| Expression and Purification of a Mammalian P2X7 Receptor from Sf9 Insect Cells
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Author:
Date:
2017-09-05
[Abstract] The P2X7 receptor is an extracellular ATP-gated ion channel found only in eukaryotes (Bartlett et al., 2014). Due to its unique properties among P2X receptors, such as formation of a large conductance pore, the P2X7 receptor has been implicated in devastating diseases like chronic pain (North and Jarvis, 2013). However, mechanisms underlying the P2X7 specific properties remain poorly understood, partly because purification of this eukaryotic membrane protein has been challenging. Here we describe a detailed protocol for expressing and purifying a mammalian P2X7 receptor using an insect cell-baculovirus system. The P2X7 receptor is expressed in Sf9 insect cells as a GFP fusion protein and solubilized with a buffer containing Triton X-100 detergent. The P2X7-GFP fusion protein is ...
[摘要] P2X7受体是仅在真核生物中发现的胞外ATP门控离子通道（Bartlett等，2014）。由于其P2X受体之间的独特性质，例如大电导孔的形成，P2X7受体已经涉及破坏性疾病如慢性疼痛（North和Jarvis，2013）。然而，P2X7特异性属性的机制仍然知之甚少，部分原因是纯化这种真核膜蛋白是一个挑战。在这里，我们描述了使用昆虫细胞 - 杆状病毒系统表达和纯化哺乳动物P2X7受体的详细方案。 P2X7受体在作为GFP融合蛋白的Sf9昆虫细胞中表达，并用含有Triton X-100洗涤剂的缓冲液溶解。然后使用Strep-Tactin亲和层析在含有十二烷基麦芽糖苷的缓冲液中纯化P2X7-GFP融合蛋白。在通过凝血酶酶切割连接的GFP和Strep-标签后，使用大小排阻色谱分离P2X7受体。该方法通常从6L的Sf9培养物产生约2mg的纯化蛋白质。纯化的蛋白质可以用含有15％甘油的缓冲液在4℃下储存至少2个月，并用于各种功能和结构研究（Karasawa和Kawate，2016）。
【背景】P2X7受体是嘌呤能P2X受体家族的七种亚型之一，并且是广泛疾病如神经退行性疾病，癫痫和神经性疼痛的有希望的新型药物靶点（North和Jarvis，2013; Bhattacharya和Biber， ...
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| Assaying the Effects of Splice Site Variants by Exon Trapping in a Mammalian Cell Line
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Author:
Date:
2017-05-20
[Abstract] There are several in silico programs that endeavor to predict the functional impact of an individual’s sequence variation at splice donor/acceptor sites, but experimental confirmation is problematic without a source of RNA from the individual that carries the variant. With the aid of an exon trapping vector, such as pSPL3, an investigator can test whether a splice site sequence change leads to altered RNA splicing, through expression of reference and variant mini-genes in mammalian cells and analysis of the resultant RNA products.
[摘要] 有几个计算机程序尝试预测个体在剪接供体/受体位点的序列变异的功能影响，但实验确认是有问题的，没有携带变体的个体的RNA来源。借助于外显子捕获载体，例如pSPL3，研究人员可以通过在哺乳动物细胞中表达参考和变体小基因来测试剪接位点序列变化是否导致改变的RNA剪接，并分析所得RNA产物。
背景 我们希望通过实验测试在TEK基因中鉴定的两个剪接供体位点变体c.760 + 2T> C和c.3300 + 2delT的功能影响（Souma等人，2016）。通常情况下，携带这些序列变体的个体不能获得细胞或mRNA的样品，因此我们利用外显子捕获方法作为功能测试。来自患者的DNA样品可用于感兴趣的基因组区域的PCR扩增。如果患者gDNA样品不可用，也可以通过诸如基于PCR的定点诱变等方法将序列变体并入野生型序列。
＆NBSP;外显子捕获方法最初是为了鉴定长期基因组DNA中的未知外显子而开发的（Duyk等人，1990）。创建了pSPL3外显子捕获载体以提高外显子鉴定的效率和可靠性，并且还允许筛选更大的基因组片段（Church et al。，1994; Nisson等，1994）。 pSPL3载体含有由SV40启动子组成的小型人造基因，具有功能性剪接供体和受体位点的外显子 - 内含子 - ...
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| Ubiquitination Assay for Mammalian Cells
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Author:
Date:
2016-07-20
[Abstract] Ubiquitin is an 8.5 kDa protein that can be activated and conjugated by ubiquitin-activating enzyme E1 and ubiquitin-conjugating enzyme E2, respectively. Ubiquitin E3 ligases then recognize protein substrates, and then transfer the ubiquitin from E2 to the targeted protein. This biological process is called ubiquitination, and it is an important biological process which can signal protein degradation via the proteasome. The aim of this protocol is to describe a procedure that determines the level of cellular ubiquitination in a protein-of-interest relative to control cells.
[摘要] 泛素是8.5kDa的蛋白质，其可以分别由泛素激活酶E1和泛素缀合酶E2激活和缀合。 然后泛素E3连接酶识别蛋白质底物，然后将泛素从E2转移到目标蛋白质。 这种生物过程称为泛素化，它是一个重要的生物过程，可以通过蛋白酶体信号蛋白降解。 该方案的目的是描述确定相对于对照细胞的目的蛋白质中的细胞泛素化水平的程序。
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