Fig. 6. The generation of oligodendrocyte progenitors from a subtype of RG cells is sonic hedgehog dependant.

LeX⁺ cells isolated from cortical VZ/SVZ of a 21 gw fetus are immunolabeled with antibodies to A) SHH and its receptor B) Patched1 (Ptc1). C) The RT-PCR analysis (n=3) shows that - Lane 1): cortical LeX⁺ cells express mRNAs for SHH, Ptc1 and Smo; SHH, Ptc1 and Smo mRNA expression in cortical VZ/SVZ (Lane 2), medial (Lane 3) and lateral (Lane 4) ganglionic eminence. D–L) Co-transfected BLBP-Cre/Floxed-YFP cells are labeled with anti-O4 antibody 7 days after being cultured in differentiation medium D–F) without SHH (control), G–I) with SHH (200ng/ml ,7 div) or J–L) with the SHH inhibitor cyclopamine (1µM, 7 div). Note the increased number of YFP/O4⁺ as well as progenitor cells labeled only with O4 antibody in SHH treated cultures (I) and the lack of YFP/O4⁺ or O4⁺ cells after cyclopamine treatment (L). Arrows point to transfected YFP⁺ cells co-labeled with O4 antibody. M) Quantification of O4+ cells generated from a subtype of RG cells. Scale bars: A–B: 10 µm; D–L: 50 µm.