Figure 2

Gene expression changes occurring during satellite cell activation. The genes significantly regulated between freshly isolated satellite cells and satellite cells isolated 12 h post-injury from wild type and Sdc4^−/− mice were plotted as a Venn diagram to identify genes unique to wild type satellite cells (A, yellow, ANOVA P ≤ 0.01, ≥ two-fold change). A heat map depicting changes in relative expression of genes unique to wild type satellite cells with more than half (56%) of the transcripts decreasing during the first 12 h following satellite cell activation (B, red is high relative expression and green low relative expression). The frequency of genes that decrease (■) more than four-fold (2²) is significantly higher than the frequency of genes that increase (□) more than four-fold (2²) during the first 12 h post-muscle injury (C). Further analysis of gene expression data using IPA 9.0 (Ingenuity® Systems, http://www.ingenuity.com) demonstrate that genes promoting cell cycle progression increase (green) while genes that inhibit the G1/S phase transition decrease (red) in wild type satellite cells 12 h post-muscle injury (D, relative intensity depicts the fold change with higher color intensity denoting a greater fold change).