Enhanced short-term repopulation of dnTCF4 BM and maintenance of normal LT-HSC activity. (A) Graphical representation of whole BM transplantation. (B) Representative flow cytometry plots from recipient mice transplanted with 5 × 10⁵ WT or dnTCF4 BM cells. PB analysis was performed 4 and 16 weeks after transplantation. The y-axes indicate Ly5.2 expression and x-axes Ly5.1 expression. Numbers indicate percentage of donor-derived Ly5.2⁺ cells. (C) Quantification of panel B. The y-axes indicate percentage of WT and dnTCF4 donor-derived Ly5.2⁺ cells in PB. Engraftment 4 and 16 weeks after transplantation is shown. Number of donor cells is indicated in the x-axes. At least 10 animals were included in each group. All data represent mean ± SD from 3 independent experiments. Two-tailed Student t test was used to assess statistical significance (*P < .05, **P < .01). (D) Percentage of donor-derived (Ly5.2⁺) Lin⁻ c-Kit⁺ cells in the BM of recipient (Ly5.1⁺) animals 16 weeks after transplantation. Recipients were transplanted with 5 × 10⁵ WT or dnTCF4 BM (Ly5.2⁺) cells along with 5 × 10⁵ competitive (Ly5.1⁺) BM cells. Data represent mean ± SD, n = 6. Two-tailed Student t test was used to assess statistical significance, ****P < .0001. (E) Frequency of functional LT-HSCs in WT and dnTCF4 mice measured by limiting dilution assay. (Left) Logarithmic plot showing the percentage of negative recipients transplanted with different cell doses of sorted WT or dnTCF4 LT-HSCs. Only recipients at 16 weeks with engraftment of ≥0.1% and contribution to 2 of 3 lineages (T, B, and myeloid cells) higher than 0.5% were considered responders. (Right) Number of responders and total number of recipients transplanted per each cell dose. Frequencies of LT-HSCs were calculated according to Poisson statistics using ELDA software (χ² test = 0.162; P = .688).