Nucleosome eviction and activated transcription require p300 acetylation of histone H3 lysine 14

Abstract

Histone posttranslational modifications and chromatin dynamics are inextricably linked to eukaryotic gene expression. Among the many modifications that have been characterized, histone tail acetylation is most strongly correlated with transcriptional activation. In Metazoa , promoters of transcriptionally active genes are generally devoid of physically repressive nucleosomes, consistent with the contemporaneous binding of the large RNA polymerase II transcription machinery. The histone acetyltransferase p300 is also detected at active gene promoters, flanked by regions of histone hyperacetylation. Although the correlation between histone tail acetylation and gene activation is firmly established, the mechanisms by which acetylation facilitates this fundamental biological process remain poorly understood. To explore the role of acetylation in nucleosome dynamics, we utilized an immobilized template carrying a natural promoter reconstituted with various combinations of wild-type and mutant histones. We find that the histone H3 N-terminal tail is indispensable for activator, p300, and acetyl-CoA-dependent nucleosome eviction mediated by the histone chaperone Nap1. Significantly, we identify H3 lysine 14 as the essential p300 acetylation substrate required for dissociation of the histone octamer from the promoter DNA. Together, a total of 11 unique mutant octamer sets corroborated these observations and revealed a striking correlation between nucleosome eviction and strong activator and acetyl-CoA-dependent transcriptional activation. These novel findings uncover an exclusive role for H3 lysine 14 acetylation in facilitating the ATP-independent and transcription-independent disassembly of promoter nucleosomes by Nap1. Furthermore, these studies directly couple nucleosome disassembly with strong, activator-dependent transcription.

Histone Chaperone Nap1 Is a Major Regulator of Histone H2A-H2B Dynamics at the Inducible GAL Locus

“…The active exchange of H2A-H2B could lead to the destabilization of the H3-H4 tetramer; thereby, Nap1 could also contribute to nucleosome disassembly. This is consistent with the findings that deletion of NAP1 reverses the cryptic transcript phenotype (interpreted as the by-product of underassembled chromatin) observed in mutant strains defective for other chromatin regulators (77) and that Nap1 has an important function in the eviction of histones during transcription in a mammalian in vitro system (17). Importantly, these varied functions of Nap1 are not redundant with other histone chaperones in vivo.…”

“…Although functional in the assembly of nucleosomes in vitro (16), a number of studies support a role for Nap1 in transcription-dependent processes of disassembly of nucleosomes. Nap1 is critical for the eviction of histones during transcription in a mammalian in vitro system (17), and Nap1 (with the ATP-dependent chromatin remodeler RSC [remodels the structure of chromatin]) can facilitate the elongation of RNA polymerase II (RNAPII) on chromatin templates using yeast in vitro systems (18,19). Our previous in vivo studies indicated that Nap1 prevents excess H2A-H2B accumulation on chromatin (20), and here, we expand our analysis to investigate the role of Nap1 in histone exchange and occupancy.…”

Mitoxantrone Induced Impediment of Histone Acetylation and Structural Flexibility of the Protein

“…For this, HEK293 cells were treated with different concentration of MTX, which were further probed for acetylation of specific lysines and compared with the untreated counterparts. We chose to analyze the specific acetylation of K9 and K14 of histone H3 as previously shown to involved in transcriptional regulation and nucleosome density [21,22]. Results show the differential pattern of acetylation with different concentration of the drug (Fig.…”

SUMOylation-disrupting WAS mutation converts WASp from a transcriptional activator to a repressor of NF-κB response genes in T cells

“…51 Sequential ChIP shows that increased HDAC6 enrichment occurs contemporaneously with decreased enrichment of acetylated H3K14 at IFNG, STAT1, and TLR1 promoters in PSM-and V75M-expressing T H 1 cells (Figures 4D and 5A). Increased HDAC6 and decreased H3K14ac enrichment at the IFNG promoter was also captured in primary T H 1 cells depleted of SUMO1 by RNA interference (Figure 5B) and in normal T H 0 cells ( Figure 5C).…”