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Climent-Cantó P, Carbonell A, Tamirisa S, Henn L, Pérez-Montero S, Boros IM, Azorín F. The tumour suppressor brain tumour (Brat) regulates linker histone dBigH1 expression in the Drosophila female germline and the early embryo. Open Biol 2021; 11:200408. [PMID: 33947246 PMCID: PMC8097206 DOI: 10.1098/rsob.200408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Linker histones H1 are essential chromatin components that exist as multiple developmentally regulated variants. In metazoans, specific H1s are expressed during germline development in a tightly regulated manner. However, the mechanisms governing their stage-dependent expression are poorly understood. Here, we address this question in Drosophila, which encodes for a single germline-specific dBigH1 linker histone. We show that during female germline lineage differentiation, dBigH1 is expressed in germ stem cells and cystoblasts, becomes silenced during transit-amplifying (TA) cystocytes divisions to resume expression after proliferation stops and differentiation starts, when it progressively accumulates in the oocyte. We find that dBigH1 silencing during TA divisions is post-transcriptional and depends on the tumour suppressor Brain tumour (Brat), an essential RNA-binding protein that regulates mRNA translation and stability. Like other oocyte-specific variants, dBigH1 is maternally expressed during early embryogenesis until it is replaced by somatic dH1 at the maternal-to-zygotic transition (MZT). Brat also mediates dBigH1 silencing at MZT. Finally, we discuss the situation in testes, where Brat is not expressed, but dBigH1 is translationally silenced too.
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Affiliation(s)
- Paula Climent-Cantó
- Institute of Molecular Biology of Barcelona, CSIC, Barcelona 08028, Spain.,Institute for Research in Biomedicine, IRB Barcelona, The Barcelona Institute for Science and Technology, Barcelona 08028, Spain
| | - Albert Carbonell
- Institute of Molecular Biology of Barcelona, CSIC, Barcelona 08028, Spain.,Institute for Research in Biomedicine, IRB Barcelona, The Barcelona Institute for Science and Technology, Barcelona 08028, Spain
| | - Srividya Tamirisa
- Institute of Molecular Biology of Barcelona, CSIC, Barcelona 08028, Spain.,Institute for Research in Biomedicine, IRB Barcelona, The Barcelona Institute for Science and Technology, Barcelona 08028, Spain
| | - Laszlo Henn
- Institute of Biochemistry, Biological Research Centre of Szeged, Szeged 6726, Hungary
| | - Salvador Pérez-Montero
- Institute of Molecular Biology of Barcelona, CSIC, Barcelona 08028, Spain.,Institute for Research in Biomedicine, IRB Barcelona, The Barcelona Institute for Science and Technology, Barcelona 08028, Spain
| | - Imre M Boros
- Institute of Biochemistry, Biological Research Centre of Szeged, Szeged 6726, Hungary.,Department of Biochemistry and Molecular Biology, Faculty of Science and Informatics, University of Szeged, Szeged 6726, Hungary
| | - Fernando Azorín
- Institute of Molecular Biology of Barcelona, CSIC, Barcelona 08028, Spain.,Institute for Research in Biomedicine, IRB Barcelona, The Barcelona Institute for Science and Technology, Barcelona 08028, Spain
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Pérez-Montero S, Carbonell A, Azorín F. Germline-specific H1 variants: the "sexy" linker histones. Chromosoma 2015; 125:1-13. [PMID: 25921218 DOI: 10.1007/s00412-015-0517-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 04/14/2015] [Accepted: 04/15/2015] [Indexed: 01/07/2023]
Abstract
The eukaryotic genome is packed into chromatin, a nucleoprotein complex mainly formed by the interaction of DNA with the abundant basic histone proteins. The fundamental structural and functional subunit of chromatin is the nucleosome core particle, which is composed by 146 bp of DNA wrapped around an octameric protein complex formed by two copies of each core histone H2A, H2B, H3, and H4. In addition, although not an intrinsic component of the nucleosome core particle, linker histone H1 directly interacts with it in a monomeric form. Histone H1 binds nucleosomes near the exit/entry sites of linker DNA, determines nucleosome repeat length and stabilizes higher-order organization of nucleosomes into the ∼30 nm chromatin fiber. In comparison to core histones, histone H1 is less well conserved through evolution. Furthermore, histone H1 composition in metazoans is generally complex with most species containing multiple variants that play redundant as well as specific functions. In this regard, a characteristic feature is the presence of specific H1 variants that replace somatic H1s in the germline and during early embryogenesis. In this review, we summarize our current knowledge about their structural and functional properties.
