Burry R W, Lah J J, Hayes D M
Department of Cell Biology, Neurobiology and Anatomy, Ohio State University, Columbus 43210-1239.
J Neurocytol. 1992 Jun;21(6):413-25. doi: 10.1007/BF01191506.
GAP-43 (F1, B-50, pp46) has been associated with neuronal development and regeneration, but precise localization within neurons is not known. Pre-embedding electron microscopic immunocytochemistry using silver-enhanced 1 nm gold particles was used to localize GAP-43 label in cell cultures of cerebellar neurons. In the plasma membranes of early cultures, high levels of GAP-43 were seen in all parts of the neuron. In older cultures, consistent with previous reports, the first loss of GAP-43 label was seen in the soma and then the axon. Growth cones had high levels of GAP-43 label on the plasma membrane, with increased distribution over unattached relative to attached filopodia. The amount of GAP-43 seen over the plasma membrane of forming presynaptic terminals is lower than over growth cones, indicating a possible correlation between the presence of GAP-43 and the stage of presynaptic terminal development. Intracellular GAP-43 in axons and growth cones was highest in membranes of smooth cisternae. The levels of GAP-43 in smooth cisternae in axons fell by seven days in culture while the levels of GAP-43 in smooth cisternae of growth cones fell at 14 days. When mini-explant cerebellar cultures were examined with light microscopic immunocytochemistry, GAP-43 label of plasma membrane was highest at the periphery of the radial axonal outgrowth, suggesting that addition of GAP-43 to the plasma membrane can occur in the distal axon or at the growth cone.
生长相关蛋白43（GAP - 43，即F1、B - 50、pp46）与神经元的发育和再生有关，但其在神经元内的确切定位尚不清楚。本研究采用银增强1纳米金颗粒的包埋前电子显微镜免疫细胞化学方法，对小脑神经元细胞培养物中的GAP - 43标记进行定位。在早期培养物的质膜中，神经元各部位均可见到高水平的GAP - 43。在较老的培养物中，与先前报道一致，首先在胞体中观察到GAP - 43标记的丢失，随后是轴突。生长锥的质膜上有高水平的GAP - 43标记，相对于附着的丝状伪足，未附着的丝状伪足上的分布增加。在形成突触前终末的质膜上观察到的GAP - 43量低于生长锥，这表明GAP - 43的存在与突触前终末发育阶段之间可能存在相关性。轴突和生长锥中的细胞内GAP - 43在光滑池膜中含量最高。培养7天时，轴突光滑池中的GAP - 43水平下降，而生长锥光滑池中的GAP - 43水平在14天时下降。当用光学显微镜免疫细胞化学检查微型外植体小脑培养物时，质膜的GAP - 43标记在放射状轴突生长的周边最高，这表明GAP - 43添加到质膜可能发生在轴突远端或生长锥处。
