Nucleosome repositioning-coupled expression divergence between species
Ontology highlight
ABSTRACT:
ORGANISM(S): Saccharomyces bayanus
PROVIDER: GSE24356 | GEO | 2011/11/10
SECONDARY ACCESSION(S): PRJNA132811
REPOSITORIES: GEO
Similar Datasets
Project description:We describe the genome-wide nucleosome profiles for S. bayanus under standard conditions Nucleosomes from S. bayanus was isolated and sequenced using the Illumina GAII platform.
2011-11-10 | E-GEOD-24356 | biostudies-arrayexpress
Project description:We describe the genome-wide nucleosome profiles of four related yeast species. All species display the same global organization features first described in S. cerevisiae: a stereotypical nucleosome organization along genes, and the classification of promoters into these which contain or lack a pronounced Nucleosome Depleted region (NDR), with the latter displaying a more dynamic pattern of gene expression. This global similarity, however, does not reflect a static evolutionary pattern, as nucleosome positioning at specific genes diverged rapidly leaving practically no similarity between S. cerevisiae and C. glabrata orthologs (~50 Myr). We show that this rapid divergence in nucleosome positioning contrasts a conserved pattern of gene expression, consistent with the idea that divergence of nucleosome patterns has a limited effect on gene expression as many different configurations can support the same regulatory outcome.
2011-12-09 | GSE23577 | GEO
Project description:We describe the genome-wide nucleosome profiles of four related yeast species. All species display the same global organization features first described in S. cerevisiae: a stereotypical nucleosome organization along genes, and the classification of promoters into these which contain or lack a pronounced Nucleosome Depleted region (NDR), with the latter displaying a more dynamic pattern of gene expression. This global similarity, however, does not reflect a static evolutionary pattern, as nucleosome positioning at specific genes diverged rapidly leaving practically no similarity between S. cerevisiae and C. glabrata orthologs (~50 Myr). We show that this rapid divergence in nucleosome positioning contrasts a conserved pattern of gene expression, consistent with the idea that divergence of nucleosome patterns has a limited effect on gene expression as many different configurations can support the same regulatory outcome. Nucleosomes from 4 different yeast species were isolated and sequenced using the Illumina GAII platform. Replicates were performed for 3 of the species
2011-12-09 | E-GEOD-23577 | biostudies-arrayexpress
Project description:The location of nucleosomes in the human genome determines the primary chromatin structure and regulates access to regulatory regions. However, genome-wide information on deregulated nucleosome occupancy and its implications in primary cancer cells is scarce. Here, we conducted a genome-wide comparison of high-resolution nucleosome maps in peripheral-blood B cells from patients with chronic lymphocytic leukaemia (CLL) and healthy individuals at single base pair resolution. Our investigation uncovered significant changes of nucleosome positioning in CLL. Globally, the spacing between nucleosomes – the nucleosome repeat length (NRL) – was shortened in CLL. This effect was stronger in the more aggressive IGHV-unmutated than in the IGHV-mutated CLL subtype. Changes in nucleosome occupancy at specific sites were linked to active chromatin remodelling and reduced DNA methylation. Nucleosomes lost or gained in CLL marked differential binding of 3D chromatin organisers such as CTCF as well as immune response-related transcription factors and delineated mechanisms of epigenetic deregulation. The principal component analysis of nucleosome occupancy in cancer-specific regions allowed classification of samples between cancer subtypes and normal controls. Furthermore, patients could be better assigned to CLL subtypes according to differential nucleosome occupancy than based on DNA methylation or gene expression. Thus, nucleosome positioning constitutes a novel readout to dissect molecular mechanisms of disease progression and to stratify patients. Furthermore, we anticipate that the global nucleosome repositioning detected in our study, such as changes in the NRL, can be exploited for liquid biopsy applications based on cell-free DNA to monitor disease progression.
