Images were taken from BPs cultured for 3 days (2 days plus Streptomycin then 1 day minus Streptomycin), with either DMSO or DAPT present for the entire culture period. Images show the middle region, with the neural half toward the top, and the distal end toward the right. A–D. ISH for Atoh1 in BPs treated with 0.5% DMSO (A), 1 μM DAPT (B), 10 μM DAPT (C), or 50 μM DAPT (D). E,F. ISH for Delta1 in BPs treated with 0.5% DMSO (E) or 50 μM DAPT (F). G,H. ISH for Serrate1 in BPs treated with 0.5% DMSO (G) or 50 μM DAPT (H). I,J. ISH for Hes5’s in BPs treated with 0.1% DMSO (I) or 10 μM DAPT (J). Scale bar in A= 15 μm (applies to A–D), and scale bar in E = 15 μm (applies to E–J).