Expression of the neural axon adhesion molecule L1 in the developing and adult rat brain.
Expression of the neural axon adhesion molecule L1 in the developing and adult rat brain.
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发表时间：
1994-12
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通讯作者：
P. Liljelund;Prabhat K. Ghosh;AN van den Pol
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作者：
P. Liljelund;Prabhat K. Ghosh;AN van den Pol
L1 是一种发育调节的粘附分子，可能在轴突引导的某些方面发挥作用。通过 Northern 印迹，我们发现发育中的大鼠大脑中 L1 RNA 在出生后第 1 天 (P1) 达到峰值表达。蛋白质印迹显示 P15 上有一个蛋白质峰。 L1 的主要形式为 200 kDa，但也发现了较低分子量的形式，包括 140 和 80 kDa，分别代表 L1 的细胞外和细胞内区域。 L1 的所有分子质量形式在发育过程中都会发生变化。尽管 L1 的表达水平低于发育过程中的水平，但 L1 存在于成年大鼠的所有大脑区域中。大脑的不同区域表现出 L1 及其肽片段的差异表达和调节。例如，下丘脑在 P10 和 P15 时表现出相对于小脑和海马表达的 L1-80/L1-200 比率增强。培养中的小脑颗粒细胞显示出较强的 L1-200，而几乎没有 L1-60、-80 或 -140，而同龄的完整小脑则显示出较弱的 L1-200 和较强的 L1-60、-80 和 -140。对照实验表明，在不同发育的大脑区域中发现的 L1 蛋白水解裂解发生在体内，而不是样品制备的结果。培养的颗粒细胞中 L1-200 的量与测量的生长轴突长度成正比。神经元活性（通过 25 mM K+、100 微米 N-甲基-D-天冬氨酸和 100 微米 4-氨基吡啶增强）增强了 L1 转录和翻译。总之，这些数据表明 L1 表达和蛋白水解裂解的差异调节对于发育年龄和大脑区域具有特异性。
L1 is a developmentally regulated adhesion molecule that may play a role in some aspects of axonal guidance. With Northern blots we find peak expression of L1 RNA at postnatal day 1 (P1) in the developing rat brain. Western blots show a peak of protein on P15. The major form of L1 is 200 kDa, but lower molecular mass forms are found including 140 and 80 kDa, representing, respectively, the extracellular and intracellular regions of L1. All molecular mass forms of L1 change during development. Although expressed at lower levels than during development, L1 is found in all brain regions in the adult rat. Different regions of the brain show differential expression and regulation of L1 and its peptide fragments. For instance, the hypothalamus showed an enhanced L1-80/L1-200 ratio at P10 and P15 relative to that expressed by cerebellum and hippocampus. Cerebellar granule cells in culture showed strong L1-200 and almost no L1-60, -80, or -140, in contrast to the intact cerebellum at the same age, which showed weaker L1-200 and strong L1-60, -80, and -140. Control experiments indicated that the L1 proteolytic cleavage found in different developing brain regions occurred in vivo and was not a result of sample preparation. The amount of L1-200 in cultured granule cells was proportional to the measured length of the growing axon. Neuronal activity (increased with 25 mM K+, 100 microns N-methyl-D-aspartate, and 100 microns 4-aminopyridine) enhanced L1 transcription and translation. Together, these data suggest differential regulation of L1 expression and proteolytic cleavage specific for developmental ages and brain regions.