The death-associated protein DAXX is a novel histone chaperone involved in the replication-independent deposition of H3.3.
The histone variant H3.3 marks active chromatin by replacing the conventional histone H3.1. In this study, we investigate the detailed mechanism of H3.3 replication-independent deposition. We found that the death domain-associated protein DAXX and the chromatin remodeling factor ATRX (alpha-thalassemia/mental retardation syndrome protein) are specifically associated with the H3.3 deposition machinery. Bacterially expressed DAXX has a marked binding preference for H3.3 and assists the deposition of (H3.3-H4)(2) tetramers on naked DNA, thus showing that DAXX is a H3.3 histone chaperone. In DAXX-depleted cells, a fraction of H3.3 was found associated with the replication-dependent machinery of deposition, suggesting that cells adapt to the depletion. The reintroduced DAXX in these cells colocalizes with H3.3 into the promyelocytic leukemia protein (PML) bodies. Moreover, DAXX associates with pericentric DNA repeats, and modulates the transcription from these repeats through assembly of H3.3 nucleosomes. These findings establish a new link between the PML bodies and the regulation of pericentric DNA repeat chromatin structure. Taken together, our data demonstrate that DAXX functions as a bona fide histone chaperone involved in the replication-independent deposition of H3.3.
Drané
Pascal
P
IGMBC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), Illkirch F-67400, France.
Ouararhni
Khalid
K
Depaux
Arnaud
A
Shuaib
Muhammad
M
Hamiche
Ali
A
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D018797:Cell Cycle Proteins / Q000378:metabolism; D002460:Cell Line; D056970:Co-Repressor Proteins; D004265:DNA Helicases / Q000378:metabolism; D006367:HeLa Cells; D006570:Heterochromatin / Q000378:metabolism; D056488:Histone Chaperones / Q000378:metabolism*; D006657:Histones / Q000378:metabolism*; D006801:Humans; D051379:Mice; D018832:Molecular Chaperones; D046912:Multiprotein Complexes; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D009707:Nucleosomes / Q000378:metabolism; D055550:Protein Stability; D014157:Transcription Factors / Q000378:metabolism; D000075924:X-linked Nuclear Protein
D048868:Adaptor Proteins, Signal Transducing; D018797:Cell Cycle Proteins; D056970:Co-Repressor Proteins; C106985:DAXX protein, human; C086057:HIRA protein, human; D006570:Heterochromatin; D056488:Histone Chaperones; D006657:Histones; D018832:Molecular Chaperones; D046912:Multiprotein Complexes; D009687:Nuclear Proteins; D009707:Nucleosomes; D014157:Transcription Factors; D004265:DNA Helicases; C092332:ATRX protein, human; D000075924:X-linked Nuclear Protein