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Ray-Gallet D, Almouzni G. The Histone H3 Family and Its Deposition Pathways. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1283:17-42. [PMID: 33155135 DOI: 10.1007/978-981-15-8104-5_2] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Within the cell nucleus, the organization of the eukaryotic DNA into chromatin uses histones as components of its building block, the nucleosome. This chromatin organization contributes to the regulation of all DNA template-based reactions impacting genome function, stability, and plasticity. Histones and their variants endow chromatin with unique properties and show a distinct distribution into the genome that is regulated by dedicated deposition machineries. The histone variants have important roles during early development, cell differentiation, and chromosome segregation. Recent progress has also shed light on how mutations and transcriptional deregulation of these variants participate in tumorigenesis. In this chapter we introduce the organization of the genome in chromatin with a focus on the basic unit, the nucleosome, which contains histones as the major protein component. Then we review our current knowledge on the histone H3 family and its variants-in particular H3.3 and CenH3CENP-A-focusing on their deposition pathways and their dedicated histone chaperones that are key players in histone dynamics.
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Affiliation(s)
- Dominique Ray-Gallet
- Institut Curie, PSL Research University, CNRS UMR3664, Paris, France.,Institut Curie, Sorbonne Université, CNRS UMR3664, Paris, France
| | - Geneviève Almouzni
- Institut Curie, PSL Research University, CNRS UMR3664, Paris, France. .,Institut Curie, Sorbonne Université, CNRS UMR3664, Paris, France.
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The Drosophila DAXX-Like Protein (DLP) Cooperates with ASF1 for H3.3 Deposition and Heterochromatin Formation. Mol Cell Biol 2017; 37:MCB.00597-16. [PMID: 28320872 DOI: 10.1128/mcb.00597-16] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 03/09/2017] [Indexed: 01/22/2023] Open
Abstract
Histone variants are nonallelic isoforms of canonical histones, and they are deposited, in contrast to canonical histones, in a replication-independent (RI) manner. RI deposition of H3.3, a histone variant from the H3.3 family, is mediated in mammals by distinct pathways involving either the histone regulator A (HIRA) complex or the death-associated protein (DAXX)/α-thalassemia X-linked mental retardation protein (ATRX) complex. Here, we investigated the function of the Drosophila DAXX-like protein (DLP) by using both fly genetic approaches and protein biochemistry. DLP specifically interacts with H3.3 and shows a prominent localization on the base of the X chromosome, where it appears to act in concert with XNP, the Drosophila homolog of ATRX, in heterochromatin assembly and maintenance. The functional association between DLP and XNP is further supported by a series of experiments that illustrate genetic interactions and the DLP-XNP-dependent localization of specific chromosomal proteins. In addition, DLP both participates in the RI deposition of H3.3 and associates with anti-silencing factor 1 (ASF1). We suggest, in agreement with a recently proposed model, that DLP and ASF1 are part of a predeposition complex, which is recruited by XNP and is necessary to prevent DNA exposure in the nucleus.
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Poplineau M, Trussardi-Régnier A, Happillon T, Dufer J, Manfait M, Bernard P, Piot O, Antonicelli F. Raman microspectroscopy detects epigenetic modifications in living Jurkat leukemic cells. Epigenomics 2012; 3:785-94. [PMID: 22126296 DOI: 10.2217/epi.11.102] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIMS Classical biochemical and molecular methods for discerning cells with epigenetic modifications are often biologically perturbing or even destructive. We wondered whether the noninvasive laser tweezer Raman spectroscopy technique allowed the discrimination of single living human cells undergoing epigenetic modifications. MATERIALS & METHODS Human Jurkat leukemic cells were treated with inhibitors of histone deacetylases (trichostatin A and MS-275). Epigenetic changes were monitored through histone electrophoresis, nuclear image cytometry and laser tweezer Raman spectroscopy. RESULTS Treatment of Jurkat cells with histone deacetylase inhibitors increased histone acetylation and induced chromatin organization changes. Characteristic vibrations, issued from laser tweezer Raman spectroscopy analyses, mostly assigned to DNA and proteins allowed discerning histone deacetylase inhibitor-treated cells from control with high confidence. Statistical processing of laser tweezer Raman spectroscopy data led to the definition of specific biomolecular fingerprints of each cell group. CONCLUSION This original study shows that laser tweezer Raman spectroscopy is a label-free rapid tool to identify living cells that underwent epigenetic changes.
