The NuRD components hdac1 , chd4a , mta2 , and rbb4 are required for blastema cell proliferation during the regenerative outgrowth phase. (A-D) Longitudinal sections of fin regenerates treated with DMSO or MGCD0103 at 2 (A-B) or 4 dpa (C-D) stained with BrdU antibody (red) and DAPI (blue). (E-H) Longitudinal sections of fin regenerates at 4 dpa injected with control (E), chd4a (F), mta2 (G), or rbb4 + rbb4l (H) MOs stained with BrdU antibody (red) and DAPI (blue). Yellow dashed lines indicate the boundary between the blastema and the wound epidermis, and white dashed lines indicate the amputation plane. Scale bars: 100 μm. (I-K) Percentage of BrdU-positive cells relative to the total number of cells (DAPI-labeled) in fin regenerates treated with DMSO or MGCD0103 at 2 dpa (I) or 4 dpa (J) or in fin regenerates injected with control, chd4a, mta2, or rbb4 + rbb4l MOs (K). Error bars represent the SEM. n = 9. *P < 0.01.