Distinctive patterns of histone H4 acetylation are associated with defined sequence elements within both heterochromatic and euchromatic regions of the human genome
TL;DR: All acetylated histone H4 isoforms were depleted in non-coding, simple repeat DNA in heterochromatin, though the extent of depletion varied with the type of heterochromaatin and with the isoform.
Abstract: The pattern of histone H4 acetylation in different genomic regions has been investigated by immunoprecipitating oligonucleosomes from a human lymphoblastoid cell line with antibodies to H4 acetylated at lysines 5, 8, 12 or 16. DNA from antibody-bound or unbound chromatin was assayed by slot blotting. Pol I and pol II transcribed genes located in euchromatin were shown to have levels of H4 acetylation at lysines 5, 8 and 12 equivalent to those in input chromatin, but to be slightly enriched in H4 acetylated at lysine 16. In no case did the acetylation level correlate with actual or potential transcriptional activity. All acetylated histone H4 isoforms were depleted in non-coding, simple repeat DNA in heterochromatin, though the extent of depletion varied with the type of heterochromatin and with the isoform. Two single copy genes that map within or adjacent to blocks of paracentric heterochromatin are depleted in H4 acetylated at lysines 5, 8 and 12, but not 16. Consensus sequences of repetitive elements of the Alu family (SINES, enriched in R bands) were associated with H4 that was more highly acetylated at all four lysines than input chromatin, while H4 associated with Kpn I elements (LINES, enriched in G bands) was significantly underacetylated.
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TL;DR: A high degree of targeting of DNA hypomethylation to centromeric and juxtacentromeric satellite DNA sequences in cancer is shown and is consistent with satellite DNA HypometHylation contributing to, but not sufficing for, karyotypic instability in cancer and possibly playing other roles in carcinogenesis.
84 citations
TL;DR: Exposure to mutant MeCP2 expression and global histone acetylation levels in clonal cell cultures from a female RTT patient with the mutant R168X allele on the active X chromosome, as well as in cells from a male hemizygous for the frameshift mutation 803delG (V288X) is examined to study the effects of two common truncating RTT mutations.
Abstract: Rett syndrome (RTT) is a mostly sporadic disorder of developmental regression, with loss of speech and purposeful hand use, microcephaly and seizures. It affects 1 in 10 000-15 000 females. RTT is caused by mutations in the MECP2 gene, which is located in Xq28 and subject to X inactivation. MECP2 encodes a methyl-CpG-binding protein that binds to 5-methyl-cytosine in DNA through its methyl-binding domain. Recruitment of a transcriptional silencing complex through MeCP2's transcriptional repression domain results in histone deacetylation and chromatin condensation. To study the effects of two common truncating RTT mutations (R168X and 803delG), we examined mutant MeCP2 expression and global histone acetylation levels in clonal cell cultures from a female RTT patient with the mutant R168X allele on the active X chromosome, as well as in cells from a male hemizygous for the frameshift mutation 803delG (V288X). Both mutant alleles generated stable RNA transcripts, but no intact MeCP2 protein was detected with an antibody against the C-terminal region of MeCP2. Western blots with antibodies against acetylated histones H3 and H4 revealed that H4, but not H3, was hyperacetylated. By using antibodies against individual acetylated lysine residues, the observed H4 hyperacetylation was attributed to increased acetylation of lysine 16. Therefore, expression of endogenous truncating MECP2 alleles, in the absence of wild-type MeCP2 protein, is specifically associated with an increase in the mono-acetylated histone isoform H4K16. This observed effect may result in over-expression of MeCP2 target genes and, thus, play a role in the pathogenesis of RTT.
80 citations
Cites background from "Distinctive patterns of histone H4 ..."
...Repetitive sequences located in constitutive heterochromatin were associated with under-acetylated H4 isoforms, whereas telomeric hexamer repeat sequences showed H4AcK16 levels similar to those in coding regions (37)....
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...Chromatin immunoprecipitation (ChIP) assays with antibodies to acetylated H4, however, did reveal associations of the H4AcK16 isoform with genomic regions or specific genes in human lymphoblasts (37)....
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TL;DR: A region of H4 hyperacetylation extending up to 120 kb upstream from the Xist somatic promoter P1 is identified, which includes the promoter P0, which gives rise to the unstable Xist transcript in undifferentiated cells.
