TIP60 methylation by SET7 promotes cell proliferation. (A) HCT116 cells were transfected with the indicated plasmids and treated with 5 mM HU for 4 h. Apoptotic cells were measured by fluorescence-activated cell sorting (FACS) analysis, and protein expression was confirmed through a western blot assay. Results were shown as the mean ± SEM; n = 3, **P < 0.01, N.S: no significant difference. (B) Representative colony formation assay was performed using HCT116 cells with TIP60 knockdown transfected with TIP60 WT or TIP60 K137R. Cells were treated with 5 mM HU for 4 h and incubated in fresh media for 7 days. Results were shown as the mean ± SEM; n = 3, *P < 0.05, N.S: no significant difference. (C) Cell viability was determined using the MTT assay. HCT116 cells with TIP60 knockdown were transfected with TIP60 WT or TIP60 K137R. Cells were treated with 5 mM HU for 4 h and incubated in fresh media for 0-72 h. Results were shown as the mean ± SEM; n = 3, **P < 0.01, N.S: no significant difference. (D) Schematic showing how SET7-mediated TIP60 methylation promotes the homologous recombination (HR)-mediated DNA repair pathway.
