Project description:This SuperSeries is composed of the following subset Series: GSE25597: Asf1/HIRA facilitate global histone deacetylation and associate with HP1 to promote nucleosome occupancy at heterochromatic loci (ChIP-chip) GSE25598: Asf1/HIRA facilitate global histone deacetylation and associate with HP1 to promote nucleosome occupancy at heterochromatic loci (expression) GSE25600: Asf1/HIRA facilitate global histone deacetylation and associate with HP1 to promote nucleosome occupancy at heterochromatic loci (MNase) Refer to individual Series
Project description:Asf1/HIRA facilitate global histone deacetylation and associate with HP1 to promote nucleosome occupancy at heterochromatic loci (expression)
Project description:Asf1/HIRA facilitate global histone deacetylation and associate with HP1 to promote nucleosome occupancy at heterochromatic loci (ChIP-chip)
Project description:Histone chaperones and chromatin remodelers control nucleosome dynamics, essential for transcription, replication, and DNA repair. The histone chaperone Anti-Silencing Factor 1 (ASF1) plays a central role in facilitating CAF-1-mediated replication-dependent H3.1 deposition and HIRA-mediated replication-independent H3.3 deposition in yeast and metazoans. Whether ASF1 function is evolutionarily conserved in plants is unknown. Here, we show that Arabidopsis ASF1 proteins display an exclusive preference for the H3.3-depositing HIRA complex. Simultaneous mutation of both Arabidopsis ASF1 genes caused a decrease in chromatin density and ectopic H3.1 occupancy at loci typically enriched with H3.3. Genetic, transcriptomic, and proteomic data indicate that ASF1 proteins strongly prefer the HIRA complex over CAF-1. asf1 mutants also displayed an increase in spurious Pol II transcriptional initiation, and showed defects in the maintenance of gene body CG DNA methylation and in the distribution of histone modifications. Furthermore, ectopic targeting of ASF1 caused excessive histone deposition, less accessible chromatin, and gene silencing. These findings reveal the importance of ASF1-mediated H3.3-H4 deposition via the HIRA pathway for proper epigenetic regulation of the genome.
Project description:Histone chaperones and chromatin remodelers control nucleosome dynamics, which are essential for transcription, replication, and DNA repair. The histone chaperone Anti-Silencing Factor 1 (ASF1) plays a central role in facilitating CAF-1-mediated replication-dependent H3.1 deposition and HIRA-mediated replication-independent H3.3 deposition in yeast and metazoans. Whether ASF1 function is evolutionarily conserved in plants is unknown. Here, we show that Arabidopsis ASF1 proteins display a preference for the HIRA complex. Simultaneous mutation of both Arabidopsis ASF1 genes caused a decrease in chromatin density and ectopic H3.1 occupancy at loci typically enriched with H3.3. Genetic, transcriptomic, and proteomic data indicate that ASF1 proteins strongly prefers the HIRA complex over CAF-1. asf1 mutants also displayed an increase in spurious Pol II transcriptional initiation and showed defects in the maintenance of gene body CG DNA methylation and in the distribution of histone modifications. Furthermore, ectopic targeting of ASF1 caused excessive histone deposition, less accessible chromatin, and gene silencing. These findings reveal the importance of ASF1-mediated histone deposition for proper epigenetic regulation of the genome.
Project description:The evolutionarily conserved HIRA/Hir histone chaperone complex and ASF1/Asf1 co-chaperone cooperate for replication-independent chromatin assembly. Here we report the molecular architecture of the Hir complex with Asf1/H3/H4 via single-particle cryo-EM and crosslinking mass spectrometry.
Project description:We utilized MNase-seq to profile nucleosome positions in wild type (Ax2) and ChdC null cells both in growing cells and a partially developed state (loose-mound) to study changes in nucleosome positioning and occupancy during development and the impact the deletion of ChdC an ATP-dependent chromatin remodeller has on nucleosome positioning and occupancy. As a control for MNase sequence bias we also digested naked DNA with MNase.
Project description:We report nucleosome positions by using native Mnase-seq. The results strongly suggest that nucleosome positions don't change at the heterochromatic locus HMR upon removal of adjacent nucleosomes via deletion of nucleosomal DNA. Positions of nucleosomes at HML are also quantified.
