The TARDIS assay was originally developed as a means of detecting and quantifying melphalan and cisplatin DNA adducts at the single cell level, but it has since been adapted to quantify topoisomerase DNA complexes that result from the actions of topoisomerase poisons and this is currently the main use of the assay. The method employs sensitive immunofluorescent detection to quantify topoisomerase molecules covalently coupled to DNA in what are often referred to as cleavage complexes. Free topoisomerase molecules, and other cellular constituents are first removed using salt-detergent extraction of agarose-embedded, unfixed cells. Using these stringent extraction conditions, genomic DNA remains in place in the agarose as “nuclear ghosts,” and any covalent attached molecules can be detected and quantified by immunofluorescence with a low background.
Lopez-Lazaro M, Willmore E, Jobson A et al (2007) Curcumin induces high levels of topoisomerase I- and II-DNA complexes in K562 leukemia cells. J Nat Prod 70:1884–1888CrossRefPubMedGoogle Scholar
Lopez-Lazaro M, Calderon-Montano JM, Burgos-Moron E, Austin CA (2011) Green tea constituents (−)-epigallocatechin-3-gallate (EGCG) and gallic acid induce topoisomerase I- and topoisomerase II-DNA complexes in cells mediated by pyrogallol-induced hydrogen peroxide. Mutagenesis 26:489–498CrossRefPubMedGoogle Scholar
Lopez-Lazaro M, Willmore E, Austin CA (2010) The dietary flavonoids myricetin and fisetin act as dual inhibitors of DNA topoisomerases I and II in cells. Mutat Res 696:41–47CrossRefPubMedGoogle Scholar
Lopez-Lazaro M, Willmore E, Elliott SL, Austin CA (2008) Selenite induces topoisomerase I and II-DNA complexes in K562 leukemia cells. Int J Cancer 123:2217–2221CrossRefPubMedGoogle Scholar
Frank AJ, Proctor SJ, Tilby MJ (1996) Detection and quantification of melphalan-DNA adducts at the single cell level in hematopoietic tumor cells. Blood 88:977–984PubMedGoogle Scholar
Willmore E, Frank AJ, Padget K et al (1998) Etoposide targets topoisomerase IIα and IIβ in leukemic cells: isoform-specific cleavable complexes visualized and quantified in situ by a novel immunofluorescence technique. Mol Pharmacol 54:78–85PubMedGoogle Scholar