2023-08-27 | GSE158745 | GEO
Project description:SH-SY5Y, neuroblastoma cells, were exposed to nicotine for 10, 60, and 90 minutes or cocaine for 5, 20, 40, and 60 minutes. Drugs of abuse modify behavior by altering gene expression in the brain. Gene expression can be regulated by changes in DNA methylation as well as by histone modifications, which alter chromatin structure, DNA compaction and DNA accessibility. In order to better understand the molecular mechanisms directing drug-induced changes in chromatin structure, we examined DNA-nucleosome interactions within promoter regions of 858 genes in human neuroblastoma cells (SH-SY5Y) exposed to nicotine or cocaine. Widespread, drug- and time-resolved repositioning of nucleosomes was identified at the transcription start site and promoter region of multiple genes. Nicotine and cocaine produced unique and shared changes in terms of the numbers and types of genes affected, as well as repositioning of nucleosomes at sites which could increase or decrease the probability of gene expression based on DNA accessibility. Half of the drug-induced nucleosome positions approximated a theoretical model of nucleosome occupancy based on physical and chemical characteristics of the DNA sequence, whereas the basal or drug-naive positions were generally DNA sequence independent. Thus we suggest that nucleosome repositioning represents an initial dynamic genome-wide alteration of the transcriptional landscape preceding more selective downstream transcriptional reprogramming, which ultimately characterizes the cell- and tissue-specific responses to drugs of abuse. SH-SY5Y, neuroblastoma cells, were exposed to nicotine for 10, 60, and 90 minutes or cocaine for 5, 20, 40, and 60 minutes. Two independently grown biological replicates for each time point and condition, and two controls were processed.
2015-08-07 | E-GEOD-71795 | biostudies-arrayexpress
Project description:A fundamental problem in biology is the molecular basis for divergence among related organisms. We have investigated the level of divergence of transcription factor binding sites for two key factors that regulate developmental processes in the budding yeasts. The genomic binding locations for the Ste12 and Tec1 transcription factors in S. cerevisiae, S. mikatae and S. bayanus were mapped by chromatin immunoprecipitation combined with microarrays (chIP chip)1, 2 and compared to one another. While there was a large core network which was conserved in all three species, there were many instances of binding events whose relative levels differ significantly quantitatively in one species relative to another and as well as species-specific binding events. One interesting class of genes were identified that were bound only in S. mikatae and S. bayanus; many of these genes are targets of Ste12 in haploid strains of S. cerevisiae, suggesting that S. cerevisiae has uniquely acquired the ability to differentially regulate these genes in haploid and diploid cells in these species. To extend these studies, the transcriptional network for the Ste12 homologue (Cph1) in Candida albicans was also mapped and compared to the Saccharomyces species. Again, there were several genes bound by Cph1 which are involved in mating in S. cerevisiae, suggesting that the precise delineation between many mating and pseudohyphal targets by Ste12 may be specific to S. cerevisiae. Overall our results demonstrate that transcription binding sites differ faster than gene content indicating that gene regulation at the level of transcription factor binding is likely to be a major mode of evolutionary divergence between related species. We expect that this divergence is essential for the distinct ecological niches inhabited by these organisms. Keywords: chIP-chip ChIP-chip was performed on Ste12 and Tec1 from S. cerevisiae, S. mikatae and S. bayanus in addition to Cph1 from S. cerevisiae. Three biological replicates were performed for each factor in each species with one replicate representing a dye swap.
2007-09-06 | E-GEOD-5421 | biostudies-arrayexpress
Project description:SH-SY5Y, neuroblastoma cells, were exposed to nicotine for 10, 60, and 90 minutes or cocaine for 5, 20, 40, and 60 minutes. Drugs of abuse modify behavior by altering gene expression in the brain. Gene expression can be regulated by changes in DNA methylation as well as by histone modifications, which alter chromatin structure, DNA compaction and DNA accessibility. In order to better understand the molecular mechanisms directing drug-induced changes in chromatin structure, we examined DNA-nucleosome interactions within promoter regions of 858 genes in human neuroblastoma cells (SH-SY5Y) exposed to nicotine or cocaine. Widespread, drug- and time-resolved repositioning of nucleosomes was identified at the transcription start site and promoter region of multiple genes. Nicotine and cocaine produced unique and shared changes in terms of the numbers and types of genes affected, as well as repositioning of nucleosomes at sites which could increase or decrease the probability of gene expression based on DNA accessibility. Half of the drug-induced nucleosome positions approximated a theoretical model of nucleosome occupancy based on physical and chemical characteristics of the DNA sequence, whereas the basal or drug-naive positions were generally DNA sequence independent. Thus we suggest that nucleosome repositioning represents an initial dynamic genome-wide alteration of the transcriptional landscape preceding more selective downstream transcriptional reprogramming, which ultimately characterizes the cell- and tissue-specific responses to drugs of abuse.
