A Live‐cell fluorescence microscopy analysis of U2OS cells stably expressing either GFPNLS empty, wild‐type (WT) USP45 or catalytically inactive USP45 [Cys199Ala]. Cells were treated with BrdU (10 μM, 24 h), psoralen or angelicin (25 μM, 3 h) and images captured at the indicated times after laser micro‐irradiation. The location of the micro‐irradiation stripe in each cell is indicated with a yellow line. Similar results were obtained in at least two independent experiments. Scale bar, 10 μm. 