Fig. 5.

Fate switching. Images show examples of loss-of-function analysis performed using SoFa. (A) Uninjected SoFa1 retina. (B) Atoh7 morphant retina in which there is a decrease in RGCs and a clear increase in the number of dACs and ACs (red and green cells), BCs (blue cells) and PRs (purple cells). (C,E) Ptf1a MO1 and MO2 morphant retinas. Ptf1a MO2 (C) is a more potent translation-blocking morpholino that interferes with both Ptf1a and Ptf1a:cytGFP expression. Ptf1a MO1 (E) is a splice-blocking morpholino, which consequently knocks down the translation of Ptf1a, but not ptf1a:cytGFP, so cells that would have been ACs and HCs can be seen in their transfated states. In these morphants, we see reductions in the generation of ACs, dACs and HCs, and an increase in the number of RGCs (red), BCs (blue) and PRs (purple). (D,F) Atoh7/Ptf1a double morphants, showing a retina devoid of RGCs and HCs, with a significant reduction in the number of dAC and ACs (red only), a significant increase in the number of PRs (purple) and BCs (blue), and an increased amount of transfating. (G,H) Knockdown of Vsx1 alone leads to a small decrease in BCs because of compensation from Vsx2, whereas simultaneous knockdown of Vsx1 and Atoh7 leads to increases in ACs [especially displaced ACs (red and green) and PRs (purple)]. (I-K) Cross sections of uninjected Vsx1:cytGFP; Vsx2:cyt dsRed retinas. Most BCs are green, indicating that they are Vsx1+. (L-N) Knockdown of Vsx1 results in loss of most Vsx1+ BCs, but there is almost a complete compensation in BC numbers via an increase in Vsx2+ BCs.