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Affiliation(s)
- Salvador Pérez-Montero
- Institute of Molecular Biology of Barcelona, CSIC, Baldiri Reixac, 4, 08028, Barcelona, Spain.,Institute for Research in Biomedicine, IRB Barcelona, Baldiri Reixac, 10, 08028, Barcelona, Spain
| | - Albert Carbonell
- Institute of Molecular Biology of Barcelona, CSIC, Baldiri Reixac, 4, 08028, Barcelona, Spain.,Institute for Research in Biomedicine, IRB Barcelona, Baldiri Reixac, 10, 08028, Barcelona, Spain
| | - Fernando Azorín
- Institute of Molecular Biology of Barcelona, CSIC, Baldiri Reixac, 4, 08028, Barcelona, Spain. .,Institute for Research in Biomedicine, IRB Barcelona, Baldiri Reixac, 10, 08028, Barcelona, Spain.
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Jedrusik-Bode M. C. elegans sirtuin SIR-2.4 and its mammalian homolog SIRT6 in stress response. WORM 2014; 3:e29102. [PMID: 26442197 DOI: 10.4161/worm.29102] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 04/26/2014] [Accepted: 05/02/2014] [Indexed: 01/09/2023]
Abstract
Stress is a significant life event. The immediate response to stress is critical for survival. In organisms ranging from the unicellular Saccharomyces cerevisiae to protozoa (Trypanosoma brucei) and metazoan (such as Caenorhabditis elegans, Homo sapiens) stress response leads to the formation of cytoplasmic RNA-protein complexes referred to as stress granules (SGs). SGs regulate cell survival during stress by the sequestration of the signaling molecules implicated in apoptosis. They are a transient place of messenger ribonucleoproteins (mRNPs) remodeling for storage, degradation, or reinitiation of translation during stress and recovery from stress. Recently, we have identified chromatin factor, the sirtuin C. elegans SIR-2.4 variant and its mammalian homolog SIRT6 as a regulator of SGs formation. SIRT6 is highly conserved NAD(+)-dependent lysine deacetylase and ADP-ribosyltransferase impacting longevity, metabolism, and cancer. We observed that the cellular formation of SGs by SIRT6 or SIR-2.4 was linked with the cell viability or C. elegans survival and was dependent on SIRT6 enzymatic activity. Here, we discuss how SIR-2.4/SIRT6 influences SGs formation and stress response. We suggest possible mechanisms for such an unanticipated function of a chromatin regulatory factor SIRT6 in assembly of stress granules and cellular stress resistance.
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Affiliation(s)
- Monika Jedrusik-Bode
- Max Planck Institute for Biophysical Chemistry; Epigenetics in C elegans group; Göttingen, Germany
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4
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Jedrusik-Bode M, Studencka M, Smolka C, Baumann T, Schmidt H, Kampf J, Paap F, Martin S, Tazi J, Müller KM, Krüger M, Braun T, Bober E. The sirtuin SIRT6 regulates stress granule formation in C. elegans and mammals. J Cell Sci 2013; 126:5166-77. [PMID: 24013546 DOI: 10.1242/jcs.130708] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
SIRT6 is a NAD(+)-dependent deacetylase that modulates chromatin structure and safeguards genomic stability. Until now, SIRT6 has been assigned to the nucleus and only nuclear targets of SIRT6 are known. Here, we demonstrate that in response to stress, C. elegans SIR-2.4 and its mammalian orthologue SIRT6 localize to cytoplasmic stress granules, interact with various stress granule components and induce their assembly. Loss of SIRT6 or inhibition of its catalytic activity in mouse embryonic fibroblasts impairs stress granule formation and delays disassembly during recovery, whereas deficiency of SIR-2.4 diminishes maintenance of P granules and decreases survival of C. elegans under stress conditions. Our findings uncover a novel, evolutionary conserved function of SIRT6 in the maintenance of stress granules in response to stress.
