Figure 1

PARylation inhibits SET7/9-dependent methylation of histone H3 and H1. (A) ARTD1 was auto-modified for the indicated times and then inhibited by addition of PJ-34. A histone mix was added to the reaction either before or after the inhibition of ARTD1. Methylation was started after PJ-34 addition by adding SET7/9 and ¹⁴C-SAM. Proteins were separated by SDS-PAGE, stained with Coomassie blue (CB, lower blot) and methylation was analyzed by autoradiography (¹⁴C, upper blot). The asterisk marks the shift of automodified ARTD1. (B) H3 was incubated with ARTD1 and 160 μM NAD⁺. Activating DNA and PARP inhibitor 3-AB were present during the reaction as indicated. Methylation was then started by addition of SET7/9 and ¹⁴C-SAM ± 3-AB was added directly before addition of SET7/9 after the PAR reaction. (C) Influence of ARTD1 on H1 methylation as in (B). The approximate molecular weight is indicated on the left of each gel/blot.