| A Small RNA Isolation and Sequencing Protocol and Its Application to Assay CRISPR RNA Biogenesis in Bacteria
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Author:
Date:
2018-02-20
[Abstract] Next generation high-throughput sequencing has enabled sensitive and unambiguous analysis of RNA populations in cells. Here, we describe a method for isolation and strand-specific sequencing of small RNA pools from bacteria that can be multiplexed to accommodate multiple biological samples in a single experiment. Small RNAs are isolated by polyacrylamide gel electrophoresis and treated with T4 polynucleotide kinase. This allows for 3’ adapter ligation to CRISPR RNAs, which don’t have pre-existing 3’-OH ends. Pre-adenylated adapters are then ligated using T4 RNA ligase 1 in the absence of ATP and with a high concentration of polyethylene glycol (PEG). The 3’ capture step enables precise determination of the 3’ ends of diverse RNA molecules. Additionally, a random hexamer in the ligated ...
[摘要] 新一代高通量测序技术能够对细胞中的RNA群体进行敏感和明确的分析。在这里，我们描述了一种从细菌中分离和链特异性测序小RNA池的方法，所述细菌可以在单个实验中多路复用以容纳多个生物样品。小RNA通过聚丙烯酰胺凝胶电泳分离并用T4多核苷酸激酶处理。这允许3'衔接头连接至CRISPR RNA，其不具有预先存在的3'-OH末端。然后使用T4 RNA连接酶1在不存在ATP和高浓度聚乙二醇（PEG）的情况下将前腺苷酸化的衔接子连接。 3'捕获步骤能够精确测定不同RNA分子的3'末端。此外，连接适配器中的随机六聚体有助于控制潜在的下游扩增偏差。逆转录后，将cDNA产物环化并通过PCR制备文库。我们显示扩增的文库不需要通过凝胶电泳可见，以期望产物的有效测序。使用这种方法，我们通常从少量纯化的小RNA制备RNA测序文库。该协议适合于通过对成熟的CRISPR RNA进行测序来测定细菌中的CRISPR RNA生物合成，但可以用于测序不同类型的小RNA。我们还提供了一个完整的数据处理管道示例，并提供了运行所提供脚本的说明。
【背景】与聚集的经常散布的短回文重复序列（CRISPR）相关的遗传模块赋予不同的原核宿主适应性免疫（Barrangou et ...
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| Accurate, Streamlined Analysis of mRNA Translation by Sucrose Gradient Fractionation
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Author:
Date:
2017-10-05
[Abstract] The efficiency with which proteins are produced from mRNA molecules can vary widely across transcripts, cell types, and cellular states. Methods that accurately assay the translational efficiency of mRNAs are critical to gaining a mechanistic understanding of post-transcriptional gene regulation. One way to measure translational efficiency is to determine the number of ribosomes associated with an mRNA molecule, normalized to the length of the coding sequence. The primary method for this analysis of individual mRNAs is sucrose gradient fractionation, which physically separates mRNAs based on the number of bound ribosomes. Here, we describe a streamlined protocol for accurate analysis of mRNA association with ribosomes. Compared to previous protocols, our method incorporates internal ...
[摘要] 从mRNA分子产生蛋白质的效率可以在转录本，细胞类型和细胞状态之间广泛变化。准确测定mRNA翻译效率的方法对获得对转录后基因调控的机理理解至关重要。测量翻译效率的一种方法是确定与mRNA分子相关的核糖体的数目，归一化为编码序列的长度。分析单个mRNA的主要方法是蔗糖梯度分级，其基于结合核糖体的数目物理分离mRNA。在这里，我们描述了精确分析与核糖体的mRNA相关性的简化方案。与以前的方案相比，我们的方法结合内部控制和改进的缓冲条件，共同减少由非特异性mRNA - 核糖体相互作用引起的伪像。此外，我们的直接分数qRT-PCR方案消除了从梯度部分中RNA纯化的需要，这大大减少了所需的手动时间量，并促进了多个条件或基因靶标的并行分析。此外，在该过程中不产生苯酚废物。我们最初开发了协议来研究S-HAC1 mRNA的翻译抑制状态。但是我们还详细介绍了哺乳动物细胞系和组织的适应程序。
【背景】将mRNA翻译成蛋白质是一种高度调节的过程，其可以以不同的速率发生，这取决于基因，细胞环境或环境。翻译起始，延伸和终止的每个步骤可以是最终影响与mRNA相关的核糖体数量的调节点（Dever和Green，2012; ...
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