Cellular proliferation in the developing claws of
. (A-D) Pedal claws at late stage 36 of development. (A) digit III, (B) digit II. (C-G) PCNA staining. (C,D - longitudinal sections) Weak eosin counterstaining in late stage 36. (E-G) Strong eosin counterstaining in stage 38. Cellular proliferation (C,D, black dots) is evident along the claw epithelium in both clawed (C) and unclawed (D) digits. Proliferation is evident at the base of claw (E) in the clawed digit (arrow) and throughout the dorsal claw epithelium (arrowheads). Cellular proliferation in the unclawed digit (F - longitudinal section) is confined to the cells underlying the surface epithelium, although it is abundantly expressed in the epithelium of the developing adhesive plates (arrows). (G) Frontal section through the claw of a pedal clawed digit (III) showing the proliferating epithelium lining the inner surface of the claw sheath, adjacent to the underlying ungual phalanx. Scale bar 500 μm for (A,B) and 100 μm for (C-G).