DEK overexpression impairs HSC reconstitution potential, while DEK haploinsufficiency rescues survival and cell cycling of Fancd2-deficient HSCs. (A) Experimental schematic for limiting dilution competitive repopulation assay. (B) The HSC frequency was calculated and the log-fraction plot was generated using extreme limiting dilution analysis (https://bioinf.wehi.edu.au/software/elda/) (n = 5 recipient mice at each cell concentration). (C) Survival curve of Dek^Con and Dek^Tg mice following sequential 5-FU injection (n = 8 mice per group). (D) Experimental schematic for competitive transplantation assay. (E) The chart shows the donor chimerism in PB of the recipient mice at indicated time points after transplantation (n = 5–6 recipient mice per group). (F) The bar graphs show the donor chimerism in myeloid cells (CD11b⁺), B cells (B220⁺), and T cells (CD3⁺) of PB of the recipient mice at indicated points after transplantation (n = 5–6 recipient mice per group). (G) The bar graphs show the donor chimerism in BM, HPCs, LSK, and HSCs of the recipient mice at the end of 1-first and 2-second transplantation (n = 5–6 recipient mice per group). (H) Representative flow plots of cell apoptosis analysis of HSCs by annexin V + DAPI staining. The bar graphs show the frequency of annexin V⁺ in HSCs (n = 5 mice per group). (I) Representative flow plots of cell cycle analysis of HSCs with indicated genotypes by Ki-67 + DAPI staining. The right bar graph shows the percentage of the cell cycle distribution (n = 5 mice per group). The data presented in panels B–I are representative of two independent experiments. Data are shown as mean ± SD. Statistical analyses were performed using a Cox–Mantel test for panel C, a two-tailed unpaired Student’s t test for panels E–G, and one-way ANOVA followed by Tukey’s post hoc test for panels H and I. P values are presented as follows: *P < 0.05, **P < 0.01, and ***P < 0.001.