Search results for "Histones"
showing 10 items of 200 documents
Bromodomain factor 1 (Bdf1) protein interacts with histones
2001
AbstractUsing a yeast two-hybrid assay we detected an interaction between the N-terminal region of histone H4 (amino acids 1–59) and a fragment of the bromodomain factor 1 protein (Bdf1p) (amino acids 304–571) that includes one of the two bromodomains of this protein. No interaction was observed using fragments of histone H4 sequence smaller than the first 59 amino acids. Recombinant Bdf1p (rBdf1p) demonstrates binding affinity for histones H4 and H3 but not H2A and H2B in vitro. Moreover, rBdf1p is able to bind histones H3 and H4 having different degrees of acetylation. Finally, we have not detected histone acetyltransferase activity associated with Bdf1p.
The yeast histone acetyltransferase A2 complex, but not free Gcn5p, binds stably to nucleosomal arrays.
2000
We have investigated the structural basis for the differential catalytic function of the yeast Gcn5p-containing histone acetyltransferase (HAT) A2 complex and free recombinant yeast Gcn5p (rGcn5p). HAT A2 is shown to be a unique complex that contains Gcn5p, Ada2p, and Ada3p, but not proteins specific to other related HAT A complexes, e.g. ADA, SAGA. Nevertheless, HAT A2 produces the same unique polyacetylation pattern of nucleosomal substrates reported previously for ADA and SAGA, demonstrating that proteins specific to the ADA and SAGA complexes do not influence the enzymatic activity of Gcn5p within the HAT A2 complex. To investigate the role of substrate interactions in the differential …
A short-range gradient of histone H3 acetylation and Tup1p redistribution at the promoter of the Saccharomyces cerevisiae SUC2 gene.
2003
Chromatin immunoprecipitation assays are used to map H3 and H4 acetylation over the promoter nucleosomes and the coding region of the Saccharomyces cerevisiae SUC2 gene, under repressed and derepressed conditions, using wild type and mutant strains. In wild type cells, a high level of H3 acetylation at the distal end of the promoter drops sharply toward the proximal nucleosome that covers the TATA box, a gradient that become even steeper on derepression. In contrast, substantial H4 acetylation shows no such gradient and extends into the coding region. Overall levels of both H3 and H4 acetylation rise on derepression. Mutation of GCN5 or SNF2 lead to substantially reduced SUC2 expression; in…
Unveiling novel interactions of histone chaperone Asf1 linked to TREX-2 factors Sus1 and Thp1
2014
13 páginas, 7 figuras, 2 yablas
Hif1 Is a Component of Yeast Histone Acetyltransferase B, a Complex Mainly Localized in the Nucleus
2004
Hat1 is the catalytic subunit of the only type B histone acetyltransferase known (HAT-B). The enzyme specifically acetylates lysine 12, and to a lesser extent lysine 5, of free, non-chromatin-bound histone H4. The complex is usually isolated with cytosolic fractions and is thought to be involved in chromatin assembly. The Saccharomyces cerevisiae HAT-B complex also contains Hat2, a protein stimulating Hat1 catalytic activity. We have now identified by two-hybrid experiments Hif1 as both a Hat1- and a histone H4-interacting protein. These interactions were dependent on HAT2, indicating a mediating role for Hat2. Biochemical fractionation and co-immunoprecipitation assays demonstrated that Hi…
DNA damage causes TP53-dependent coupling of self-renewal and senescence pathways in embryonal carcinoma cells.
2013
Recent studies have highlighted an apparently paradoxical link between self-renewal and senescence triggered by DNA damage in certain cell types. In addition, the finding that TP53 can suppress senescence has caused a re-evaluation of its functional role in regulating these outcomes. To investigate these phenomena and their relationship to pluripotency and senescence, we examined the response of the TP53-competent embryonal carcinoma (EC) cell line PA-1 to etoposide-induced DNA damage. Nuclear POU5F1/OCT4A and P21CIP1 were upregulated in the same cells following etoposide-induced G 2M arrest. However, while accumulating in the karyosol, the amount of OCT4A was reduced in the chromatin fract…
Regulation of the p19(Arf)/p53 pathway by histone acetylation underlies neural stem cell behavior in senescence-prone SAMP8 mice.
2015
Brain aging is associated with increased neurodegeneration and reduced neurogenesis. B1/neural stem cells (B1-NSCs) of the mouse subependymal zone (SEZ) support the ongoing production of olfactory bulb interneurons, but their neurogenic potential is progressively reduced as mice age. Although age-related changes in B1-NSCs may result from increased expression of tumor suppressor proteins, accumulation of DNA damage, metabolic alterations, and microenvironmental or systemic changes, the ultimate causes remain unclear. Senescence-accelerated-prone mice (SAMP8) relative to senescence-accelerated-resistant mice (SAMR1) exhibit signs of hastened senescence and can be used as a model for the stud…
Expression and intracellular localization of H1° mRNA-containing complexes in developing rat brain and astrocytes
2015
INTRODUCTION: Post-transcriptional regulation of gene expression relies on RNA-binding proteins (RBPs), which regulate intracellular transport, stability, and translation of mRNAs [1]. We previously identified a set of proteins which interact with mRNAs encoding H1° and H3.3 histones [2-5]. All these proteins are probably part of a ribonucleoprotein particle [6]. Here we report more details on the expression and intracellular localization of some of these RBPs, during rat brain development and in isolated rat astrocytes. METHODS: Affinity chromatography was performed as already described [6]. Preparation of total lysates and cellular sub-fractions was done as reported in [3]. Possible co-lo…
Functional antagonism between histone H3K4 demethylases in vivo
2011
Dynamic regulation of histone modifications is critical during development, and aberrant activity of chromatin-modifying enzymes has been associated with diseases such as cancer. Histone demethylases have been shown to play a key role in eukaryotic gene transcription; however, little is known about how their activities are coordinated in vivo to regulate specific biological processes. In Drosophila, two enzymes, dLsd1 (Drosophila ortholog of lysine-specific demethylase 1) and Lid (little imaginal discs), demethylate histone H3 at Lys 4 (H3K4), a residue whose methylation is associated with actively transcribed genes. Our studies show that compound mutation of Lid and dLsd1 results in increa…
The Expanding Constellation of Histone Post-Translational Modifications in the Epigenetic Landscape
2021
The emergence of a nucleosome-based chromatin structure accompanied the evolutionary transition from prokaryotes to eukaryotes. In this scenario, histones became the heart of the complex and precisely timed coordination between chromatin architecture and functions during adaptive responses to environmental influence by means of epigenetic mechanisms. Notably, such an epigenetic machinery involves an overwhelming number of post-translational modifications at multiple residues of core and linker histones. This review aims to comprehensively describe old and recent evidence in this exciting field of research. In particular, histone post-translational modification establishing/removal mechanism…