ATAC-king the complexity of SAGA during evolution

Molecular Cancer Research, Netherlands Proteomics Center, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands.
Genes & development (Impact Factor: 10.8). 03/2012; 26(6):527-41. DOI: 10.1101/gad.184705.111
Source: PubMed


The yeast SAGA (Spt-Ada-Gcn5-acetyltransferase) coactivator complex exerts functions in gene expression, including activator interaction, histone acetylation, histone deubiquitination, mRNA export, chromatin recognition, and regulation of the basal transcription machinery. These diverse functions involve distinct modules within this multiprotein complex. It has now become clear that yeast SAGA has diverged during metazoan evolution into two related complexes, SAGA and ATAC, which exist in two flavors in vertebrates. The compositions of metazoan ATAC and SAGA complexes have been characterized, and functional analyses indicate that these complexes have important but distinct roles in transcription, histone modification, signaling pathways, and cell cycle regulation.

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Available from: Wwm Pim Pijnappel, Nov 15, 2014
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    • "TFIID and SAGA (Spt–Ada–Gcn5–acetyltransferase) interact with the promoter and participate in the recruitment of the pre-initiation complex (PIC). SAGA specifically activates gene transcription in response to environmental stress [11-13]. After SAGA or TFIID binding to the promoter, several transcription factors are recruited to form the PIC. "
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    Cancer Cell International 02/2014; 14(1):18. DOI:10.1186/1475-2867-14-18 · 2.77 Impact Factor
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    • "This association is functionally required for acetylation at various residues of histones H3 and H4 (notably K14/K27 and K8/K12, respectively ) on their promoter region and for their efficient induction by light (Benhamed et al., 2006). GCN5 is part of the SAGA complex in yeast, a transcriptional co-activator that promotes gene expression at a post-initiation step (Weake and Workman, 2008; Spedale et al., 2012), a function that seems to be conserved in Arabidopsis (Vlachonasios et al., 2003; Servet et al., 2010). At least two HDACs counterbalance acetylation levels on histone H3 and H4 on light-regulated genes, HISTONE DEACETYLASE 1/19 (HD1/HDA19) and HDA15, in addition to HDA6 that impacts light-triggered heterochromatin dynamics. "
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    • "ChIP was carried out as described previously (39), with minor modifications. In short, 225 ml of cultures was cross-linked with 1% formaldehyde for 20 min at RT at 50 rpm. "
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    ABSTRACT: Chromatin structure in transcribed regions poses a barrier for intragenic transcription. In a comprehensive study of the yeast chromatin remodelers and the Mot1p-NC2 regulators of TATA-binding protein (TBP), we detected synthetic genetic interactions indicative of suppression of intragenic transcription. Conditional depletion of Mot1p or NC2 in absence of the ISW1 remodeler, but not in the absence of other chromatin remodelers, activated the cryptic FLO8 promoter. Likewise, conditional depletion of Mot1p or NC2 in deletion backgrounds of the H3K36 methyltransferase Set2p or the Asf1p-Rtt106p histone H3-H4 chaperones, important factors involved in maintaining a repressive chromatin environment, resulted in increased intragenic FLO8 transcripts. Activity of the cryptic FLO8 promoter is associated with reduced H3 levels, increased TBP binding and tri-methylation of H3K4 and is independent of Spt-Ada-Gcn5-acetyltransferase function. These data reveal cooperation of negative regulation of TBP with specific chromatin regulators to inhibit intragenic transcription.
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