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Affiliation(s)
- Mathilde Poplineau
- Unité MEDyC, UMR URCA CNRS 6237, IFR53, Faculté de Pharmacie, Université de Reims, Reims, France
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Oct4 kinetics predict cell lineage patterning in the early mammalian embryo. Nat Cell Biol 2011; 13:117-23. [PMID: 21258368 DOI: 10.1038/ncb2154] [Citation(s) in RCA: 177] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Accepted: 11/07/2010] [Indexed: 12/13/2022]
Abstract
Transcription factors are central to sustaining pluripotency, yet little is known about transcription factor dynamics in defining pluripotency in the early mammalian embryo. Here, we establish a fluorescence decay after photoactivation (FDAP) assay to quantitatively study the kinetic behaviour of Oct4, a key transcription factor controlling pre-implantation development in the mouse embryo. FDAP measurements reveal that each cell in a developing embryo shows one of two distinct Oct4 kinetics, before there are any morphologically distinguishable differences or outward signs of lineage patterning. The differences revealed by FDAP are due to differences in the accessibility of Oct4 to its DNA binding sites in the nucleus. Lineage tracing of the cells in the two distinct sub-populations demonstrates that the Oct4 kinetics predict lineages of the early embryo. Cells with slower Oct4 kinetics are more likely to give rise to the pluripotent cell lineage that contributes to the inner cell mass. Those with faster Oct4 kinetics contribute mostly to the extra-embryonic lineage. Our findings identify Oct4 kinetics, rather than differences in total transcription factor expression levels, as a predictive measure of developmental cell lineage patterning in the early mouse embryo.
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Emelyanov AV, Konev AY, Vershilova E, Fyodorov DV. Protein complex of Drosophila ATRX/XNP and HP1a is required for the formation of pericentric beta-heterochromatin in vivo. J Biol Chem 2010; 285:15027-15037. [PMID: 20154359 DOI: 10.1074/jbc.m109.064790] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
ATRX belongs to the family of SWI2/SNF2-like ATP-dependent nucleosome remodeling molecular motor proteins. Mutations of the human ATRX gene result in a severe genetic disorder termed X-linked alpha-thalassemia mental retardation (ATR-X) syndrome. Here we perform biochemical and genetic analyses of the Drosophila melanogaster ortholog of ATRX. The loss of function allele of the Drosophila ATRX/XNP gene is semilethal. Drosophila ATRX is expressed throughout development in two isoforms, p185 and p125. ATRX185 and ATRX125 form distinct multisubunit complexes in fly embryo. The ATRX185 complex comprises p185 and heterochromatin protein HP1a. Consistently, ATRX185 but not ATRX125 is highly concentrated in pericentric beta-heterochromatin of the X chromosome in larval cells. HP1a strongly stimulates biochemical activities of ATRX185 in vitro. Conversely, ATRX185 is required for HP1a deposition in pericentric beta-heterochromatin of the X chromosome. The loss of function allele of the ATRX/XNP gene and mutant allele that does not express p185 are strong suppressors of position effect variegation. These results provide evidence for essential biological functions of Drosophila ATRX in vivo and establish ATRX as a major determinant of pericentric beta-heterochromatin identity.
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Affiliation(s)
- Alexander V Emelyanov
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Alexander Y Konev
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Elena Vershilova
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Dmitry V Fyodorov
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461.
