ID #1045 N-terminal modification of Histone H3 inhibits H3K27M-mediated loss of H3K27 trimethylation
Nicolas Poux, Gabriel Boyle, Daren Zhang, Jacqueline Caplan, Adam Fiseha Kebede, Isabella Gainey, Olohireme Famous, Rameen Beroukhim, Jay Sarthy, Pratiti BandopadhayayAbstract
The use of short epitope tags is widespread in the study of histone biology as they allow for the antibody-mediated detection and pulldown of post-translationally modified histones or exogenous histone transgenes. However, H3 is particularly sensitive to sequence modification and the addition of epitope tags may interfere with the native function of H3. Here, we use the known relationship between lysine-to-methionine K27M mutations and the loss of trimethylation at the H3 K27 residue to test whether the addition of epitope tags to the N or C terminus of H3 affects the levels of histone H3 post-translation modifications. We find that all tested N-terminal tags abrogate the H3K27M-mediated loss of H3K27 trimethylation despite robust deposition in chromatin. These results suggest that the addition of epitope tags to the N-terminus of H3 should be performed with caution, and these findings may be of particular interest for the study of H3-driven cancers, like diffuse midline gliomas.