Luziga Claudius, Nakamura Orie, Deshapriya R M C, Usui Masaru, Miyaji Masanori, Wakimoto Miho, Wada Naomi, Mbassa Gabriel, Yamamoto Yoshimi
Department of Veterinary Anatomy, Faculty of Veterinary Medicine, Sokoine University of Agriculture, P.O. Box 3016, Morogoro, Tanzania.
Brain Res. 2008 Apr 14;1204:40-52. doi: 10.1016/j.brainres.2008.01.067. Epub 2008 Feb 6.
Cytotoxic T-lymphocyte antigen-2 alpha (CTLA-2alpha) is a novel cysteine proteinase inhibitor protein originally discovered and expressed in mouse activated T-cells and mast cells. Expressed recombinant CTLA-2alpha is shown to exhibit selective inhibition of cathepsin L-like cysteine proteinases. We have recently reported the expression pattern of CTLA-2alpha mRNA in mouse brain by in situ hybridization, demonstrating that it is mainly enriched within neuronal populations. In this study we present the distribution profile of the protein by immunohistochemical analysis. Results showed that CTLA-2alpha protein is preferentially localized in dendritic and axonal compartments. In telencephalon, strong labeling was detected in dendrites in the cerebral cortices, stratum radiatum and stratum lacunosum moleculare and within axonal fibers of stratum lucidum where mossy fibers emanating from all parts of the granule cell layer of dentate gyrus terminate at pyramidal neurons and interneurons. In diencephalon, moderate staining was found in all thalamic nuclei but was strong in medial habenular nucleus and the hypothalamic nuclei including suprachiasmatic nucleus, optic chiasm, arcuate nucleus and median eminence. In mesencephalon, strong immunoreactivity was detected in superior colliculus, inferior colliculus and paramedian raphe nucleus. In the rhombencephalon, the pontine nucleus and transverse fibers of the pons revealed strong staining but were moderate in vestibular nuclei. Strong immunoreactivity was also observed in the internal white matter, granule cell layer and Purkinje cell layer within cerebellum. On Western blot analysis, a band of 14 kDa for CTLA-2alpha from protein extracts of the cerebrum, cerebellum, pons and medulla was detected. The distribution pattern and functional considerations of CTLA-2alpha in the brain are discussed.
细胞毒性T淋巴细胞抗原2α（CTLA - 2α）是一种新型的半胱氨酸蛋白酶抑制蛋白，最初在小鼠活化T细胞和肥大细胞中发现并表达。表达的重组CTLA - 2α显示出对组织蛋白酶L样半胱氨酸蛋白酶的选择性抑制作用。我们最近通过原位杂交报道了CTLA - 2α mRNA在小鼠脑中的表达模式，表明它主要富集在神经元群体中。在本研究中，我们通过免疫组织化学分析展示了该蛋白的分布情况。结果显示，CTLA - 2α蛋白优先定位于树突和轴突区室。在端脑，在大脑皮质的树突、辐射层和分子层空洞以及透明层的轴突纤维中检测到强染色，其中来自齿状回颗粒细胞层各部分的苔藓纤维在锥体细胞和中间神经元处终止。在间脑，所有丘脑核均有中度染色，但在内侧缰核和下丘脑核包括视交叉上核、视交叉、弓状核和正中隆起中染色较强。在中脑，在上丘、下丘和中缝旁核中检测到强免疫反应性。在菱脑，脑桥核和脑桥横纤维显示强染色，但在前庭核中为中度染色。在小脑的内部白质、颗粒细胞层和浦肯野细胞层中也观察到强免疫反应性。在蛋白质印迹分析中，从大脑、小脑、脑桥和延髓的蛋白质提取物中检测到一条14 kDa的CTLA - 2α条带。本文讨论了CTLA - 2α在脑中的分布模式及其功能意义。
