Fig. 7.

Retroviral Math5 overexpression does not stimulate RGC fate or cell cycle exit in retinal explant cultures. (A) Experimental design. Retinas were explanted from E13.5 embryos, flattened on polycarbonate membranes, infected at low density with the indicated MSCV retrovirus, and cultured for 7 days in vitro (DIV). Isolated GFP+ clones were scored for RGC number by Brn3a immunoreactivity and clone size. (B–C) Example clones from explants infected with IRES-GFP (B) or Math5-IRES-GFP (C) retroviruses. (D) Plot showing the fraction of GFP+ cells that developed as Brn3a+ RGCs in transduced explants. There was no significant difference in the RGC fraction of explants transduced with Math5-IRES-GFP or IRES-GFP control. A modest increase in RGCs was observed when Notch signaling was autonomously blocked in clones with the IRES-dnMAML virus. Error bars show binomial standard deviation. (E) Clone size distribution. There was no difference between Math5-IRES-GFP and IRES-GFP explants, but clone size was significantly reduced in explants infected with IRES-dnMAM. Scale bar, 50 µm.