Figure 2

Increased apoptosis is a common denominator of Mysm1-deficient BM progenitors, thymi, and other affected tissues. (a) Significantly increased Annexin V-positive apoptotic cell fractions in Mysm1^−/− KO thymi in FACS analyses (representative FACS plots shown). Bar graphs represent mean values of six to eight age-matched mice of each genotype. (b) TUNEL assays performed on frozen tissue sections, to detect apoptosis in Mysm1^−/− (KO) thymi in situ compared with age-matched wild-type (WT) controls (nuclei blue, TUNEL green, white bar corresponds to 10 μm; n=4, representative photographs shown, original magnification as indicated). To quantify TUNEL⁺ apoptotic cells, positively stained cells were counted in 12–15 high-power fields (HPFs), and distributions and medians presented in scatter plots for all tissues analyzed (n≥3). (c) Detection and quantification of TUNEL-positive cells (green) in Mysm1^−/− brain (neocortex) and (d) skin sections compared with controls (n=3, representative stainings shown; e, epidermis; d, dermis; hf, hair follicle; white arrows point to apoptotic cells). (e) Overall proportions of BrdU incorporating LSK cells from BM prepared 2 h after BrdU pulse (representative plots shown). (f) Proportions of BrdU incorporating thymocytes of indicated subsets prepared 2 h after a BrdU pulse measured by FACS analysis (representative plots shown, n>3, bar graphs represent average values of at least three mice of each genotype)