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6
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Ohniwa RL, Morikawa K, Kim J, Kobori T, Hizume K, Matsumi R, Atomi H, Imanaka T, Ohta T, Wada C, Yoshimura SH, Takeyasu K. Atomic force microscopy dissects the hierarchy of genome architectures in eukaryote, prokaryote, and chloroplast. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2007; 13:3-12. [PMID: 17234031 DOI: 10.1017/s1431927607070055] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2006] [Accepted: 09/18/2006] [Indexed: 05/13/2023]
Abstract
Because of its applicability to biological specimens (nonconductors), a single-molecule-imaging technique, atomic force microscopy (AFM), has been particularly powerful for visualizing and analyzing complex biological processes. Comparative analyses based on AFM observation revealed that the bacterial nucleoids and human chromatin were constituted by a detergent/salt-resistant 30-40-nm fiber that turned into thicker fibers with beads of 70-80 nm diameter. AFM observations of the 14-kbp plasmid and 110-kbp F plasmid purified from Escherichia coli demonstrated that the 70-80-nm fiber did not contain a eukaryotic nucleosome-like "beads-on-a-string" structure. Chloroplast nucleoid (that lacks bacterial-type nucleoid proteins and eukaryotic histones) also exhibited the 70-80-nm structural units. Interestingly, naked DNA appeared when the nucleoids from E. coli and chloroplast were treated with RNase, whereas only 30-nm chromatin fiber was released from the human nucleus with the same treatment. These observations suggest that the 30-40-nm nucleoid fiber is formed with a help of nucleoid proteins and RNA in E. coli and chroloplast, and that the eukaryotic 30-nm chromatin fiber is formed without RNA. On the other hand, the 70-80-nm beaded structures in both E. coli and human are dependent on RNA.
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Affiliation(s)
- R L Ohniwa
- Kyoto University Graduate School of Biostudies, Sakyo-ku, Kyoto 606-8502, Japan
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Morikawa K, Ohniwa RL, Kim J, Maruyama A, Ohta T, Takeyasu K. Bacterial nucleoid dynamics: oxidative stress response in Staphylococcus aureus. Genes Cells 2006; 11:409-23. [PMID: 16611244 DOI: 10.1111/j.1365-2443.2006.00949.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A single-molecule-imaging technique, atomic force microscopy (AFM) was applied to the analyses of the genome architecture of Staphylococcus aureus. The staphylococcal cells on a cover glass were subjected to a mild lysis procedure that had maintained the fundamental structural units in Escherichia coli. The nucleoids were found to consist of fibrous structures with diameters of 80 and 40 nm. This feature was shared with the E. coli nucleoid. However, whereas the E. coli nucleoid dynamically changed its structure to a highly compacted one towards the stationary phase, the S. aureus nucleoid never underwent such a tight compaction under a normal growth condition. Bioinformatic analysis suggested that this was attributable to the lack of IHF that regulate the expression of a nucleoid protein, Dps, required for nucleoid compaction in E. coli. On the other hand, under oxidative conditions, MrgA (a staphylococcal Dps homolog) was over-expressed and a drastic compaction of the nucleoid was detected. A knock-out mutant of the gene encoding the transcription factor (perR) constitutively expressed mrgA, and its nucleoid was compacted without the oxidative stresses. The regulatory mechanisms of Dps/MrgA expression and their biological significance were postulated in relation to the nucleoid compaction.
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Affiliation(s)
- Kazuya Morikawa
- Institute of Basic Medical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennoh-dai, Tsukuba 305-8575, Japan.
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Affiliation(s)
- Dirk Schübeler
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland.
