THE DISTRIBUTION AND CHARACTERIZATION OF ENDOGENOUS PROTEIN ARGININE N-METHYLTRANSFERASE 8 IN MOUSE CNS
THE DISTRIBUTION AND CHARACTERIZATION OF ENDOGENOUS PROTEIN ARGININE N-METHYLTRANSFERASE 8 IN MOUSE CNS
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DOI：
10.1016/j.neuroscience.2009.06.061
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发表时间：
2009-11-10
期刊：
影响因子：
3.3
通讯作者：
Tohyama, M.
中科院分区：
文献类型：
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作者：
Kousaka, A.;Mori, Y.;Tohyama, M.
蛋白质精氨酸N-甲基转移酶（PRMT）8首先从数据库搜索中发现，该数据库搜索具有四个保守的甲基转移酶基序的基因，其在氨基酸中与PRMT 1具有超过80%的同源性[Lee J，Sayegh J，丹尼尔J，Clarke S，贝德福德MT（2005）PRMT 8，蛋白质精氨酸甲基转移酶家族的新的膜结合组织特异性成员。J Biol Chem 280：32890-32896]。有趣的是，其组织分布明显限于小鼠CNS。为了表征在CNS神经元中的功能，我们提出了针对PRMT 8的抗血清以进行免疫组织化学（IHC）和Western印迹分析。通过免疫组化，内源性PRMT 8的免疫反应性广泛分布在中枢神经系统神经元中，在小脑、海马结构和皮质中具有显著强的信号，但在小脑颗粒层中未检测到。在某些神经元亚群中，在树突和轴突束中观察到免疫反应性。免疫反应性的亚细胞定位主要是核，这与外源表达的PRMT 8通过N-末端肉豆蔻酰化定位于质膜的原始报道相反。对一系列具有不同框内翻译起始密码子的外源表达蛋白进行了测试，以在分子大小上与内源蛋白进行比较。第三个起始密码子产生的蛋白质大小与内源性蛋白质相当，并在PC 12细胞中显示出类似的定位模式。总之，PRMT 8是神经元特异性核酶，并且N-末端不包含豆蔻酰化靶的甘氨酸末端。(C)2009年IBRO。由爱思唯尔有限公司出版。保留所有权利。
Protein arginine N-methyltransferase (PRMT) 8 was first discovered from a database search for genes harboring four conserved methyltransferase motifs, which shares more than 80% homology to PRMT1 in amino acid [Lee J, Sayegh J, Daniel J, Clarke S, Bedford MT (2005) PRMT8, a new membrane-bound tissue-specific member of the protein arginine methyltransferase family. J Biol Chem 280:32890-32896]. Interestingly, its tissue distribution is strikingly restricted to mouse CNS. To characterize the function in the CNS neurons, we raised an antiserum against PRMT8 to perform immunohistochemistry (IHC) and Western blot analysis. By IHC, the immunoreactivity of endogenous PRMT8 was broadly distributed in the CNS neurons with markedly intense signals in the cerebellum, hippocampal formation, and cortex, but was not detected in the cerebellar granular layer. In some subset of the neurons, the immunoreactivity was observed in the dendrites and axon bundles. The subcellular localization of the immunoreactivity was dominantly nuclear, arguing against the original report that exogenously expressed PRMT8 localizes to the plasma membrane via the N-terminal myristoylation. A series of the exogenously expressed proteins with different in-frame translation initiation codons was tested for comparison with the endogenous protein in molecular size. The third initiator codon produced the protein that was equivalent in size to the endogenous and showed a similar localizing pattern in PC12 cells. In conclusion, PRMT8 is a neuron-specific nuclear enzyme and the N-terminus does not contain the glycine end for myristoylation target. (C) 2009 IBRO. Published by Elsevier Ltd. All rights reserved.