Figure 1.

(A). Map of mutant eGFP gene, integrated in HCT 116 cells. The wild-type and mutant sequence of the eGFP gene, where the point mutation is in the eGFP cassette, TAG, are shown above (base is in bold and underlined). This is the target for the 47-mer oligonucleotide, EGFP3S/47NT, directed to the non-transcribed strand of the eGFP gene. EGFP3S/47NT is a single-stranded oligonucleotide with three phosphorothioate modifications on each terminus. (B). Selenomethionine is not cytotoxic in HCT 116 cells. Cells were incubated with selenomethionine at concentrations of 0, 50, 200, 400, and 1000 μM, respectively. Viability was determined by an MTT-reduction assay; each data point represent mean of three (± S.D.), non-treated cells are normalized to 100% viable. (C). Exposure to selenomethionine does not induce DSBs in HCT 116 cells. Cells were grown with respective treatment for 24 hours prior to harvesting and prepared for pulsed-field gel electrophoresis (PFGE). The gel was run for 24 hrs and subsequently stained with ethidium bromide. Lane M, S. cerevisiae chromosomal DNA size marker presented in kilobases; Lane C, non-treated control HCT 116 genomic DNA; Selenmethionine-treated (100 μM, 200 μM, 400 μM) HCT 116 cells; Lane MMS, MMS (150 μM) -treated HCT 116 genomic DNA.