Loss of CBP in newborn neurons interferes with synaptic maturation and SRF-dependent neuronal growth

We used genome-wide sequencing methods to study the consequences of eliminating the CREB-binding protein (CBP) in newborn neurons. We found that CBP-deficient newborn neurons show impaired growth and activity-dependent transcription. In particular, genes downstream of the serum response factor (SRF) and related to neuronal growth and activity-dependent plasticity were affected. The expression of a constitutively active SRF protein with the ability to transactivate target genes in a CBP-independent manner reduced the growth and transcriptional defects associated with CBP ablation. RNA-seq experiment: Crebbpf/f and Nestin-cre mice were crossed to selectively eliminate CBP in the newborn neurons of the central nervous system (CNS). Primary cortical neurons were obtained from E17. Nestin-cKO and cWT embryos are used for RNA-seq analysis and processed separately. The day of plating was considered day in vitro 1 (DIV1). At DIV10, cortical cultures were stimulated with 25 μM bicuculline and 1 mM AP-4 for 2 h and 30 min. The analysed samples represent two variables, effect of selectively eliminate CBP in the newborn neurons after 10 days in culture and effect of selectively eliminate CBP in the newborn neurons after bicuculline stimulation in cultures at DIV10. ChIP-seq experiment: Primary hippocampal neurons were obtained from E17 embryos. Cultured neurons were infected with syn-VP16-SRF/Syn-GFP viral vector at DIV3. After 7 days post-infection, neurons were collected and genomic DNA from 5x10e6 hippocampal neurons was fragmented by sonication and immunoprecipitated with anti-VP16 antibody (Santa Cruz, sc-7545) as previously described (Scandaglia et al., 2015). Immunoprecipitated DNA was resuspended in 40 μL of water.