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Tanaka Y, Tawaramoto-Sasanuma M, Kawaguchi S, Ohta T, Yoda K, Kurumizaka H, Yokoyama S. Expression and purification of recombinant human histones. Methods 2005; 33:3-11. [PMID: 15039081 DOI: 10.1016/j.ymeth.2003.10.024] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/30/2003] [Indexed: 11/25/2022] Open
Abstract
Nucleosomes reconstituted from bacterially expressed histones are useful for functional and structural analyses of histone variants, histone mutants, and histone post-translational modifications. In the present study, we developed a new method for the expression and purification of recombinant human histones. The human histone H2A, H2B, and H3 genes were expressed well in Escherichia coli cells, but the human histone H4 gene was poorly expressed. Therefore, we designed a new histone H4 gene with codons optimized for the E. coli expression system and constructed the H4 gene by chemically synthesized oligodeoxyribonucleotides. The recombinant human histones were expressed as hexahistidine-tagged proteins and were purified by one-step chromatography with nickel-nitrilotriacetic acid agarose in the presence of 6 M urea. The H2A/H2B dimer and the H3/H4 tetramer were refolded by dialysis against buffer without urea, and the hexahistidine-tags of the histones in the H2A/H2B dimer and the H3/H4 tetramer were removed by thrombin protease digestion. The H2A/H2B dimer and the H3/H4 tetramer obtained by this method were confirmed to be proficient in nucleosome formation by the salt dialysis method. The human CENP-A gene, the centromere-specific histone H3 variant, contains 28 minor codons for E. coli. A new CENP-A gene optimized for the E. coli expression system was also constructed, and we found that the purified recombinant CENP-A protein formed a nucleosome-like structure with histones H2A, H2B, and H4.
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Affiliation(s)
- Yoshinori Tanaka
- RIKEN Genomic Sciences Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
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Takeyasu K, Kim J, Ohniwa RL, Kobori T, Inose Y, Morikawa K, Ohta T, Ishihama A, Yoshimura SH. Genome architecture studied by nanoscale imaging: analyses among bacterial phyla and their implication to eukaryotic genome folding. Cytogenet Genome Res 2005; 107:38-48. [PMID: 15305055 DOI: 10.1159/000079570] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2004] [Accepted: 05/28/2004] [Indexed: 11/19/2022] Open
Abstract
The proper function of the genome largely depends on the higher order architecture of the chromosome. Our previous application of nanotechnology to the questions regarding the structural basis for such macromolecular dynamics has shown that the higher order architecture of the Escherichia coli genome (nucleoid) is achieved via several steps of DNA folding (Kim et al., 2004). In this study, the hierarchy of genome organization was compared among E. coli, Staphylococcus aureus and Clostridium perfringens. A one-molecule-imaging technique, atomic force microscopy (AFM), was applied to the E. coli cells on a cover glass that were successively treated with a detergent, and demonstrated that the nucleoids consist of a fundamental fibrous structure with a diameter of 80 nm that was further dissected into a 40-nm fiber. An application of this on-substrate procedure to the S. aureus and the C. perfringens nucleoids revealed that they also possessed the 40- and 80-nm fibers that were sustainable in the mild detergent solution. The E. coli nucleoid dynamically changed its structure during cell growth; the 80-nm fibers releasable from the cell could be transformed into a tightly packed state depending upon the expression of Dps. However, the S. aureus and the C. perfringens nucleoids never underwent such tight compaction when they reached stationary phase. Bioinformatic analysis suggested that this was possibly due to the lack of a nucleoid protein, Dps, in both species. AFM analysis revealed that both the mitotic chromosome and the interphase chromatin of human cells were also composed of 80-nm fibers. Taking all together, we propose a structural model of the bacterial nucleoid in which a fundamental mechanism of chromosome packing is common in both prokaryotes and eukaryotes.
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Affiliation(s)
- K Takeyasu
- Laboratory of Plasma Membrane and Nuclear Signaling, Kyoto University Graduate School of Biostudies, Kyoto, Japan.
