Morgan J I, Slemmon J R, Danho W, Hempstead J, Berrebi A S, Mugnaini E
Department of Neuroscience, Roche Institute of Molecular Biology, Nutley, New Jersey 07110.
Synapse. 1988;2(2):117-24. doi: 10.1002/syn.890020203.
The rat cerebellum was previously shown to contain two polypeptides, a hexadecapeptide termed cerebellin and an apparent metabolite des-Ser1-cerebellin. The cerebellins have a high degree of sequence homology with residues 625-641 of the polyimmunoglobulin (polyIg)-receptor adjacent to its membrane-spanning domain. Since the cerebellins are localized in Purkinje cells and enriched in synaptosomes, this might indicate that cerebellin is a specific proteolytic cleavage fragment of a synaptic protein involved in the transcytosis of an unknown ligand. Using a specific cerebellin radioimmunoassay described here combined with high-performance liquid chromatography, cerebellin immunoreactivity could be demonstrated in the cerebella of all vertebrates examined from man to chicken. Cerebellin immunoreactivity is localized to Purkinje cells in the rat, mouse, and chicken. Furthermore, cerebellin expression is under developmental regulation in both the chicken and mouse. In addition, neurodevelopmental mutations of mice that eliminate granule cells cause a large deficit in cerebellin levels, suggesting some form of transneuronal regulation.
先前研究表明，大鼠小脑含有两种多肽，一种是由十六个氨基酸组成的肽，称为小脑素，另一种是明显的代谢产物脱丝氨酸 - 小脑素。小脑素与多聚免疫球蛋白（polyIg）受体跨膜结构域附近的625 - 641位残基具有高度的序列同源性。由于小脑素定位于浦肯野细胞且在突触体中富集，这可能表明小脑素是一种参与未知配体转胞吞作用的突触蛋白的特异性蛋白水解裂解片段。使用本文所述的特异性小脑素放射免疫测定法结合高效液相色谱法，在从人到鸡的所有被检查脊椎动物的小脑中都能检测到小脑素免疫反应性。小脑素免疫反应性定位于大鼠、小鼠和鸡的浦肯野细胞。此外，小脑素的表达在鸡和小鼠中都受到发育调控。此外，消除颗粒细胞小鼠的神经发育突变会导致小脑素水平大幅下降，提示存在某种形式的跨神经元调节。
