Fig. 4. Olomoucine induces premature neurogenesis. Double immunofluorescence for TIS21 (a-d, b', green) and MAP2 (a'-d', red) on sagittal cryosections through the rostral telencephalon of littermate (a vs. b, c vs. d) E9.5 embryos developed for 24 hours in WEC in the presence of 80 µM iso-olomoucine (isoolo; a, a' and c, c') or olomoucine (olo; b, b' and d, d'). Arrowheads, apical (ventricular) side of neuroepithelium. Arrows indicate prematurely generated neurons. The white box in b indicates the area shown at higher magnification in b'. b' and d' show different degrees of premature neurogenesis upon olomoucine treatment, with few (b') and many (d) neurons being generated. Open arrows in a', c' and d' indicate reaction of the anti-mouse secondary antibody with the skin, presumably with adsorbed mouse immunoglobulins present in the mouse serum used for WEC. Dotted lines in a' and c' delineate the boundaries of the neuroepithelium.