Microarray-based fluorescence assay of endonuclease functionality and inhibition†
Here, a double-strand (ds) DNA microarray-based fluorescence assay has been deployed for studying endonuclease functionality and inhibition. The dsDNA microarrays are fabricated by hybridization of the Cy5-labeled oligonucleotides with the immobilized complementary oligonucleotide probes on the glass slide. The microarray displays significant fluorescence decrease in response to endonuclease, which is able to cleave the oligonucleotide moiety of dsDNA. Two endonucleases, EcoRI and BamHI, and four potential inhibitors, doxorubicin hydrochloride (DOX), 5-fluorouracil (5-FU), ethidium bromide (EB) and actinomycin D (ACTD), were selected to address the feasibility of this assay. Enzyme activities of the endonucleases are detected with high specificity down to the limits of 1.1 U mL−1 for EcoRI and 2.0 U mL−1 for BamHI, respectively. In addition, BamHI and EcoRI inhibition by the inhibitors are also shown, demonstrating the potential for high-throughput screening for inhibitors.