Genome-wide analysis of transcription, H2A.Z, nucleosomes and HSF1 dynamics in response to temperature increase in Arabidopsis thaliana
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ABSTRACT:
ORGANISM(S): Arabidopsis thaliana
PROVIDER: GSE79355 | GEO | 2017/09/29
SECONDARY ACCESSION(S): PRJNA315568
REPOSITORIES: GEO
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Project description:Plants are sessile organisms and therefore must sense and respond to changes of their surrounding conditions such as ambient temperature, which vary diurnally and seasonally. It is not yet clear how plants sense temperature and integrate this information into their development. We have previously shown that H2A.Z-nucleosomes are evicted in response to warmer temperatures. It is not clear however, whether the link between transcriptional responsiveness and changes in H2A.Z binding in context of temperature shifts is a global trend that can be seen throughout the genome, or the phenomenon is specific to a specialised set of temperature-responsive genes. In addition to the role of H2A.Z-nucleosome dynamics in the transcriptional response to temperature, it was shown that genes strongly misregulated in the h2a.z mutant are enriched for gene categories involved in response to multiple environmental cues. This suggests that H2A.Z could be implicated in the transcriptional response to various environmental inputs, raising the question: What brings the specificity of H2A.Z dynamics in response to temperature? To address this question we have profiled H2A.Z-nucleosome occupancy genome wide (using ChIP-seq) during a time course after temperature variation and compared its dynamics to transcriptional changes. We identified a fast, targeted and transient eviction of H2A.Z associated with transcriptional activation in response to temperature for a few hundreds genes. This eviction is associated with a reduction of the stability of the nucleosome. Moreover the genes with a fast H2A.Z eviction were strongly enriched in heat shock elements in their promoter and we observed a strong association between HSF1 binding and H2AZ eviction at warm temperature. These results highlight the importance of the interplay between transcription factors and chromatin to allow a controlled and dynamics response to temperature.
2017-09-29 | GSE94900 | GEO
Project description:Plants are sessile organisms and therefore must sense and respond to changes of their surrounding conditions such as ambient temperature, which vary diurnally and seasonally. It is not yet clear how plants sense temperature and integrate this information into their development. We have previously shown that H2A.Z-nucleosomes are evicted in response to warmer temperatures. It is not clear however, whether the link between transcriptional responsiveness and changes in H2A.Z binding in context of temperature shifts is a global trend that can be seen throughout the genome, or the phenomenon is specific to a specialised set of temperature-responsive genes. In addition to the role of H2A.Z-nucleosome dynamics in the transcriptional response to temperature, it was shown that genes strongly misregulated in the h2a.z mutant are enriched for gene categories involved in response to multiple environmental cues. This suggests that H2A.Z could be implicated in the transcriptional response to various environmental inputs, raising the question: What brings the specificity of H2A.Z dynamics in response to temperature? To address this question we have profiled H2A.Z-nucleosome occupancy genome wide (using ChIP-seq) during a time course after temperature variation and compared its dynamics to transcriptional changes. We identified a fast, targeted and transient eviction of H2A.Z associated with transcriptional activation in response to temperature for a few hundreds genes. This eviction is associated with a reduction of the stability of the nucleosome. Moreover the genes with a fast H2A.Z eviction were strongly enriched in heat shock elements in their promoter and we observed a strong association between HSF1 binding and H2AZ eviction at warm temperature. These results highlight the importance of the interplay between transcription factors and chromatin to allow a controlled and dynamics response to temperature.
2017-09-29 | GSE79353 | GEO
Project description:Plants are sessile organisms and therefore must sense and respond to changes of their surrounding conditions such as ambient temperature, which vary diurnally and seasonally. It is not yet clear how plants sense temperature and integrate this information into their development. We have previously shown that H2A.Z-nucleosomes are evicted in response to warmer temperatures. It is not clear however, whether the link between transcriptional responsiveness and changes in H2A.Z binding in context of temperature shifts is a global trend that can be seen throughout the genome, or the phenomenon is specific to a specialised set of temperature-responsive genes. In addition to the role of H2A.Z-nucleosome dynamics in the transcriptional response to temperature, it was shown that genes strongly misregulated in the h2a.z mutant are enriched for gene categories involved in response to multiple environmental cues. This suggests that H2A.Z could be implicated in the transcriptional response to various environmental inputs, raising the question: What brings the specificity of H2A.Z dynamics in response to temperature? To address this question we have profiled H2A.Z-nucleosome occupancy genome wide (using ChIP-seq) during a time course after temperature variation and compared its dynamics to transcriptional changes. We identified a fast, targeted and transient eviction of H2A.Z associated with transcriptional activation in response to temperature for a few hundreds genes. This eviction is associated with a reduction of the stability of the nucleosome. Moreover the genes with a fast H2A.Z eviction were strongly enriched in heat shock elements in their promoter and we observed a strong association between HSF1 binding and H2AZ eviction at warm temperature. These results highlight the importance of the interplay between transcription factors and chromatin to allow a controlled and dynamics response to temperature.