Abstract: We have investigated the role of histone acetylation in X chromosome inactivation, focusing on its possible involvement in the regulation of Xist, an essential gene expressed only from the inactive X (Xi). We have identified a region of H4 hyperacetylation extending up to 120 kb upstream from the Xist somatic promoter P1. This domain includes the promoter P0, which gives rise to the unstable Xist transcript in undifferentiated cells. The hyperacetylated domain was not seen in male cells or in female XT67E1 cells, a mutant cell line heterozygous for a partially deleted Xist allele and in which an increased number of cells fail to undergo X inactivation. The hyperacetylation upstream of Xist was lost by day 7 of differentiation, when X inactivation was essentially complete. Wild-type cells differentiated in the presence of the histone deacetylase inhibitor Trichostatin A were prevented from forming a normally inactivated X, as judged by the frequency of underacetylated X chromosomes detected by immunofluorescence microscopy. Mutant XT67E1 cells, lacking hyperacetylation upstream of Xist, were less affected. We propose that (i) hyperacetylation of chromatin upstream of Xist facilitates the promoter switch that leads to stabilization of the Xist transcript and (ii) that the subsequent deacetylation of this region is essential for the further progression of X inactivation.
75 citations
Cites background or methods from "Distinctive patterns of histone H4 ..."
...A 3- to 5-fold drop in the acetylation of centric heterochromatin occurred on differentiation of both male (not shown) and female cells (Figures 5 and 6), and by day 4 it had reached the low level characteristic of adult cells (O’Neill and Turner, 1995; Johnson et al., 1998)....
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...Levels of H4 acetylation in this region are higher than we have observed previously in genes and chromosome domains from a variety of cell types (O’Neill and Turner, 1995; Johnson et al., 1998)....
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...Chromatin was immunoprecipitated with affinity-purified antibodies to acetylated H4 exactly as described previously (O’Neill and Turner, 1995; Johnson et al., 1998)....
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...Specific DNA sequences were detected by hybridization with 32P-labelled DNA probes and quantified on a PhosphorImager (Molecular Dynamics) as described previously (O’Neill and Turner, 1995; Johnson et al., 1998)....
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TL;DR: In this article, the authors analyzed the pattern of core histone acetylation across 250 kb of the telomeric region of the short arm of human chromosome 16 and found that an erythroid-specific domain of histone H4 was conserved across several species, encompassing not only the α-globin genes but also a neighboring widely expressed gene.
Abstract: We have analyzed the pattern of core histone acetylation across 250 kb of the telomeric region of the short arm of human chromosome 16. This gene-dense region, which includes the α-globin genes and their regulatory elements embedded within widely expressed genes, shows marked differences in histone acetylation between erythroid and non-erythroid cells. In non-erythroid cells, there was a uniform 2- to 3-fold enrichment of acetylated histones, compared with heterochromatin, across the entire region. In erythroid cells, an ≈100-kb segment of chromatin encompassing the α genes and their remote major regulatory element was highly enriched in histone H4 acetylated at Lys-5. Other lysines in the N-terminal tail of histone H4 showed intermediate and variable levels of enrichment. Similar broad segments of erythroid-specific histone acetylation were found in the corresponding syntenic regions containing the mouse and chicken α-globin gene clusters. The borders of these regions of acetylation are located in similar positions in all three species, and a sharply defined 3′ boundary coincides with the previously identified breakpoint in conserved synteny between these species. We have therefore demonstrated that an erythroid-specific domain of acetylation has been conserved across several species, encompassing not only the α-globin genes but also a neighboring widely expressed gene. These results contrast with those at other clusters and demonstrate that not all genes are organized into discrete regulatory domains.
75 citations
TL;DR: It is suggested that the selective marking of nucleosomes flanking the CpG island by hMOF is required to maintain TMS1 gene activity and suggest that the loss of H4K16Ac, mobilization ofucleosomes, and transcriptional down-regulation may be important events in the epigenetic silencing of certain tumor suppressor genes in cancer.