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Abstract
Histones are best known as the architectural proteins that package the DNA of eukaryotic organisms, forming octameric nucleosome cores that the double helix wraps tightly around. Although histones have traditionally been viewed as slowly evolving scaffold proteins that lack diversification beyond their abundant tail modifications, recent studies have revealed that variant histones have evolved for diverse functions. H2A and H3 variants have diversified to assume roles in epigenetic silencing, gene expression and centromere function. Such diversification of histone variants and 'deviants' contradicts the perception of histones as monotonous members of multigene families that indiscriminately package and compact the genome. How these diverse functions have evolved from ancestral forms can be addressed by applying phylogenetic tools to increasingly abundant sequence data.
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Affiliation(s)
- Harmit S Malik
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
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12
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Attema JL, Reeves R, Murray V, Levichkin I, Temple MD, Tremethick DJ, Shannon MF. The human IL-2 gene promoter can assemble a positioned nucleosome that becomes remodeled upon T cell activation. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 169:2466-76. [PMID: 12193716 DOI: 10.4049/jimmunol.169.5.2466] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Controlled production of the cytokine IL-2 plays a key role in the mammalian immune system. Expression from the gene is tightly regulated with no detectable expression in resting T cells and a strong induction following T cell activation. The IL-2 proximal promoter (+1 to -300) contains many well-defined transcriptional activation elements that respond to T cell stimulation. To determine the role of chromatin structure in the regulation of interleukin-2 gene transcription, nucleosome assembly across the IL-2 promoter region was examined using in vitro chromatin reconstitution assays. The IL-2 promoter assembles a nucleosome that is both translationally and rotationally positioned, spanning some of the major functional control elements. The binding of transcription factors to these elements, with the exception of the architectural protein HMGA1, was occluded by the presence of the nucleosome. Analysis of the chromatin architecture of the IL-2 gene in Jurkat T cells provided evidence for the presence of a similarly positioned nucleosome in vivo. The region encompassed by this nucleosome becomes remodeled following activation of Jurkat T cells. These observations suggest that the presence of a positioned nucleosome across the IL-2 proximal promoter may play an important role in maintaining an inactive gene in resting T cells and that remodeling of this nucleosome is important for gene activation.
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Affiliation(s)
- Joanne L Attema
- Division of Molecular Bioscience, John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital Territory, Australia
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13
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Abstract
Over the past few years we have seen enormous progress in uncovering the critical roles that chromatin structure has on the control of gene expression, the regulation of developmental processes, and the control of cell cycle checkpoints. No longer is chromatin research the "last bastion of scoundrels." The recent intensity of chromatin research, however, might lead a young scientist to conclude that the field is saturated or that all the big mysteries have been solved. This view could not be further from the truth! Here I briefly outline four areas of chromatin research where new paradigms and mysteries are still waiting to be discovered.Key words: chromatin, DNA repair, SWI/SNF.
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Alvelo-Ceron D, Niu L, Collart DG. Growth regulation of human variant histone genes and acetylation of the encoded proteins. Mol Biol Rep 2000; 27:61-71. [PMID: 11092552 DOI: 10.1023/a:1007156629024] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The family of human histone genes consists of replication-dependent and independent subtypes. The replication-independent histone genes, also known as variants, give rise to distinct mRNAs, whose expression is regulated depending on the growth state of the cell, tissue type and developmental stage. In turn, the histone variants are differentially synthesized and modified by acetylation. Consequently, chromatin structure is altered resulting in complex changes in gene expression. The high conservation among histone protein subtypes suggests that they are indispensable. In addition, conservation of the positions of acetylation within subtypes suggests that the location of these sites is functionally important for the eukaryotic cell. For example, the structures of transcriptionally active and repressed chromatin are different depending on the acetylation state of histone proteins [1-3]. In addition, transcriptionally active and repressed chromatin contains distinct histone variants [4]. Specialized histone variants are targeted to the centromere of the chromosome, where they are essential for chromosome segregation [5]. Other specialized histones exist that are essential for development [6]. Changes in histone acetylation have been implicated in the down-regulation of a tumour suppressor gene in human breast cancer [7]. Acetylation also plays an important role in X chromosome inactivation as well as hormone-mediated transcriptional regulation [8, 9]. We propose here a novel model for histone variant gene regulation at the post-transcriptional level, which provides the groundwork to define the pathways regulating the synthesis of these variants.
