Ascl1-dependent MG proliferation in the injured mouse retina is enhanced by Lin28a expression. A, Experimental timeline. B, Sox9 and BrdU immunofluorescence on retinal sections from injured retinas shows forced expression of Ascl1 stimulates a small amount of MG proliferation that is enhanced when combined with Lin28a expression injured retina. Scale bar, 100 μm. C, Quantification of proliferating MG in injured retinas that were infected with the indicated AAV ShH10 virus; n = 5 different experiments. Error bars are SD. *p < 0.05, ***p < 0.001. D, P17 mouse retinas were infected with either AAV ShH10-Ascl1-GFP or AAV ShH10-Lin28a-mCherry and then treated with NMDA and BrdU, and killed as indicated in A. BrdU/GFP or BrdU/mCherry immunofluorescence on retinal section showed BrdU+ MG expressed Ascl1-GFP or Lin28a-mCherry (Lin28a-mCh), respectively. Scale bar, 100 μm. E, PCR shows retinas infected with AAV ShH10-Ascl1 express Ascl1, but do not activate the endogenous Lin28a gene.