2017-09-29 | GSE102898 | GEO
Project description:Plants are sessile organisms and therefore must sense and respond to changes of their surrounding conditions such as ambient temperature, which vary diurnally and seasonally. It is not yet clear how plants sense temperature and integrate this information into their development. We have previously shown that H2A.Z-nucleosomes are evicted in response to warmer temperatures. It is not clear however, whether the link between transcriptional responsiveness and changes in H2A.Z binding in context of temperature shifts is a global trend that can be seen throughout the genome, or the phenomenon is specific to a specialised set of temperature-responsive genes. In addition to the role of H2A.Z-nucleosome dynamics in the transcriptional response to temperature, it was shown that genes strongly misregulated in the h2a.z mutant are enriched for gene categories involved in response to multiple environmental cues. This suggests that H2A.Z could be implicated in the transcriptional response to various environmental inputs, raising the question: What brings the specificity of H2A.Z dynamics in response to temperature? To address this question we have profiled H2A.Z-nucleosome occupancy genome wide (using ChIP-seq) during a time course after temperature variation and compared its dynamics to transcriptional changes. We identified a fast, targeted and transient eviction of H2A.Z associated with transcriptional activation in response to temperature for a few hundreds genes. This eviction is associated with a reduction of the stability of the nucleosome. Moreover the genes with a fast H2A.Z eviction were strongly enriched in heat shock elements in their promoter and we observed a strong association between HSF1 binding and H2AZ eviction at warm temperature. These results highlight the importance of the interplay between transcription factors and chromatin to allow a controlled and dynamics response to temperature.
2017-09-29 | GSE79354 | GEO
Project description:Temperature influences the distribution, range, and phenology of plants. The key transcriptional activators of heat shock response in eukaryotes, the heat shock factors (HSFs), have undergone large-scale gene amplification in plants. While HSFs are central in heat stress responses, their role in the response to ambient temperature changes is less well understood. We show here that the warm ambient temperature transcriptome is dependent upon the HSFA1 clade of Arabidopsis HSFs, which cause a rapid and dynamic eviction of H2A.Z nucleosomes at target genes. A transcriptional cascade results in the activation of multiple downstream stress-responsive transcription factors, triggering large-scale changes to the transcriptome in response to elevated temperature. H2A.Z nucleosomes are enriched at temperature-responsive genes at non-inducible temperature, and thus likely confer inducibility of gene expression and higher responsive dynamics. We propose that the antagonistic effects of H2A.Z and HSF1 provide a mechanism to activate gene expression rapidly and precisely in response to temperature, while preventing leaky transcription in the absence of an activation signal.
| S-EPMC6175055 | biostudies-literature
Project description:Genome-wide analysis of transcription, H2A.Z, nucleosomes and HSF1 dynamics in response to temperature increase in Arabidopsis thaliana
| PRJNA315568 | ENA
Project description:FACT complex is involved in elongation and ensures fidelity in the initiation step of transcription by RNA polymerase (pol) II. Histone variant H2A.Z is found in nucleosomes at the 5'-end of many genes. We report here H2A.Z-chaperone activity of the yeast FACT complex on the short, nucleosome-free, non-coding, pol III-transcribed yeast tRNA genes. On a prototype gene, yeast SUP4, chromatin remodeler RSC and FACT regulate its transcription through novel mechanisms, wherein the two gene-flanking nucleosomes containing H2A.Z, play different roles. Nhp6, which ensures transcription fidelity and helps load yFACT onto the gene flanking nucleosomes, has inhibitory role. RSC maintains a nucleosome abutting the gene terminator downstream, which results in reduced transcription rate in active state while H2A.Z probably helps RSC in keeping the gene nucleosome-free and serves as stress-sensor. All these factors maintain an epigenetic state which allows the gene to return quickly from repressed to active state and tones down the expression from the active SUP4 gene, required probably to maintain the balance in cellular tRNA pool.