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Affiliation(s)
- D Alvelo-Ceron
- Department of Biological Sciences, Clark Atlanta University, GA 30314, USA
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15
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Affiliation(s)
- F D Bushman
- Infectious Disease Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037, USA
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16
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Hansen MS, Carteau S, Hoffmann C, Li L, Bushman F. Retroviral cDNA integration: mechanism, applications and inhibition. GENETIC ENGINEERING 1998; 20:41-61. [PMID: 9666555 DOI: 10.1007/978-1-4899-1739-3_3] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- M S Hansen
- Infectious Disease Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
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Carteau S, Hoffmann C, Bushman F. Chromosome structure and human immunodeficiency virus type 1 cDNA integration: centromeric alphoid repeats are a disfavored target. J Virol 1998; 72:4005-14. [PMID: 9557688 PMCID: PMC109628 DOI: 10.1128/jvi.72.5.4005-4014.1998] [Citation(s) in RCA: 119] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Integration of retroviral cDNA into host chromosomal DNA is an essential and distinctive step in viral replication. Despite considerable study, the host determinants of sites for integration have not been fully clarified. To investigate integration site selection in vivo, we used two approaches. (i) We have analyzed the host sequences flanking 61 human immunodeficiency virus type 1 (HIV-1) integration sites made by experimental infection and compared them to a library of 104 control sequences. (ii) We have also analyzed HIV-1 integration frequencies near several human repeated-sequence DNA families, using a repeat-specific PCR-based assay. At odds with previous reports from smaller-scale studies, we found no strong biases either for or against integration near repetitive sequences such as Alu or LINE-1 elements. We also did not find a clear bias for integration in transcription units as proposed previously, although transcription units were found somewhat more frequently near integration sites than near controls. However, we did find that centromeric alphoid repeats were selectively absent at integration sites. The repeat-specific PCR-based assay also indicated that alphoid repeats were disfavored for integration in vivo but not as naked DNA in vitro. Evidently the distinctive DNA organization at centromeres disfavors cDNA integration. We also found a weak consensus sequence for host DNA at integration sites, and assays of integration in vitro indicated that this sequence is favored as naked DNA, revealing in addition an influence of target primary sequence.
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Affiliation(s)
- S Carteau
- Infectious Disease Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
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Payen E, Verkerk T, Michalovich D, Dreyer SD, Winterpacht A, Lee B, De Zeeuw CI, Grosveld F, Galjart N. The centromeric/nucleolar chromatin protein ZFP-37 may function to specify neuronal nuclear domains. J Biol Chem 1998; 273:9099-109. [PMID: 9535899 DOI: 10.1074/jbc.273.15.9099] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Murine ZFP-37 is a member of the large family of C2H2 type zinc finger proteins. It is characterized by a truncated NH2-terminal Krüppel-associated box and is thought to play a role in transcriptional regulation. During development Zfp-37 mRNA is most abundant in the developing central nervous system, and in the adult mouse expression is restricted largely to testis and brain. Here we show that at the protein level ZFP-37 is detected readily in neurons of the adult central nervous system but hardly in testis. In brain ZFP-37 is associated with nucleoli and appears to contact heterochromatin. Mouse and human ZFP-37 have a basic histone H1-like linker domain, located between KRAB and zinc finger regions, which binds double-stranded DNA. Thus we suggest that ZFP-37 is a structural protein of the neuronal nucleus which plays a role in the maintenance of specialized chromatin domains.
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Affiliation(s)
- E Payen
- Department of Cell Biology and Genetics, Erasmus University, P. O. Box 1738, 3000 DR Rotterdam, The Netherlands
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