Figure 6.

Experimental validation of developmental expression of predicted brain- and organoid-specific genes

(A and B) Developmental expression profiles of SATB2, POU3F2, and PSMB5 mRNAs in human organoids (A) and human neocortex (B), determined by BOMA. Time correspondence for each segment ID can be found in Figure 5D.

(C, F, and I) Immunostaining of cortical organoids (n = 3) revealed percentages of cells expressing SATB2 (C), POU3F2 (F), and PSMB5 (I) during the maturation at 8, 10.5, and 14 weeks.

(D, G, and J) Quantification of SATB2+, POU3F2+, and PSMB5+ cells showed significant enrichment for human cortical plate (PCW 19, correspond to segment 9) compared with organoids (14 weeks, corresponding to segment 9). Differences between organoid and cortical plate were tested using unpaired t test with Welch’s correction, p = 0.0038 for SATB2+ cells, p = 0.001 for POU3F2+ cells, and p = 0.0011 for PSMB5+ cells.

(E, H, and K) Representative images of organoid and human brain sections. Scale bar: 50 μm.