Fig. 6. Restoration of Brn3b downstream target genes in retinas at E14.5 by Brn3a^ki expression. For each in situ hybridization set of retinal sections at E14.5, left, middle and right panels represent wild-type control, Brn3b^AP/lacZ mutant and Brn3b^3a/3a knock-in, respectively. (A) Control Brn3b probe shows the absence of Brn3b expression in Brn3b^AP/lacZ and Brn3b^3a/3a retinas. (B) Brn3a ORF probe detects the endogenous and ectopic Brn3a expression. Expression of the following genes is downregulated in Brn3b^AP/lacZ mice but is restored by Brn3a^ki expression: (C) endogenous Brn3a, (D) Ablim, (G) Gfi1, (H) Gli1, (I) Isl2, (J) Irx4, (K) Irx6, (L) Olf1, (M) Gap43, (N) L1, (O) Shh and (P) Hermes. Conversely, Dlx1 (E) and Dlx2 (F) expression is upregulated in the absence of Brn3b but restored to near-normal levels in Brn3b^3a/3a knock-in retina. Scale bar: 100 µm.