Genome-wide maps of nucleosome positions in purified quiescent S. cerevisiae cells [MNase-Seq]
Ontology highlight
ABSTRACT:
ORGANISM(S): Saccharomyces cerevisiae
PROVIDER: GSE67148 | GEO | 2015/08/20
SECONDARY ACCESSION(S): PRJNA279129
REPOSITORIES: GEO
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Project description:Map of nucleosome positions on the HIV DNA
| PRJNA580246 | ENA
Project description:HSV is a large double stranded DNA virus, capable of causing a variety of diseases from the common cold sore to devastating encephalitis. Although DNA within the HSV virion does not contain any histone protein, within 1 h of infecting a cell and entering its nucleus the viral genome acquires some histone protein (nucleosomes). During acute infection, partial micrococcal nuclease (MNase) digestion does not give the classic ladder band pattern, seen on digestion of cell DNA or latent viral DNA. However, complete digestion does give a mono-nucleosome band, strongly suggesting that there are some nucleosomes present on the viral genome during the acute infection, but that they are not evenly positioned like cell DNA, with a 200bp repeat pattern. Where then are the nucleosomes positioned? Here we perform HSV-1 genome wide nucleosome mapping, at a time when viral replication is strong (6hr PI), using a microarray consisting of 50mer oligonucleotides, covering the whole viral genome (152kb). Arrays were probed with MNase-protected fragments of DNA from infected cells. Cells were not treated with crosslinking agents, thus we are only mapping tightly bound nucleosomes. The data show that nucleosome deposition is not random. The distribution of signal on the arrays suggest that nucleosomes are located at preferred positions on the genome, and that there are some positions that are not occupied (NFR or NDR), or occupied at a low frequency in the population of genomes. Occupancy of only a fraction of the possible sites may explain the lack of a typical MNase partial digestion band ladder pattern for HSV DNA during acute infection. On average, DNA encoding Immediate Early, Early and Late genes appear to have a similar density of nucleosomes. This distribution of nucleosomes is discussed in relation to genome DNA sequence and gene expression.
2015-06-01 | GSE59108 | GEO
Project description:The distribution of nucleosomes along the genome is a significant aspect of chromatin structure and is thought to influence gene regulation through modulation of DNA accessibility. However, properties of nucleosome organization remain poorly understood, particularly in mammalian genomes where nucleosome positions have not been examined beyond isolated loci and promoter regions. Towards this goal we used tiled microarrays to identify stable nucleosome positions along the HOX gene clusters in human cell lines. We show that nucleosome positions exhibit sequence properties and long-range organization that are different from those characterized in other organisms. Despite overall variability of inter-nucleosome distances, specific loci contain regular nucleosomal arrays with 195bp periodicity. Moreover, such arrays tend to occur preferentially toward the 3’ ends of genes. Through comparison of different cell lines, we find that increased gene expression correlates with increased positioning of nucleosomes, suggesting an unexpected role for transcription in the establishment of well-positioned nucleosomes. Keywords: human chromatin nucleosome positions, nucleosomes, ChIP-chip
2008-02-20 | GSE10042 | GEO
Project description:The eukaryotic nuclear genome is organized into the fundamental units of chromatin, nucleosomes. The positions and biochemical states of nucleosomes on DNA can regulate protein-DNA interactions, and in turn influence DNA-templated events. Despite the increasing number of genome-wide maps of nucleosome position, how global changes in nucleosome position relate to changes in gene expression is poorly understood. Using micrococcal nuclease (MNase) to map nucleosome positions, we show that in the maize genome, nucleosome occupancy signals are remarkably uniform between different tissues, whereas particular genomic regions are highly susceptible to variation. We demonstrate that much of this variation is associated with the degree to which chromatin is digested with MNase. Using high-density DNA microarrays, we exploited this digestion-linked variation to identify protein footprints in the maize genome that are hypersensitive to MNase digestion, a method we term Differential Nuclease-Sensitivity profiling (DNS-chip). Hypersensitive footprints were enriched at the 5’ and 3’ ends of genes, associated with gene-expression levels, and significantly overlapped with conserved noncoding sequences and the binding sites of the homeobox transcription-factor Knotted1, suggesting a functional role in genome regulation. We also found that the tissue-specific regulation of gene expression was linked to tissue-specific hypersensitive footprints in gene promoters. These results demonstrate the value of DNS-chip for revealing biochemical features of nucleosome organization that correlate with gene expression levels and colocalize with functional DNA elements. This approach to chromatin profiling should be broadly applicable to other species and should shed light on how chromatin organization might influence protein-DNA interactions and genome regulation.
