Fig. 6: 6-thio-dG suppresses telomerase elongation of telomeres in cells.
a Schematic for expression of C50/56A hTR variant harboring the template sequence 3’-AAAUCCAAAUC-5’ via lentiviral transduction into HCT116 cells, and detection of newly added (TTAGGT)n repeats with a 5’-Cy3-(ACCTAA)3-3’ probe by FISH. Created in BioRender. Sanford, S. (2025) https://BioRender.com/v6tf1o8. b Representative images of interphase cells stained with PNA probes for wildtype and variant sequence 6 days post-transduction with empty vector (EV) or C50/56A hTR, and after 72 h treatment with 0, 1, 2.5 or 5 µM 6-thio-dG (6dG). c Quantification of the number of variant telomeric foci per nucleus from panel b. Error bars represent the mean ± s.d. from n cells analyzed as indicated by dots from 3 independent experiments. Statistical significance was determined by one-way ANOVA (*P = 0.0490; ****P < 0.0001). d Quantification of the variant telomere sum intensity. Error bars represent the mean ± s.d. of n variant telomere foci analyzed as indicated by dots, from 3 independent experiments. Statistical significance was determined by one-way ANOVA (**P = 0.0026; ****P < 0.0001). e HCT116 cell counts obtained 72 hours after treatment with the indicated 6-thio-dG concentrations, relative to untreated cells. Error bars represent the mean ± s.d. from 4 independent experiments. Statistical significance was determined by one-way ANOVA (*P = 0.0103; ***P = 0.0010; ****P < 0.0001). f Size of nuclear area (μm2) obtained 72 hours after 0 or 5 µM 6-thio-dG treatment. Error bars represent the mean ± s.d. from the indicated n number of nuclei analyzed as indicated by dots, from two independent experiments. Statistical analysis by two-tailed t test (ns = not significant). g Representative images of β-galactosidase (β-gal) staining 72 hr after 0 or 5 µM 6-thio-dG treatment. Arrows indicate β-gal positive cells of 500 cells analyzed per condition from two independent experiments. Scale bar = 100 μm. Source data are provided as a Source Data file.
