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. 2023 Mar 15;133(6):e164354. doi: 10.1172/JCI164354

Figure 2. TRIM21 downregulates mutp53 protein levels in cells.

Figure 2

(A) The effect of ectopic TRIM21 expression on the levels of different endogenous mutp53, including R175H, G245S, R248Q, and R273H, as well as wtp53 proteins in different human cancer cells. Cells were transduced with control (–) or TRIM21-Flag (+) expression vectors for Western blot assays. (B) The effect of TRIM21 KO on levels of R175H and R273H mutp53 protein in SK-BR3 and HT29 cells, respectively, analyzed by Western blot assays. (C) The effect of knockdown of endogenous TRIM21 by shRNA vectors on the levels of G245S and R248Q mutp53 in LS1034 and HCC70 cells, respectively, and wtp53 proteins in MCF7 and p53+/+ RKO cells. Cells were transduced with control (Con) vectors or 2 different shRNA vectors against TRIM21 for Western blot assays. (D) Higher mutp53 protein levels in TRIM21−/− p53R172H/R172H MEFs compared with TRIM21+/+ p53R172H/R172H MEFs analyzed by Western blot assays. (E) Ectopic TRIM21-Flag expression did not affect the mRNA levels of mutp53 or wtp53 in different human cancer cells. (F) TRIM21 KO did not affect mutp53 mRNA levels in SK-BR3 and HT29 cells. (G) TRIM21 knockdown by shRNA vectors did not affect the mRNA levels of mutp53 or wtp53 in different human cancer cells. (H) TRIM21 loss did not affect the mRNA levels of R172H mutp53 in p53R172H/R172H MEFs or wtp53 in p53+/+ MEFs. Mouse R172H mutp53 is equivalent to human R175H mutp53. In E–H, the mRNA levels of mutp53 or wtp53 in cells were measured by TaqMan real-time PCR assays and normalized with Actin. The TRIM21 did not show significant effect on mutp53 or wtp53 mRNA levels in these cells. Data are shown as the mean ± SD (n = 6). Statistical analysis was performed using 2-tailed unpaired Student’s t test (E and H) or 1-way ANOVA followed by Dunnett’s test (F and G).