需要订阅 JoVE 才能查看此. 登录或开始免费试用。
Method Article
Provided is a protocol for developing a real-time recombinase polymerase amplification assay to quantify initial concentration of DNA samples using either a thermal cycler or a microscope and stage heater. Also described is the development of an internal positive control. Scripts are provided for processing raw real-time fluorescence data.
It was recently demonstrated that recombinase polymerase amplification (RPA), an isothermal amplification platform for pathogen detection, may be used to quantify DNA sample concentration using a standard curve. In this manuscript, a detailed protocol for developing and implementing a real-time quantitative recombinase polymerase amplification assay (qRPA assay) is provided. Using HIV-1 DNA quantification as an example, the assembly of real-time RPA reactions, the design of an internal positive control (IPC) sequence, and co-amplification of the IPC and target of interest are all described. Instructions and data processing scripts for the construction of a standard curve using data from multiple experiments are provided, which may be used to predict the concentration of unknown samples or assess the performance of the assay. Finally, an alternative method for collecting real-time fluorescence data with a microscope and a stage heater as a step towards developing a point-of-care qRPA assay is described. The protocol and scripts provided may be used for the development of a qRPA assay for any DNA target of interest.
定量核酸扩增是用于检测环境,食源性和水生病原体,以及用于临床诊断的一项重要技术。实时定量聚合酶链反应(qPCR的)可以灵敏,特异和定量检测的核酸, 例如,HIV-1的病毒载量检测,检测的细菌病原体,并筛选许多其他生物体1的金标准方法- 3。在实时定量PCR,引物扩增在周期病原体的DNA和荧光信号被产生成比例的扩增的DNA的样品,在每个循环中的量。将含有未知浓度的病原体的DNA的样品可以使用涉及标准样品的初始DNA浓度和在该荧光信号达到一定的阈值的时间( 即,循环阈值,或(C T))的标准曲线进行定量。
因为实时定量PCR需要昂贵的热循环设备及几个小时来接收结果,替代等温扩增技术,如重组酶聚合酶扩增(RPA),已经开发了4。这些平台通常提供结果更快和扩增核酸在一个较低的,单一的温度,其可以实现与更便宜,更简单的设备。 RPA,其用于护理点的应用特别有吸引力的,放大的DNA在几分钟内,需要低放大温度(37℃),并且在杂质5,6存在下保持有效。 RPA试验已经开发了用于范围广泛的应用,包括食品分析,病原体检测,癌症药物筛选,并检测生物威胁因子7 - 12。然而,使用的RPA的用于核酸定量一直局限于13,14。
在以往的工作,这是笑WN的实时定量RPA(qRPA)是可行的15。这里,更详细的协议提供了一种用于使用实时定量RPA量化使用标准曲线中,一种方法使用qPCR即类似于量化未知样品。本协议描述了如何执行在热循环的RPA反应检测HIV-1 DNA作为概念证明的,以及如何开发一个内部阳性对照(IPC),以保证系统正常运行。使用热循环仪或显微镜和数据分析使用训练数据构建的标准曲线数据收集也详细叙述。最后,该方法用于定量用标准曲线与自定义脚本未知样品被证实。此qRPA技术使具有未知浓度的样品进行定量,并具有比传统的实时定量PCR的许多优点。
1.程序的实时qRPA反应的热循环仪
2.准备HIV-1 qRPA实验
3.装配的HIV-1 qRPA标准曲线
4.制定一个内部阳性对照
5.建立来自多个实验标准曲线
6.试验验证和未知样品使用的量化标准曲线
7.筹备数据收集使用荧光显微镜和加热芯片
8.数据收集和ANALYSIS使用荧光显微镜
选择一个序列作为IPC在qRPA实验目标之前(HIV-1)的DNA,内部阳性对照(IPC)的候选人中产生和筛选它们放大的qRPA反应无HIV-1 DNA存在的能力。 IPC考生比目标(HIV-1)的DNA,以防止出竞争的HIV-1扩增子形成IPC形成更长的时间。 如图2A所示 ,两个C的代孢子虫 IPC候选人是由使 用凝胶电泳415和435 bp的条带的存在验证。在qRPA反应,较短的IPC候选呈现小的扩增( 图2B),<...
为了获得使用MATLAB算法有意义的量化数据,系统提示时,用户必须选择合适的输入值。开始在第5和第6的每个脚本之后,所有的输入变量自动征求在命令窗口中,并自动生成输出。在第5.7节中提示用户选择斜率阈值。的斜率阈值影响契合的相关系数(R 2)的平方。当使用从热循环仪导出原始荧光数据,在2.0和5.0的值趋向于产生高R 2系数。在第5.8节,用户必须指定背景以上的标准偏?...
The authors declare they have no competing financial interests.
