Inhibition of GSK3β does not alter number of dedifferentiating Müller glia. Zebrafish larvae were exposed to intense-light at 6 dpf and incubated in BrdU with either DMSO as a vehicle control or 1-azakenpaullone from 0 to 3 dpl. (A, B) Light-lesioned fish treated with DMSO or 1-azakenpaullone from 0 to 3 dpl had no difference in the number of BrdU-positive cells in the INL and in the ONL. (C) Zebrafish that did not have a light lesion were soaked in 2.5 μM 1-azakenpaullone from 6 to 8 dpf to test whether it was sufficient to induce Müller glial proliferation in the absence of a lesion. We saw no PCNA or BrdU-positive nuclei in unlesioned fish. Scale Bar = 100 μm.