FIGURE 4.

MN1 knock-out calvarial cells have reduced proliferation in vivo. The BrdUrd-labeled calvaria from WT or MN1 KO E18.5 embryos were prepared as described under “Experimental Procedures.” Three distinct sections from different areas of each calvarium were analyzed for BrdUrd (BrdU) incorporation and counterstained with 4′,6-diamidino-2-phenylindole (DAPI). A, representative images of BrdUrd and 4′,6-diamidino-2-phenylindole stained sections. B, the percentage of BrdUrd-positive cells was quantitated. Five embryos from each genotype were analyzed. Data represent the mean ± S.D. (n = 15 individual sections in each group).