Project description:Linker histone H1 plays a key role in chromatin organization and maintenance, however, our knowledge of the regulation of H1 functions by its posttranslational modifications (PTMs) is very limited. In this study, we report on the generation of homogeneously and site-specifically mono- and di-acetylated H1 (H1 Ac) using genetic code expansion. We used these modified histones to identify and comprehensively characterize the acetylation-dependent cellular interactome for linker histone H1 and show that site-specific acetylation results in overlapping, but distinct groups of interacting partners. Intriguingly, H1 acetylation-specific interactors comprise translational initiation factors and are involved in transcriptional regulation, suggesting that acetylation of H1 may indeed act as a regulator of the linker histone H1 by modulation of protein-protein interactions.
Project description:There are six histone H1 variant in chicken. 01H1/02H1/03H1/.10H1/H1L and H1R. In those variant we forcused on H1L and H1R those molecule were most similar H1 among six H1 variants. we established linker histone H1L and H1R deleted mutant in chicken B-cell derived DT40 cell and assay gene expression in normal condition in those mutant cells. The detail charactalization of those mutant cell was published in Takami et al., BBRC 268, 501-508 (2000) and Hashimoto et al., DNA repair (in press) Experiment Overall Design: There are six linker histone H1 variant in chicken. Linker histone was thought to be general gene supplesser. We established linker histone H1 variant mutant in chicken B-cell derived DT40 cell, and analyze total protein by 2D-PAGE to find up- or down- regulatd protein. In these mutant, there are some up regulated protein expression and down regulated protein expression (Takami et al., BBRC 268, 501-508 (2000), PubMedID 10679234). Experiment Overall Design: These 2D-PAGE experiment were limited at low density protein region, we use Affymetrix array to search the gene that were regulated specific linker histone H1 variant mutant. Experiment Overall Design: We assayed total gene expression profile in H1L and H1R deleted mutant cells. Experiment Overall Design: all mutant cells were cultured in normal culture condition in RPMI 1640 medium supplemented with 10 µM 2-mercaptoethanol, 10% FCS (Biowest) and 1% chicken serum (Gibco) at 39.5ËC. Total RNA were isolated from exponently growing DT40 cells.
Project description:Indicated cells were subjected to RNAi against linker histone H1, Nautilus (control), or GFP (control). RNA was isolated and subjected to Affymetrix GeneChIP Drosophila Genome 2.0 arrays RNA was compared from cells treated with RNAi against control (Nautilus in the case of salivary glands or GFP in the case of Kc cells) and linker histone H1. Kc cells were treated once with RNAi and RNA was collected 6 days later.
Project description:Decoding the role of histone posttranslational modifications (PTMs) is key to understand the fundamental process of epigenetic regulation. While this process is well studied for core histones and many of their PTMs, this is not the case for linker histone H1 in general and its ubiquitylation in particular due to a lack of proper tools. Here, we report on the generation of site-specifically mono-ubiquitylated H1.2 via click chemistry and identify its ubiquitin-dependent interactome on a proteome-wide scale. We show that the H1 interactome is generally modulated by ubiquitylation and that site-specific ubiquitylation results in overlapping, but distinct interactomes. We further demonstrate that site-specific ubiquitylation of H1 affects the interaction with enzymes relevant for deubiquitylation and deacetylation. We finally show that site-specific ubiquitylation at position K64 impacts H1-dependent chromatosome assembly as well as H1-induced phase separation. In summary, we demonstrate that site-specific ubiquitylation is a general functional regulator for linker histone H1.
Project description:Decoding the role of histone posttranslational modifications (PTMs) is key to understand the fundamental process of epigenetic regulation. While this process is well studied for core histones and many of their PTMs, this is not the case for linker histone H1 in general and its ubiquitylation in particular due to a lack of proper tools. Here, we report on the generation of site-specifically mono-ubiquitylated H1.2 via click chemistry and identify its ubiquitin-dependent interactome on a proteome-wide scale. We show that the H1 interactome is generally modulated by ubiquitylation and that site-specific ubiquitylation results in overlapping, but distinct interactomes. We further demonstrate that site-specific ubiquitylation of H1 affects the interaction with enzymes relevant for deubiquitylation and deacetylation. We finally show that site-specific ubiquitylation at position K64 impacts H1-dependent chromatosome assembly as well as H1-induced phase separation. In summary, we propose that site-specific ubiquitylation plays a general regulatory role for linker histone H1.
Project description:At least six histone H1 variants exist in mammalian somatic cells that bind to the linker DNA and stabilize the nucleosome particle contributing to higher order chromatin compaction. In addition, H1 seems to be involved in the active regulation of gene expression. It is not well known whether the different variants have specific roles, are distributed differentially along the genome, or regulate specific promoters. By taking advantage of specific antibodies to H1 variants and HA-tagged recombinant H1 variants expressed in a breast cancer-derived cell line, we have investigated the distribution of the different somatic H1 variants (H1.2 to H1.5, H1.0 and H1X) in particular promoters and genome-wide. Genome-wide analysis of H1.0, H1.2, H1.4, H1X and H3
Project description:There are six histone H1 variant in chicken. 01H1/02H1/03H1/.10H1/H1L and H1R. In those variant we forcused on H1L and H1R those molecule were most similar H1 among six H1 variants. we established linker histone H1L and H1R deleted mutant in chicken B-cell derived DT40 cell and assay gene expression in normal condition in those mutant cells. The detail charactalization of those mutant cell was published in Takami et al., BBRC 268, 501-508 (2000) and Hashimoto et al., DNA repair (2007) Keywords: gene expression array-based, count
Project description:In flowering plants, heterochromatin is demarcated by the histone variant H2A.W, elevated levels of the linker histone H1, and specific epigenetic modifications, such as high levels of DNA methylation at both CG and non-CG sites. How H2A.W regulates heterochromatin organization and interacts with other heterochromatic features is unclear. Here, we create an h2a.w null mutant via CRISPR-Cas9, h2a.w-2, to analyze the in vivo function of H2A.W. We find that H2A.W antagonizes deposition of H1 at heterochromatin and that non-CG methylation and accessibility are moderately decreased in h2a.w-2 heterochromatin. Compared to H1 loss alone, combined loss of H1 and H2A.W greatly increases accessibility and facilitates non-CG DNA methylation in heterochromatin, suggesting co-regulation of heterochromatic features by H2A.W and H1. Our results suggest that H2A.W helps maintain optimal heterochromatin accessibility and DNA methylation by promoting chromatin compaction together with H1, while also inhibiting excessive H1 incorporation.