Fig. 7. CS-GAGs are necessary for neuronal differentiation of precursors in vivo. (A) Photomicrographs of immunohistochemical stainings of E14.5 mouse forebrain cryosections 1 day after ventricular injection of ACSF control (upper panels) or ChABC (lower panels). Cell nuclei were counterstained with bisbenzimide and are shown in blue (DAPI). The prominent presence of the 473HD epitope on cells with radial morphology in the germinal layers of control sections was lost after ChABC injection, as expected. Concomitantly, a substantial reduction in young postmitotic ßIII-tubulin-positive neurons in the germinal layers of the cortex and ganglionic eminence was observed. Note, however, that we observed an accumulation of neurons in the cortical plate (lower right-hand panel). (B) The changes were quantified by counting immunopositive cells 2 hours after plating of single-cell suspensions obtained from embryos injected with ACSF or ChABC. Note that ChABC treatment caused a clear reduction in the number of ßIII-tubulin-positive cells. We also recorded a small increase in the number of GFAP-positive cells. ^**, P<0.01; ^***, P<0.001. Scale bar: 100 µm.