2014-08-06 | GSE60090 | GEO
Project description:To map nucleosome positions in WT and delta isw2 cells Keywords: Nucleosomal DNA hybridization
2007-09-10 | GSE8814 | GEO
Project description:The exact positions of nucleosomes along genomic DNA can influence many aspects of chromosome function, yet existing methods for mapping nucleosomes do not provide the necessary single base pair accuracy to determine these positions. Here we develop and apply a new approach for direct mapping of nucleosome centers based on chemical modification of engineered histones. The resulting map locates nucleosome center positions genome-wide in unprecedented detail and accuracy. It reveals novel aspects of the in vivo nucleosome organization that are linked to transcription factor binding, RNA polymerase pausing, and the higher order structure of the chromatin fiber itself.
2012-05-17 | GSE36063 | GEO
Project description:The eukaryotic nuclear genome is organized into the fundamental units of chromatin, nucleosomes. The positions and biochemical states of nucleosomes on DNA can regulate protein-DNA interactions, and in turn influence DNA-templated events. Despite the increasing number of genome-wide maps of nucleosome position, how global changes in nucleosome position relate to changes in gene expression is poorly understood. Using micrococcal nuclease (MNase) to map nucleosome positions, we show that in the maize genome, nucleosome occupancy signals are remarkably uniform between different tissues, whereas particular genomic regions are highly susceptible to variation. We demonstrate that much of this variation is associated with the degree to which chromatin is digested with MNase. Using high-density DNA microarrays, we exploited this digestion-linked variation to identify protein footprints in the maize genome that are hypersensitive to MNase digestion, a method we term Differential Nuclease-Sensitivity profiling (DNS-chip). Hypersensitive footprints were enriched at the 5’ and 3’ ends of genes, associated with gene-expression levels, and significantly overlapped with conserved noncoding sequences and the binding sites of the homeobox transcription-factor Knotted1, suggesting a functional role in genome regulation. We also found that the tissue-specific regulation of gene expression was linked to tissue-specific hypersensitive footprints in gene promoters. These results demonstrate the value of DNS-chip for revealing biochemical features of nucleosome organization that correlate with gene expression levels and colocalize with functional DNA elements. This approach to chromatin profiling should be broadly applicable to other species and should shed light on how chromatin organization might influence protein-DNA interactions and genome regulation.
2014-08-06 | GSE60089 | GEO
Project description:We used MNase-seq to measure nucleosome positions in wild type, tup1 knockouts, and isw2 knockouts.
2022-08-17 | GSE210929 | GEO
Project description:The structural complexity of nucleosomes underlies their functional versatility. Here we report a new type of complexity – nucleosome fragility, manifested as high sensitivity to micrococcal nuclease, in contrast to the common presumption that nucleosomes are similar in resistance to MNase digestion. Using differential MNase digestion of chromatin and high-throughput sequencing, we have identified a special group of nucleosomes termed fragile nucleosomes throughout the yeast genome, nearly one thousand of which are at previously determined “nucleosome free” loci. Nucleosome fragility is broadly implicated in multiple chromatin processes, including transcription, translocation and replication, in correspondence to specific physiological states of cells. In the environmental-stress-response genes, the presence of fragile nucleosomes prior to the occurrence of environmental changes suggests that nucleosome fragility poises genes for swift up-regulation in response to the environmental changes. We propose that nucleosome fragility underscores distinct functional statuses of the chromatin and provides a new dimension for portraying the landscape of genome organization. Comparing nucleosome occupancy under different MNase digestion levels and growth conditions.
2011-01-24 | E-GEOD-26412 | biostudies-arrayexpress
Project description:The exact positions of nucleosomes along genomic DNA can influence many aspects of chromosome function, yet existing methods for mapping nucleosomes do not provide the necessary single base pair accuracy to determine these positions. Here we develop and apply a new approach for direct mapping of nucleosome centers based on chemical modification of engineered histones. The resulting map locates nucleosome center positions genome-wide in unprecedented detail and accuracy. It reveals novel aspects of the in vivo nucleosome organization that are linked to transcription factor binding, RNA polymerase pausing, and the higher order structure of the chromatin fiber itself. 6 samples were analyzed with high throughout parallel sequencing. All samples were created using the same chemical mapping protocol except with varying reaction times. The different reaction times did not make any significant difference in the nucleosome maps so all the data, for the 6 samples, were combined into one data set for the paper and are all considered replicates. The 6 samples are as follows: 1. 20 minute reaction time (single-end sequencing) 2. 20 minute reaction time (single-end sequencing) 3. 1 minute reaction time (single-end sequencing) 4. 1.5 minute reaction time (single-end sequencing) 5. 20 minute reaction time (paired-end sequencing) 6. 1.5 minute reaction time (paired-end sequencing)
2012-05-16 | E-GEOD-36063 | biostudies-arrayexpress