Fig 3. p53-null Mdm2^la/la MEFs and sarcoma cells have defects in and increased and G2-M transition hyperploidy.

(A) Cell cycle profiles of Mdm2^la/la: TP53^R/R and Mdm2^+/+: TP53^R/R MEFs (passage 6) by flow cytometry. Dip, diploid, An, aneuploid. (B) Increased phospho-Histone 3 at Serine 10 (pH3(S10) in p53-deficient Mdm2^la/la sarcoma tissues. Representative histochemical staining of pH3(S10) (a, b) and Ki67 (c, d) in sarcoma tissues from p53^-/-: Mdm2^+/+ (a, c) or p53^-/-: Mdm2^la/la (b, d) mice. Left images at 10x magnification and at 40x magnification of image areas in frame shown on the right. (C) Quantitative analysis of pH3(S10) staining in two p53^-/-: Mdm2^+/+ and three p53^-/-: Mdm2^la/la sarcoma samples. *, t test, p = 0.0106. (D) Quantitative analysis of Ki67-positive cells in two p53^-/-: Mdm2^+/+ and three p53^-/-: Mdm2^la/la sarcoma samples. ns, t test, p = 0.604. (E) Mdm2^+/+-tetp53 and Mdm2^la/la-tetp53 MEFs were used for BrdU labeling experiments. Gating settings are shown to define viable, singlet and BrdU-positive cells. (F) Diploid S (Dip S) and hyperploid S (Hyp S) fractions of Mdm2^+/+-tetp53 and Mdm2^la/la-tetp53 MEFs were presented. (G) Diploid S (Dip S) and hyperploid S (Hyp S) fractions of etoposide-treated (5μM, 24h) Mdm2^+/+-tetp53 and Mdm2^la/la-tetp53 MEFs were shown.