text_1: H4 G94P proteins suppress degradation of free histones via Rad53-dependent mechanisms.
text_2: We have also identified the ubiquitin conjugating enzymes (E2) Ubc4 and Ubc5, as well as the ubiquitin ligase (E3) Tom1 (temperature dependent organization in mitotic nucleus 1), as enzymes involved in the ubiquitylation of excess histones.