Figure 5. Single cell gel electrophoresis assay.
A: Individual cell nuclei are embedded in an agarose gel and subjected to electrophoresis. Relaxation of DNA supercoiling as a result of strand breaks results in the DNA being pulled out of the nucleus to form a comet ‘tail’. The fluorescence intensity of the image and extent of DNA migration can be quantified by image analysis. B: Crosslinking molecules antagonise the extent of DNA migration. Top panel: HaCaT nuclei treated with Cisplatin showing no DNA migration; Middle panel: HaCaT nuclei treated with clastogen to introduce strand breaks and produce significant DNA migration; Bottom panel: combination of cisplatin and clastogen showing inhibition of DNA migration caused by the crosslinking effect of cisplatin.