MOF and histone H4 acetylation at lysine 16 are critical for DNA Damage Response and DSB Repair

Washington University School of Medicine, St. Louis, Missouri 63108, USA.
Molecular and Cellular Biology (Impact Factor: 4.78). 07/2010; 30(14):3582-95. DOI: 10.1128/MCB.01476-09
Source: PubMed


The human MOF gene encodes a protein that specifically acetylates histone H4 at lysine 16 (H4K16ac). Here we show that reduced levels of
H4K16ac correlate with a defective DNA damage response (DDR) and double-strand break (DSB) repair to ionizing radiation (IR).
The defect, however, is not due to altered expression of proteins involved in DDR. Abrogation of IR-induced DDR by MOF depletion
is inhibited by blocking H4K16ac deacetylation. MOF was found to be associated with the DNA-dependent protein kinase catalytic
subunit (DNA-PKcs), a protein involved in nonhomologous end-joining (NHEJ) repair. ATM-dependent IR-induced phosphorylation
of DNA-PKcs was also abrogated in MOF-depleted cells. Our data indicate that MOF depletion greatly decreased DNA double-strand
break repair by both NHEJ and homologous recombination (HR). In addition, MOF activity was associated with general chromatin
upon DNA damage and colocalized with the synaptonemal complex in male meiocytes. We propose that MOF, through H4K16ac (histone
code), has a critical role at multiple stages in the cellular DNA damage response and DSB repair.

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    • "The rapid recruitment of ZMYND8 at damage sites was significantly reduced in TIP60-depleted cells (Fig. 2J, quantified in K; siRNA knockdown efficiency in Supplemental Fig. S2B), as were H4K16Ac and H4 tetra- Ac (acetylation of H4 at K5, K8, K12, and K16.) levels (Fig. 2L; Supplemental Fig. S2C). As a control, we depleted the HAT MOF, which targets histone H4 and is involved in the DDR (Sharma et al. 2010; Gong and Miller 2013). Depletion of MOF, unlike TIP60, did not reduce ZMYND8 recruitment to DNA damage (Supplemental Fig. S2D–G). "
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    ABSTRACT: How chromatin shapes pathways that promote genome-epigenome integrity in response to DNA damage is an issue of crucial importance. We report that human bromodomain (BRD)-containing proteins, the primary "readers" of acetylated chromatin, are vital for the DNA damage response (DDR). We discovered that more than one-third of all human BRD proteins change localization in response to DNA damage. We identified ZMYND8 (zinc finger and MYND [myeloid, Nervy, and DEAF-1] domain containing 8) as a novel DDR factor that recruits the nucleosome remodeling and histone deacetylation (NuRD) complex to damaged chromatin. Our data define a transcription-associated DDR pathway mediated by ZMYND8 and the NuRD complex that targets DNA damage, including when it occurs within transcriptionally active chromatin, to repress transcription and promote repair by homologous recombination. Thus, our data identify human BRD proteins as key chromatin modulators of the DDR and provide novel insights into how DNA damage within actively transcribed regions requires chromatin-binding proteins to orchestrate the appropriate response in concordance with the damage-associated chromatin context. © 2015 Gong et al.; Published by Cold Spring Harbor Laboratory Press.
    Full-text · Article · Jan 2015 · Genes & Development
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    • "CONCLUSIONS H4K16 acetylation has a demonstrated role in DNA repair in mice and human cells (Krishnan et al., 2011; Li et al., 2010; Sharma et al., 2010), and the loss of H4K16 acetylation has been associated with human cancers (Fraga et al., 2005; Pfister et al., 2008). Studies in human cells support that H4 acetylation is important in promoting HR events; for example, TIP60-dependent H4 acetylation has been shown to diminish 53BP1 binding and promote BRCA1- dependent HR (Tang et al., 2013), and depletion of the H4K16- specific HAT MOF leads to deficient recruitment of repair factors to IR foci and a decrease in sister chromatid exchanges (Sharma et al., 2010; Li et al., 2010). Therefore, a role for H4 acetylation in promoting SCR may be conserved from yeast to humans. "
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    ABSTRACT: CAG/CTG trinucleotide repeats are unstable, fragile sequences that strongly position nucleosomes, but little is known about chromatin modifications required to prevent genomic instability at these or other structure-forming sequences. We discovered that regulated histone H4 acetylation is required to maintain CAG repeat stability and promote gap-induced sister chromatid recombination. CAG expansions in the absence of H4 HATs NuA4 and Hat1 and HDACs Sir2, Hos2, and Hst1 depended on Rad52, Rad57, and Rad5 and were therefore arising through homology-mediated postreplication repair (PRR) events. H4K12 and H4K16 acetylation were required to prevent Rad5-dependent CAG repeat expansions, and H4K16 acetylation was enriched at CAG repeats during S phase. Genetic experiments placed the RSC chromatin remodeler in the same PRR pathway, and Rsc2 recruitment was coincident with H4K16 acetylation. Here we have utilized a repetitive DNA sequence that induces endogenous DNA damage to identify histone modifications that regulate recombination efficiency and fidelity during postreplication gap repair.
    Full-text · Article · Aug 2014 · Molecular Cell
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    • "Immunofluorescence, Microirradiation, and Protein Retention Assay The procedure for immunofluorescence analysis was the same as previously described (Agarwal et al., 2008; Gupta et al., 2009; Hunt et al., 2007; Pandita et al., 1999, 2006). For microirradiation, cells transfected with YFP-labeled ATM or 53BP1 were grown on glass-bottom culture dishes and then microirradiated , and the signal was quantified as described (Sharma et al., 2010). "
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    ABSTRACT: Cell-cycle phase is a critical determinant of the choice between DNA damage repair by nonhomologous end-joining (NHEJ) or homologous recombination (HR). Here, we report that double-strand breaks (DSBs) induce ATM-dependent MOF (a histone H4 acetyl-transferase) phosphorylation (p-T392-MOF) and that phosphorylated MOF colocalizes with γ-H2AX, ATM, and 53BP1 foci. Mutation of the phosphorylation site (MOF-T392A) impedes DNA repair in S and G2 phase but not G1 phase cells. Expression of MOF-T392A also blocks the reduction in DSB-associated 53BP1 seen in wild-type S/G2 phase cells, resulting in enhanced 53BP1 and reduced BRCA1 association. Decreased BRCA1 levels at DSB sites correlates with defective repairosome formation, reduced HR repair, and decreased cell survival following irradiation. These data support a model whereby ATM-mediated MOF-T392 phosphorylation modulates 53BP1 function to facilitate the subsequent recruitment of HR repair proteins, uncovering a regulatory role for MOF in DSB repair pathway choice during S/G2 phase.
    Full-text · Article · Jun 2014 · Cell Reports
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