Human S3 co-localizes with 8-oxoG residues in cells exposed to hydrogen peroxide. HEK 293 cells were exposed to 0.25 mM hydrogen peroxide for 24 h, and 8-oxoG/hS3 co-localization was evaluated by immunofluorescence microscopy. Human S3 was detected by staining the cells with a rabbit monoclonal anti-hS3 primary antibody and rhodamine red labeled secondary antibody (red fluorescence). For 8-oxoG localization, anti-8-oxoG primary antibody and FITC labeled secondary antibody (green fluorescence) were used. After staining with DAPI, samples were analyzed by fluorescence microscopy. A representative of images obtained with rhodamine (hS3), FITC (8-oxoG), and UV (nuclei) filters are shown. Additionally, a merge of rhodamine, FITC, and UV images is shown. Arrows in the magnified area of the merged image indicate foci of the co-localization of hS3 and 8-oxoG within the nuclei.