Association of the ROSlow subsets with properties defining osteoblastic niche–derived HSCs. (A) Flow cytometry histograms for CaR, N-cadherin, Bcrp, TERT, and mTOR. The dotted gray lines are isotype controls. (B) Western analysis for Notch1, p53, and p16. (C) G0 activity and p21 quantitative PCR. Values represent the means plus or minus SEM. *P < .05. (D) Stem cell surface marker analysis. The variability of CD34−LSK cell frequency in 14 independent experiments. The lines represent the means.