1. Academic Validation
  2. DAXX-dependent supply of soluble (H3.3-H4) dimers to PML bodies pending deposition into chromatin

DAXX-dependent supply of soluble (H3.3-H4) dimers to PML bodies pending deposition into chromatin

  • Genome Res. 2013 Mar;23(3):440-51. doi: 10.1101/gr.142703.112.
Erwan Delbarre 1 Kristina Ivanauskiene Thomas Küntziger Philippe Collas
Affiliations

Affiliation

  • 1 Stem Cell Epigenetics Laboratory, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, 0317 Oslo, Norway.
Abstract

Replication-independent chromatin deposition of histone variant H3.3 is mediated by several chaperones. We report a multistep targeting of newly synthesized epitope-tagged H3.3 to chromatin via PML bodies. H3.3 is recruited to PML bodies in a DAXX-dependent manner, a process facilitated by ASF1A. DAXX is required for enrichment of ATRX, but not ASF1A or HIRA, with PML. Nonetheless, the chaperones colocalize with H3.3 at PML bodies and are found in one or more complexes with PML. Both DAXX and PML are necessary to prevent accumulation of a soluble, nonincorporated pool of H3.3. H3.3 targeting to PML is enhanced with an (H3.3-H4)2 tetramerization mutant of H3.3, suggesting H3.3 recruitment to PML as an (H3.3-H4) dimer rather than as a tetramer. Our data support a model of DAXX-mediated recruitment of (H3.3-H4) dimers to PML bodies, which may function as triage centers for H3.3 deposition into chromatin by distinct chaperones.

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