Albala J S, Kress Y, Liu W K, Weidenheim K, Yen S H, Shafit-Zagardo B
Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
J Neurochem. 1995 Jun;64(6):2480-90. doi: 10.1046/j.1471-4159.1995.64062480.x.
Microtubule-associated protein-2 (MAP-2) functions to maintain neuronal morphology by promoting the assembly of microtubules. MAP-2c is an alternately spliced form of MAP-2, containing the first 151 amino acids of high-molecular-weight (HMW) MAP-2 joined to the last 321 amino acids, eliminating 1,352 amino acids specific to HMW MAP-2. A polyclonal antibody generated to the splice site of human MAP-2c was used to determine its cellular localization. The MAP-2c antiserum was depleted of any HMW MAP-2 reactivity by absorption with HMW MAP-2 fusion protein. Western blot analysis of human fetal spinal cord homogenates demonstrated that the antibody is specific for human MAP-2c. MAP-2c immunoreactivity was found in the perinuclear cytoplasm and processes of anterior motor neurons and large processes of the posterior column in sections from 22-24-week human fetal spinal cord. Double-label confocal microscopy was performed using the MAP-2c polyclonal antibody and either a HMW MAP-2 or a neurofilament protein (highly phosphorylated 160- and 200-kDa protein) monoclonal antibody to identify these processes as dendrites or axons, respectively. HMW MAP-2 and MAP-2c colocalized in cell bodies and dendrites of anterior motor neurons, demonstrating for the first time the presence of native MAP-2c within dendrites. In addition, immunoelectron microscopy showed MAP-2c associated with microtubules in dendrites of motor neurons. MAP-2c and the neurofilament proteins were found in axons of the dorsal and ventral roots. The presence of MAP-2c within axons and dendrites suggests that MAP-2c contributes to neuronal plasticity during human fetal development.
微管相关蛋白2（MAP-2）通过促进微管组装来维持神经元形态。MAP-2c是MAP-2的一种可变剪接形式，包含高分子量（HMW）MAP-2的前151个氨基酸与后321个氨基酸相连，去除了HMW MAP-2特有的1352个氨基酸。针对人MAP-2c剪接位点产生的多克隆抗体用于确定其细胞定位。通过用HMW MAP-2融合蛋白吸收，去除了MAP-2c抗血清中任何HMW MAP-2反应性。对人胎儿脊髓匀浆的蛋白质免疫印迹分析表明，该抗体对人MAP-2c具有特异性。在22 - 24周人胎儿脊髓切片中，在前运动神经元的核周细胞质和突起以及后柱的大突起中发现了MAP-2c免疫反应性。使用MAP-2c多克隆抗体和HMW MAP-2或神经丝蛋白（高度磷酸化的160 kDa和200 kDa蛋白）单克隆抗体进行双标共聚焦显微镜检查，分别将这些突起鉴定为树突或轴突。HMW MAP-2和MAP-2c在前运动神经元的细胞体和树突中共定位首次证明了树突中存在天然的MAP-2c。此外，免疫电子显微镜显示MAP-2c与运动神经元树突中的微管相关。在背根和腹根的轴突中发现了MAP-2c和神经丝蛋白。轴突和树突中存在MAP-2c表明MAP-2c在人胎儿发育过程中有助于神经元可塑性。
