Use of the Neural Cell Adhesion Molecule VASE Exon by Neurons Is Associated with a Specific Down‐Regulation of Neural Cell Adhesion Molecule‐Dependent Neurite Outgrowth in the Developing Cerebellum and Hippocampus
Use of the Neural Cell Adhesion Molecule VASE Exon by Neurons Is Associated with a Specific Down‐Regulation of Neural Cell Adhesion Molecule‐Dependent Neurite Outgrowth in the Developing Cerebellum and Hippocampus
复制标题
神经元对神经细胞粘附分子 VASE 外显子的使用与发育中的小脑和海马中神经细胞粘附分子依赖性神经突生长的特异性下调相关
作者：
F. Walsh;J. Furness;S. Moore;S. Ashton;P. Doherty
摘要：CNS的发展与神经细胞粘附分子（NCAM）中30 bp可变选择剪接外显子（VASE）的使用增加有关。我们已经通过逆转录酶连接聚合酶链反应评估了VASE在发育中的小脑和海马中的相对使用，当从这些组织中分离的神经元可以通过增加轴突生长对底物相关NCAM做出反应时，以及在后期发育阶段，当它们不再对底物相关NCAM做出反应时。出生后第6天从发育中的小脑分离的神经元对NCAM的反应是神经突生长增加。发现来自这些细胞的NCAM转录物具有可忽略的VASE使用水平。相比之下，在发育后期（出生后第8、10和11天）分离的神经元，对NCAM没有反应，发现其合成的含有VASE的NCAM转录物比例要高得多。在海马中，胚胎第18天对NCAM有反应的神经元表达低水平的VASE，而出生后第4天和第5天对NCAM无反应的神经元则有更大比例的含有VASE的转录本。因此，神经元使用NCAM VASE外显子的水平似乎是这些细胞通过增加神经突生长对不含VASE的NCAM（在细胞基质中表达）做出反应的能力的良好指标。
Abstract: The development of the CNS is associated with an increasing use of the 30‐bp variable alternative, spliced exon (VASE) in neural cell adhesion molecule (NCAM). We have assessed the relative usage of VASE by reverse transcriptase‐linked polymerase chain reaction in the developing cerebellum and hippocampus at times when neurons isolated from these tissues can respond to substrate‐associated NCAM by increased axonal growth and also at later developmental stages, when they are no longer responsive to substrate‐associated NCAM. Neurons isolated from the developing cerebellum at postnatal day 6 respond to NCAM with increased neurite growth. NCAM transcripts from these cells were found to have negligible levels of VASE usage. In contrast, neurons that are isolated at later stages of development (postnatal days 8, 10, and 11) and do not respond to NCAM were found to synthesise a much higher proportion of NCAM transcripts containing VASE. In the hippocampus, embryonic day 18 neurons, which are responsive to NCAM, express low levels of VASE, whereas postnatal days 4 and 5 neurons, which are not responsive to NCAM, have a greater proportion of transcripts containing VASE. Thus, the level of NCAM VASE exon usage by neurons appears to be a good indicator of the ability of these cells to respond to non‐VASE‐containing NCAM (expressed in a cellular substratum) by increased neurite outgrowth.