Fig. 7: Delta-catenin binds to the proximal Kcc2 promoter at two Kaiso sites, regulated by Kenpaullone.

a Structure of mouse Kcc2 gene encompassing 2.5 kb surrounding the transcription start site (TSS; +1). Location of DNA-binding sites: Kaiso1 (−1456 to −1449), Kaiso2 (+83 to +90) and TCF (−1845 to −1838) relative to TSS, all three sites can bind δ-cat via Kaiso (Kaiso1, −2 sites) and ß-cat (TCF). Bottom, bar diagram: Chromatin immuno-precipitation (ChIP) using anti-δ-cat antibody in rat primary cortical neurons reveals binding of δ-cat to all three sites. KP treatment (100 nM, DIV5-8) significantly increases binding of δ-cat to the Kcc2 promoter on the Kaiso2-binding site, significantly reduces binding to Kaiso1, and no significant increase at TCF. Data are represented as mean values ± SEM. n = 6 independent neuronal cultures were subjected to ChIP; *p = 0.011, p = 0.018; KP-treatment vs. vehicle, two-sided t-test. b Top panel: mouse Kcc2 promoter constructs, Kaiso1, −2 were deleted also a ∆K1/K2 construct was built devoid of both sites. Dual-RE1 sites and TCF site is shown for orientation, also TSS at +1. Bottom, bar diagrams: Luciferase (LUC) activity of Kcc2 promoter constructs in N2a cells with neuronal differentiation (Supplementary Fig. 6a), treatment with 100 nM KP for 3 days. Left-hand: ∆K1 significantly increased over WT, ∆K2 and ∆K1/K2 significantly decreased vs. WT, n = 3 independent culture per transfection, *p = 0.014, p = 0.014, p = 0.032, 1-way ANOVA. Right-hand: repressive Kaiso1-binding site deletion with enhanced activity of the Kcc2 promoter, significantly enhanced further in response to KP. Data are represented as mean values ± SEM. n = 3 independent cultures per transfection; ***p = 0.0003 KP-treatment vs vehicle for the respective construct, two-sided t-test. Source data are provided as source data files.