Fig. 3

Fig. 3 The nuclear β-catenin profile in developing catshark habenulae reveals dynamic, Nodal-dependent asymmetries.

a–e Confocal images of transverse sections of catshark habenulae at stages 26 (a,b), 28 (c), 29 (d) and 31 (e) following DAPI staining (blue) and immunohistochemistry (IHC) with antibodies directed against β-catenin (red) (a–e) and HuC/D (green) (a,b). f Hybridization chain reaction-based fluorescent in situ hybridization (HCR-FISH) image of a section adjacent to (e) with territories for ScSox1, ScKctd12b, and ScProx1 respectively in yellow, magenta and cyan. White arrowheads in (e,f) point to the Right-LHb. Dotted lines in (e,f) delimit Right-LHb and MHb subdomains, respectively positive for ScProx1 and ScKctd12b. The same β-catenin profiles were consistently obtained at each stage on at least three different specimens. g,h Confocal images of transverse sections of stage 31 catshark habenulae, after in ovo injection of DMSO (g, control) or SB-505124 (h) following neural tube closure. The section shown in (a) is located anteriorly to the one shown in (b), sections in (c–h) are located at a medial organ level. A white arrowhead in (h) points to a lateral left territory showing a high density of β-catenin-positive nuclei, present in SB-505124-treated embryos but absent from control ones. i Schemes showing the experimental procedure and the habenular phenotypes observed, with lateral territories of nuclear β-catenin accumulation in red. Dorsal is to the top in all panels. Magnifications of boxed areas in (a–e,g,h) are respectively shown in (a1–a4,b1–b4,c1–c4,d1–d4,e1–e4,g1–g4,h1–h4). Thin white arrows point to β-catenin-labeled nuclei. Abbreviations: L, left; R, right; st., stage. Scale bar = 100 µm.