Figure 4. CD34+/− sorted populations contain a similar number of satellite cells that vary in gene expression.

(A) The majority of freshly sorted cytocentrifuged CD34+/− cells stained positive for Pax7 DAB; 89% (±1.7% SEM) of CD34+ and 70% (±2.6% SEM) of CD34− cells were positive (n = 3, 2 month old C57BL/6). Although this difference was statistically significant (Students t-test, P≤0.05), the majority of CD34+ and CD34− cells were Pax7+ indicating a high purity of satellite cells within both populations. Arrowheads indicate Pax7+ cells while line arrows point to Pax7- cells. Cultured CD34+/− cells from Myf5^nlacZ/+ and 3F-nlacZ-2F mice gave rise to β-galactosidase+ myogenic colonies as indicated by X-gal staining. The presence of Myf5^nlacZ/+ and 3F-nlacZ-2F reporters in culture suggests both populations have similar myogenic potential. 60× scale bar for cytocentrifuged photos was unavailable. Scale bars for cultured cells = 50 µm. (B) q-RT-PCR of freshly sorted cells confirms α7 expression in both populations and low CD34 expression in CD34− cells (n = 3, 2 month old C57BL/6). Although higher in CD34+ cells, both populations expressed satellite cell markers Pax3/7, and myogenic regulatory factors Myf5, MyoD, and myogenin. Expression of satellite cell associated genes CXCR4, c-met, and NCAM was also higher in CD34+ cells. Student's t-test calculated * P≤0.05 and ** P≤0.005. Error bars represent ±SEM.