Fig. 5. IPCD is delayed in Bmp7 homozygous mutant limbs. (A,B) TUNEL analysis of IPCD in E13.5 Bmp7 mutants (B) revealed a delay in IPCD between digits II and III (arrow), when compared with age-matched heterozygous controls (A, arrowhead). (C,D) Bright-field analysis of the same Bmp7 heterozygous and mutant limbs shown in A and B. (E-G) Analysis of Hoxa13 induction by exogenous BMP2 or BMP7. Wild-type limbs treated with 0.1 mg/ml BMP2 (E) or BMP7 (F) did not exhibit any increase in Hoxa13 expression when compared with PBS controls (G), indicating that in the developing autopod, BMP2 and BMP7 do not regulate Hoxa13 expression.