RNA levels of MPB HSC.

Mobilized G₀/G₁ and S/G₂/M HSC isolated from BM or blood of day +5 CY/G-CSF–treated mice have higher average levels of total RNA than the corresponding populations from BM of untreated mice. LT-HSC were double sorted and then stained with the RNA-staining dye PY and the DNA-staining dye Hoechst 33342 as described in “Materials and methods.” The horizontal line passing through all plots is a reference line approximating the G₀/G₁ boundary of HSC from BM of untreated mice. Vertical lines separate G₀/G₁ from S/G₂/M HSC. The numbers in the corners of the plots indicate the percentage of HSC in each quadrant. Heavy bars indicate the mean fluorescence intensity (MFI) in the phycoerythrin (PE) channel, on which emitted fluorescence from PY was recorded (PE MFI data from all experiments are normalized and presented in Table 2). Note the small fraction (2.3%) of MPB HSC with more than 2n DNA content. The representative data presented are from experiment 1 of Table 2. PY indicates pyronine Y; CV, coefficient of variation (of the indicated means).