Development of a bidirectional isothermal amplification strategy for the sensitive detection of transcription factors in cancer cells.

We develop a new strategy to sensitively detect transcription factors (TFs) based on the integration of bidirectional isothermal exponential amplification reaction (EXPAR) with endonuclease IV (Endo IV)-assisted cycle digestion of signal probes. This assay exhibits ultrahigh sensitivity with a detection limit of 1.29 × 10-14 M, and it can measure endogenous NF-κB p50 in HeLa cell extracts. Moreover, this strategy can be applied to screen TF inhibitors and detect other TFs by simply changing the TF-binding sequence.