Figure 1.

Aspm knockdown decreases neural progenitor proliferation in the developing cortex. (A) Images of E15 mouse cortices electroporated at E12 with nontargeting (top panels, Control) or ASPM-directed small hairpin (bottom panels, shASPM) and GFP expression plasmids. Images were stained for GFP and either Hoechst (left) or Tuj1 (right). Dashed lines in the left panels represent the CP/IZ (top) and IZ/ SVZ (bottom) borders. Bar, 50 μm. (B) Distribution of cells across cortical zones 72 h post-electroporation at E15. (C) Fraction of GFP⁺ cells that overlap with Tuj1 staining in slices. (D) Images of E15 cortices electroporated with control small hairpin (left) or shASPM (right) plasmid. The left images in each set (see panels i,v) show the full span of the cortex. The right images in each set show GFP (panels ii,vi), PHH3 (panels iii,vii), or a merge of GFP and PHH3 (panels iv,viii) from the boxed area on the left. Asterisks indicate GFP, PHH3 double-positive cells. Bar, 25 μm. (E) Mitotic index of the GFP-positive cell population 72 h post-electroporation as measured by PHH3 staining. (F) Images of E15 cortices electroporated with control (left) or shASPM (right) plasmid. (Left panels) GFP staining. (Middle panels) Merge of BrdU (blue) and Ki67 (red). (Right panel) Merge of GFP with BrdU and Ki67. Arrowheads mark GFP, BrdU double-positive cells. Arrows mark GFP, BrdU, Ki67 triple-positive cells. Bar, 50 μm. (G) A 24-h BrdU labeling index as measured at E15. (H) Cell cycle exit index measured at E15.