Figure 2: The Sca1⁺ SP phenotype identifies clonogenic, self-renewing cardiac cells.

(a) Bar graph showing the % of adult cardiac clone-forming cells from Lin⁻ Sca1⁺ SP and non-SP fractions, after single-cell deposition. n=7; *P≤0.02. (b) Long-term growth of cloned cardiac SP cells. Clones shown are those used for grafting in Figs 3e and 4; Supplementary Fig. 4. (c) Lack of increased senescence-associated β-galatosidase (SA-β-gal) in four independent clones at increased passage number. *P≤0.02; **P≤0.0005. (d) Persistent Sca1 expression (left) and enrichment for the SP phenotype (right) in cardiac SP clones after long-term culture. Results shown here (clone 16 at passage 29) were confirmed in four additional clones. (e,f) Enrichment for 2° clone formation in cloned cardiac SP cells. (e) Serial bright-field images showing generation of 2° clone by a single cell from clone 3, passage 14. Scale bar, 100 μm. (f) 2° clone formation by six independent clones at passage 13–14. *P≤0.005. Data are shown as the mean±s.e.m. between independent experiments.