Epigenetics is the study of how genes are regulated within cells without altering the DNA sequence of the genome. UHRF1 and UHRF2 are two epigenetic proteins that regulate histone modification and DNA methylation. The tandem Tudor domain (TTD) and the plant homeo domain (PHD) of these proteins are histone binding domains that interact with the H3 tail trimethylated at lysine 9 (H3K9me3). While the structure of UHRF1 in complex with an H3K9me3 peptide has been solved, there remains a lack of structural data that provides the exact requirements for this histone interaction in UHRF2. Here we seek to further investigate the histone binding function by elucidating the UHRF2 TTD-PHD and H3K9me3 structural complex through x-ray crystallography.
