Fig. 5. Raldh3 overexpression in the presence of ATR reproduces the effects of RA treatments on eye DV polarity. (A) Embryos were bilaterally injected with a total of 1 ng Raldh3 mRNA and treated with 0.5 µM ATR from stage 12.5/13, followed by molecular marker analysis at stage 33. The combination of Raldh3 and ATR expands Pax2 expression, while ATR alone has only a weak effect. A comparable expansion of Pax2 is obtained by a dose of 2 µM ATR in the absence of exogenous Raldh3. (B) The combination of 4 ng Raldh3 mRNA and 2.5 µM ATR can upregulate Vax2 in the DR, while ATR alone has only a weak effect. Strong Vax2 upregulation is also caused by a dose of 10 µM ATR in the absence of exogenous Raldh3, as shown in both lateral (upper row) and anterior view (lower row).