The methyl binding domain 3 (MBD3) family proteins promote Tet2 enzymatic activity for mediating 5mC conversion [microarray]. Homo sapiens

Ten-eleven translocation (TET) proteins are key players involved in the dynamic regulation of cytosine methylation and demethylation. Inactivating mutations of TET2 are frequently found in human malignancies, highlighting the essential role of TET2 in cellular transformation. However, the factors that control TET enzymatic activity remain largely unknown. Here we found that MBD3 and its analogue MBD3L2 can specifically modulate the enzymatic activity of Tet2 protein, but not Tet1 and Tet3 proteins, in converting 5mC into 5hmC. Moreover, MBD3L2 is more effective than MDB3 in promoting Tet2 enzymatic activity via strengthening the binding affinity between Tet2 and the methylated DNA target. Further analysis revealed pronounced decreases in 5mC levels at MBD3L2 and Tet2 co-occupied genomic regions, most of which are promoter elements associated with either cancer-related genes or genes involved in the regulation of cellular metabolic processes. Our data add new insights into the regulation of Tet2 activity by MBD3 and MBD3L2 in modulating its target gene activities in cancer development and have important applications in understanding how dysregulation of TET2 may contribute to human malignancy. Overall design: In order to investigate the biological function of MBD3L2 in regulating Tet2 enzymatic activity in mammalian cells, we extracted RNA and perform microarray profiling analysis to detect the genes regulated by Tet2 and MBD3L2.