PTRF expression increased during aging and skewed differentiation potential of HSCs. (A) PTRF mRNA levels in the bone marrow of young (2-mo) and old mice (20-mo), n=3. (B) Immunoblot showing PTRF protein expression in the bone marrow (BM) of young and old mice, n=3. (C) PTRF mRNA levels in the BM of 2-month old PTRF transgenic and wild-type (WT) mice, n=3. (D) Immunoblot showing PTRF protein expression in the BM of young PTRF and WT mice, n=3. (E–G) The percentage of B cells (E), M cells (F) and T cells (G) in the peripheral blood, BM and spleen of young PTRF transgenic mice. Data represent the mean ± SD of three independent experiments. *, P < 0.05; **, P < 0.01. Data were normalized against GAPDH expression.