Abstract: Epigenetic silencing of tumor suppressor genes in human cancers is associated with aberrant methylation of promoter region CpG islands and local alterations in histone modifications. However, the mechanisms that drive these events remain unclear. Here, we establish an important role for histone H4 lysine 16 acetylation (H4K16Ac) and the histone acetyltransferase hMOF in the regulation of TMS1/ASC, a proapoptotic gene that undergoes epigenetic silencing in human cancers. In the unmethylated and active state, the TMS1 CpG island is spanned by positioned nucleosomes and marked by histone H3K4 methylation. H4K16Ac was uniquely localized to two sharp peaks that flanked the unmethylated CpG island and corresponded to strongly positioned nucleosomes. Aberrant methylation and silencing of TMS1 was accompanied by loss of the H4K16Ac peaks, loss of nucleosome positioning, hypomethylation of H3K4, and hypermethylation of H3K9. In addition, a single peak of histone H4 lysine 20 trimethylation was observed near the transcription start site. Down-regulation of hMOF or another component of the MSL complex resulted in a gene-specific decrease in H4K16Ac, loss of nucleosome positioning, and silencing of TMS1. Gene silencing induced by H4K16 deacetylation occurred independently of changes in histone methylation and DNA methylation and was reversed on hMOF reexpression. These results indicate that the selective marking of nucleosomes flanking the CpG island by hMOF is required to maintain TMS1 gene activity and suggest that the loss of H4K16Ac, mobilization of nucleosomes, and transcriptional down-regulation may be important events in the epigenetic silencing of certain tumor suppressor genes in cancer.
75 citations
Cites background from "Distinctive patterns of histone H4 ..."
...and euchromatic regions and has been linked to gene activation (30, 33, 41)....
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References
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Book•
15 Jan 2001
TL;DR: Molecular Cloning has served as the foundation of technical expertise in labs worldwide for 30 years as mentioned in this paper and has been so popular, or so influential, that no other manual has been more widely used and influential.
Abstract: Molecular Cloning has served as the foundation of technical expertise in labs worldwide for 30 years. No other manual has been so popular, or so influential. Molecular Cloning, Fourth Edition, by the celebrated founding author Joe Sambrook and new co-author, the distinguished HHMI investigator Michael Green, preserves the highly praised detail and clarity of previous editions and includes specific chapters and protocols commissioned for the book from expert practitioners at Yale, U Mass, Rockefeller University, Texas Tech, Cold Spring Harbor Laboratory, Washington University, and other leading institutions. The theoretical and historical underpinnings of techniques are prominent features of the presentation throughout, information that does much to help trouble-shoot experimental problems. For the fourth edition of this classic work, the content has been entirely recast to include nucleic-acid based methods selected as the most widely used and valuable in molecular and cellular biology laboratories. Core chapters from the third edition have been revised to feature current strategies and approaches to the preparation and cloning of nucleic acids, gene transfer, and expression analysis. They are augmented by 12 new chapters which show how DNA, RNA, and proteins should be prepared, evaluated, and manipulated, and how data generation and analysis can be handled. The new content includes methods for studying interactions between cellular components, such as microarrays, next-generation sequencing technologies, RNA interference, and epigenetic analysis using DNA methylation techniques and chromatin immunoprecipitation. To make sense of the wealth of data produced by these techniques, a bioinformatics chapter describes the use of analytical tools for comparing sequences of genes and proteins and identifying common expression patterns among sets of genes. Building on thirty years of trust, reliability, and authority, the fourth edition of Mol
215,169 citations
01 Jan 1979
TL;DR: The Chromatin Pattern in Situ: Dependence upon Cell Cycle, Preimplantation and Development, and Cellular Aging in Vitro, and Generalized Biological Effects.
