Knockdown constructs shows Sdc1 is necessary for NPC maintenance and proliferation in vivo.

<p>In utero electroporation was performed at E13 and results assessed at E15. (A) Sdc1 UTR and ORF shRNAs reduced NPC proliferation and promoted neuronal differentiation, indicated by Ki67 and Tuj1, respectively (scale bar = 50 um), as quantified in (B) (scrambled, N = 4; Sdc1 UTR, N = 3; Sdc1 ORF, N = 5). (C) Sdc1 UTR and ORF shRNAs decreased both RGC and IPC populations, indicated by reduced Pax6 and Tbr2, respectively (scale bar = 50 um) and quantified in (D) (scrambled, N = 4; Sdc1 UTR, N = 3; Sdc1 ORF, N = 5). (E) The distribution of eGFP<sup>+</sup> cells in the cortical layers (scrambled, N = 5; Sdc1 ORF, N = 4). CP, cortical plate; IZ, intermediate zone; SVZ, subventricular zone; VZ, ventricular zone. Error bars represent S.E.M, *P<0.05, **P<0.01, ***p<0.001.</p>