A simple and sensitive fluorescence method for detection of telomerase activity using fusion protein bouquets

Telomerase is considered as a widely accepted cancer biomarker for early cancer diagnostics. Herein, we develop a simple, ultrahigh sensitivity method for detection of telomerase activity, which relied on that RecA-GFP fusion proteins wrapped around telomeric DNA to form fluorescence bouquets. RecA-GFP fusion protein was synthesized through fusion protein technology. In the presence of telomerase, telomerase elongation products are wrapped around by RecA-GFP fusion protein to form big fluorescent bouquets, which resulted in strong fluorescence. This method has the linear range from 50 to 1000 HeLa cells and the detection limit is 8 HeLa cells, based on a signal-to-noise ratio (S/N) of 3. Compared with conventional methods, this method has the advantages of low toxicity, outstanding sensitivity, and excellent selectivity. Hence, it provides a promising approach for the detection of telomerase activity and diagnosis of cancer.