| Visualization of RNA 3’ ends in Escherichia coli Using 3’ RACE Combined with Primer Extension
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Author:
Date:
2018-03-05
[Abstract] In this assay, 3’ RACE (Rapid Amplification of cDNA 3’ Ends) followed by PE (primer extension), abbreviated as 3’ RACE-PE is used to identify the mRNA 3’ ends. The following protocol describes the amplification of the mRNA 3’ ends at the galactose operon in E. coli and the corresponding visualization of the PCR products through PE. In PE, the definite primer is 5’ end-labeled using [γ-(32) P] ATP and T4 polynucleotide kinase, which anneals to the specific DNA molecules within the PCR product of the 3’ RACE. The conventional PE can only be used to locate the 5’ end of an mRNA transcript since reverse transcriptase (RTase) polymerizes only in the 5’ → 3’ direction. Thus, Taq polymerase is used instead of RTase, PCR is performed. Therefore, we are able to locate the 3’ end of the ...
[摘要] 在该测定中，使用缩写为3'RACE-PE的3'RACE（cDNA3'末端快速扩增），随后是PE（引物延伸），以鉴定mRNA3'末端。以下方案描述E中半乳糖操纵子的mRNA 3'末端的扩增。并通过PE对相应的PCR产物进行可视化。在PE中，使用[γ-（32）P] ATP和T4多核苷酸激酶对确定的引物进行5'末端标记，其退火至3'RACE的PCR产物内的特定DNA分子。由于逆转录酶（RTase）仅在5'→3'方向聚合，常规PE只能用于定位mRNA转录物的5'末端。因此，使用Taq聚合酶代替RTase，进行PCR。因此，我们能够使用此测定法定位mRNA的3'末端。通过在变性8％尿素-PAGE（聚丙烯酰胺凝胶电泳）凝胶中分离DNA产物，可以直接显示和定量3'末端的相对量。 3'末端的确切位置可以通过比较这些最终的DNA产物与相应的DNA测序阶梯进行测序。
【背景】mRNA 3'末端的合成是E中的重要步骤。产生稳定的信使RNA（mRNA）的大肠杆菌。在真核细胞中，mRNA 3'末端形成是通过从内部磷酸二酯键切割，然后加入聚（A）尾;而在原核细胞中，通过终止转录或通过加工初级转录产生mRNA的3'末端（Altman和Robertson，1973; Nudler和Gottesman，2002; Zhao等人，1999年）。因此，分析mRNA ...
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| Determination of the Secondary Structure of an RNA fragment in Solution: Selective 2`-Hydroxyl Acylation Analyzed by Primer Extension Assay (SHAPE)
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Author:
Date:
2015-01-20
[Abstract] This protocol describes the methodology for the determination of the secondary structure of an RNA fragment in solution using Selective 2´-Hydroxyl Acylation analyzed by Primer Extension, abbreviation SHAPE. It consists in the very fast chemical modification of flexible and therefore possibly single-stranded nucleotides in a sequence-independent manner using benzoyl cyanide (BzCN), forming 2´-O-adducts. The modifications in the RNA are then analyzed by primer extension. Reverse transcriptase is blocked by the 2´-O-adducts formed. The advantage of the method is, first, that not each RNA molecule studied but the primer used in the extension reaction is labelled and, second, that the resulting cDNA analyzed in sequencing gels is much more stable than the modified RNA.
[摘要] 该方案描述了使用通过引物延伸（缩写为SHAPE）分析的选择性2'-羟基酰化来确定溶液中RNA片段的二级结构的方法。 其包括使用苯甲酰氰（BzCN）以序列非依赖性方式非常快速地化学修饰柔性且因此可能的单链核苷酸，形成2'-O-加合物。 然后通过引物延伸分析RNA中的修饰。 逆转录酶被形成的2'-O-加合物阻断。 该方法的优点是，首先，不是每个RNA分子研究，而是在延伸反应中使用的引物被标记，其次，在测序凝胶中分析得到的cDNA比修饰的RNA更稳定。
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