Biomaterial Database

Label-free molecular beacons-based cascade amplification DNA machine for sensitive detection of telomerase activity. 2017

Kan Li, and Lei Wang, and Xiaowen Xu, and Wei Jiang

Key Laboratory for Colloid and Interface Chemistry of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, 250100 Jinan, PR China.

Sensitive detection of telomerase activity is critical to cancer diagnosis, screening of anticancer drugs and evaluation of cancer therapy. Herein, a label-free molecular beacons-based DNA machine was developed for sensitive detection of telomerase activity. The DNA machine consisted of T7 exonuclease (T7 Exo), label-free recognition molecular beacon (RMB) and signal molecular beacon (SMB) with projecting 5'-terminuses, which can protect RMB and SMB from being digested by T7 Exo. Firstly, telomerase elongated telomerase substrate (TS) primer, generating a telomerase elongation production (TEP) with tandem repeats (TTAGGG)n. Next, TEP activated the DNA machine by hybridizing with RMB, unfolding RMB with a recessed 5'-terminus, making RMB deprotection from T7 Exo. Then T7 Exo-assisted cycling cleavage was incurred, releasing intact TEP and numerous DNA fragments (trigger DNA), which got recycling I. Subsequently, trigger DNA specifically opened SMB and was recycled by T7 Exo, liberating multiple G-quadruplex (G4) structures, which got recycling II. Finally, TEP and the liberative G4 structures strongly interacted with N-methyl-mesoporphyrin IX (NMM), yielding a significantly enhanced fluorescence together. In this way, per telomerase-mediated elongation event was efficiently converted into the greatly amplified fluorescence signals. Telomerase activity in crude HeLa cells extracts equivalent to 50 cells/mL was successfully measured with a linear range from 50 cells/mL to 2000 cells/mL. Besides, the strategy was also successfully used to assay the inhibition effect of a telomerase-inhibiting drug, demonstrating the strategy holds the potential to screen telomerase inhibitors.

UI	MeSH Term	Description	Entries
D004247	DNA	A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).	DNA, Double-Stranded,Deoxyribonucleic Acid,ds-DNA,DNA, Double Stranded,Double-Stranded DNA,ds DNA
D004791	Enzyme Inhibitors	Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.	Enzyme Inhibitor,Inhibitor, Enzyme,Inhibitors, Enzyme
D005453	Fluorescence	The property of emitting radiation while being irradiated. The radiation emitted is usually of longer wavelength than that incident or absorbed, e.g., a substance can be irradiated with invisible radiation and emit visible light. X-ray fluorescence is used in diagnosis.
D006367	HeLa Cells	The first continuously cultured human malignant CELL LINE, derived from the cervical carcinoma of Henrietta Lacks. These cells are used for, among other things, VIRUS CULTIVATION and PRECLINICAL DRUG EVALUATION assays.	Cell, HeLa,Cells, HeLa,HeLa Cell
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D013050	Spectrometry, Fluorescence	Measurement of the intensity and quality of fluorescence.	Fluorescence Spectrophotometry,Fluorescence Spectroscopy,Spectrofluorometry,Fluorescence Spectrometry,Spectrophotometry, Fluorescence,Spectroscopy, Fluorescence
D015335	Molecular Probes	A group of atoms or molecules attached to other molecules or cellular structures and used in studying the properties of these molecules and structures. Radioactive DNA or RNA sequences are used in MOLECULAR GENETICS to detect the presence of a complementary sequence by NUCLEIC ACID HYBRIDIZATION.	Molecular Probe,Probe, Molecular,Probes, Molecular
D015374	Biosensing Techniques	Any of a variety of procedures which use biomolecular probes to measure the presence or concentration of biological molecules, biological structures, microorganisms, etc., by translating a biochemical interaction at the probe surface into a quantifiable physical signal.	Bioprobes,Biosensors,Electrodes, Enzyme,Biosensing Technics,Bioprobe,Biosensing Technic,Biosensing Technique,Biosensor,Electrode, Enzyme,Enzyme Electrode,Enzyme Electrodes,Technic, Biosensing,Technics, Biosensing,Technique, Biosensing,Techniques, Biosensing
D056945	Hep G2 Cells	A human liver tumor cell line used to study a variety of liver-specific metabolic functions.	Cell Line, Hep G2,Cell Line, Hepatoblastoma G2,Hep G2 Cell Line,HepG2 Cells,Hepatoblastoma G2 Cell Line,Cell, Hep G2,Cell, HepG2,Cells, Hep G2,Cells, HepG2,Hep G2 Cell,HepG2 Cell
D019098	Telomerase	An essential ribonucleoprotein reverse transcriptase that adds telomeric DNA to the ends of eukaryotic CHROMOSOMES.	Telomerase Catalytic Subunit,Telomerase Reverse Transcriptase,Telomerase Reverse Transcriptase Catalytic Subunit,Catalytic Subunit, Telomerase,Reverse Transcriptase, Telomerase,Subunit, Telomerase Catalytic,Transcriptase, Telomerase Reverse