "embryonic" neural cell adhesion molecule isoform continues to be expressed in certain adult neuronal systems, and in particular, in those that can undergo structural plasticity. In the present study, we performed light microscopic immunocytochemistry with an antibody specific for polysialylated neural cell adhesion molecule and confirmed our earlier observations [Bonfanti L. et al. (1992) Neuroscience 49, 419-436] showing polysialylated neural cell adhesion molecule-immunoreactive cells in the subependymal layer of the lateral ventricle of the adult rat, a region where cell proliferation continues into the postnatal period. In addition, we used an antibody raised against the proliferating cell nuclear antigen and found that proliferating cells continue to be visible in this area, even in the adult. Double immunolabeling showed that many of these newly generated cells displayed high polysialylated neural cell adhesion molecule immunoreactivity. Cells from a portion of the subependymal layer migrate to the olfactory bulb and contribute to the continual replacement of its granule neurons [Luskin M. B. (1993) Neuron 11, 173-189]. We found polysialylated neural cell adhesion molecule-immunoreactive cells all along the pathway purported to be followed by the newly generated cells to their final destination and in neurons corresponding to granular and periglomerular cells in the olfactory bulb. Our present observations thus support the contention that polysialylation is a feature of neurons capable of dynamic change and may contribute to the molecular mechanisms permitting cell proliferation and migration not only during development but also in the adult.
神经细胞黏附分子的高度唾液酸化异构体被认为主要在发育中的神经系统中表达，在那里它参与了与神经形态发生相关的各种动态事件。然而，越来越明显的是，这种“胚胎型”神经细胞黏附分子异构体在某些成年神经元系统中持续表达，特别是在那些能够发生结构可塑性的系统中。在本研究中，我们用一种针对多唾液酸化神经细胞黏附分子的特异性抗体进行了光学显微镜免疫细胞化学实验，并证实了我们早期的观察结果[Bonfanti L.等人（1992年）《神经科学》49卷，419 - 436页]，即在成年大鼠侧脑室室管膜下层存在多唾液酸化神经细胞黏附分子免疫反应性细胞，该区域的细胞增殖会持续到出生后时期。此外，我们使用了一种针对增殖细胞核抗原产生的抗体，发现即使在成年期，该区域仍可见增殖细胞。双重免疫标记显示，许多这些新生成的细胞表现出高多唾液酸化神经细胞黏附分子免疫反应性。室管膜下层一部分的细胞迁移到嗅球，并参与其颗粒神经元的持续替换[Luskin M. B.（1993年）《神经元》11卷，173 - 189页]。我们在新生成细胞据称通往其最终目的地的整个路径上，以及在嗅球中与颗粒细胞和球周细胞相对应的神经元中，都发现了多唾液酸化神经细胞黏附分子免疫反应性细胞。因此，我们目前的观察结果支持了这样一种观点，即多唾液酸化是能够发生动态变化的神经元的一个特征，并且可能不仅在发育过程中，而且在成年期都有助于细胞增殖和迁移的分子机制。
