Figure 6.

Evidence for loss of PGK expression and increased proliferation rate in mutant growth plate chondrocytes. (a,b) In situ hybridization analysis with PGK cRNA on histological sections from E15.5 wild-type and mutant tibias and fibulas; the darkfields for both wild-type and mutant specimens are shown. (c,d) Detection of BrdU positive cells on histological sections from E15.5 wild-type and mutant tibias, respectively. Sections were counterstained with methyl green. (e) Quantification of BrdU positive cells outside of regions of necrosis, defined as cells more than one cell layer from clearly necrotic regions; percent positive is as a function of total cells counted in the selected region. A significant increase in incorporation in nullizygous chondrocytes is seen. Error bars represent one standard error; counts were done on 10 growth plate regions from the long bones of five independent embryos for each genotype. (Open bar) Wild type (WT); (red bar) Null.