Cross model validation of PKA subunit regulated genes versus human myotube differentiation genes. A. Heat map of the hierarchical clustering of gene expression accompanying myotube induction following the withdrawal of serum from myoblasts in culture from baseline (day 0) to day 9. B. GSMA results using genelists corresponding to the top 250 RIα and RIIβ significantly up- or down-regulated genes versus either the myotube dataset or IFN-treated myoblasts (as a negative control). Significant concordance between RIα up-regulated and, conversely, RIIβ down-regulated genes with myoblast up-regulated genes is shown. GSMA scores are shown as significance values [1-log(p)] generated from a two-tailed test of the Standard Normal Distribution.