Search results for "histone code"
showing 10 items of 41 documents
Chromatin Domains and Regulation of Transcription
2007
Compartmentalization and compaction of DNA in the nucleus is the characteristic feature of eukaryotic cells. A fully extended DNA molecule has to be compacted 100,000 times to fit within the nucleus. At the same time it is critical that various DNA regions remain accessible for interaction with regulatory factors and transcription/replication factories. This puzzle is solved at the level of DNA packaging in chromatin that occurs in several steps: rolling of DNA onto nucleosomes, compaction of nucleosome fiber with formation of the so-called 30 nm fiber, and folding of the latter into the giant (50-200 kbp) loops, fixed onto the protein skeleton, the nuclear matrix. The general assumption is…
Subcellular localization and nucleosome specificity of yeast histone acetyltransferases
1991
We have previously reported [López-Rodas et al. (1989) J. Biol. Chem. 264, 19028-19033] that the yeast Saccharomyces cerevisiae contains four histone acetyltransferases, which can be resolved by ion-exchange chromatography, and their specificity toward yeast free histones was studied. In the present contribution we show that three of the enzymes are nuclear, type A histone acetyltransferases and they are able to acetylate nucleosome-bound histones. They differ in their histone specificity. Enzyme A1 acetylates H2A in chicken nucleosomes, although it is specific for yeast free H2B; histone acetyltransferase A2 is highly specific for H3, and histone acetyltransferase A3 preparations acetylate…
Histone carbonylation occurs in proliferating cells
2012
12 páginas, 10 figuras (que no es encuentran en este documento, se pueden ver en: http://www.sciencedirect.com/science/article/pii/S0891584912000664)
Constitutive Promoter Occupancy by the MBF-1 Activator and Chromatin Modification of the Developmental Regulated Sea Urchin α-H2A Histone Gene
2007
The tandemly repeated sea urchin alpha-histone genes are developmentally regulated. These genes are transcribed up to the early blastula stage and permanently silenced as the embryos approach gastrulation. As previously described, expression of the alpha-H2A gene depends on the binding of the MBF-1 activator to the 5' enhancer, while down-regulation relies on the functional interaction between the 3' sns 5 insulator and the GA repeats located upstream of the enhancer. As persistent MBF-1 binding and enhancer activity are detected in gastrula embryos, we have studied the molecular mechanisms that prevent the bound MBF-1 from trans-activating the H2A promoter at this stage of development. Her…
Interaction between N-terminal domain of H4 and DNA is regulated by the acetylation degree.
1998
Abstract To study whether the acetylation of one or more of the four acetylatable lysines of histone H4 affects its binding to DNA, we have designed a protection experiment with a model system consisting in phage lambda DNA as substrate, Stu I as restriction endonuclease and histone H4 with different degrees of acetylation as the protective agent. It can be deduced from the experimental data that the protection afforded by the histone is not dependent on the number of positive charges lost by acetylation. Thus, non-acetylated H4 and mono-acetylated H4 cause similar protection, while di-acetylation of the histone seems to be the crucial step in significantly weakening the interaction between…
Gcn5p is involved in the acetylation of histone H3 in nucleosomes.
1997
Abstract Enzymatic extracts from a gcn5 mutant and wild-type strains of Saccharomyces cerevisiae were chromatographically fractionated and the histone acetyltransferase activities compared. When free histones were used as substrate, extracts from wild-type cells showed two peaks of activity on histone H3 but extracts from gcn5 mutant cells showed only one. With nucleosomes as substrate, the histone acetyltransferase activities present in extracts from the gcn5 mutant strain were not able to modify H3 whereas wild-type cell extracts acetylated intensely this histone. The activity that acetylated nucleosome-bound H3 behaved as a 170-kDa complex. We suggest that Gcn5p represents a catalytic su…
Promoter-Targeted Histone Acetylation of Chromatinized Parvoviral Genome Is Essential for the Progress of Infection
2015
ABSTRACT The association of host histones with parvoviral DNA is poorly understood. We analyzed the chromatinization and histone acetylation of canine parvovirus DNA during infection by confocal imaging and in situ proximity ligation assay combined with chromatin immunoprecipitation and high-throughput sequencing. We found that during late infection, parvovirus replication bodies were rich in histones bearing modifications characteristic of transcriptionally active chromatin, i.e., histone H3 lysine 27 acetylation (H3K27ac). H3K27ac, in particular, was located in close proximity to the viral DNA-binding protein NS1. Importantly, our results show for the first time that in the chromatinized …
Epigenetic modifiers are necessary but not sufficient for reprogramming non-myelinating cells into myelin gene-expressing cells.
2010
Background Modifications on specific histone residues and DNA methylation play an essential role in lineage choice and cellular reprogramming. We have previously shown that histone modifications or combinatorial codes of transcription factors (TFs) are critical for the differentiation of multipotential progenitors into myelinating oligodendrocytes. In this study we asked whether combining global manipulation of DNA methylation and histone acetylation together with the expression of oligodendrocyte- specific TFs, was sufficient to switch the identity of fibroblasts into myelin gene-expressing cells. Methodology/Principal Findings Transfection of six oligodendrocyte-specific TFs (Olig1, Olig2…
The Sas3p and Gcn5p histone acetyltransferases are recruited to similar genes.
2006
A macroarray platform was used to identify binding sites of yeast histone acetyltransferase catalytic subunits and to correlate their positions with acetylation of lysine 14 of histone H3, revealing that Sas3p and Gcn5p are recruited to similar sets of intensely transcribed genes.
Characterization of the NAD-Dependent Human Histone Deacetylases Gene Sirtuin 1 and Its Implications on Aging and the Development of Malignant Diseas…
2006
Abstract A dysregulation of the tightly controlled equilibrium of acetylation and deacetylation plays a causative role in the generation as well as in the suppression of cancer. Histone acetylation modifiers are therefore gaining increasing attention as potential targets in the treatment of cancer. Sirtuin 1 (SIRT1) is a nicotinamide adenine dinucleotide (NAD+)-dependent deacetylase, which belongs to the silent information regulator 2 (Sir2) family of sirtuin histone deacetylases (HDACs). The yeast Sir2 protein and its mammalian derivatives play a central role in epigenetic gene silencing, DNA repair and recombination, cell-cycle, microtubule organization, and in the regulation of aging. We…