The evolution and functional divergence of the histone H2B family in plants
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ABSTRACT:
ORGANISM(S): Arabidopsis thaliana
PROVIDER: GSE151166 | GEO | 2020/07/21
REPOSITORIES: GEO
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Project description:Diversification of histone variants is marked by the acquisition of distinct motifs and features through convergent evolution. H2A variants tend to be associated with defined domains of the genome. Specific features distinguish H2A variants in eukaryotes but whether evolution of these features predated the evolution of deposition mechanisms or vice-versa has remained unclear.In flowering plants, the variant H2A.W is tightly associated with heterochromatin. H2A.W evolved in land plants through acquisition of an extended C-terminal tail enriched with basic residues and a KSPK motif. Here, we used a synthetic approach in fission yeast, which lacks H2A.W and its dedicated deposition mechanism, to recapitulate the evolutionary steps that led to H2A.W and to assess the impact of the KSPK motif on heterochromatin composition and its properties. In conclusion, the acquisition of the KSPK motif in yeast promotes chromatin properties that are comparable to the properties and function of H2A.W in plant heterochromatin. Hence, the KSPK motif could have been selected before the evolution of direct heterochromatin deposition mechanisms. We propose that the acquisition of functional histone variant motifs can confer properties which affect only specific chromatin states, thereby driving the evolution of specific deposition mechanisms.
2020-08-23 | GSE152085 | GEO
Project description:Diversification of histone variants is marked by the acquisition of distinct motifs and features through convergent evolution. H2A variants tend to be associated with defined domains of the genome. Specific features distinguish H2A variants in eukaryotes but whether evolution of these features predated the evolution of deposition mechanisms or vice-versa has remained unclear.In flowering plants, the variant H2A.W is tightly associated with heterochromatin. H2A.W evolved in land plants through acquisition of an extended C-terminal tail enriched with basic residues and a KSPK motif. Here, we used a synthetic approach in fission yeast, which lacks H2A.W and its dedicated deposition mechanism, to recapitulate the evolutionary steps that led to H2A.W and to assess the impact of the KSPK motif on heterochromatin composition and its properties. In conclusion, the acquisition of the KSPK motif in yeast promotes chromatin properties that are comparable to the properties and function of H2A.W in plant heterochromatin. Hence, the KSPK motif could have been selected before the evolution of direct heterochromatin deposition mechanisms. We propose that the acquisition of functional histone variant motifs can confer properties which affect only specific chromatin states, thereby driving the evolution of specific deposition mechanisms.
2020-08-23 | GSE152083 | GEO
Project description:Diversification of histone variants is marked by the acquisition of distinct motifs and features through convergent evolution. H2A variants tend to be associated with defined domains of the genome. Specific features distinguish H2A variants in eukaryotes but whether evolution of these features predated the evolution of deposition mechanisms or vice-versa has remained unclear.In flowering plants, the variant H2A.W is tightly associated with heterochromatin. H2A.W evolved in land plants through acquisition of an extended C-terminal tail enriched with basic residues and a KSPK motif. Here, we used a synthetic approach in fission yeast, which lacks H2A.W and its dedicated deposition mechanism, to recapitulate the evolutionary steps that led to H2A.W and to assess the impact of the KSPK motif on heterochromatin composition and its properties. In conclusion, the acquisition of the KSPK motif in yeast promotes chromatin properties that are comparable to the properties and function of H2A.W in plant heterochromatin. Hence, the KSPK motif could have been selected before the evolution of direct heterochromatin deposition mechanisms. We propose that the acquisition of functional histone variant motifs can confer properties which affect only specific chromatin states, thereby driving the evolution of specific deposition mechanisms.
