Bush M S, Gordon-Weeks P R
Developmental Biology Research Centre, Randall Institute, King's College, London, UK.
J Neurocytol. 1994 Nov;23(11):682-98. doi: 10.1007/BF01181643.
The distribution and expression of developmentally regulated phosphorylation epitopes on the microtubule-associated protein 1B and on neurofilament proteins recognized by monoclonal antibody (mAb) 150 and mAb SMI-31 was investigated in the developing rat spinal cord. In the embryonic day 11 spinal cord, mAb 150 stained the first axons to appear, whereas mAb SMI-31 staining did not appear until embryonic day 12. At the start of axonogenesis, mAb 150 stained neuronal cell bodies and axons whereas at later times only the distal axon was stained, this is the first demonstration in vivo of a mAb 150 axonal gradient similar to that seen previously in vitro (Mansfield et al., 1991). During the postnatal period, axonal staining by mAb 150 dramatically declined so that by the third postnatal week, only the corticospinal tract, which contains axons that are still growing, was labelled. There was no evidence of dendritic staining except of adult primary motoneurons. In contrast, mAb SMI-31 staining of axons was not present as a gradient. Instead, mAb SMI-31 staining increased progressively throughout this period, persisted into adulthood and was shown by immunoblotting to be related to the increased phosphorylation of the medium and heavy neurofilament proteins. Axonal staining by mAb 150 re-appears in a sub-population of the SMI-31-labelled myelinated axons in the adult spinal cord and PNS and in the perikarya and dendrites of primary motoneurons, where it probably recognizes a phosphorylation epitope on heavy neurofilament proteins. This late appearing epitope has some similarities to that recognized by mAb SMI-31 on neurofilaments, but it is not identical. These cross-reactivities of mAbs that recognize phosphorylation epitopes on otherwise unrelated proteins dictate caution in interpreting immunohistochemical data. It may now be necessary in some cases to re-appraise published studies using these two antibodies.
在发育中的大鼠脊髓中，研究了微管相关蛋白1B以及单克隆抗体（mAb）150和mAb SMI-31识别的神经丝蛋白上发育调控的磷酸化表位的分布和表达。在胚胎第11天的脊髓中，mAb 150标记了最早出现的轴突，而mAb SMI-31的标记直到胚胎第12天才出现。在轴突发生开始时，mAb 150标记神经元细胞体和轴突，而在后期仅远端轴突被标记，这是首次在体内证明mAb 150轴突梯度，类似于先前在体外观察到的情况（曼斯菲尔德等人，1991年）。在出生后时期，mAb 150的轴突标记显著下降，因此到出生后第三周，仅含有仍在生长的轴突的皮质脊髓束被标记。除了成年初级运动神经元外，没有树突标记的证据。相比之下，mAb SMI-31的轴突标记不存在梯度。相反，mAb SMI-31的标记在此期间逐渐增加，持续到成年，免疫印迹显示其与中等和重神经丝蛋白磷酸化增加有关。mAb 150的轴突标记在成年脊髓和周围神经系统中SMI-31标记的有髓轴突亚群以及初级运动神经元的胞体和树突中重新出现，在那里它可能识别重神经丝蛋白上的磷酸化表位。这种后期出现的表位与mAb SMI-31在神经丝上识别的表位有一些相似之处，但并不相同。识别不相关蛋白上磷酸化表位的单克隆抗体的这些交叉反应性表明在解释免疫组化数据时需谨慎。现在在某些情况下可能有必要重新评估使用这两种抗体发表的研究。
