Monoubiquitination of histone H2B (H2B-Ub) plays a role in transcription and DNA replication, and is required for normal localization of the histone chaperone, FACT. In yeast, H2B-Ub is deubiquitinated by Ubp8, a subunit of SAGA, and Ubp10. Although they target the same substrate, loss of Ubp8 and Ubp10 cause different phenotypes and alter the transcription of different genes. We show that Ubp10 has poor activity on yeast nucleosomes, but that the addition of FACT stimulates Ubp10 activity on nucleosomes and not on other substrates. Consistent with a role for FACT in deubiquitinating H2B in vivo, a FACT mutant strain shows elevated levels of H2B-Ub. Combination of FACT mutants with deletion of Ubp10, but not Ubp8, confers increased sensitivity to hydroxyurea and activates a cryptic transcription reporter, suggesting that FACT and Ubp10 may coordinate nucleosome assembly during DNA replication and transcription. Our findings reveal unexpected interplay between H2B deubiquitination and nucleosome dynamics.
- Cynthia Wolberger
- Tim Formosa
- Melesse Nune
- Ashraf Brik
- Muhammad Jbara
- Melesse Nune
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
- Geeta J Narlikar, University of California, San Francisco, United States
© 2019, Nune et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.