Figure 1.

Hdac1 and Hdac2 collectively control cell cycle progression. (A) Western blot analysis of Hdac2-deficient MEF protein lysates for indicated proteins. Tubulin served as a loading control. (B) Representative photographs of MEF cell cultures with indicated genotypes grown without 4-OHT or with 200 nM 4-OHT. Representative details of MEF cultures with indicated genotypes are shown in the third row. Note the presence of large, flat cells in 4-OHT-treated RCM2⁺;Hdac1^L/L;Hdac2^−/− cultures. Bottom panels show representative pictures of senescence-associated β-galactosidase-stained MEF cultures with indicated genotypes. (C) Growth curve analysis of Hdac1KO (closed squares), Hdac2KO (closed triangles) or DKO MEFs (open circles). All experiments were performed in triplicate. (D) Percentage of SA-bgalactosidase positive cells in MEF cultures with indicated genotypes. (E) Cell cycle analysis of wild-type and DKO MEFs for G₁, S and G₂/M cell cycle phases by BrdU-PI FACS. Values represent the average of three independent experiments.