Fig. 2. In vivo occupancy of neuronal-specific promoters by ATH5 and NGN2 as a function of developmental stage. Antibodies directed against ATH5 (A,C) and NGN2 (B) were used to immunoprecipitate crosslinked chromatin fragments prepared from E3 to E12 neuroretinas and optic tecta. Immunoprecipitates were analyzed for the abundance of ATH5 (A,B), ß3 (B,C), NeuroM (A) regulatory sequences and ß3 ORF (C) by real-time PCR. Data are normalized relative to ATH5 promoter occupancy by ATH5 protein (A,C) in E6 retina (IP efficiency: 0.08%), and for NGN2 protein (B) in E3 retina (IP efficiency: 0.08%). NR, neuroretina; OT, optic tectum. *P=0.02, Student's t-test.