The presence of CEBPα/β and NeuroD on the Fos, Egr1 and Egr2 promoters is dependent on Trk receptor signaling. (a-c) In vivo detection of Fos, Egr1 and Egr2 promoter occupancy by C/EBPs and NeuroD in the absence of multiple trkB/C alleles. ChIP analysis was performed three times on a pool of four newborn forebrain lysates from wild-type (wt) and trkB-/-;trkC+/- mice using antibodies specific for C/EBPα, C/EBPβ, NeuroD, and acetylated-H3 (Ac-H3). Following ChIP analysis the samples were subjected to qPCR, and the DNA quantification was calculated as percentage of the input. In all cases, no PCR product was detected in the absence of DNA. The p value refers to the difference between wild-type and mutant animals. (d,e) Control experiments. (d) H3 ChIP analysis and qPCR were performed with primer pairs located in the Egr2-coding region. A similar amount of PCR product was detected in wild-type and mutant animals. (e) Cebpa, Cebpb and Neurod mRNA levels were not affected in the absence of Trk signaling. qRT-PCR was performed on total mRNA from newborn forebrain of wild-type (grey bars) and trkB-/-;trkC+/- (red bars) mice using primers specific for Cebpa, Cebpb and Neurod. After normalization to gapdh, mRNA levels were expressed relative to those for the wild-type animals, which were given the arbitrary value of 1. Error bars represent the standard error based on three independent experiments. *p < 0.05, **p < 0.002.