Multi-Potent Sca-1+ CPCs Figure 1. Characteristics and genetic background of colony-derived cell populations obtained from adult mouse heart. A, Surface marker expression analysis by flow cytometry. All selected cell populations were analyzed for expression of Sca-1, c-kit, CD45, CD34, CD31, and CD29. B, Left, Growth curve of individual cell populations in expansion medium. Right, calculated doubling time of individual cell populations (*p,0.01 vs all other cell populations). Abbreviations: CSH, colony-derived Sca-1 high expression group; CSL, colony-derived Sca-1 low expression group; MSH, magnetic beads sorted Sca-1 high expression group. C, Expression of stem cell-related genes analyzed by RT-PCR. RNA extracted from mouse embryonic stem (mES) cells was used as positive control. D, Sphere-like cell cluster formed on ultra-low attaching dish was stained with Ki67 (green) and DAPI (blue). Bar = 100 mm. doi:10.1371/journal.pone.0025265.g001 Sca-1 expressing populations (CSH1 and CSH2), and two low Sca-1 expressing populations (CSL1 and CSL2). Non-colony- derived Sca-1+ cells selected with MACS (MSH) were used as controls. These cells rarely expressed CD45, a known hematopoietic lineage marker. Besides, these cells occasionally expressed hematopoietic progenitor and endothelial cell markers CD34 and CD31 [16,17] whereas frequently expressed mesen- chymal stem cell marker CD44. Although all of colony-derived PLoS ONE | www.plosone.org 3 September 2011 | Volume 6 | Issue 9 | e25265