DUX4 recruits p300/CBP through its C-terminus and induces global H3K27 acetylation changes

Abstract

Ectopic expression of the double homeodomain transcription factor DUX4 causes facioscapulohumeral muscular dystrophy (FSHD). Mechanisms of action of DUX4 are currently unknown. Using immortalized human myoblasts with a titratable DUX4 transgene, we identify by mass spectrometry an interaction between the DUX4 C-terminus and the histone acetyltransferases p300/CBP. Chromatin immunoprecipitation shows that DUX4 recruits p300 to its target gene, ZSCAN4, displaces histone H3 from the center of its binding site, and induces H3K27Ac in its vicinity, but C-terminal deleted DUX4 does not. We show that a DUX4 minigene, bearing only the homeodomains and C-terminus, is transcriptionally functional and cytotoxic, and that overexpression of a nuclear targeted C-terminus impairs the ability of WT DUX4 to interact with p300 and to regulate target genes. Genomic profiling of DUX4, histone H3, and H3 modifications reveals that DUX4 binds two classes of loci: DNase accessible H3K27Ac-rich chromatin and inaccessible H3K27Ac-depleted MaLR-enriched chromatin. At this latter class, it acts as a pioneer factor, recruiting H3K27 acetyltransferase activity and opening the locus for transcription. In concert with local increased H3K27Ac, the strong H3K27Ac peaks at distant sites are significantly depleted of H3K27Ac, thus DUX4 uses its C-terminus to induce a global reorganization of H3K27 acetylation.

Ret function in muscle stem cells points to tyrosine kinase inhibitor therapy for facioscapulohumeral muscular dystrophy

“…Transgenic analysis has shown that in mouse, 1.9 kb 5’ of the Transcriptional Start Site (TSS) of Ret is sufficient to drive tissue specific expression (Zordan et al, 2006). However, analysing two published ChIP-Seq datasets of DUX4 overexpression in human myoblasts (Geng et al, 2012; Choi et al, 2016), we failed to identify significant peaks within 15 kb 5’ of the Ret TSS. In addition, sequence analysis also failed to find a DUX4 consensus binding site (TAATCTAATCA – [Zhang et al, 2016]) within this same 15 kb region.…”

“…In addition, sequence analysis also failed to find a DUX4 consensus binding site (TAATCTAATCA – [Zhang et al, 2016]) within this same 15 kb region. It is of note however, that the C-terminus of DUX4 can recruit acetyltransferases (p300/CBP) to histones to induce acetylation, hence promoting transcription at sites distant to DUX4 DNA binding (Choi et al, 2016), so DUX4 could still directly controlling Ret in an epigenetic manner. However, also arguing against Ret being a direct transcriptional target of DUX4 is our observation that Ret expression is not only enhanced by DUX4 and the constitutively active tMALDUX4-VP16, but also by our DUX4 dominant-negative tMALDUX4-ERD construct in the microarray analysis.…”

DUX4 induces a transcriptome more characteristic of a less-differentiated cell state and inhibits myogenesis

“…Although DUX4 binding motifs have been identified (Dixit et al, 2007; Ferri et al, 2015; Geng et al, 2012; Young et al, 2013; Choi et al, 2016), and ChIP-Seq performed (Geng et al, 2012; Choi et al, 2016), a set of target genes that explains both anti-myogenic and apoptotic phenotypes induced by DUX4 has not been comprehensibly defined.…”

HIST1H1C Regulates Interferon-β and Inhibits Influenza Virus Replication by Interacting with IRF3

“…Similar studies have also found that histones are involved in epigenetic regulation; for example, HP1-beta genome-wide localization follows H3K9me3-enrichment, and the artificial bridging of chromatin fibers is sufficient to maintain cellular heterochromatic conformation (33, 34). DNA methylation plays an unexpected dual role at enhancer regions and is anti-correlated focally at transcription factor-binding sites but positively correlated globally with the active H3K27ac mark to ensure structural enhancer integrity (35, 36). …”