Fig. 6.

Mis-regulation of the bone marker gene expression in crocc2 mutants. Network output of partial correlations (from table 2). Red lines represent correlations between genes in different modules, whereas black lines represent correlations within modules. Colors denote distinct modules in each analysis. Panel (A) illustrates the interaction between bone marker expression in WT animals at the young adult stage (3–5 months), whereas panel (B) shows data for comparably staged mutants. Note that, although there are a greater number of correlations in WT versus crocc2 mutant animals, both networks are characterized by four interconnected modules. Covariation of gene expression in old adult (10–15 months) bone is shown for WT (C) and mutant (D) animals. WT zebrafish show a relatively high number of correlations both within and between modules, consistent with a tightly integrated gene network. Alternatively, mutants show a dissociated pattern characterized by two distinct modules, which is reflected in in vivo patterns of bone cell activity (insets, C and D). In WT bone (i.e., interopercle), TRAP and AP are generally in close approximation, whereas in mutants these factors are often expressed in distinct areas of the bone. Scale bars equal 200 µm.