Research Paper Volume 6, Issue 1 pp 70—81
Serines 440 and 467 in the Werner syndrome protein are phosphorylated by DNA-PK and affects its dynamics in response to DNA double strand breaks
Figure 6. Cells overexpressing the phosphorylation mutants are moderately sensitive to etoposide. (A) Comet assay with AG11395 cells overexpressing either EGFP-WRN wild type (WT) or mutant (S440A, S467A or S440A/S467A) 24 h after 35 μM etoposide treatment. Representive images are shown. (B) Tail length in (A) are indicated. At least 17 cells were measured. Asterisks (*) indicate significant difference between 0 h and 24 h (p<0.05). Plus (+) indicate significant difference between Wild type and mutants. (C) AG11395 cells overexpressing either EGFP-WRN wild type (WT), S440A, S467A or S440A/S467A were treated with 0, 15, 25 or 35 μM etoposide. 24 h after the treatment, cell proliferation was evaluated by the MTT assay. Significant difference between cells expressing empty vector and WT, or three mutants at concentration of 35 μM (p<0.05).