Fig. 6. TOPORS promotes ubiquitination of SUMOylated DNMT1.

a Outline of mass spectrometric analysis on ubiquitinated proteins in MDS-L cells after DAC exposure. b GO terms enriched in ubiquitinated peptides detected in WT MDS-L cells compared to those in TOPORS-KO MDS-L cells. c Heat map showing enrichment of the DNMT1-derived ubiquitinated peptides in WT MDS-L cells compared to TOPORS-KO MDS-L cells. The abundance of ubiquitinated DNMT1 was normalized to the abundance of total DNMT1. d SUMOylation and ubiquitination levels of DNMT1 in WT and TOPORS-KO MDS-L cells treated with 10 nM DAC for 2 h. Endogenous DNMT1 immunoprecipitated with anti-DNMT1 nanobody was subjected to western blotting. β-actin was served as a loading control of the inputs. The samples derive from the same experiment but different gels for all were processed in parallel. e A model of TOPORS function found in this study. Source data are provided as a Source Data file.