Fig 3.

Activation of cell cycle inhibitors after HdCTD intoxication. (A) U2-OS p53DD cells were treated with HdCDT in the presence (p53DD OFF) or the absence (p53DD ON) of tetracycline (Tet off system) and lysed at different time-points after the intoxication. Cell extracts were separated by SDS-PAGE and analysed by Western blotting with anti-p53, anti-P-p53 (Ser15) and anti-p21 antibodies. GAPDH expression was used as a loading control. (B) Immunoblot analysis of cell lysates prepared from HdCDT-intoxicated IMR-90 fibroblasts after different time-points. Untreated cells were used as negative control (CTR). Blots were probed with anti-p21, anti-p16 and anti-Rb as indicated; GAPDH was used as a loading control.