2020-08-23 | GSE152081 | GEO
Project description:Nucleosomes package eukaryotic DNA and are composed of four different histone proteins, H3, H4, H2A and H2B. Histone H3 has two main variants, H3.1 and H3.3, which show different genomic localization patterns in animals. We profiled H3.1 and H3.3 variants in the genome of the plant Arabidopsis thaliana and show that the localization of these variants shows broad similarity in plants and animals, in addition to some unique features. H3.1 was enriched in silent areas of the genome including regions containing the repressive chromatin modifications H3 lysine 27 methylation, H3 lysine 9 methylation, and DNA methylation. In contrast, H3.3 was enriched in actively transcribed genes, especially peaking at the 3’ end of genes, and correlated with histone modifications associated with gene activation such as histone H3 lysine 4 methylation, and H2B ubiquitylation, as well as by RNA Pol II occupancy. Surprisingly, both H3.1 and H3.3 were enriched on defined origins of replication, as was overall nucleosome density, suggesting a novel characteristic of plant origins. Our results are broadly consistent with the hypothesis that H3.1 acts as the canonical histone that is incorporated during DNA replication, whereas H3.3 acts as the replacement histone that can be incorporated outside of S-phase during chromatin disrupting processes like transcription. ChIP-seq - 4 samples: 2 experiment and 2 controls RNA-seq - 1 sample
2012-03-05 | E-GEOD-34840 | biostudies-arrayexpress
Project description:Nucleosomes package eukaryotic DNA and are composed of four different histone proteins, H3, H4, H2A and H2B. Histone H3 has two main variants, H3.1 and H3.3, which show different genomic localization patterns in animals. We profiled H3.1 and H3.3 variants in the genome of the plant Arabidopsis thaliana and show that the localization of these variants shows broad similarity in plants and animals, in addition to some unique features. H3.1 was enriched in silent areas of the genome including regions containing the repressive chromatin modifications H3 lysine 27 methylation, H3 lysine 9 methylation, and DNA methylation. In contrast, H3.3 was enriched in actively transcribed genes, especially peaking at the 3’ end of genes, and correlated with histone modifications associated with gene activation such as histone H3 lysine 4 methylation, and H2B ubiquitylation, as well as by RNA Pol II occupancy. Surprisingly, both H3.1 and H3.3 were enriched on defined origins of replication, as was overall nucleosome density, suggesting a novel characteristic of plant origins. Our results are broadly consistent with the hypothesis that H3.1 acts as the canonical histone that is incorporated during DNA replication, whereas H3.3 acts as the replacement histone that can be incorporated outside of S-phase during chromatin disrupting processes like transcription.
2012-03-05 | GSE34840 | GEO
Project description:Eukaryotic chromatin structure is highly conserved, with the canonical histone proteins revealing only small sequence changes across species. Yet, all vertebrates exhibit three much larger histone H2A variants, macroH2A. A distinctive feature of these atypical histones is the globular macrodomain module, which can bind metabolites and is connected to the histone fold through a flexible linker. MacroH2A variants impact heterochromatin organization, transcription regulation and establish a barrier for cellular reprogramming. However, the mechanisms of how these large H2A variants are incorporated into chromatin and the identity of any chaperones required for histone deposition have remained elusive. Here, we developed a split-GFP-based cellular readout for histone incorporation and conducted a genome-wide mutagenesis screen in haploid human cells to identify proteins that regulate macroH2A dynamics. We identified and validated the histone chaperone ANP32B as a regulator of macroH2A chromatin deposition. ANP32B associates with macroH2A in cells and in vitro binds to histones with low nanomolar affinity. In vitro nucleosome assembly assays show that ANP32B stimulates deposition of macroH2A-H2B and not of H2A-H2B onto tetraso me. In cells, depletion of ANP32B in cells strongly affects global macroH2A deposition, revealing ANP32B as a macroH2A chaperone. Our study highlights the power of haploid cell functional genomics coupled with cellular imaging to identify factors that are required for chromatin plasticity and diversity.
2023-11-07 | GSE241387 | GEO
Project description:Histone proteins, including their variants, play indispensable roles in chromatin structure and function. The specific histone incorporation is the key to epigenetic features and contributes to cell differentiation and development. To understand how each histone is targeted to and incorporated into the specific chromatin region, we used a new method, in which we introduced epitope-tagged histone complexes in permeabilized cells and let them incorporated into the chromatin. The newly incorporated histone complex is easily distinguished from the parental histones by the epitope-tag. We name this as RhIP (Reconstituted histone complex Incorporation into chromatin of Permeabilized cell) assay. We analyzed the correlation between the histone incorporation and the chromatin structure, using the H2A-H2B and H2A.Z-H2B complexes. The histone incorporation mainly occurred at less condensed chromatin (open), suggesting that the condensed chromatin (closed) is a barrier for histone incorporation. To overcome this barrier, H2A, but not H2A.Z, uses a replication-coupled deposition mechanism. This led to the genome-wide distribution of H2A and the exclusion of H2A.Z from the closed chromatin.
