Fig. 2.

BMP4 is required for the generation of PV⁺ interneurons from medial ganglionic eminence (MGE) progenitors in vitro. (A-I′) bFGF (20 ng/ml)-responsive neurospheres were grown from E12 MGE, dissociated and plated for 7 days in low bFGF (0.5 ng/ml) alone (Control) or in the presence of BMP4 (20 ng/ml) or noggin (250 ng/ml). Differentiated cells immunostained for GABA (red, A-C′), SST (red, D-F′) or PV (red, G-I′), βIII-tubulin (green), with DAPI-labeled nuclei in blue. Note the absence of PV⁺ cells in the control (G) and noggin-treated (I) groups. A′-I′ are merged images. (J-L) Quantification of the average percentages of GABA⁺, SST⁺ and PV⁺ interneurons under each condition (see key). ^**P<0.01, ^***P<0.001 by ANOVA; n.d., not detected. Scale bar: 50 μm.