Distinct roles for H4 and H2A.Z acetylation in RNA transcription in African trypanosomes
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA608391 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR11165200_1.fastq.gz | Fastqsanger.gz | |||
| SRR11165200_2.fastq.gz | Fastqsanger.gz | |||
| SRR11165201_1.fastq.gz | Fastqsanger.gz | |||
| SRR11165201_2.fastq.gz | Fastqsanger.gz | |||
| SRR11165202_1.fastq.gz | Fastqsanger.gz |
Items per page: 5 1 - 5 of 166 |
Similar Datasets
Project description:Both, acetylation of histones and of histone variant H2A.Z are conserved features of eukaryotic transcription start sites (TSSs) and both features appear to be critical for correct transcription initiation. However, complex patterns of transcriptional regulation have complicated the establishment of functional links between histone acetylation, H2A.Z deposition and their importance in transcription regulation. To elucidate these links, we took advantage of the unusual genome organization in Trypanosoma brucei, a highly divergent eukaryote. In T. brucei genes are organized in long polycistronic transcription units, drastically reducing the sites of transcription initiation. Employing a highly sensitive and quantitative mass-spectrometry-based approach, we quantified the genome-wide histone acetylation and methylation pattern and identified various acetyl and methyl marks exclusively enriched at TSSs In addition, we show that deletion of histone acetyltransferase 2 results in a loss of H4 acetylation at TSSs, a loss of H2A.Z deposition at TSSs and a shift in the sites of transcription initiation. Combined, our findings demonstrate an evolutionary conserved link between histone H4 acetylation, H2A.Z deposition and RNA transcription initiation.
2020-03-24 | PXD014452 | Pride
Project description:Despite histone H2A variants and acetylation of histones occurring in almost every eukaryotic organism, it has been difficult to establish direct functional links between canonical histones or H2A variant acetylation, deposition of H2A variants and transcription. To disentangle these complex interdependent processes, we devised a highly sensitive strategy for quantifying histone acetylation levels at specific genomic loci. Taking advantage of the unusual genome organization in Trypanosoma brucei, we identified 58 histone modifications enriched at transcription start sites (TSSs). Furthermore, we found TSS-associated H4 and H2A.Z acetylation to be mediated by two different histone acetyltransferases, HAT2 and HAT1, respectively. Whereas depletion of HAT2 decreases H2A.Z deposition and shifts the site of transcription initiation, depletion of HAT1 does not affect H2A.Z deposition but reduces total mRNA levels by 50%. Thus, specifically reducing H4 or H2A.Z acetylation levels enabled us to reveal distinct roles for these modifications in H2A.Z deposition and RNA transcription.
| S-EPMC7083915 | biostudies-literature
Project description:High levels of the histone variant H2A.Z are characteristic for melanoma progression and correlate with poor prognosis of melanoma patients. Two chaperone complexes are reported to deposit H2A.Z isoforms into chromatin: SRCAP and P400-TIP60. YL1 is a common subunit of both complexes and directly binds to the H2A.Z-H2B dimer. Here, we showed that the knockdown of SRCAP (SRCAP-specific), P400 (P400-TIP60-specific) and YL1 (shared subunit) results in loss of H2A.Z deposition into chromatin in melanoma cells, confirming them as H2A.Z chaperone subunits in this system. Further, we demonstrated that H2A.Z, YL1 and the SRCAP-specific subunit ZNHIT1 co-localize at active promoters of cell cycle-related genes, such as the transcription factor E2F1. Knockdown of YL1, SRCAP and P400 downregulates E2F1 and its targets, resulting in a loss of proliferation and cell cycle arrest in melanoma cells as seen after knockdown of H2A.Z (Vardabasso et al. 2015). Strikingly, besides H2A.Z loss, we observed a dramatic loss of H4 acetylation in melanoma chromatin upon knockdown of H2A.Z chaperone subunits. The majority of genes whose promoters showed a reduction in H4 acetylation were previously bound by H2A.Z, YL1 and ZNHIT1. This is suggestive of a direct link between H2A.Z deposition and H4 acetylation to promote the expression of underlying genes. In agreement, the genes that lost H4 acetylation were enriched for E2F1 target genes. Interestingly, we additionally found that knockdown of YL1 did not only prohibit cell cycle progression, but also induces apoptosis, which is in contrast to H2A.Z knockdown affecting cell cycle only. In addition, YL1 (but not SRCAP or P400) was found to be overexpressed in melanoma and high YL1 levels were a predictor of poor melanoma patient outcome. These findings provide a rationale for targeting the H2A.Z-YL1 interaction as novel epigenetic strategy for melanoma treatment.
