MNase digestion assays on mutated +1 nucleosomes of yeast
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ABSTRACT:
PROVIDER: PRJEB25388 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:MNase, as a probe to study the sequence-dependent site exposures in the +1 nucleosomes of yeast
| PRJEB25382 | ENA
Project description:MNase, as a probe to study the sequence-dependent site exposures in the +1 nucleosomes of yeast
| PRJEB25383 | ENA
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 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.
2011-01-24 | GSE26412 | GEO
Project description:Micrococcal nuclease (MNase) is commonly used to map nucleosomes genome-wide, but nucleosome maps are affected by the degree of digestion. It has been proposed that many yeast promoters are not nucleosome-free but occupied by easily digested, unstable, “fragile” nucleosomes. We analyzed the histone content of all MNase-sensitive complexes by MNase-ChIP-seq and Sonication-ChIP-seq. We find that yeast promoters are predominantly bound by non-histone protein complexes, with little evidence for fragile nucleosomes. We do detect MNase-sensitive nucleosomes elsewhere in the genome, including transcription termination sites. However, they have high A/T-content, suggesting that MNase sensitivity does not indicate instability, but the preference of MNase for A/T-rich DNA, such that A/T-rich nucleosomes are digested faster than G/C-rich nucleosomes. We confirm our observations by analyzing ChIP-exo, chemical mapping and ATAC-seq data from other laboratories. Thus, histone ChIP-seq experiments are essential to distinguish nucleosomes from other DNA-binding proteins that protect against MNase.
2016-12-15 | GSE83123 | GEO
Project description:Nucleosomes in active chromatin are dynamic, but whether they have distinct structural conformations is unknown. To identify nucleosomes with alternative structures genome-wide, we used H4S47C-anchored cleavage mapping, which revealed that nucleosomes at 5% of budding yeast nucleosome positions have asymmetric histone-DNA interactions. These asymmetric interactions are enriched at nucleosome positions that flank promoters. Micrococcal nuclease (MNase) sequence-based profiles of asymmetric nucleosome positions revealed a corresponding asymmetry in MNase protection near the dyad axis, suggesting that the loss of DNA contacts around H4S47 is accompanied by protection of the DNA from MNase. Chromatin immunoprecipitation mapping of selected nucleosome remodelers indicated that asymmetric nucleosomes are bound by the RSC chromatin remodeling complex, which is required for maintaining nucleosomes at asymmetric positions. These results imply that the asymmetric nucleosome-RSC complex is a metastable intermediate representing partial unwrapping and protection of nucleosomal DNA on one side of the dyad axis during chromatin remodeling.
2014-12-04 | GSE59523 | GEO
Project description:Nucleosomes in active chromatin are dynamic, but whether they have distinct structural conformations is unknown. To identify nucleosomes with alternative structures genome-wide, we used H4S47C-anchored cleavage mapping, which revealed that nucleosomes at 5% of budding yeast nucleosome positions have asymmetric histone-DNA interactions. These asymmetric interactions are enriched at nucleosome positions that flank promoters. Micrococcal nuclease (MNase) sequence-based profiles of asymmetric nucleosome positions revealed a corresponding asymmetry in MNase protection near the dyad axis, suggesting that the loss of DNA contacts around H4S47 is accompanied by protection of the DNA from MNase. Chromatin immunoprecipitation mapping of selected nucleosome remodelers indicated that asymmetric nucleosomes are bound by the RSC chromatin remodeling complex, which is required for maintaining nucleosomes at asymmetric positions. These results imply that the asymmetric nucleosome-RSC complex is a metastable intermediate representing partial unwrapping and protection of nucleosomal DNA on one side of the dyad axis during chromatin remodeling. We have analyzed the chromatin landscape of the yeast genome using paired-end MNase-seq and the chromatin binding of yeast remodelers Swr1, Ino80 and RSC at base-pair resolution using native chromatin immunoprecipitation followed by sequencing (N-ChIP-seq).
2014-12-04 | E-GEOD-59523 | biostudies-arrayexpress
Project description:DNA are packaged into nucleosomes and chromatin. We performed incomplete MNase digestion of chromatin to identify nucleosome-free regions that may indicate active promoters and regulatory regions. Additionally, HpaII digestion was performed which cleaves CCGG sites when the internal C remains unmodified. The hypomethylation state and nuclease sensitivity of the chromatin are indicators of transcription regulatory regions.
2015-02-25 | E-MTAB-1958 | biostudies-arrayexpress
Project description: Not available
| S-EPMC5328195 | biostudies-literature
Project description:In higher eukaryotes, enhancers and promoters share many properties, including binding of transcription factors, existing in open chromatin, and bidirectional transcription. Yet the structural features that distinguish enhancers and promoters are unclear. Genome-wide micrococcal nuclease (MNase) studies previously interpreted MNase hypersensitivity to indicate that active enhancers and promoters are nucleosome-free, yet other studies found histone variants and post-translational modifications at active enhancers. We find that prior MNase genomic studies have an overdigestion bias and that low-level MNase digestion, coupled with mapping core histones, reveals two classes of MNase-hypersensitive sites: at active promoters, which are nucleosome depleted, and at tissue-specific enhancers, which retain core histones and co-bound transcription factors substantially more than promoters. Hypersensitivity of active enhancer nucleosomes may reflect their preferential exposure in chromatin and can be maintained by pioneer transcription factors such as FoxA. These findings unveil fundamental differences in the chromatin structure of active enhancers and promoters.
2016-04-08 | GSE57558 | GEO