Notch signaling is required for proper development of the myelencephalic choroid plexus.
Pan Notch Inhibition with DAPT (B, dorsal-mounted live larvae and G, transverse section) results in an increase in the mCP epithelial domain compared to vehicle-treated control larvae (A, dorsal mounted live larvae and F, transverse section). This increase in domain size is due to lateral spreading as the mCP remains as a monolayer (G, DAPT-treated versus F, vehicle treated). Further analysis showed that this effect is mediated by inhibition of notch1b (D, 5 dpf live larvae) dla, and dld (E, 5 dpf live larvae). Inhibition of notch1a (C, 5 dpf live larvae) did not significantly alter the size of the mCP epithelial domain but did effect overt structure. Panels A–F are dorsal views with anterior to the left, and panels G and H are 6 μm cryosections labeled with an antibody against GFP (green) and DAPI (blue) staining the nuclei. Quantitative measurements show the distribution mCP sizes in individual fish. Measurements are shown for Notch receptor inhibition by DAPT and morpholino experiments (H), and for Notch ligand inhibition by morpholinos (I) Each point in the histograms represents a measurement of a live larval zebrafish mCP. The mean±s.e.m. is indicated by the line and error bars respectively. Significant effects on mCP size are observed for 10 μM DAPT, notch1b, dla, and dld knockdown (* p = 0.02 and *** p<0.0001). For a full list of mean, s.e.m., and p-values, see table S2. Abbreviations: eye (E), pectoral fin (Pf), and otic vesicle (Ov). Arrows indicate mCP. Scale bars are 50 μm.