Nazarenko Irina
Research and Development, Digene Corporation, Gaithersburg, MD, USA.
Methods Mol Biol. 2006;335:95-114. doi: 10.1385/1-59745-069-3:95.
Multiplex quantitative polymerase chain reaction (PCR) based on novel design of fluorescent primers is described. Self-quenched fluorogenic primers are labeled with a single fluorophore on a base close to the 3'-end with no quencher required. A tail of 5-7 nucleotides is added to the 5'-end of the primer to form a blunt-end hairpin when the primer is not incorporated into a PCR product. This design provides a low initial fluorescence of the primers that increases upon formation of the PCR product. The hairpin oligonucleotides (DeltaG from -1.6 to -5.8 kcal/mol) are as efficient as linear primers and provide additional specificity to the PCR by preventing primer-dimers and mispriming. Self-quenched primers could be designed manually or by specialized software and could be used for real-time gene quantitation. Targets of 10-107 copies could be detected with precision in PCR using fluorescein-labeled primers for variable genes and JOE-labeled primers for the reference genes. This method could also be used to detect single nucleotide polymorphism by allele-specific PCR. In conclusion, self-quenched primers are an efficient and cost-effective alternative to fluorescence resonance energy transfer-labeled oligonucleotides.
描述了基于新型荧光引物设计的多重定量聚合酶链反应(PCR)。自猝灭荧光引物在靠近3'端的碱基上用单个荧光团标记,无需猝灭剂。在引物的5'端添加5-7个核苷酸的尾巴,当引物未掺入PCR产物时形成平端发夹结构。这种设计使得引物的初始荧光较低,而在PCR产物形成时荧光增加。发夹寡核苷酸(ΔG为-1.6至-5.8千卡/摩尔)与线性引物一样有效,并通过防止引物二聚体和错配为PCR提供额外的特异性。自猝灭引物可以手动设计或通过专门软件设计,可用于实时基因定量。使用针对可变基因的荧光素标记引物和针对参考基因的JOE标记引物,在PCR中可以精确检测10-107个拷贝的靶标。该方法还可用于通过等位基因特异性PCR检测单核苷酸多态性。总之,自猝灭引物是荧光共振能量转移标记寡核苷酸的一种高效且经济的替代方法。