Effects of the human TIP110-expressing transgene on HPCs. (A) Diagram of the TIP110 transgene cassette consisting of the CMV promoter, human TIP110 cDNA (NM_014706), and bovine growth hormone poly(A) tail. (B) Bone marrow (BM) and spleen cells were harvested from TIP110^TG mice for genomic DNA isolation and PCR genotyping for the TIP110 transgene. (C) Murine embryonic fibroblasts were prepared from embryos of TIP110-transgene–expressing mice and analyzed for TIP110 protein expression by Western blotting. Cells were treated with MG132 (a proteasome inhibitor) to stabilize Tip10 protein (unpublished data). *Endogenous TIP110 expression; **transgene expression including a 6× His tag. (D-E) Cells were isolated from BM and spleens of age-matched C57B/L6 control mice and TIP110^TG mice and assessed for HPCs by colony assay with progenitors expressed as absolute numbers per organ (D) or progenitors were evaluated for percentage of cells in the S phase using the tritiated thymidine kill assay for determination of cycling status (E). Open bars show WT cells; closed bars, TIP110^TG cells. Data for panels B and C are from 1 of at least 3 reproducible experiments. Data in panels D and E are shown as means ± SEM for 8 individually assessed mice for each group in a total of 2 independent experiments.