Journal: Cellular and Molecular Life Sciences
Article Title: Loss of fragile WWOX gene leads to senescence escape and genome instability
doi: 10.1007/s00018-023-04950-1
Figure Lengend Snippet: p53 inactivation causes the failure of senescence induction in Wwox −/− MEFs. a The upper panel is the schematic diagram of p53 protein. The amino acid sequence alignment of human and mouse p53 DBD is shown in the lower panel. TAD, transactivation domain; PRD, proline-rich domain; DBD, DNA-binding domain; TD, tetramerization domain; CRD, C-terminal regulatory domain. b , c The sequencing results of p53 gene coding region from Wwox +/− (clone no. 54) and Wwox −/− (clone no. 56) MEFs at passages 1 (early), 8 (intermediate) and 20 (late) are shown. In b , the nucleotide 638 from the translational start site of murine p53 changed from thymine to guanine, leading to a substitution of valine to glycine at position 213 in the intermediate and late-passage Wwox −/− MEF clone no. 56. In c , the change of nucleotide 403 from guanine to cytosine resulted in a substitution of alanine to proline in p53 in the late-passage Wwox −/− MEF clone no. 56. d Subcellular protein fractionation and western blotting were performed to examine the nuclear and cytosolic expression of p53 and p21 Cip1/Waf1 in late-passage Wwox +/− and Wwox −/− MEFs (clone no. 54 and 56, respectively). Histone H3 and GAPDH were used as nuclear and cytosolic protein controls, respectively. e ChIP assay was conducted using the chromatin isolated from late-passage Wwox +/− and Wwox −/− MEFs (clone no. 54 and 56, respectively). The immunoprecipitated chromatin using a control or anti-p53 antibody was analyzed for the presence of p21 Cip1/Waf1 promoter sequence (from − 200 to 98) by real-time PCR using the specific primers shown in Supplementary Table 1. The quantitative results of ChIP assay were normalized by the input control groups. Data are presented as mean ± SD from three independent experiments. *** P ≤ 0.005; Two-tailed paired t test. f A reporter construct containing a p53-driven promoter sequence (pp53-TA-Luc) was transfected into MEFs. The thymidine kinase promoter-Renilla luciferase reporter plasmid (pRL-TK) was used as an internal control. Luciferase activities were determined at 16 h after transfection. Data are presented as mean ± SD from three independent experiments. *** P ≤ 0.005; Two-tailed t test. g The protein expression of endogenous p21 Cip1/Waf1 (black arrow), p53 and WWOX and ectopic GFP-tagged human p53 (GFP-p53; black arrowhead) in late-passage Wwox +/+ , Wwox +/− , Wwox −/− MEFs (clone no. 32-5, 54 and 56, respectively) was examined by western blotting. β-actin was used as an internal control. M.W., molecular weight. h Cell growth rates of late-passage Wwox +/+ , Wwox +/− , Wwox −/− (clone no. 32-5, 54 and 56, respectively) and Wwox −/− MEFs expressing ectopic GFP-p53 or GFP protein. N.S. not significant; *** P ≤ 0.005; Two-tailed t test. i SA-β-gal staining of late-passage Wwox +/+ , Wwox +/− , Wwox −/− (clone no. 32-5, 54 and 56, respectively) and Wwox −/− MEFs expressing ectopic GFP-p53 protein. The lower panel pictures are the magnified images from the blue boxed areas in the upper panel. The percentages of SA-β-gal-positive senescent cells (red arrowheads) are shown at the right panel. Scale bars = 100 µm. * P ≤ 0.05; *** P ≤ 0.005; Two-tailed t test
Article Snippet: The pp53-TA-Luc luciferase-based reporter plasmid harboring a p53 response element (#PT3511-5W; Clontech, Mountain View, CA, USA) was used for monitoring p53-mediated signaling in MEFs.
Techniques: Sequencing, Binding Assay, Fractionation, Western Blot, Expressing, Isolation, Immunoprecipitation, Real-time Polymerase Chain Reaction, Two Tailed Test, Construct, Transfection, Luciferase, Plasmid Preparation, Molecular Weight, Staining