Fig. 5. XSu(H)Ank enhances co-expressed Xath5 activity through its effect on the cell cycle. (A-B) Stage 41 retina lipofected with Xath5 alone (A) and in combination with XSu(H)Ank (B). (C) Almost all RGCs induced by overexpression of Xath5 and XSu(H)Ank send axons that exit the eye through the optic nerve head (ONH). (D) Ratio of cells in the retina lipofected with Xath5 and/or XSu(H)Ank. Retina was lipofected with the indicated constructs at stage 15. The effect on cell type distribution was analysed at stage 41. (E) Effect of XSu(H)Ank on RGC versus Müller cell ratios as a function of stage of transfection. XSu(H)Ank plus GFP was lipofected at the indicated stages, and the effects on cell fate determination analyzed at stage 41. In control, GFP was lipofected at stage 15. Control at stage 18, 21, or 24 was similar to that of stage 15. (F) XSu(H)Ank induces earlier cell cycle exit of RGC precursors induced by Xath5. Xath5 was colipofected with XSu(H)Ank or with XSu(H)Ank plus cyclin E1 at stage 15. BrdU injection started at stage 32. At stage 41, the ratio of BrdU-positive cells in the lipofected RGCs was analyzed. (G) Model of RGC generation in retina overexpressing Xath5 alone or XSu(H)Ank plus Xath5.