Formation of G-quadruplex-hemin DNAzyme based on human telomere elongation and its application in telomerase activity detection

In the present study, a chemiluminescence method for sensitive detection of human telomerase activity was developed based on the formation of G-quadruplex-hemin DNAzyme. In the presence of telomerase, the telomerase substrate (TS) primer elongated and a long single-strand DNA containing the telomere repeat units (TTAGGG)n was formed. When K+ was introduced, the telomere repeat units could form G-quadruplex and then combined with hemin to form DNAzymes which could stimulate the generation of chemiluminescence (CL) in the presence of luminol and H2O2. The amount of telomerase elongation product was controlled by the content of telomerase extracted from HeLa cells, so the amount of DNAzymes and the intensity of chemiluminescence signal were all related to the number of HeLa cells. Using this simple method, the telomerase activity extracted from 100 cultured cancer cells could be detected without the polymerase chain reaction (PCR) amplification of telomerase elongated product.