Figure 6.
TRIM13 stabilizes proteins associated with cell cycle. (A) Volcano plot comparing identified protein expression from T13WT with T13RINGdel in nuclear or cytoplasmic extracts. Results are calculated from 3 independent submissions. Red shaded region indicates proteins significantly upregulated (P < .05) in T13RINGdel compared with T13WT. (B) Volcano plot comparing differentially ubiquitinated peptides in T13RINGdel vs T13WT U937 cells. Blue shading indicates ubiquitinated peptides significantly lost in T13RINGdel (P < .05). (C) Venn diagram comparing differentially ubiquitinated peptides lost in T13RINGdel with proteins significantly upregulated (P < .05; more than twofold change in peptide spectrum match, or PSMs). (D) Gene ontology (GO) analysis of proteins with a ubiquitination site lost in T13RINGdel U937 cells. (E) Cell cycle (EdU vs FxCycle) analysis in multiple T13RINGdel clones and TRIM13 overexpression on day 5 after infection in each AML cell line. Bars indicate mean ± SD, and ∗P < .05 for each specific cell cycle phase within each cell type compared with CTRLsg, as determined using one-way ANOVA on 3 independent biological replicates. (F) Representative imaging cytometry of CCNA1 and TRIM13 localization through cell cycle in MA9.NRAS. (G) Similarity of CCNA1/TRIM13 through cell cycle. Red dashed line is line of best fit by linear regression. Nonzero slope calculated by linear regression modeling and P value listed. Blue shading indicates more similar TRIM13/CCNA1 than dissimilar, and cell cycle stages listed (G0/G1, S, G2, and M) as determined by DNA content and nuclear morphology. (H) Western blot analysis of PBSC expressing TRIM13sh 72-hours after infection and U937 T13RINGdel AML cell line at steady state. (I) Western blot analysis of T13WT vs T13RINGdel U937 cells expressing a dox-inducible CCNA1 at indicated time points after dox induction. Results shown are representative of 2 biological replicates. (J) Colony assay of indicated genotypes of U937 cells expressing either empty vector or CCNA1 in the presence of dox. Results shown are mean ± SD from 4 biological replicates, dots indicate individual replicates. ∗P < .05 between noted groups (E,H), as determined using one-way ANOVA with Bonferroni post hoc test (H).