Loss of SKP2 increases the size of the LSK pool and decreases the number of hematopoietic progenitors. (A) Dot blots indicate the LSK population by showing Sca1 and c-Kit expression on Lin⁻ cells in a representative experiment. Numbers indicate the percentage of cells in each quadrant. Bar graph on the right summarizes 8 independent experiments (n = 15-18). Values are average of absolute number of LSK cells per femur. (B) Bar graphs represent average percentage of each population in the gated Lin⁻ population; n = 15-18. LSK cells are shown on the left and were further subdivided into LT-HSC (LSK IL7R⁻CD34⁻Flt3⁻; middle) and ST-HSC (LSK IL7R⁻CD34⁺Flt3⁺; right); n = 6-10. (C) LK cells (Lin⁻ Sca1⁻ c-Kit⁺ IL7R⁻) were analyzed for CD34 and FcγRII/III expression to determine CMP (CD34⁺ FcγRII/III^lo), GMP (CD34⁺ FcγRII/III^hi), and MEP (CD34⁻ FcγRII/III^lo) progenitors. Values indicate average percentages in the Lin⁻ population; n = 11-15 mice. Data expressed as mean ± SEM *P < .05 vs Skp2^+/+. **P < .005 vs Skp2^+/+. #P < .05 vs Skp2^+/−.