Figure 7. PA200‐proteasome degrades acetylated histones.

• A
  Western blots of HeLa cells pre‐treated with the E1 enzyme inhibitor PYR‐41 (10 μM) 1 h before UV irradiation and lysed at different time points after UV (16 J/m²). Blots were stained with the indicated antibodies, and representative blots are shown.
• B
  Quantification of histone acetylation levels, normalized against histone H4 levels, average of five experiments. Error bars represent SEM.
• C
  Representative Western blots of siControl or siPA200 (two independent siRNAs, a and b) transfected cells, lysed at indicated time points after UV irradiation (16 J/m²).
• D, E
  (D) Quantification of histone H4 and (E) histone acetylation levels, normalized against tubulin and non‐treated levels are set as 1. The average of at least nine independent experiments and SEM is shown.
• F
  Clonogenic survival of HeLa cells treated with different doses of UV‐C. Relative survival (in percentage) is plotted against UV‐C dose. N ≥ 2, error bars represent SEM.
• G
  Unscheduled DNA synthesis in non‐cycling C5RO cells measured by the incorporation of EdU (20 μM) after UV irradiation (16 J/m²) visualized by ATTO594 labeling using Click‐chemistry. Levels in siControl cells were set as 1. N = 2, > 200 cells analyzed, error bars represent SEM.

Data information: Significant differences, calculated by t‐test are indicated with *P < 0.1, **P < 0.05, and ***P < 0.01.