Figure 2.

Loss of BubR1 induces microcephaly. (A) BubR1^H/H and BubR1 CKO mice exhibit dramatic reduction in body size. (B) BubR1 CKO, but not BubR1^H/H, has smaller cortex compared to WT. (C and D) H&E staining shows significantly reduced cortical thickness in BubR1 CKO, but not in BubR1^H/H compared to WT. (E and F) Production of early-born neurons (FoxP2+ cells in layer VI, Ctip2+ cells in layer V) is not significantly affected, but late-born neurons (Cux1+ cells in layers II–IV) are severely depleted in BubR1 CKO cortex. Some Cux1+ late-born neurons are present in deeper cortical layers (arrows). ^*P < 0.05, ^***P < 0.001. Scale bar, 200 μm.