发布: 2019年04月20日第9卷第8期 DOI: 10.21769/BioProtoc.3219 浏览次数: 10300
评审: Gal HaimovichPabitra Kumar SahooSwati MeghaAnca Savulescu
Abstract
Northern blot is a molecular biology technique that can detect, quantify, and determine the molecular weight of RNA. Recently, we published a protocol utilizing near-infrared (IR) fluorescent probes in Northern blot (irNorthern). Our method is as sensitive as other non-radioactive methods but is more straightforward and versatile. Additionally, we found that IR-labeled probes can be used to multiplex or detect different species of RNA at the same time. Here we describe three methods for generating an IR-labeled probe as well as how to perform irNorthern blot. In conclusion, our irNorthern protocol offers a convenient method for RNA detection.
Keywords: Northern blot (Northern杂交)Background
Northern blot analysis is one of the foundational techniques available to biochemists and molecular biologists. While newer and more high-throughput techniques have been adopted, the Northern blot remains a powerful and adaptable method of analyzing RNA size and quantity simultaneously. In brief, DNA or RNA oligonucleotides labeled with radioactive phosphorus-32 (32P) are hybridized to a membrane crosslinked with RNA and subsequently detected using autoradiography (Alwine et al., 1977). Nonetheless, the use of 32P is subject to institutional regulation, and safety precautions must be observed during its use (Jones, 2005). Additionally, 32P probes have short lifespans increasing their cost for use. Alternative protocols using digoxigenin (DIG) conjugated to dNTP or NTP have been developed to replace 32P (Seibl et al., 1990). While successful, DIG probes require secondary detection by antibodies, more hands-on time and expensive reagents, deterring its wider adoption. Our recently published method, irNorthern, is straightforward and adaptable. It utilizes IR dyes which reduce auto-fluorescent background (Zarnegar et al., 2016; Miller et al., 2018). These IR dyes are conjugated with a dibenzocyclooctyne group (DBCO), which forms a covalent bond with the azide on the probes through copper-free click chemistry. To demonstrate its applications, we performed irNorthern to detect microRNA let-7a and small nuclear RNA U6 in total RNAs extracted from HCT116 wild-type and Drosha knockout cells (Kim et al., 2016). In addition, we provide details on how to generate three different azide-containing DNA or RNA probes for IR-dye labeling: a chemically synthesized DNA probe with an internal azide modification on dT, a DNA probe labeled with azide-dU by terminal transferase (TdT), and an RNA probe labeled with azide-U by T7 RNA polymerase.
Materials and Reagents
Equipment
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Procedure
文章信息
版权信息
© 2019 The Authors; exclusive licensee Bio-protocol LLC.
如何引用
Fields, C., Sheng, P., Miller, B., Wei, T. and Xie, M. (2019). Northern Blot with IR Fluorescent Probes: Strategies for Probe Preparation. Bio-protocol 9(8): e3219. DOI: 10.21769/BioProtoc.3219.
分类
分子生物学 > RNA > RNA 检测
生物化学 > RNA > miRNA标记
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