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Glycerol (Molecular Biology), Fisher BioReagentsTM

Glycerol (Molecular Biology), Fisher BioReagentsTM

Company: Fisher Scientific
Catalog#: BP229
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RNA Cap Methyltransferase Activity Assay
Author:
Date:
2018-03-20
[Abstract]  Methyltransferases that methylate the guanine-N7 position of the mRNA 5’ cap structure are ubiquitous among eukaryotes and commonly encoded by viruses. Here we provide a detailed protocol for the biochemical analysis of RNA cap methyltransferase activity of biological samples. This assay involves incubation of cap-methyltransferase-containing samples with a [32P]G-capped RNA substrate and S-adenosylmethionine (SAM) to produce RNAs with N7-methylated caps. The extent of cap methylation is then determined by P1 nuclease digestion, thin-layer chromatography (TLC), and phosphorimaging. The protocol described here includes additional steps for generating the [32P]G-capped RNA substrate and for preparing nuclear and cytoplasmic extracts from mammalian cells. This assay is ... [摘要]  甲基化mRNA 5'帽结构的鸟嘌呤-N7位置的甲基转移酶在真核生物中普遍存在并且通常由病毒编码。这里我们提供生物样品的RNA帽甲基转移酶活性的生化分析的详细方案。该测定包括将含有帽 - 甲基转移酶的样品与[32 P] G-加帽的RNA底物和S-腺苷甲硫氨酸(SAM)温育以产生具有N7-甲基化帽的RNA。然后通过P1核酸酶消化,薄层色谱(TLC)和磷成像确定帽甲基化的程度。此处描述的方案包括用于产生[32 P] G-加帽的RNA底物和用于从哺乳动物细胞制备核和细胞质提取物的附加步骤。该分析也适用于分析其他生物样品(包括重组蛋白制剂和来自分析分离和免疫沉淀/下拉实验的级分)的帽甲基转移酶活性。

【背景】mRNA的5'端的N7-甲基鸟苷帽是适当的真核mRNA加工,定位和翻译所必需的修饰。 ...

An Improved Method for Measuring Chromatin-binding Dynamics Using Time-dependent Formaldehyde Crosslinking
Author:
Date:
2018-02-20
[Abstract]  Formaldehyde crosslinking is widely used in combination with chromatin immunoprecipitation (ChIP) to measure the locations along DNA and relative levels of transcription factor (TF)-DNA interactions in vivo. However, the measurements that are typically made do not provide unambiguous information about the dynamic properties of these interactions. We have developed a method to estimate binding kinetic parameters from time-dependent formaldehyde crosslinking data, called crosslinking kinetics (CLK) analysis. Cultures of yeast cells are crosslinked with formaldehyde for various periods of time, yielding the relative ChIP signal at particular loci. We fit the data using the mass-action CLK model to extract kinetic parameters of the TF-chromatin interaction, including the on- and ... [摘要]  甲醛交联广泛用于与染色质免疫沉淀(ChIP)相结合来测量沿着DNA的相对位置以及转录因子(TF)-DNA相互作用的体内相对水平。但是,通常所做的测量不能提供关于这些交互的动态属性的明确信息。我们已经开发了一种方法来评估来自时间依赖性甲醛交联数据的结合动力学参数,称为交联动力学(CLK)分析。酵母细胞的培养物与甲醛交联不同的时间段,在特定位点产生相对的ChIP信号。我们使用质量作用CLK模型来拟合数据,以提取TF-染色质相互作用的动力学参数,包括开关速率和交联速率。从停车费和停车费中我们可以获得停车和停车时间。以下方案是该方法的第二次迭代,CLKv2,更新了改进的交联和淬火条件,更多关于交联速率的信息以及对观察到的动力学模型建模的系统程序。已应用CLKv2分析来研究TATA结合蛋白(TBP)和其他TF的选定子集的结合行为。该协议使用酵母细胞开发,但也可适用于来自其他生物体的细胞。

【背景】转录起始是一个复杂的过程,涉及染色质化启动子上数十种蛋白的协作和协调相互作用(Kim等人,2005; Encode Consortium,2012; Rhee等人, ,2012; Dowen等人,2014年)。许多研究已经研究了体外核心转录机器的组装和调控(Zawel和Reinberg,1992; Conaway和Conaway,1993; Roeder,1996; ...

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