Open AccessPML is recruited to heterochromatin during S phase and represses DAXX-mediated histone H3.3 chromatin assembly
Author(s) -
Prashanth K. Shastrula,
Isabel Sierra,
Zhong Deng,
Frederick Keeney,
James Hayden,
Paul M. Lieberman,
Susan M. Janicki
Publication year - 2019
Publication title -
journal of cell science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.384
H-Index - 278
eISSN - 1477-9137
pISSN - 0021-9533
DOI - 10.1242/jcs.220970
Subject(s) - death associated protein 6 , biology , atrx , heterochromatin , chromatin , microbiology and biotechnology , chromodomain , chromatin remodeling , histone , histone h3 , sumo protein , nucleosome , genetics , nuclear protein , transcription factor , dna , rna , helicase , ubiquitin , gene , mutation
The incorporation of the histone H3 variant, H3.3, into chromatin by the H3.3-specific chaperone, DAXX, and the ATP-dependent chromatin remodeling factor, ATRX, is a critical mechanism for silencing repetitive DNA. DAXX and ATRX are also components of promyelocytic nuclear bodies (PML-NBs), which have been identified as sites of H3.3 chromatin assembly. Here, we use a transgene array that can be visualized in single living cells to investigate the mechanisms that recruit PML-NB proteins (i.e. PML, DAXX, ATRX, and SUMO1/2/3) to heterochromatin and their functions in H3.3 chromatin assembly. We show that DAXX and PML are recruited to the array through distinct SUMOylation-dependent mechanisms. Additionally, PML is recruited during S phase and its depletion increases H3.3 deposition. Since this effect is abrogated when PML and DAXX are co-depleted, it suggests that PML represses DAXX-mediated H3.3 chromatin assembly. Taken together, these results suggest that, at heterochromatin, PML-NBs coordinate H3.3 chromatin assembly with DNA replication, which has important implications for understanding how transcriptional silencing is established and maintained.