Petitto J M, Huang Z
Department of Psychiatry, University of Florida College of Medicine, Gainesville 32610-0256, USA.
J Neuroimmunol. 1995 Jun;59(1-2):135-41. doi: 10.1016/0165-5728(95)00035-z.
Interleukin-2 (IL-2) has various trophic and neuromodulatory actions in the mammalian central nervous system (CNS). The interleukin-2 receptor alpha (IL-2R alpha) is an accessory subunit of the IL-2 receptor heterotrimer complex which is essential for 'high' affinity IL-2 binding. Although an IL-2R alpha (or IL-2R alpha-like) epitope has been localized in brain by immunohistocytochemistry, it was unknown whether the IL-2R alpha subunit expressed in brain was derived from the same or a different gene than the lymphocyte IL-2R alpha. Therefore, in the present study, the cDNA comprising the full length coding region was cloned and sequenced from saline-perfused forebrain. The brain IL-2R alpha cDNA was found to be 100% homologous with the corresponding lymphocyte IL-2R alpha cDNA sequence. IL-2R alpha mRNA was expressed at very low levels in saline-perfused forebrain of non-challenged BALB/c mice as well as in saline-perfused forebrain from severe combined immunodeficiency (SCID) mice. The present data, demonstrating IL-2R alpha gene expression in both well-perfused normal and SCID mouse forebrain from which no CD3 gamma gene expression was detected by PCR, provides evidence that the IL-2R alpha clones isolated are from resident brain cells and not from blood lymphocytes (e.g. T lymphocytes). Thus, these findings demonstrate that the protein coding sequence of the mouse brain IL-2R alpha is derived from the same gene coding sequence as the lymphocyte IL-2R alpha, and indicate that previously reported differences in the size of their respective mRNA transcripts appear to be due to differences in untranslated regions.
白细胞介素-2（IL-2）在哺乳动物中枢神经系统（CNS）中具有多种营养和神经调节作用。白细胞介素-2受体α（IL-2Rα）是IL-2受体异源三聚体复合物的一个辅助亚基，对于“高”亲和力的IL-2结合至关重要。尽管通过免疫组织化学已将IL-2Rα（或类IL-2Rα）表位定位于脑内，但尚不清楚脑内表达的IL-2Rα亚基是否与淋巴细胞IL-2Rα源自相同或不同的基因。因此，在本研究中，从经生理盐水灌注的前脑中克隆并测序了包含全长编码区的cDNA。发现脑IL-2Rα cDNA与相应的淋巴细胞IL-2Rα cDNA序列100%同源。在未受刺激的BALB/c小鼠的经生理盐水灌注的前脑以及严重联合免疫缺陷（SCID）小鼠的经生理盐水灌注的前脑中，IL-2Rα mRNA的表达水平非常低。本数据表明在经良好灌注的正常和SCID小鼠前脑中均有IL-2Rα基因表达，通过PCR未检测到这些前脑中的CD3γ基因表达，这提供了证据表明分离出的IL-2Rα克隆来自脑内驻留细胞而非血淋巴细胞（如T淋巴细胞）。因此，这些发现表明小鼠脑IL-2Rα的蛋白质编码序列与淋巴细胞IL-2Rα源自相同的基因编码序列，并表明先前报道的它们各自mRNA转录本大小的差异似乎是由于非翻译区的差异所致。
