Fig. 6. Downregulation of Ptf1a expression in the Foxn4^-/- retina. (A) Real-time qRT-PCR analysis of Ptf1a, Foxn4 and Gapdh mRNA levels in E14.5 Foxn4^+/- and Foxn4^-/- retinas. Each histogram represents the mean±s.d. for four retinas. (B-E) Retinal sections of the indicated stages from wild-type and mutant mice were hybridized with a Ptf1a riboprobe. The absence of Ptf1a signals from Foxn4^-/- retinas (C,E). Scale bar: 50 µm in B,C; 25 µm in D,E. Abbreviations: onbl, outer neuroblastic layer; inbl, inner neuroblastic layer.