Beer J, Mielke K, Zipp M, Zimmermann M, Herdegen T
II. Institute of Physiology, University of Heidelberg, Im Neuenheimer Feld 326, 69120 Heidelberg, Germany.
Brain Res. 1998 Jun 1;794(2):255-66. doi: 10.1016/s0006-8993(98)00233-9.
The present study has investigated the congruence of mRNA induction and protein expression of inducible transcription factors (ITFs). The patterns of c-jun, junB, c-fos, fra-1 and fra-2 mRNAs were studied by radioactive and non-radioactive in situ hybridization in the adult rat brain following kainate-induced seizure activity and axotomy. In the same animals, the expression of c-Jun, JunB and c-Fos proteins was compared with the respective mRNA signals. Using radioactive labeled probes all investigated mRNAs showed an onset within 1 h after systemic kainate application and the maximal levels were generally reached after 3 h. Each mRNA displayed a specific temporo-spatial expression pattern. Whereas fra-1 and fra-2 were restricted to the hippocampus, c-jun, junB and c-fos were additionally induced in the cortex, amygdala and thalamus. The areas with maximal labeling were the dentate gyrus and the hippocampal CA1 and CA3 subfields. The expression patterns between c-jun, junB and c-fos mRNA were virtually congruent with the respective protein. Labeling of the junB and fra-2 probes with digoxigenin yielded similar results. Twenty-four hours, 3 and 10 days following transection of the medial forebrain bundle and the mamillo-thalamic tract, high levels of c-jun mRNA (either digoxigenin or radioactive labeled probes) and protein were seen in the axotomized neurons of the substantia nigra pars compacta and mamillary body whereas the other mRNAs studied and the JunB or c-Fos proteins could not be detected. These findings demonstrate that mRNAs encoding for ITFs are translated into the respective proteins following excitotoxic seizures and axotomy, and that the antisera used for immunocytochemistry yield specific expression patterns of homologous proteins.
本研究调查了诱导型转录因子（ITF）的mRNA诱导与蛋白质表达的一致性。在成年大鼠脑内，通过放射性和非放射性原位杂交技术，研究了在红藻氨酸诱导的癫痫发作活动和轴突切断后，c-jun、junB、c-fos、fra-1和fra-2 mRNA的表达模式。在相同动物中，将c-Jun、JunB和c-Fos蛋白的表达与各自的mRNA信号进行了比较。使用放射性标记探针，所有研究的mRNA在全身应用红藻氨酸后1小时内开始出现，最大水平通常在3小时后达到。每种mRNA都显示出特定的时空表达模式。fra-1和fra-2局限于海马体，而c-jun、junB和c-fos在皮质、杏仁核和丘脑也有额外诱导表达。标记最强的区域是齿状回以及海马体CA1和CA3亚区。c-jun、junB和c-fos mRNA的表达模式与各自的蛋白质基本一致。用地高辛标记junB和fra-2探针也得到了类似结果。在内侧前脑束和乳头体 - 丘脑束横断后24小时、3天和10天，在黑质致密部和乳头体的轴突切断神经元中可见高水平的c-jun mRNA（地高辛或放射性标记探针）和蛋白质，而其他研究的mRNA以及JunB或c-Fos蛋白未被检测到。这些发现表明，编码ITF的mRNA在兴奋性毒性癫痫发作和轴突切断后被翻译成各自的蛋白质，并且用于免疫细胞化学的抗血清产生同源蛋白质的特异性表达模式。
