Fig. 6. Expression of DLX1, DLX2 and BRN3b in the ocular retardation (or^J/or^J) mouse. (A-C) Or^J/or^J mutants (Chx10 null) lack expression of BRN3b (A), DLX1 (B) and DLX2 (C) at E13.5, indicating absent RGCs. (D-F)Wild-type controls exhibit normal patterns of expression of these markers. By E16.5, there are BRN3b-expressing cells in or^J/or^J mutants (G). BRN3b expression coincides with the onset of DLX1 and DLX2 expression (H, DLX1; I, DLX2). (J-L) Expression in controls (J, BRN3b; K, DLX1; L, DLX2). By E18.5, BRN3b expression is localized in the central inner retina in both or^J/or^J mutants and controls (M, mutant; P, wild type). DLX1 expression is not detected (N, mutant; Q, wild type) at E18.5. DLX2 expression is found in the inner and outer retina in both mutants and wild types (O, mutant; R, wild-type). The expression pattern of DLX2 is considerably disorganized in the or^J/or^J mutant compared with wild-type controls at this stage (O,R). Scale bars: 100 µm in F; 50 µm in L; 50 µm in R.