Mpl agonist treatment induces HSC division and self-renewal. (A) Representative BM FACS plots and sorting gates (pregated on donor LKS Flt3⁻) from animals transplanted 3 weeks prior with CFSE-labeled LKS cells and subsequently treated with PBS, G-CSF, or Mpl agonist as indicated in “Study design” and Figure 1B. (B) Donor chimerism in peripheral blood (PB) observed over 4 months of recipients of cells sorted from 0×- to 1×-, 2×- to 4×-, and >5×-divided cells from PBS, G-CSF, and Mpl agonist-treated animals as indicated. Graphs show individual donor chimerism from animals transplanted with 7 cells (blue line, n = 1), 12 cells (red lines, n = 2), 17 cells (green line, n = 1), and 20 to 22 cells (black lines). Number of animals engrafted (positive cutoff >0.4%)/number of animals transplanted is indicated on each graph. (C) Donor cell engraftment (cutoff >0.4%) and lineage distribution (myeloid lineage, T cells and B cells) in recipient mice PB at month 4. (D) Donor chimerism in PB over 4 months in recipients of whole BM from animals in panels B and C. Number of engrafted vs transplanted animals (positive cutoff >0.4%) is shown in each graph. N.A., not applicable.