Research Paper Advance Articles

Key elements of cellular senescence involve transcriptional repression of mitotic and DNA repair genes through the p53-p16/RB-E2F-DREAM complex

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Figure 2. Senescent cells display decreased mitotic gene expression. (A) IPA analysis of significantly downregulated gene sets demonstrates many cell cycle dependent genes including cyclins and CDKs that are essential for G1/ and G2/M transitions. Many mitotic genes that play roles in check points, spindle assembly, and chromosome segregation were downregulated in senescence. (B) mRNA expression levels of selected targets including CDK2, CDC25, PLK1, and E2F4 were validated using RT-PCR. GAPDH levels were used for normalization. Means ± SD are presented in the graph. (C) Protein expression of selected cell cycle genes was validated by Western blot in cells exposed to different concentrations of TNF-α for 72 hours.