Repair of mitomycin C mono- and interstrand cross-linked DNA adducts by UvrABC: a new model

Abstract

Mitomycin C induces both MC-mono-dG and cross-linked dG-adducts in vivo. Interstrand cross-linked (ICL) dG-MC-dG-DNA adducts can prevent strand separation. In Escherichia coli cells, UvrABC repairs ICL lesions that cause DNA bending. The mechanisms and consequences of NER of ICL dG-MC-dG lesions that do not induce DNA bending remain unclear. Using DNA fragments containing a MC-mono-dG or an ICL dG-MC-dG adduct, we found (i) UvrABC incises only at the strand containing MC-mono-dG adducts; (ii) UvrABC makes three types of incisions on an ICL dG-MC-dG adduct: type 1, a single 5′ incision on 1 strand and a 3′ incision on the other; type 2, dual incisions on 1 strand and a single incision on the other; and type 3, dual incisions on both strands; and (iii) the cutting kinetics of type 3 is significantly faster than type 1 and type 2, and all of 3 types of cutting result in producing DSB. We found that UvrA, UvrA + UvrB and UvrA + UvrB + UvrC bind to MC-modified DNA specifically, and we did not detect any UvrB- and UvrB + UvrC–DNA complexes. Our findings challenge the current UvrABC incision model. We propose that DSBs resulted from NER of ICL dG-MC-dG adducts contribute to MC antitumor activity and mutations.

Quantitative DNA Interstrand Cross-Link Formation by Coumarin and Thymine: Structure Determination, Sequence Effect, and Fluorescence Detection

“…The residue was purified by column chromatography (EtOAc:hexane:Et 3 N = 49:50:1) providing 11 as a white solid (120 mg, 55%). 31 7-(1-(3-Hydroxypropyl)-1H-1,2,3-triazol-5-yl)-4-methyl-2H-chromen-2-one (6). To a suspension of 7-ethynyl-4-methyl-2H-chromen-2-one (15, 184 mg, 1 mmol), 3-azidopropan-1-ol (152 mg, 1.5 mmol) and copper(II) sulfate (pentahydrate) (50 mg, 0.2 mmol) in a mixture of water (10 mL) and tert-butyl alcohol (10 mL), sodium ascorbate (119 mg, 0.6 mmol) was added and stirred at room temperature overnight.…”

Mitomycin C and doxorubicin elicit conflicting signals by causing accumulation of cyclin E prior to p21WAF1/CIP1 elevation in human hepatocellular carcinoma cells

“…Metabolically reactive mitomycin C induces DNA damage via DNA-alkylation, DNA-mono-adduct formation, and intrastrand cross-linking (8,9). Such reactions eventually result in antitumor effects in a broad range of human cancers (10)(11)(12)(13).…”

Photoswitchable Formation of a DNA Interstrand Cross‐Link by a Coumarin‐Modified Nucleotide

“…Chemical agents capable of inducing ICLs have been developed for biological applications, such as for DNA damage and repair studies, [1–5] as anticancer agents, [6] for nucleic acid detection, [7,8] for targeting telomeric G-quadruplex structures, [9,10] and for construction of DNA nanomaterials. [11] Over the past few decades, several research groups have developed novel chemical methods for inducing ICL formation, such as photoirradiation, oxidation, reduction, fluoride induction, and H 2 O 2 induction.…”