Acetylation-dependent Multimerization of SAGA Regulates Gene Transcription
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ABSTRACT:
PROVIDER: PRJNA679784 | ENA |
REPOSITORIES: ENA
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Project description:In Saccharomyces cerevisiae, the SAGA complex regulates its own activity by undergoing multimerization. This multimerization is triggered by SAGA autoacetylation at three sites on its Ada3 subunit, allowing recognition of this acetylation by the bromodomain of the Gcn5/Spt7 SAGA subunit. Once multimerized, SAGA is capable of cooperatively acetylating chromatin, and an inability to autoacetylate Ada3 leads to transcriptional and phenotypic defects in a wide range of stress-activated genes. The SAGA multimerization increased significantly in media with Sucorse as the only carbon resource than that with Glucose. In this study, the high-throughput sequence of wild type (WT) strain, Ada3 acetylation mutant (Ada3-3KR), Gcn5 bromodomain mutant (Gcn5m) and Spt7 bromodomain mutant (Spt7m) indicate a new function for Ada3 acetylation, show which genes transcription can be regulated by SAGA multimers.
2021-11-29 | GSE161887 | GEO
Project description:The SAGA-like complex SLIK is a modified version of the Spt-Ada-Gcn5-Acetyltransferase (SAGA) complex. SLIK is formed through C-terminal truncation of the Spt7 SAGA subunit, causing loss of Spt8 that interacts with the TATA-binding protein. SLIK and SAGA are both coactivators of RNA polymerase II transcription in yeast. In addition, both SAGA and SLIK perform chromatin modifications and the two complexes have been speculated to uniquely contribute to transcription regulation. To test the respective contribution of SAGA vs. SLIK in transcription regulation, we assayed the chromatin modifying functions of SAGA vs. SLIK, revealing identical kinetics on minimal substrates in vitro. Furthermore, we determined a low-resolution cryo-EM structure of SLIK, revealing a modular architecture identical to SAGA. Finally, we performed a comprehensive study of DNA-binding properties of both coactivators. Purified SAGA and SLIK both associate with ssDNA and dsDNA with high affinity (KD = 10-17 nM) and the binding is sequence-independent. In conclusion, our study shows that the cleavage of Spt7 and the absence of Spt8 subunit in SLIK neither drive any major conformational differences in its structure compared to SAGA, nor significantly affect HAT, DUB or DNA binding activities in vitro.
2021-04-19 | PXD024640 | Pride
Project description:SAGA is a modular cofactor complex that is essential for eukaryotic transcription. SAGA’s complement of ~20 proteins exist within four structurally and functionally distinct modules, two of which are catalytic. Within the KAT module, GCN5 acetylates histone tails, leading to increased chromatin accessibility and bromodomain protein recruitment. The DUB module contains the ubiquitin hydrolase USP22. In yeast, the USP22 ortholog deubiquitylates H2B, resulting in Pol II S2 phosphorylation and subsequent transcriptional elongation. We report here that metazoan SAGA, and USP22 specifically, are required at a more proximal stage in activator-driven transcription, i.e. pre-initiation complex (PIC) assembly. A combination of genome-wide and proteomic analyses revealed that H2B deubiquitylation is not linked to USP22-dependent transcription. Instead, USP22 controls Mediator tail subunit ubiquitylation. Mechanistically, USP22 controls loading of Mediator tail and GTFs onto promoters, with Mediator core recruitment being USP22-independent. These findings place human SAGA function at the earliest steps in activator-driven transcription.
2019-10-24 | GSE121798 | GEO
Project description:SAGA is a modular cofactor complex that is essential for eukaryotic transcription. SAGA’s complement of ~20 proteins exist within four structurally and functionally distinct modules, two of which are catalytic. Within the KAT module, GCN5 acetylates histone tails, leading to increased chromatin accessibility and bromodomain protein recruitment. The DUB module contains the ubiquitin hydrolase USP22. In yeast, the USP22 ortholog deubiquitylates H2B, resulting in Pol II S2 phosphorylation and subsequent transcriptional elongation. We report here that metazoan SAGA, and USP22 specifically, are required at a more proximal stage in activator-driven transcription, i.e. pre-initiation complex (PIC) assembly. A combination of genome-wide and proteomic analyses revealed that H2B deubiquitylation is not linked to USP22-dependent transcription. Instead, USP22 controls Mediator tail subunit ubiquitylation. Mechanistically, USP22 controls loading of Mediator tail and GTFs onto promoters, with Mediator core recruitment being USP22-independent. These findings place human SAGA function at the earliest steps in activator-driven transcription.
2021-04-12 | GSE158108 | GEO
Project description:The SAGA complex is a conserved, multifunctional coactivator that plays broad roles in eukaryotic transcription. Previous studies suggested that Tra1, the largest SAGA component, is required either for SAGA assembly or for recruitment by DNA-bound transcriptional activators. In contrast to S. cerevisiae and mouse, a tra1? mutant is viable in S. pombe, allowing us to test these issues in vivo. We find that, in a tra1? mutant, SAGA assembles and is recruited to some, but not all promoters. Consistent with these findings, Tra1 regulates the expression of only a subset of SAGA-dependent genes. We previously reported that the SAGA subunits Gcn5 and Spt8 have opposing regulatory roles during S. pombe sexual differentiation. We show here that, like Gcn5, Tra1 represses this pathway, although by a distinct mechanism. Thus, our study reveals that Tra1 has specific regulatory roles, rather than global functions, within SAGA.
