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Updated: Apr 23, 2026
Fluorescence-Based Detection of FEN1 Nuclease Activity and Screening of Small-Molecule Inhibitors
Published on: June 27, 2025
Label-free fluorometric detection of S1 nuclease activity by using polycytosine oligonucleotide-templated silver
Lihui Wang1, Keke Ma1, Yaodong Zhang1
1Key Laboratory of Applied Surface and Colloid Chemistry of Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, China; Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, China.
Abstract:
S1 nuclease has an important function in DNA transcription, replication, recombination, and repair. A label-free fluorescent method for the detection of S1 nuclease activity has been developed using polycytosine oligonucleotide-templated silver nanoclusters (dC12-Ag NCs). In this assay, dC12 can function as both the template for the stabilization of Ag NCs and the substrate of the S1 nuclease. Fluorescent Ag NCs could be effectively formed using dC12 as the template without S1 nuclease. In the presence of S1 nuclease, dC12 is degraded to mono- or oligonucleotide fragments, thereby resulting in a reduction in fluorescence. S1 nuclease with an activity as low as 5×10(-8)Uμl(-1) (signal/noise=3) can be determined with a linear range of 5×10(-7) to 1×10(-3)Uμl(-1). The promising application of the proposed method in S1 nuclease inhibitor screening has been demonstrated using pyrophosphate as the model inhibitor. Furthermore, the S1 nuclease concentrations in RPMI 1640 cell medium were validated. The developed method for S1 nuclease is sensitive and facile because its operation does not require any complicated DNA labeling or laborious fluorescent dye synthesis.
