Nucleosome-depleted chromatin gaps recruit assembly factors for the H3.3 histone variant Journal Article
| Authors: | Schneiderman, J. I.; Orsi, G. A.; Hughes, K. T.; Loppin, B.; Ahmad, K. |
| Article Title: | Nucleosome-depleted chromatin gaps recruit assembly factors for the H3.3 histone variant |
| Abstract: | Most nucleosomes that package eukaryotic DNA are assembled during DNA replication, but chromatin structure is routinely disrupted in active regions of the genome. Replication-independent nucleosome replacement using the H3.3 histone variant efficiently repackages these regions, but how histones are recruited to these sites is unknown. Here, we use an inducible system that produces nucleosome-depleted chromatin at the Hsp70 genes in Drosophila to define steps in the mechanism of nucleosome replacement. We find that the Xnp chromatin remodeler and the Hira histone chaperone independently bind nucleosome-depleted chromatin. Surprisingly, these two factors are only displaced when new nucleosomes are assembled. H3.3 deposition assays reveal that Xnp and Hira are required for efficient nucleosome replacement, and double-mutants are lethal. We propose that Xnp and Hira recognize exposed DNA and serve as a binding platform for the efficient recruitment of H3.3 predeposition complexes to chromatin gaps. These results uncover the mechanisms by which eukaryotic cells actively prevent the exposure of DNA in the nucleus. |
| Keywords: | unclassified drug; gene mutation; nonhuman; protein analysis; cytology; animals; nuclear protein; protein depletion; transcription initiation; drosophila; ovary follicle; chromatin; chromatin immunoprecipitation; histone h3; transcription; heat shock protein 70; protein variant; histones; hsp70 heat-shock proteins; chromatin structure; nucleosome; nucleosomes; chromatin assembly factor 1; nucleosome assembly; hira histone; xnp protein |
| Journal Title: | Proceedings of the National Academy of Sciences of the United States of America |
| Volume: | 109 |
| Issue: | 48 |
| ISSN: | 0027-8424 |
| Publisher: | National Academy of Sciences |
| Date Published: | 2012-11-27 |
| Start Page: | 19721 |
| End Page: | 19726 |
| Language: | English |
| DOI: | 10.1073/pnas.1206629109 |
| PROVIDER: | scopus |
| PMCID: | PMC3511725 |
| PUBMED: | 23150573 |
| DOI/URL: | |
| Notes: | --- - "Export Date: 2 January 2013" - "CODEN: PNASA" - "Source: Scopus" |
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