Figure 4.

Cyclin E and A levels. Cell extracts were prepared from immortalized wild-type (Wt) or Nrf2−/− murine embryonic fibroblasts and then probed by immunoblot for cyclin levels. (A) Cyclin E. Both Wt and Nrf2−/− cells were obtained from Passage 27. (B) Cyclin A. Wt cells were obtained from Passage 29, whereas Nrf2−/− cells were obtained from Passage 28. For each antibody, the immunostained band was quantified with Quantity one software (Bio-Rad), and the results normalized to the density of the corresponding lane stained with Ponceau S. Results from representative blots are shown. Genetic deletion of Nrf2 resulted in a significant decrease of the levels of cyclin E but not of cyclin A.