Fig.3

Suppression of TCAB1 expression induced senescence by regulating the ubiquitination of p21. a A549 cells were infected with shTCAB1 or shCon lentivirus. Cellular senescence was measured by Senescence-associated (SA)-β-gal assay (arrows pointing to cells with representative senescent phenotype). The percentage of cells positive for (SA)-β-gal was quantized (n = 8). b A549 cells infected with lentivirus encoding the indicated shRNA were treated with DMSO or MG132 (20 μM) for 6 h. The protein levels of TCAB1 and p21 were detected by western blotting. c The shTCAB1 transformed A549 cells from lentiviral infections were treated with MG132 (20 μM) for 6 h. Lysates were immunoprecipitated with anti-p21 antibody. The ubiquitination of the p21 was analysed by western blotting using antibody against ubiquitin. d–f Senescence phenotypes and the degradation and p21 ubiquitination were detected in TCAB1 knockdown H1299 cells