p18INK4c, which negatively regulates HSC repopulating potential, is undetectable in HSPCs from TC mice. (A) Quantitative RT-PCR analysis was performed with fluorescence-activated cell sorted LSK cells from 2 TC or B6 mice. cDNA input was normalized to the level of β-actin. Relative expression levels of each gene transcript in TC LSK cells relative to those in B6 controls are shown as the mean ± SD of 3 independent experiments. *P < .05; ***P < .001. (B) The relative expression level of p18INK4c in Lin− BM cells from BM chimeras engrafted with MSCV-p18 transduced BM cells (p18) is presented as fold induction compared with that detected in B6 Lin− BM cells (WT). ***P < .001, n = 3. (C) Peripheral engraftment was examined by fluorescence-activated cell sorting analysis with antibodies against CD45.1 and CD45.2. Percentages of donor (CD45.2) and recipient PBL (CD45.1) are indicated in the dot plots. Histograms show GFP expression within the donor population. (D) Left contour plots show the percentage of LSK cells in mice reconstituted with BM cells transduced with control MSCV retroviral vector (mock) or with MSCV-p18 vector (p18). Right contour plots show the chimerisms of the LSK population.
