Figure 5. Nucleostemin expression in cardiac stem cells declines upon differentiation.

(A) Myocardial section from a mouse at two days after birth shows c-kit⁺ cells (green) with coincident expression of nucleostemin (magenta) at arrows. Sarcomeres are labeled with tropomyosin (red), nuclei detected with Topro-3 (white). Single channel scans used for creation of overlays are shown on the left of each panel. (B) Cultured cardiac c-kit+ cells (green) express high levels of nucleostemin (magenta). Cardiac stem cell cultures induced to differentiate by dexamethasone treatment show decreased nucleostemin expression and increased labeling for GATA-4 (blue). Lectin (right panel) is used a cytoplasmic marker due to loss of c-kit expression. (C) Decreased nucleostemin expression in cardiac stem cell culture following dexamethasone treatment. (D) Quantitation demonstrates a significant decrease in expression of nucleostemin in cardiac stem cell cultures following dexamethasone treatment. Whole cell lysates are normalized to GAPDH to correct for minor variation in protein loading.