Casanovas A, Ribera J, Hager G, Kreutzberg G W, Esquerda J E
Unitat de Neurobiologia Cellular, Departament de Ciències Mèdiques Bàsiques, Facultat de Medicina, Universitat de Lleida, Spain.
J Neurosci Res. 2001 Mar 15;63(6):469-79. doi: 10.1002/jnr.1041.
Motoneurons respond to peripheral nerve transection by either regenerative or degenerative events depending on their state of maturation. Since the expression of c-Jun has been involved in the early signalling of the regenerative process that follows nerve transection in adults, we have investigated c-Jun on rat neonatal axotomized motoneurons during the period in which neuronal death is induced. Changes in levels of c-Jun protein and its mRNA were determined by means of quantitative immunocytochemistry and in situ hybridization. Three hours after nerve transection performed on postnatal day (P)3, c-Jun protein and mRNA is induced in axotomized spinal cord motoneurons, and high levels were reached between 1 and 10 days after. This response is associated with a detectable c-Jun activation by phosphorylation on serine 63. No changes were found in the levels of activating transcription factor -2. Most of dying motoneurons were not labelled by either a specific c-Jun antibody or a c-jun mRNA probe. However, dying motoneurons were specifically stained by a polyclonal anti c-Jun antibody, indicating that some c-Jun antibodies react with unknown epitopes, probably distinct from c-Jun p39, that are specifically associated with apoptosis.
运动神经元根据其成熟状态，通过再生或退化事件对周围神经横断作出反应。由于c-Jun的表达参与了成体神经横断后再生过程的早期信号传导，我们研究了在诱导神经元死亡的时期，大鼠新生期轴突切断的运动神经元中的c-Jun。通过定量免疫细胞化学和原位杂交确定c-Jun蛋白及其mRNA水平的变化。在出生后第（P）3天进行神经横断后3小时，轴突切断的脊髓运动神经元中诱导出c-Jun蛋白和mRNA，并在1至10天后达到高水平。这种反应与通过丝氨酸63磷酸化检测到的c-Jun激活有关。激活转录因子-2的水平未发现变化。大多数即将死亡的运动神经元未被特异性c-Jun抗体或c-jun mRNA探针标记。然而，即将死亡的运动神经元被多克隆抗c-Jun抗体特异性染色，表明一些c-Jun抗体与未知表位反应，可能不同于与细胞凋亡特异性相关的c-Jun p39。
