Fig. 8. Elevated pSTAT and pERK1/2 in Bmpr1a^CKO;1b^+/- growth plates. All sections are E16.5 distal femurs. (A) p-STAT1 immunostaining. (B) Quantification of increased p-STAT1 in mutants, expressed as percent positive cells. (C) p-ERK1/2 immunostaining in the hypertrophic (upper) and periarticular (lower) region. P-ERK1/2 immunostaining can be detected in hypertrophic chondrocytes, but there is no detectable difference in the number of positive cells in this region. An increased percentage of p-ERK1/2-staining cells can be observed in the outlined periarticular (resting) zone in mutants. ^*P<0.01; ^**P<0.001.