Abstract: of Part A.- Section I: What is the Chromatin?.- Properties and Composition of Isolated Chromatin.- Expressed and Nonexpressed Portions of the Genome: Their Separation and Their Characterization.- Discussion.- Section II: Physical, Chemical and Biological Techniques for Studying Nucleosome, Chromatin, Chromosome and Nuclei.- Electron Microscopy: A Tool for Visualizing Chromatin.- Transcriptional Control of Native Chromatin.- Circular Dichroism of DNA, Protein and Chromatin.- Important Hydrodynamic and Spectroscopic Techniques in the Field of Chromatin Structure.- Preparation and Analysis of Core Particles and Nucleosomes: A Conveinient Method For Studying the Protein Composition of Nucleosomes Using Protamine-Release into Triton-Acid-Urea Gels.- The Interaction of Histones with DNA: Equilibrium Binding Studies.- Nucleosome Shape and Structure in Solution from Flow Birefringence.- Scattering and Diffraction by Neutrons and X-rays in the Study of Chromatin.- Nuclear Magnetic Resonance Studies of Nucleic Acids and Proteins.- Techniques for Cytochemical Studies of the Nucleus and its Substructures.- Chromatin Study in Situ: I. Image Analysis.- Chromatin Study in Situ: II. Static and Flow Microfluorimetry.- Chromatin Study in Situ: III. Differential Effects of Feulgen Hydrolysis.- Scanning and Flow Photometry of Chromosomes.- Discussion.- Section III: Various Levels of Chromatin Organization and Mechanisms for Transcriptional Control.- Histones Assembly and Their Structural Role for Nucleosome Core.- Nuclease Digestion and the Structure of Chromatin.- Reconstitution of Nucleosomes.- Conformation of Polynucleosomes in Low Ionic Strength Solution.- Chromatin Structure: Relation of Nucleosomes of DNA Sequences.- Histone Complexes, Nucleosomes, Chromatin and Cell-Cycle Dependent Modification of Histones.- Evidence for Superstructures of Wet Chromatin.- Chromatin Fractionation and the Properties of Transcriptionally Active Regions of Chromatin.- Chromatin Reconstitution and Non-Histone Proteins.- Discussion.- Section IV: Structure-Function of the Genetic Apparatus and Cell Cycle, Aging, Neoplastic Transformation, Differentiation, Chemical Carcinogenesis.- The Structure and Function of Chromatin in Lower Eukaryotes.- Chromatin Structure from Angstrom to Micorn Levels, and Its Relationship to Mammalian Cell Proliferation.- Chromatin Pattern in Situ: Dependence upon Cell Cycle, Preimplantation and Development, and Cellular Aging in Vitro.- Neoplastic Transformation: The Relevance of in Vitro Studies for the Understanding of Tumor Pathenogenesis and Neoplastic Growth.- Cell Differentiation and Malignancy in Leukemia.- Cellular Morphometry in Transformation, Differentiation and Aging.- Basic Mechanisms in Chemical Carcinogenesis.- Carcinogen Induced Alteration in Gene Packing and Its Possible Significance in Carcinogenesis.- Covalent Binding of a Carcinogen to DNA as a Probe of Chromatin Structure.- Carcinogenesis, DNA Repair and Chromatin.- Electromagnetic Induction of Electrochemical Information at Cell Surfaces: Application to Chromatin Structure Modification.- Discussion.- Section V: Review and Summary of the Genetic Apparatus.- Session I: Basic Components of the Genetic Apparatus.- Session II: The Second Level of Organization - Chromatin.- Session III: The Third Level of Organization.- Session IV: Generalized Biological Effects.
1,058 citations
Book•
01 Jan 1987
TL;DR: The induction and enumeration of antibody-forming cells in vitro and the development of human B lymphoblastoid cell lines using epstein are studied.
Abstract: Preparation of lymphocytes and accessory cells Preparation of lymphocyte subpopulations Fractionation of lymphocytes by immunomagnetic beads Immunofluorescence and immunohisto-chemistry The induction and enumeration of antibody-forming cells in vitro In vitro culture of T cell lines and clones Generation of human B lymphoblastoid cell lines using epstein Limiting dilution analysis Lymphocyte proliferation assays Assays for interleukins and other related factors Biochemical characterization of lymphocyte surface antigens
185 citations
TL;DR: Clear localization with oligonucleotides from alphoid (centromeric sequences), simple sequence (satellite) DNAs, a variety of Alu-dispersed repeated sequences, and oligon nucleotides derived from the Tetrahymena and Trypanosoma telomere-specific sequences is obtained.
Abstract: Oligonucleotides were annealed to complementary sequences in fixed human metaphase chromosomes and extended with DNA polymerase. The newly synthesized fragments were labeled by incorporating bio-11-dU
100 citations
Book•
01 Jan 2000
TL;DR: The objective is to establish a protocol for quantification of antigen-specific T-cells HLA -peptide tetrameric complexes and investigate the role of T-cell reprograming in the selection of lymphocytes for HLA typing.
Abstract: Preface Preparation of lymphocytes and idenfication of lymphocyte subpopulations Immunohistochemistry of lymphoid organs T and B-cell hybridomas Murine T-cell culture Human CD4+ T-cell culture Human Cytotoxic T-cell culture Limiting dilution analysis for quantification of antigen-specific T-cells HLA -peptide tetrameric complexes Expansion of human T-cells for immunotheraphy HLA typing Characterisation of lymphocyte surface markers Apoptosis assays for lymphocytes Thymic organ culture Index
29 citations