| 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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| Polysome Analysis
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Author:
Date:
2017-03-20
[Abstract] Polysome analysis is a method to separate mRNAs from a cell into actively translating and non-translating fractions depending on their association with polysomes. By this protocol, cell lysates are fractionated by sucrose density gradient ultracentrifugation. Free mRNA fraction and various ribosomal fractions, such as 40S, 60S, monosomes and polysomes are collected by fractionation. Association of particular mRNAs with these fractions is detected by reverse transcription – PCR to investigate the translational state of the mRNA.
[摘要] 多聚赖氨酸分析是一种将mRNA从细胞分离为主动翻译和非翻译部分的方法，这取决于它们与多核糖体的关联。通过该方案，通过蔗糖密度梯度超速离心分离细胞裂解物。通过分级收集游离mRNA级分和各种核糖体级分，例如40S，60S，单体和多核糖体。通过逆转录PCR检测特异性mRNA与这些级分的关联，以研究mRNA的翻译状态。
背景 细胞mRNA在任何时间点分布到主动翻译和非翻译池中，并可响应于各种刺激而在这些池之间动态地重新分布。主动翻译的mRNA具有较高数量的与它们相关的核糖体，与mRNA相关的核糖体数量是mRNA的翻译状态的量度。因此，从细胞中分离核糖体时，会在多核糖体组分中发现主要转录的mRNA，而在游离mRNA部分或与40S核糖体亚基相关的非翻译/不良翻译mRNAs。因此，多聚赖氨酸分析是根据其与多核糖体的关联将mRNA从细胞分离为主动翻译和非翻译部分的方法（Ray et al。，2009; Poria等人， >。，2016）。可以通过RT-PCR检测单个mRNA与翻译/非翻译级分的关联，而通过RNA测序或微阵列分析可以鉴定mRNA的整个翻译或非翻译池。
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| Subcellular Fractionation of Mouse Brain Homogenates
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Author:
Date:
2013-08-05
[Abstract] This subcellular fractionation protocol is used for separation of cellular organelles based on their density. We have designed and optimized the protocol for separation of subcellular compartments of brain homogenates with focus on the localization and trafficking of transmembrane proteins, but we have also successfully used this protocol for fractionation of other types of tissue. The protocol has two major steps 1) preparation of homogenate from dissected tissue and 2) separation of organelles by centrifugation of homogenates using a continuous sucrose gradient.
[摘要] 这种亚细胞分馏方案用于根据细胞密度分离细胞器。 我们设计和优化了用于分离脑匀浆物的亚细胞区域的方案，重点是跨膜蛋白的定位和运输，但是我们也已经成功地使用该方案来分离其他类型的组织。 方案有两个主要步骤：1）从解剖组织制备匀浆物; 2）通过使用连续蔗糖梯度离心匀浆分离细胞器。
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