Nucleosomal chromatin in the mature sperm of Drosophila melanogaster.

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However, recent evidence suggests that sperm of many species, including human and mouse retain a small compartment of nucleosomal chromatin, particularly near genes important for embryogenesis. As in mammals, spermiogenesis in the fruit fly, Drosophila melanogaster has also been shown to undergo a programmed substitution of nucleosomes with protamine-like proteins. Using chromatin immunoprecipitation (ChIP) and whole-genome tiling array hybridization (ChIP-chip), supported by immunocytochemical evidence, we show that in a manner analogous to nucleosomal chromatin retention in mammalian spermatozoa, distinct domains packaged by the canonical histones H2A, H2B, H3 and H4 are present in the fly sperm nucleus. We also find evidence for the retention of nucleosomes with specific histone H3 trimethylation marks characteristic of chromatin repression (H3K9me3, H3K27me3) and active transcription (H3K36me3). Raw and processed data from the experiments are available at GEO, accession GSE52165.", "claims": [{"id": "claim-method", "statement": "Spearman correlations for probe intensities.", "kind": "methodological", "target": null, "evidence": [{"asset": "source:pmid:26981400", "locator": "sections[8] \"Data analysis\" paragraph 3", "quote": "Spearman correlations for probe intensities."}], "state": "complete"}, {"id": "claim-data-access", "statement": "Raw and processed data from the experiments are available at GEO, accession GSE52165.", "kind": "methodological", "target": null, "evidence": [{"asset": "source:pmid:26981400", "locator": "sections[0] \"Abstract\" paragraph 2", "quote": "Raw and processed data from the experiments are available at GEO, accession GSE52165."}], "state": "complete"}, {"id": "claim-target-result", "statement": "Using chromatin immunoprecipitation (ChIP) and whole-genome tiling array hybridization (ChIP-chip), supported by immunocytochemical evidence, we show that in a manner analogous to nucleosomal chromatin retention in mammalian spermatozoa, distinct domains packaged by the canonical histones H2A, H2B, H3 and H4 are present in the fly sperm nucleus.", "kind": "qualitative", "target": null, "evidence": [{"asset": "source:pmid:26981400", "locator": "sections[0] \"Abstract\" paragraph 1", "quote": "Using chromatin immunoprecipitation (ChIP) and whole-genome tiling array hybridization (ChIP-chip), supported by immunocytochemical evidence, we show that in a manner analogous to nucleosomal chromatin retention in mammalian spermatozoa, distinct domains packaged by the canonical histones H2A, H2B, H3 and H4 are present in the fly sperm nucleus."}, {"asset": "source:pmid:26981400", "locator": "sections[0] \"Abstract\" paragraph 2", "quote": "Raw and processed data from the experiments are available at GEO, accession GSE52165."}, {"asset": "source:pmid:26981400", "locator": "sections[8] \"Data analysis\" paragraph 2", "quote": "Data were normalized by variance-stabilizing normalization [6] and smoothed by computing the median ratios of ChIP/input signals for probes contained within sliding 800 bp windows."}], "state": "complete"}], "gaps": []}, "experiment": {"state": "complete", "objective": "Using chromatin immunoprecipitation (ChIP) and whole-genome tiling array hybridization (ChIP-chip), supported by immunocytochemical evidence, we show that in a manner analogous to nucleosomal chromatin retention in mammalian spermatozoa, distinct domains packaged by the canonical histones H2A, H2B, H3 and H4 are present in the fly sperm nucleus.", "steps": [{"id": "read_published_estimate", "order": 1, "name": "Read the published estimate from the source", "kind": "other", "state": "complete", "blocked_on": null, "description": "The claim, method and evidence span published with the source article.", "duration_hours": null, "parameters": {}, "inputs": ["source:pmid:26981400"], "outputs": ["the published estimate and its evidence"], "instruments": [], "reagents": []}, {"id": "obtain_source_data", "order": 2, "name": "Obtain the source data from the named repository", "kind": "data-preparation", "state": "complete", "blocked_on": null, "description": "The GEO series accession resolves and its sample accessions are listed. 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