2015-08-07 | GSE71795 | GEO
Project description:Cell differentiation is associated with changes in chromatin organization and gene expression. In this study, we examine chromatin structure following differentiation of the human myeloid leukemia cell line (HL-60/S4) into granulocytes with retinoic acid (RA) or into macrophage with phorbol ester (TPA). We performed ChIP-seq of histone H3 and its modifications, analyzing changes in nucleosome occupancy, nucleosome repeat length, eu-/heterochromatin redistribution and properties of epichromatin (surface chromatin adjacent to the nuclear envelope). Nucleosome positions changed genome-wide, exhibiting a specific class of alterations involving nucleosome loss in extended (~1kb) regions, pronounced in enhancers and promoters. Genes that lost nucleosomes at their promoters showed a tendency to be upregulated. On the other hand, nucleosome gain was not systematic at functional elements and did not show simple effects on transcript levels. The average genome-wide nucleosome repeat length (NRL) did not change significantly with differentiation. However, we detected an approximate 10 bp NRL decrease around the hematopoietic transcription factor (TF) PU.1 and the architectural protein CTCF, suggesting an effect on NRL proximal to TF binding sites. Nucleosome occupancy changed in regions associated with H3K4me3 in differentiated cells, compared to untreated HL-60/S4 cells. Epichromatin regions, largely unaffected by cell differentiation, revealed an increased GC content and high nucleosome density compared to surrounding chromatin. Epichromatin showed depletion of major (permissive and repressive) histone modifications and revealed enrichment with PML body-associated genes. In general, chromatin changes during HL-60/S4 differentiation appeared to be more localized, compared to changes among diverse cell types studied elsewhere, suggesting that the cell lineage differentiation of HL-60/S4 cells involves less drastic nucleosome repositioning.
2017-04-27 | GSE90992 | GEO
Project description:A fundamental problem in biology is the molecular basis for divergence among related organisms. We have investigated the level of divergence of transcription factor binding sites for two key factors that regulate developmental processes in the budding yeasts. The genomic binding locations for the Ste12 and Tec1 transcription factors in S. cerevisiae, S. mikatae and S. bayanus were mapped by chromatin immunoprecipitation combined with microarrays (chIP chip)1, 2 and compared to one another. While there was a large core network which was conserved in all three species, there were many instances of binding events whose relative levels differ significantly quantitatively in one species relative to another and as well as species-specific binding events. One interesting class of genes were identified that were bound only in S. mikatae and S. bayanus; many of these genes are targets of Ste12 in haploid strains of S. cerevisiae, suggesting that S. cerevisiae has uniquely acquired the ability to differentially regulate these genes in haploid and diploid cells in these species. To extend these studies, the transcriptional network for the Ste12 homologue (Cph1) in Candida albicans was also mapped and compared to the Saccharomyces species. Again, there were several genes bound by Cph1 which are involved in mating in S. cerevisiae, suggesting that the precise delineation between many mating and pseudohyphal targets by Ste12 may be specific to S. cerevisiae. Overall our results demonstrate that transcription binding sites differ faster than gene content indicating that gene regulation at the level of transcription factor binding is likely to be a major mode of evolutionary divergence between related species. We expect that this divergence is essential for the distinct ecological niches inhabited by these organisms. Keywords: chIP-chip
2007-09-06 | GSE5421 | GEO
Project description:Chromatin replication requires tight coordination of nucleosome assembly machinery with DNA replication machinery. While significant progress has been made in characterizing histone chaperones in this process, the mechanism of whereby nucleosome assembly couples with DNA replication remains largely unknown. Here we show that replication protein A (RPA), a single-stranded DNA (ssDNA) binding protein that is essential for DNA replication provides a binding platform for H3-H4 deposition by histone chaperons and is required for nucleosome formation on nascent chromatin. RPA binds free histone H3-H4 but not nucleosomal histones, and a RPA coated ssDNA stimulates assembly of H3-H4 onto double strand DNA in vitro. RPA mutant with reduced H3-H4 binding exhibits synthetic genetic interaction with mutations at key factors involved in replication-coupled (RC) nucleosome assembly, and are defective in assembly of replicating DNA into nucleosomes in cells. These results reveal a novel function for RPA in nucleosome assembly and a mechanism whereby nucleosome assembly is coordinated with DNA replication.
2017-01-27 | GSE83648 | GEO