title: A fluorescence-based assay for the apurinic/apyrimidinic-site cleavage activity of human tyrosyl-DNA phosphodiesterase 1.
abstract: Tyrosyl-DNA phosphodiesterase 1 (Tdp1) catalyzes the hydrolysis of phosphodiester bonds between the DNA 3'-phosphate and tyrosine residues and plays a major role in the repair of stalled topoisomerase I-DNA covalent complexes. Given this role, Tdp1 is of interest as a potential target for anticancer therapy. Inhibiting Tdp1 in combination with clinically used Top1 inhibitors may potentiate the effects of the latter and help to overcome some of the chemoresistance issues currently observed. In addition, Tdp1 can function during DNA repair to remove a variety of other 3' adducts from DNA such as phosphoglycolates and abasic or apurinic/apyrimidinic (AP) sites. Here we describe a new mix-and-read homogeneous fluorogenic assay for the measurement of the AP-site cleavage activity of Tdp1 that is compatible with high-throughput screening. The application of such an assay will open up further avenues for the discovery of novel Tdp1 inhibitors.
authors.affiliation: Cancer Research UK Drug Discovery Unit, Paterson Institute for Cancer Research, University of Manchester, Manchester, UK. gthomson@picr.man.ac.uk
authors.forename: Graeme J
authors.initials: GJ
authors.lastname: Thomson
authors.forename: Nicola S
authors.initials: NS
authors.lastname: Hamilton
authors.forename: Gemma V
authors.initials: GV
authors.lastname: Hopkins
authors.forename: Ian D
authors.initials: ID
authors.lastname: Waddell
authors.forename: Amanda J
authors.initials: AJ
authors.lastname: Watson
authors.forename: Donald J
authors.initials: DJ
authors.lastname: Ogilvie
mesh_terms: D053837:DNA Cleavage; D004260:DNA Repair; D057075:Enzyme Assays / Q000379:methods*; D005453:Fluorescence; D057166:High-Throughput Screening Assays / Q000379:methods*; D006801:Humans; D010727:Phosphoric Diester Hydrolases / Q000737:chemistry*; D011687:Purines / Q000737:chemistry; D011743:Pyrimidines / Q000737:chemistry
chemical_list: D011687:Purines; D011743:Pyrimidines; D010727:Phosphoric Diester Hydrolases; C498508:TDP1 protein, human
keywords: Assay; DNA repair; High-throughput screen; Inhibitor; Tdp1; Topoisomerase