Hypersensitive detection of transcription factors by multiple amplification strategy based on molecular beacon

Abstract Detection and quantification of specific targets at ultralow concentrations are crucial in biotechnological applications and biomedical diagnostics. However, traditional detection methods are time-consuming and complex. In this study, a simple, sensitive, and specific fluorescence-based strategy to detect transcription factors (TFs) was developed by combining molecular beacon (MB) with exonuclease III (Exo III). The strategy was validated using nuclear factor-kappa B (NF-κB) p65 as a model case. In this assay, the TF concentration is determined by estimating the concentration of the nucleic acid released through the reactions of TFs with DNA-1/DNA-2 duplex probe and Exo III; thus, this method can overcome the limitations of the traditional methods. The nucleic acid is then cyclically amplified in the presence of MB and Exo III, and the sequence fragments containing the fluorescent group are released. This method is sensitive, expandable, and suitable for the direct detection of TFs in crude nuclear extracts of cancer cells. Furthermore, it can provide key test data for studies of coronavirus disease 2019-induced acute respiratory distress syndrome and related research.