该研究是由来自比尔和梅林达·盖茨基金会通过大挑战全球健康计划的资助。
Name | Company | Catalog Number | Comments |
qRPA Assay | |||
HIV-1 forward primer | Integrated DNA Technologies | custom DNA oligos | 5’-TGG CAG TAT TCA TTC ACA ATT TTA AAA GAA AAG G-3’ |
HIV-1 reverse primer | Integrated DNA Technologies | custom DNA oligos | 5’-CCC GAA AAT TTT GAA TTT TTG TAA TTT GTT TTT G-3’ |
HIV-1 probe | BioSearch Technologies | custom DNA oligos | 5’- TGC TAT TAT GTC TAC TAT TCT TTC CCC [SIMA/HEX] GC [THF] C [dT-BHQ1] GTA CCC CCC AAT CCC C -3’ |
IPC probe | BioSearch Technologies | custom DNA oligos | 5’-AGG TAG TGA CAA GAA ATA ACA ATA CAG GAC [FAM] T [THF] T [dT-BHQ1] GGT TTT GTA ATT GGA A -3’ |
RPA exo reagents (pellets, rehydration buffer, magnesium acetate | TwistDx | TwistAmp exo | |
PCR tube strips | BioRad | TLS0801 | |
PCR flat cap tube strips | BioRad | TCS0803 | |
Micro-seal adhesive | BioRad | 558/MJ | |
HIV-1 target (pHIV-IRES- eYFPΔEnvΔVifΔVpr) | custom plasmid, see: Segall, H. I., Yoo, E. & Sutton, R. E. Characterization and detection of artificial replication-competent lentivirus of altered host range. Molecular Therapy 8, 118–129, doi:10.1016/S1525-0016(03)00134-5 (2003). | ||
Human male genomic DNA | Applied Biosystems | 360486 | |
96 well cold-block | Cole Parmer | EW-36700-48 | |
Thermal cycler | BioRad | CFX96 | |
MiniFuge | VWR | 93000-196 | |
Vortex | VWR | 58816-121 | |
Tris buffer 1.0 M, pH 8.0 | EMD Millipore | 648314 | |
EDTA 0.5 M, pH 8.0 | Promega | V4321 | |
Nuclease free water | Ambion | AM9937 | |
IPC Development | |||
Cryptosporidium parvum IPC template | Waterborne Inc | P102C | It is also possible to order a double stranded synthetic target from IDT if the user is unequipped to work with C. parvum (a BSL-2 infectious agent). PCR and RPA primers for C. parvum were designed using GenBank accession number AF115377.1 |
PCR long forward primer | Integrated DNA Technologies | custom DNA oligos | 5’-TGG CAG TAT TCA TTC ACA ATT TTA AAA GAA AAG G/ ATC TAA GGA AGG CAG CAG GC-3’ |
PCR long reverse primer | Integrated DNA Technologies | custom DNA oligos | 5’- CCC GAA AAT TTT GAA TTT TTG TAA TTT GTT TTT G/ TGC TGG AGT ATT CAA GGC ATA -3’ |
Phusion High-Fidelty DNA Polymerase | New England Biolabs | M0530S | |
Qiaquick Gel Extraction Kit | Qiagen | 28704 | |
TAE 10X buffer | EMD Millipore | 574797 | |
Agarose | Sigma Aldrich | A9539 | |
Microscope Experiments | |||
Upright fluorescence microscope | Zeiss | Zeiss Imager.J1 | |
Stage heater | Bioscience Tools | TC-GSH | |
1-Channel Precision High Stability Temperature Controller | Bioscience Tools | TC-1100S | |
FAM/GFP filter cube | Zeiss | filter set 38 (000000-1031-346) | excitation BP 470/40 nm, emission BP 520/50 nm |
HEX filter cube | Chroma | 49014 | excitation BP 530/30 nm, emission BP 575/40 nm |
Laser cutter | Engraver's Network | VLS3.60 | |
1/8" black acrylic | McMaster Carr | 8505K113 | |
1.5 mm clear acrylic | McMaster Carr | PD-72268940 | |
Super glue | Office Depot | Duro super glue | |
PCR grade mineral oil | Sigma Aldrich | M8662-5VL | |
Data Analysis | |||
Microsoft Excel | Microsoft | ||
MATLAB | MATLAB | ||
MATLAB script: "JoVE_qRPA_standard_curve.m” | Included in SI | ||
MATLAB script: "JoVE_qRPA_validation_and_quantification.m” | Included in SI | ||
MATLAB script: "JoVE_real_time_intensity_to_excel.m” | Included in SI | ||
Adobe Illustrator | Adobe | ||
JoVE_qRPA_well.ai | Included in SI | ||
JoVE_qRPA_base.ai | Included in SI | ||
AxioVision software | Zeiss | ||
JoVE_AxioVision_Script.ziscript | Included in SI |
请求许可使用此 JoVE 文章的文本或图形
请求许可This article has been published
Video Coming Soon
版权所属 © 2025 MyJoVE 公司版权所有,本公司不涉及任何医疗业务和医疗服务。