Niinobe M, Maeda N, Ino H, Mikoshiba K
Division of Regulation of Macromolecular Function, Osaka University, Japan.
J Neurochem. 1988 Oct;51(4):1132-9. doi: 10.1111/j.1471-4159.1988.tb03078.x.
Microtubule-associated protein (MAP) 2 was purified from the microtubule fraction of mouse brain by heat treatment and BioGel A-5m gel filtration. The purified preparation showed a single protein band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis using both a gradient gel (3.75-12.5%) and a low-percentage gel (5%), a finding indicating that MAP2B was absent under the conditions used. Amino acid analysis revealed that mouse MAP2 was an acidic protein with an isoelectric point (pI 4.5) and amino acid composition similar to those of porcine brain MAP2. Immunoblot analysis indicated that the antigens that reacted with MAP2 antiserum were present in large quantities in mouse brain. However, we also found a weak reaction in various tissues other than brain, and the major antigens involved were recognized to be common molecular species with the same molecular mass, 162 and 170 kilodaltons. Using antiserum against mouse brain MAP2, the developmental localization patterns of MAP2 in the mouse cerebellar cortex were studied by immunohistochemistry. MAP2 was mainly localized in the neuronal cells throughout development, with the expression in Purkinje cell dendrites being especially remarkable in the growth of arborization from postnatal day 3 to day 20. At the mature stage, the reaction was strong in the dendritic tree but very weak in the proximal dendrites and cell bodies.
微管相关蛋白（MAP）2通过热处理和BioGel A - 5m凝胶过滤从小鼠脑的微管部分中纯化出来。在使用梯度凝胶（3.75 - 12.5%）和低百分比凝胶（5%）的十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳中，纯化制剂显示出单一蛋白条带，这一发现表明在所使用的条件下不存在MAP2B。氨基酸分析表明，小鼠MAP2是一种酸性蛋白，其等电点（pI 4.5）和氨基酸组成与猪脑MAP2相似。免疫印迹分析表明，与MAP2抗血清反应的抗原在小鼠脑中大量存在。然而，我们也发现在脑以外的各种组织中有微弱反应，并且所涉及的主要抗原被认为是具有相同分子量（162和170千道尔顿）的常见分子种类。使用针对小鼠脑MAP2的抗血清，通过免疫组织化学研究了MAP2在小鼠小脑皮质中的发育定位模式。在整个发育过程中，MAP2主要定位于神经元细胞，在出生后第3天至第20天的树突生长过程中，浦肯野细胞树突中的表达尤为显著。在成熟阶段，树突中的反应强烈，但近端树突和细胞体中的反应非常微弱。