| S-EPMC3105386 | biostudies-literature
Project description:PRDM9 directs human meiotic crossover hot spots to intergenic sequence motifs, whereas budding yeast hot spots overlap regions of low nucleosome density (LND) in gene promoters. To investigate hot spots in plants, which lack PRDM9, we used coalescent analysis of genetic variation in Arabidopsis thaliana. Crossovers increased toward gene promoters and terminators, and hot spots were associated with active chromatin modifications, including H2A.Z, histone H3 Lys4 trimethylation (H3K4me3), LND and low DNA methylation. Hot spot-enriched A-rich and CTT-repeat DNA motifs occurred upstream and downstream, respectively, of transcriptional start sites. Crossovers were asymmetric around promoters and were most frequent over CTT-repeat motifs and H2A.Z nucleosomes. Pollen typing, segregation and cytogenetic analysis showed decreased numbers of crossovers in the arp6 H2A.Z deposition mutant at multiple scales. During meiosis, H2A.Z forms overlapping chromosomal foci with the DMC1 and RAD51 recombinases. As arp6 reduced the number of DMC1 or RAD51 foci, H2A.Z may promote the formation or processing of meiotic DNA double-strand breaks. We propose that gene chromatin ancestrally designates hot spots within eukaryotes and PRDM9 is a derived state within vertebrates.
| S-EPMC3812125 | biostudies-literature
Project description:BackgroundLong non-coding RNAs (lncRNAs) have emerged as new class of regulatory molecules in animals where they regulate gene expression at transcriptional and post-transcriptional level. Recent studies also identified lncRNAs in plant genomes, revealing a new level of transcriptional complexity in plants. Thousands of lncRNAs have been predicted in the Arabidopsis thaliana genome, but only a few have been studied in depth.ResultsHere we report the identification of Arabidopsis lncRNAs that are expressed during the vegetative stage of development in either the shoot apical meristem or in leaves. We found that hundreds of lncRNAs are expressed in these tissues, of which 50 show differential expression upon an increase in ambient temperature. One of these lncRNAs, FLINC, is down-regulated at higher ambient temperature and affects ambient temperature-mediated flowering in Arabidopsis.ConclusionA number of ambient temperature responsive lncRNAs were identified with potential roles in the regulation of temperature-dependent developmental changes, such as the transition from the vegetative to the reproductive (flowering) phase. The challenge for the future is to characterize the biological function and molecular mode of action of the large number of ambient temperature-regulated lncRNAs that have been identified in this study.
| S-EPMC6045843 | biostudies-literature
Project description:The nucleus is a definitive feature of eukaryotic cells, comprising twin bilamellar membranes, the inner and outer nuclear membranes, which separate the nucleoplasmic and cytoplasmic compartments. Nuclear pores, complex macromolecular assemblies that connect the two membranes, mediate communication between these compartments. To explore the morphology, topology, and dynamics of nuclei within living plant cells, we have developed a novel method of confocal laser scanning fluorescence microscopy under time-lapse conditions. This is used for the examination of the transgenic expression in Arabidopsis thaliana of a chimeric protein, comprising the GFP (Green-Fluorescent Protein of Aequorea victoria) translationally fused to an effective nuclear localization signal (NLS) and to beta-glucuronidase (GUS) from E. coli. This large protein is targeted to the nucleus and accumulates exclusively within the nucleoplasm. This article provides online access to movies that illustrate the remarkable and unusual properties displayed by the nuclei, including polymorphic shape changes and rapid, long-distance, intracellular movement. Movement is mediated by actin but not by tubulin; it therefore appears distinct from mechanisms of nuclear positioning and migration that have been reported for eukaryotes. The GFP-based assay is simple and of general applicability. It will be interesting to establish whether the novel type of dynamic behavior reported here, for higher plants, is observed in other eukaryotic organisms.
| S-EPMC14952 | biostudies-literature