Research Paper Volume 10, Issue 10 pp 2585—2605

H3K9me3 and H4K20me3 represent the epigenetic landscape for 53BP1 binding to DNA lesions

Figure 4. The level of γH2AX in irradiated chromatin. Recruitment of HP1β protein at γH2AX-positive DNA lesions and H3K9 deacetylation in UV-damaged chromatin. (A) Analysis of the level of γH2AX (red) in (a) Suv39h1/h2 wt and (b) Suv39h1/h2-deficient fibroblasts (MEFs). The appearance of γH2AX (red) was studied in micro-irradiated ROIs (see yellow arrows) induced by UVA laser (355 mm). (B) Levels of γH2AX (green) in non-irradiated and γ-irradiated (a) Suv39h1/h2 wt and (b) Suv39h1/h2 dn MEFs. Whole cell populations were irradiated by γ-rays. DAPI (blue) was used as a counterstain. Scale bars represent 10 µm. (C) Accumulation of HP1β (green) and the level of H3K9 deacetylation (red) in locally micro-irradiated (a) Suv39h1/h2 wt and (b) Suv39h1/h2 dn MEFs. DAPI was used as a counterstain of a whole nuclear volume. (D) Quantification of H3K9ac (red) in micro-irradiated chromatin showed an identical decrease of H3K9ac in micro-irradiated regions of interest (ROIs shown by yellow arrows in panels (Ca, b). Studies were performed in locally micro-irradiated Suv39h1/h2 wt and Suv39h1/h2 dn MEFs. Scale bars are 10 µm.