(A) Flag-tagged hTERT was expressed in 293 cells and immunoprecipitated with hSSB1 antibody. hTERT was detected by Flag antibody. (B) Detection of hSSB1 in HCT116 cells with and without p53. hSSB1 was depleted with specific siRNA. (C) Depletion of hTERT by UTR-specific siRNA and detection by western blots. (D, E) Detection (D) and quantification (E) of hSSB1 at the telomeres by chromatin-immunoprecipitation analysis using an hSSB1 antibody. Lanes 1, 2: control; lanes 3, 4: hSSB1 depleted by specific siRNA; lane 5: p53+/+ cells with over-expression of hTERT; lane 6: p53+/+ cells with over-expression of hTERT and hSSB1; lane 7: p53−/− cells with over-expression of hTERT; lane 8: p53−/− cells with over-expression of hTERT and hSSB1. (F, G) ChIP analysis by using Flag-antibody to analyze Flag-hTERT at the telomeres; lane 1 : p53+/+ cells; lane 2 : p53−/− cells; lane 3: p53+/+ cells with depleted hTERT and lane 4: p53−/− cells with depleted hTERT (H) Interaction of ΔOB−hSSB1 with hTERT was determined by immunoprecipitation. (I, J) Effect of hTERT deletion or expression of hSSB1 with OB-depletion (GFP-???????????ΔOB−hSSB1) on the interaction of hSSB1 with telomeres determined by ChIP. Lane 1: HEK293 cells with hTERT depletion by specific siRNA and ChIP with hSSB1 antibody; lane 2: 293 cells ChIP with hSSB1 antibody; lane 3: 293 cells with depletion of endogenous hSSB1 and expression of GFP-ΔOB−hSSB1, ChIP with GFP antibody and; lane 4: 293 cells with expression of GFP-ΔOB−hSSB1 and ChIP with GFP antibody.