Increased RNA editing in EAAT2 pre-mRNA from amyotrophic lateral sclerosis patients: Involvement of a cryptic polyadenylation site
Increased RNA editing in EAAT2 pre-mRNA from amyotrophic lateral sclerosis patients: Involvement of a cryptic polyadenylation site
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DOI：
10.1016/j.neulet.2011.04.047
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发表时间：
2011-06-22
影响因子：
2.5
通讯作者：
Makoff, Andrew
中科院分区：
文献类型：
--
作者：
Flomen, Rachel;Makoff, Andrew
星形胶质细胞 EAAT2 谷氨酸转运蛋白对于清除中枢神经系统中的谷氨酸和防止兴奋性毒性至关重要。它与肌萎缩侧索硬化症（ALS，最常见的运动神经元疾病类型）有关，其中 EAAT2 含量较少，可能涉及异常的内含子 7 保留转录本。我们报告了 EAAT2 前体 mRNA 内含子 7 中的一个新位点的腺嘌呤/肌苷 RNA 编辑，该位点似乎激活了一个神秘的替代多腺苷酸化位点，生成内含子 7 保留转录本。该聚腺苷酸化位点包括两个重叠的聚腺苷酸化信号，与强茎环中的编辑位点相对，这在灵长类动物中高度保守。在前 mRNA 中，我们观察到该位点的可变编辑水平，在 ALS 患者的脊髓 (p = 0.001) 和运动皮层 (p = 0.005) 中显着较高，但在小脑中则不然，这表明了临床相关区域的特异性。相比之下，内含子 7 中多聚腺苷酸化的不完整 mRNA 分子总是被完全编辑。细胞培养实验证实了内含子 7 中编辑和聚腺苷酸化之间的这种强相关性，强烈表明通过编辑激活了替代聚腺苷酸化位点。根据已发表的数据预测肌苷碱基配对表明，RNA 编辑从茎环释放聚腺苷酸化信号，提供了一种合理的机制。据我们所知，这是 RNA 编辑激活替代多腺苷酸化信号的第一份报告。 (C) 2011 Elsevier Ireland Ltd. 保留所有权利。
The astroglial EAAT2 glutamate transporter is essential for clearing glutamate in the central nervous system and protecting against excitotoxicity. It is implicated in amyotrophic lateral sclerosis (ALS, the most common type of motor neurone disease) where less EAAT2 is found, possibly involving aberrant intron 7 retention transcripts. We report adenine/inosine RNA editing at a novel site in intron 7 of EAAT2 pre-mRNA that appears to activate a cryptic alternative polyadenylation site, generating intron 7 retention transcripts. This polyadenylation site includes two overlapping polyadenylation signals opposite the editing site in a strong stem-loop, which is highly conserved in primates. In pre-mRNA, we observed variable editing levels at this site, which were significantly higher in spinal cord (p = 0.001) and motor cortex (p = 0.005) from ALS patients, but not in cerebellum, demonstrating specificity for clinically relevant regions. By contrast, incomplete mRNA molecules polyadenylated in intron 7 are always completely edited. Cell culture experiments confirm this strong correlation between editing and polyadenylation in intron 7, strongly suggesting activation of the alternative polyadenylation site by editing. Prediction of inosine base-pairing from published data suggests that RNA editing releases the polyadenylation signals from the stem-loop, providing a plausible mechanism. To the best of our knowledge, this is the first report of RNA editing activating an alternative polyadenylation signal. (C) 2011 Elsevier Ireland Ltd. All rights reserved.