Expression of Ink4a is down-regulated in ETPs isolated from old Fgf7-treated mice. Levels of Ink4a expression in ETPs (A) and the indicated DN populations (B) after Fgf7 treatment. Cells were isolated from 15- to 18-month-old mice 15 days after 1 round of Fgf7 treatment and gene expression was examined by qRT-PCR. (C) Expression of cell cycle–related genes in ETPs from the mice described in panel A as determined with the mouse cellular senescence RT2 PCR array PAMM-050A-2 (QIAGEN). (D) The changes in gene expression observed with the array were validated by qRT-PCR. P values for the differences in expression levels between ETPs isolated from Fgf7- and PBS-treated mice are indicated. All experiments were performed in triplicate and data are expressed as means ± SD. ## indicates not detectable.