2021-04-15 | GSE130947 | GEO
Project description:Histone proteins, including their variants, play indispensable roles in chromatin structure and function. The specific histone incorporation is the key to epigenetic features and contributes to cell differentiation and development. To understand how each histone is targeted to and incorporated into the specific chromatin region, we used a new method, in which we introduced epitope-tagged histone complexes in permeabilized cells and let them incorporated into the chromatin. The newly incorporated histone complex is easily distinguished from the parental histones by the epitope-tag. We name this as RhIP (Reconstituted histone complex Incorporation into chromatin of Permeabilized cell) assay. We analyzed the correlation between the histone incorporation and the chromatin structure, using the H2A-H2B and H2A.Z-H2B complexes. The histone incorporation mainly occurred at less condensed chromatin (open), suggesting that the condensed chromatin (closed) is a barrier for histone incorporation. To overcome this barrier, H2A, but not H2A.Z, uses a replication-coupled deposition mechanism. This led to the genome-wide distribution of H2A and the exclusion of H2A.Z from the closed chromatin.
2021-04-15 | GSE163502 | GEO
Project description:Background: Histones organize DNA into chromatin through a variety of processes. Among them, a vast diversity of histone variants can be incorporated into chromatin to finely modulate its organization and functionality. Classically, the study of histone variants has largely relied on antibody-based assays. However, antibodies have a limited efficiency to discriminate between highly similar histone variants. Results: In this study, we established a mass spectrometry-based analysis to address this challenge. We developed a targeted proteomics method, using Single Reaction Monitoring (SRM) or Parallel Reaction Monitoring (PRM), to quantify a maximum number of histone variants in a single multiplexed assay, even when histones are present in a crude extract. This strategy was developed on H2A and H2B variants, using 55 peptides corresponding to 25 different histone sequences, among which a few differ by a single amino acid. The methodology was then applied to mouse testis extracts in which almost all histone variants are expressed. It confirmed the abundance profiles of several testis-specific histones during successive stages of spermatogenesis and the existence of predicted H2A.L.1 isoforms. This methodology was also used to explore the over-expression pattern of H2A.L.1 isoforms in a mouse model of male infertility. Conclusions: Our results demonstrate that targeted proteomics is a powerful method to quantify highly similar histone variants and isoforms. The developed method can be easily transposed to the study of human histone variants, whose abundance can be deregulated in various diseases.
2018-01-16 | PXD008358 | Pride
Project description:Chromatin is composed of DNA wrapped around nucleosomes, complexes consisting of highly basic proteins called histones. Histone variants are non-canonical variants of histones that have specific functions. The Apicomplexan parasite Toxoplasma gondii possesses conserved histone variants CenH3, H3.3, H2A.Z, H2A.X, as well as the parasite-specific H2B variant, H2BV (or H2B.Z). We surveyed the genome-wide distribution of T. gondii histone variants by chromatin immunoprecipitation coupled with microarray (ChIP-chip) and next generation sequencing (ChIP-seq). Histone variants have specific localisations in chromosomes and in relation to genomic features. Histones H2BV and H2AZ localise to promoter regions with the transcriptional activation mark H3K4me3. Sites where H2BV, H2AZ and H3K4me3 colocalise are enriched in motifs recognised by AP2 transcription factors, particularly in the nucleosome-free region just upstream of the transcription start site. In contrast, histone variants H3.3 and H2AX are largely absent from promoters but enriched in gene bodies. Consistent with previous biochemical work, the majority of H2AX and H2AZ loci do not overlap, suggesting that they are present in different nucleosomes. In addition, the T. gondii homologue of the centromeric histone CenH3 demarcates centromeric chromatin and appears to be part of a unique centromeric histone complex including H3.3 that localises to centromeric chromatin as detected in proteomic analysis of co-immunoprecipitated CenH3 complexes. Together, these data suggest that the position of variant histones demarcates specific functional regions of chromatin and that exchange of histone variants is an important transcriptional regulatory mechanism in T. gondii.
2019-04-30 | GSE87834 | GEO