Fig. 4. BMP4 overexpression results in enlarged ciliary ganglia. Embryos, infected at E2 with mBMP4-RCAS display enlarged ciliary ganglia at stage 24/25 as detected by expression of Phox2b and ChAT (A). (B) Quantification of the area of Phox2b and ChAT-positive cells revealed a strong increase in comparison to the control side (Phox2b, P=0.008; ChAT, P=0.039; Student's t-test). Also the number of TH-positive cells (C) was significantly increased (P=0.002). However, the ratio between cholinergic markers and Phox2b (D) or noradrenergic markers and Phox2b (E) showed no significant difference between mBMP4 implanted and control side (P=0.051 and P=0.155, respectively), indicating that BMP4 increases ciliary neuron development but does not affect the phenotype. Scale bar: 250 µm.