Run-on gene transcription in human neocortical nuclei - Inhibition by nanomolar aluminum and implications for neurodegenerative disease
Run-on gene transcription in human neocortical nuclei - Inhibition by nanomolar aluminum and implications for neurodegenerative disease
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DOI：
10.1385/jmn:11:1:67
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发表时间：
1998-08-01
影响因子：
3.1
通讯作者：
Bazan, NG
中科院分区：
文献类型：
--
作者：
Lukiw, WJ;Leblanc, HJ;Bazan, NG
在短死后间隔（PMI）人脑新皮质核（n，22; PMI，0.5-24 h）中，使用连续基因转录检查[α-P-32]-尿苷三磷酸掺入DNA转录产物。反向北方斑点杂交新合成的RNA对总cDNA或Alu重复DNA表明，人脑新皮层核的4小时PMI是有效的，在将放射性标记到新的转录产物，之后有一个渐进的下降，从头RNA生物合成能力。为了测试0-3000 nM浓度的环境铝对RNA聚合酶I（RNAP I）和RNA聚合酶II（RNAP II）转录的影响，对（1）人特异性Alu重复元件（2）神经丝轻链（NFL），（3）胶质细胞酸性蛋白（GFAP）与新合成的放射性标记总RNA进行北方杂交。这些DNA分别代表异质核RNA（hnRNA）、神经元和神经胶质特异性标志物。我们在这里报告的剂量依赖性抑制脑RNAP II的生物合成能力在50-100 nM铝的范围内，赤字类似于先前描述的使用兔新皮质核转录系统和浓度已报告在阿尔茨海默病（AD）常染色质。RNAP II和神经元特异性NFL基因在铝存在下的转录被发现特别受影响。这些发现支持了这样的假设，即在微量环境铝的存在下，大脑基因转录会损害哺乳动物大脑DNA以充分读取遗传信息。
The incorporation of [alpha-P-32]-uridine triphosphate into DNA transcription products was examined in short post-mortem interval (PMI) human brain neocortical nuclei (n, 22; PMI, 0.5-24 h) using run-on gene transcription. Reverse Northern dot-blot hybridization of newly synthesized RNA against either total cDNA or Alu repetitive DNA indicated that human brain neocortical nuclei of up to 4-h PMI were efficient in incorporating radiolabel into new transcription products, after which there was a graded decline in de novo RNA biosynthetic capacity. To test the effects of 0-3000 nM concentrations of ambient aluminum on RNA polymerase I (RNAP I) and RNA polymerase II (RNAP II) transcription, dot blots containing 0.5, 1.0, 2.0, and 5.0 mu g of DNA for (1) the human-specific Alu repetitive element (2) the neurofilament light (NFL) chain, and (3) glial fibrillary acidic protein (GFAP) were Northern hybridized against newly synthesized radiolabeled total RNA. These DNAs represent heterogeneous nuclear RNA (hnRNA), neuronal-, and glial-specific markers, respectively. We report here a dose-dependent repression in the biosynthetic capabilities of brain RNAP II in the range of 50-100 nM aluminum, deficits similar to those previously described using a rabbit neocortical nuclei transcription system and at concentrations that have been reported in Alzheimer's disease (AD) euchromatin. Transcription from RNAP II and the neuron-specific NFL gene in the presence of aluminum was found to be particularly affected. These findings support the hypothesis that brain gene transcription in the presence of trace amounts of ambient aluminum impairs mammalian brain DNA to adequately read out genetic information.