Fig. 8. Loss of interdigital tissue in N-Myc-deficient mouse limbs. (A) Staining for BrdU incorporation at E13.5. Note the interdigital channel of predominantly BrdU-negative cells of PC limbs is lost in interdigital regions of PC-NMyc^f/f limbs. The boxed regions are shown at higher magnification and the percentage of BrdU-positive cells in the specific regions marked by red boxes is indicated. (B) TEM of interdigital regions in PC and PC-NMyc^f/f paws. Scale bars: 10 µm. (C) Staining for the blood vessel marker Pecam (green) with propidium iodide. C, cartilage condensations; P, perichondrium; E, epithelium.