Either c-Myc or Bmi-1 rescue hTERT-expressing c-myc+/− cells from senescence. (A) Schematic representation of cell line pedigrees. c-myc+/− cells were sequentially infected with hTERT in pBABE-hygro (BH), c-Myc in pWZL-blast (WB), or Bmi-1 in pBABE-puro (BP) in the indicated order. EV, empty vector control. (B) Growth histories of c-myc+/− cells reconstituted with c-Myc, Bmi-1, or hTERT alone. (C) Growth histories of c-myc+/− cells reconstituted with c-Myc or Bmi-1 in conjunction with hTERT.