2024-05-10 | GSE242227 | GEO
Project description:High levels of the histone variant H2A.Z are characteristic for melanoma progression and correlate with poor prognosis of melanoma patients. Two chaperone complexes are reported to deposit H2A.Z isoforms into chromatin: SRCAP and P400-TIP60. YL1 is a common subunit of both complexes and directly binds to the H2A.Z-H2B dimer. Here, we showed that the knockdown of SRCAP (SRCAP-specific), P400 (P400-TIP60-specific) and YL1 (shared subunit) results in loss of H2A.Z deposition into chromatin in melanoma cells, confirming them as H2A.Z chaperone subunits in this system. Further, we demonstrated that H2A.Z, YL1 and the SRCAP-specific subunit ZNHIT1 co-localize at active promoters of cell cycle-related genes, such as the transcription factor E2F1. Knockdown of YL1, SRCAP and P400 downregulates E2F1 and its targets, resulting in a loss of proliferation and cell cycle arrest in melanoma cells as seen after knockdown of H2A.Z (Vardabasso et al. 2015). Strikingly, besides H2A.Z loss, we observed a dramatic loss of H4 acetylation in melanoma chromatin upon knockdown of H2A.Z chaperone subunits. The majority of genes whose promoters showed a reduction in H4 acetylation were previously bound by H2A.Z, YL1 and ZNHIT1. This is suggestive of a direct link between H2A.Z deposition and H4 acetylation to promote the expression of underlying genes. In agreement, the genes that lost H4 acetylation were enriched for E2F1 target genes. Interestingly, we additionally found that knockdown of YL1 did not only prohibit cell cycle progression, but also induces apoptosis, which is in contrast to H2A.Z knockdown affecting cell cycle only. In addition, YL1 (but not SRCAP or P400) was found to be overexpressed in melanoma and high YL1 levels were a predictor of poor melanoma patient outcome. These findings provide a rationale for targeting the H2A.Z-YL1 interaction as novel epigenetic strategy for melanoma treatment.
2024-05-10 | GSE246121 | GEO
Project description:This SuperSeries is composed of the SubSeries listed below.
2020-02-24 | GSE145812 | GEO
Project description:H2A.Z acetylation has been suggested to regulate genes but effects on gene expression globally have not been reported. We find that the H2A.Z acetylation sites are required for normal growth in the presence of caffeine and therefore examined the gene expression response to caffeine when H2A.Z can’t be acetylated. Surprisingly we found little or no change in gene induction but a marked failure to remove H2A.Z from activated promoters. Caffeine causes a proteasome-dependent degradation of H2A.Z that is impaired in the absence of the H2A.Z acetylation sites. The proteasomal regulator Blm10 that has previously been implicated in acetylation-dependent histone degradation is required for H2A.Z degradation, revealing a novel role for acetylation in regulating H2A.Z protein levels. When H2A.Z levels are raised, either through loss of the acetylation sites or overexpression of the protein, a shared set of genes aberrantly retains H2A.Z at their 5’ ends during the caffeine response. As a result, expression of these genes fails to return to normal levels. H2A.Z is therefore subject to post-translational proteasomal regulation that controls protein levels, and the fine-tuning of gene expression during a stress response requires the normal function of this pathway. This regulation of H2A.Z degradation by acetylation is a previously unrecognised aspect of gene regulation.
2018-04-05 | GSE97822 | GEO
Project description:The MYST HAT Sas2 is part of the SAS-I complex. The target for acetylation by Sas2 is Lys16 of histone H4 (H4 K16Ac). This acetylation site marks euchromatic regions and opposes the spreading of heterochromatin at telomere-proximal regions. Changes of SAS-I-mediated H4 K16Ac on a genome-wide scale comparing wt and sas2M-bM-^HM-^F cells were investigated in this study. We found a pronounced, genome-wide loss of H4 K16 acetylation in the body of transcribed genes in the absence of Sas2. Furthermore, the influence of Sas2 on gene expression was investigated in RNA expression arrays. H4 K16Ac and H4 in wt and sas2M-bM-^HM-^F was ChIPed. ChIP experiments were performed three times with independent chromatin preparations.
2012-01-18 | E-GEOD-19962 | biostudies-arrayexpress
Project description:H2A.Z chaperones promote melanoma cell growth by facilitating transcription of E2F target genes through H2A.Z deposition and H4 acetylation
| PRJNA1012308 | ENA
Project description:H2A.Z chaperones promote melanoma cell growth by facilitating transcription of E2F target genes through H2A.Z deposition and H4 acetylation
| PRJNA1031572 | ENA
Project description:Genome-wide transcription studies are revealing increasing examples of ‘dispersed promoters’ that unlike ‘focused promoters’, lack well-conserved sequence motifs and tight regulation. Dispersed promoters are nevertheless marked by well-defined chromatin structures, suggesting that specific sequence elements must exist in these unregulated promoters. Here, we have analyzed regions of transcription initiation in the eukaryotic parasite Trypanosoma brucei, in which RNA polymerase II transcription initiation and occurs over broad regions without distinct promoter motifs and lacks regulation. Using a combination of site-specific and genome-wide assays, we identified GT-rich promoters that can drive unidirectional transcription and promote the targeted deposition of the histone variant H2A.Z in a genomic context dependent manner. In addition, upon mapping nucleosome occupancy at high resolution, we find nucleosome positioning to correlate with RNA pol II enrichment and gene expression, pointing to a role in RNA maturation. Nucleosome positioning may thus represent a previously unrecognized layer of gene regulation in trypanosomes. Our findings show that even highly dispersed, unregulated promoters contain specific DNA elements that are able to induce transcription and changes in chromatin structure.
2017-05-31 | GSE98061 | GEO