FIGURE 10.
Low level Kdm4b overexpression confers decreased sensitivity to γ-irradiation. A, stable U2OS/Kdm4b-EGFP cells were sorted for low levels of Kdm4b-EGFP expression. The resulting U2OS/Kdm4b-EGFPlow and parental U2OS cells were plated at low levels for the colony formation assay. 24 h after plating, the cells were irradiated and then were allowed to recover until the resulting colonies reached at least 50 cells. The plates were then stained with crystal violet to allow visualization of the colonies; both cell lines were plated and stained on the same day. The experiment was performed in triplicate. Colonies were counted and expressed relative to untreated controls. B, U2OS cells were treated with G9a inhibitor or DMSO (control). On day 2 of treatment the pretreated cells were plated for the colony formation assay, as above. C, the sensitivity of the Suv39h1/h2-dn and isogenic wild type MEFs was compared using the colony formation assay, as above γIR, γ-irradiation.