2011-06-13 | E-MTAB-678 | biostudies-arrayexpress
Project description:Deletions within genes coding for subunits of the transcription coactivator SAGA caused strong genome-wide defects in transcription and SAGA-mediated chromatin modifications. In contrast, rapid SAGA depletion produced only modest transcription defects at 13% of protein-coding genes – genes that are generally more sensitive to rapid TFIID depletion. However, transcription of these “coactivator-redundant” genes is strongly affected by rapid depletion of both factors, showing the overlapping functions of TFIID and SAGA at this gene set. We suggest that this overlapping function is linked to TBP-DNA recruitment. The remaining 87% of expressed genes that we term “TFIID-dependent” are highly sensitive to rapid TFIID depletion and insensitive to rapid SAGA depletion. Genome-wide mapping of SAGA and TFIID found binding of both factors at many genes independent of gene class. DNA analysis suggests that the distinction between the gene classes is due to multiple components rather than any single regulatory factor or promoter sequence motif.
2020-01-09 | GSE133004 | GEO
Project description:Deletions within genes coding for subunits of the transcription coactivator SAGA caused strong genome-wide defects in transcription and SAGA-mediated chromatin modifications. In contrast, rapid SAGA depletion produced only modest transcription defects at 13% of protein-coding genes – genes that are generally more sensitive to rapid TFIID depletion. However, transcription of these “coactivator-redundant” genes is strongly affected by rapid depletion of both factors, showing the overlapping functions of TFIID and SAGA at this gene set. We suggest that this overlapping function is linked to TBP-DNA recruitment. The remaining 87% of expressed genes that we term “TFIID-dependent” are highly sensitive to rapid TFIID depletion and insensitive to rapid SAGA depletion. Genome-wide mapping of SAGA and TFIID found binding of both factors at many genes independent of gene class. DNA analysis suggests that the distinction between the gene classes is due to multiple components rather than any single regulatory factor or promoter sequence motif.
2020-01-09 | GSE142120 | GEO
Project description:Deletions within genes coding for subunits of the transcription coactivator SAGA caused strong genome-wide defects in transcription and SAGA-mediated chromatin modifications. In contrast, rapid SAGA depletion produced only modest transcription defects at 13% of protein-coding genes – genes that are generally more sensitive to rapid TFIID depletion. However, transcription of these “coactivator-redundant” genes is strongly affected by rapid depletion of both factors, showing the overlapping functions of TFIID and SAGA at this gene set. We suggest that this overlapping function is linked to TBP-DNA recruitment. The remaining 87% of expressed genes that we term “TFIID-dependent” are highly sensitive to rapid TFIID depletion and insensitive to rapid SAGA depletion. Genome-wide mapping of SAGA and TFIID found binding of both factors at many genes independent of gene class. DNA analysis suggests that the distinction between the gene classes is due to multiple components rather than any single regulatory factor or promoter sequence motif.
2020-01-09 | GSE142183 | GEO
Project description:Deletions within genes coding for subunits of the transcription coactivator SAGA caused strong genome-wide defects in transcription and SAGA-mediated chromatin modifications. In contrast, rapid SAGA depletion produced only modest transcription defects at 13% of protein-coding genes – genes that are generally more sensitive to rapid TFIID depletion. However, transcription of these “coactivator-redundant” genes is strongly affected by rapid depletion of both factors, showing the overlapping functions of TFIID and SAGA at this gene set. We suggest that this overlapping function is linked to TBP-DNA recruitment. The remaining 87% of expressed genes that we term “TFIID-dependent” are highly sensitive to rapid TFIID depletion and insensitive to rapid SAGA depletion. Genome-wide mapping of SAGA and TFIID found binding of both factors at many genes independent of gene class. DNA analysis suggests that the distinction between the gene classes is due to multiple components rather than any single regulatory factor or promoter sequence motif.
2020-01-09 | GSE142182 | GEO
Project description:Eukaryotic genomes are pervasively transcribed by RNA polymerase II (RNAPII), and transcription of long non-coding RNAs often overlaps with coding gene promoters. This might lead to coding gene repression in a process named Transcription Interference (TI). In Saccharomyces cerevisiae (S. cerevisiae), TI is mainly driven by antisense non-coding transcription and occurs through re-shaping of promoter Nucleosome-Depleted Regions (NDRs). In this study, we developed a genetic screen to identify new players involved in Antisense-Mediated Transcription Interference (AMTI). Among the candidates, we found the HIR histone chaperone complex known to be involved in de novo histone deposition. Using genome-wide approaches, we reveal that HIR-dependent histone deposition represses the promoters of SAGA-dependent genes via antisense non-coding transcription. However, while antisense transcription is enriched at promoters of SAGA-dependent genes, this feature is not sufficient to define the mode of gene regulation. We further show that the balance between HIR-dependent nucleosome incorporation and transcription factor binding at promoters directs transcription into a SAGA- or TFIID-dependent regulation. This study sheds light on a new connection between antisense non-coding transcription and the nature of coding transcription initiation.
2021-06-03 | GSE175991 | GEO