Fig. 3

Foxj1 is a target for transcriptional activation by NFIX. a-b En face view of the apical surface of wall of the lateral ventricle following immunostaining with N-cadherin (red) at P10 in control (a) and Nfix^−/− mutant (b) mice. In the control, N-cadherin labelling revealed the regular, cobblestone-like appearance of the ependymal epithelial sheet (arrowheads in a). In the mutant, however, ependymal cell shape was very irregular, and no coherent cobblestone-like array was observed (arrows in b). c, d En face imaging was also performed using antibodies against acetylated tubulin. In the control, wave-like patterns were clearly discernible in the cilia of the ependymal cells (arrows in c indicate the direction of bulk cilia movement). Conversely, in the mutant, ependymal cilia projected directly out into the ventricular lumen (d). e NFI binding motifs were identified in the basal promoters of numerous genes previously implicated in ependymal cell development using an in silico genome-wide screen. We identified two potential NFI binding sites within the Foxj1 promoter. f ChIP-qPCR revealed significant enrichment of NFIX binding to the − 935 and − 2856 genomic sites in comparison to a non-specific antibody (IgG) in vivo. * p < 0.05, t-test. g A reporter gene assay revealed that NFIX was able to activate luciferase gene expression under the control of a fragment of the Foxj1 promoter containing the − 935 site. * p < 0.05, ANOVA. Scale bar (in a): 20 μm