Distribution of acetylated histones resulting from Gal4-VP16 recruitment of SAGA and NuA4 complexes

Abstract

We analyzed the targeting of histone acetyltransferase (HAT) complexes by DNA-binding activators during transcriptional activation and the resulting distribution of acetylated histones. An in vitro competition assay was developed to acetylate and transcribe a nucleosomal array template in the presence of excess non-speci®c chromatin, which mimics in vivo conditions. Stimulation of transcription from the nucleosomal array template under competitive conditions by the SAGA and NuA4 HAT complexes depended on the presence of the Gal4-VP16 activator, which recognizes sites in the promoter and directly interacts with these HATs. Importantly, the stimulation of transcription by SAGA and NuA4 depended on the presence of Gal4-VP16 during histone acetylation, and Gal4-VP16-bound nucleosomal templates were acetylated preferentially by SAGA and NuA4 relative to the competitor chromatin. While targeting of the SAGA complex led to H3 acetylation of promoter-proximal nucleosomes, targeting of the NuA4 complex led to a broader domain of H4 acetylation of >3 kbp. Thus, either promoter-proximal H3 acetylation by SAGA or broadly distributed acetylation of H4 by NuA4 activated transcription from chromatin templates.

Intracellular Interleukin-1α Functionally Interacts with Histone Acetyltransferase Complexes

“…Surprisingly, deletion of the AHC1 gene product, a unique structural subunit of the yeast ADA transcriptional activation complex, did not relieve the Gal4BD/IL-1NTP-mediated growth inhibition. These data suggested specific interference of Gal4BD/IL-1NTP with certain components of the yeast SAGA complex as it has been described for the acidic coactivators Gal4p, E1A, or VP16 (26,27,46). Similar results were obtained when identical yeast strains harboring the UAS GAL1 -TATA GAL1 -lacZ reporter and expressing Gal4BD, mouse Gal4BD/IL-1NTP, or the strong Gal4BD/ VP16 activator were assayed for their respective ␤-galactosidase activities (Fig.…”

Orchestration of chromatin-based processes: mind the TRRAP

“…HAT complexes from both GNAT and MYST families were shown to be recruited to activator-bound nucleosomes resulting in transcriptional activation (Brownell et al, 1996;Vignali et al, 2000;Utley et al, 2005). The recruitment of SAGA leads to acetylation of promoter-proximal H3, whereas recruitment of NuA4 results in a broader domain of H4 acetylation (>3 kbp) (Vignali et al, 2000).…”

“…The recruitment of SAGA leads to acetylation of promoter-proximal H3, whereas recruitment of NuA4 results in a broader domain of H4 acetylation (>3 kbp) (Vignali et al, 2000). This hyperacetylation of histones was linked to transcription activation (Nourani et al, 2001) and NuA4-dependent acetylation of histone H4 was shown to affect transcription of specific genes such as His4, Lys2 (Galarneau et al, 2000), ribosomal proteins and heat-shock proteins (Reid et al, 2000).…”

Polyglutamine-expanded ataxin-7 inhibits STAGA histone acetyltransferase activity to produce retinal degeneration

“…STAGA and PCAF complexes differ from the related TFTC (TBP-free TAF-containing) complex (12) in that they do not contain TAFs 2, 4, 5, 6, and 7. These complexes contain either GCN5 or PCAF as the HAT that, after activator-dependent recruitment of the complex, specifically acetylates histone H3 tails in adjacent nucleosomes and facilitates transcription initiation (13).…”