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Affiliation(s)
- Monika Jedrusik-Bode
- Max Planck Institute for Biophysical Chemistry, Epigenetics in C. elegans group, Am Faßberg 11, 37077 Göttingen, Germany
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5
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Wenzel D, Palladino F, Jedrusik-Bode M. Epigenetics in C. elegans: facts and challenges. Genesis 2011; 49:647-61. [PMID: 21538806 DOI: 10.1002/dvg.20762] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Revised: 04/14/2011] [Accepted: 04/15/2011] [Indexed: 12/31/2022]
Abstract
Epigenetics is defined as the study of heritable changes in gene expression that are not accompanied by changes in the DNA sequence. Epigenetic mechanisms include histone post-translational modifications, histone variant incorporation, non-coding RNAs, and nucleosome remodeling and exchange. In addition, the functional compartmentalization of the nucleus also contributes to epigenetic regulation of gene expression. Studies on the molecular mechanisms underlying epigenetic phenomena and their biological function have relied on various model systems, including yeast, plants, flies, and cultured mammalian cells. Here we will expose the reader to the current understanding of epigenetic regulation in the roundworm C. elegans. We will review recent models of nuclear organization and its impact on gene expression, the biological role of enzymes modifying core histones, and the function of chromatin-associated factors, with special emphasis on Polycomb (PcG) and Trithorax (Trx-G) group proteins. We will discuss how the C. elegans model has provided novel insight into mechanisms of epigenetic regulation as well as suggest directions for future research.
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Affiliation(s)
- Dirk Wenzel
- Electron Microscopy Group 3 Epigenetics in C. elegans Group, Max Planck Institute for Biophysical Chemistry, Am Faβberg 11, 37077 Göttingen, Germany
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HIS-24 linker histone and SIR-2.1 deacetylase induce H3K27me3 in the Caenorhabditis elegans germ line. Mol Cell Biol 2009; 29:3700-9. [PMID: 19380489 DOI: 10.1128/mcb.00018-09] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
HIS-24 linker histone and SIR-2.1 deacetylase are involved in chromatin silencing in Caenorhabditis elegans. Depletion of SIR-2.1 results in cytoplasmic retention of HIS-24 in oocytes. However, the molecular working mechanisms of HIS-24 and SIR-2.1 are unclear. We show here a synergistic function of SIR-2.1 and HIS-24 that are together essential for maintenance of the H3K27me3 mark in the germ line of C. elegans. We demonstrate the synthetic effects of the two factors on brood size, embryogenesis, and fertility. SIR-2.1 and HIS-24 associate with the subtelomeric regions but apparently do not interact directly. We report that SIR-2.1 deacetylates H3K9 at subtelomeric regions and suggest that deacetylation of H3K9 is a prerequisite for H3K27 methylation. In turn, we found that HIS-24 specifically interacts with the histone H3 K27 region, when unmodified or in the trimethylated state. Overall, our data indicate that SIR-2.1 and HIS-24 contribute to the propagation of a specialized chromatin state at the subtelomeric regions and elsewhere in the genome.
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Greiss S, Hall J, Ahmed S, Gartner A. C. elegans SIR-2.1 translocation is linked to a proapoptotic pathway parallel to cep-1/p53 during DNA damage-induced apoptosis. Genes Dev 2008; 22:2831-42. [PMID: 18923081 DOI: 10.1101/gad.482608] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Caenorhabditis elegans SIR-2.1, a member of the sirtuin family related to Saccharomyces cerevisiae Sir2p, has previously been implicated in aging. The mammalian homolog SIRT1 plays important roles in multiple cellular processes including transcriptional repression and stress response. We show that sir-2.1 is essential for the execution of apoptosis in response to DNA damage, and that sir-2.1 genetically acts in parallel to the worm p53-like gene cep-1. This novel cep-1-independent proapoptotic pathway does not require the daf-16 FOXO transcription factor. Cytological analysis of SIR-2.1 suggests a novel mechanism of apoptosis induction. During apoptosis SIR-2.1 changes its subcellular localization from the nucleus to the cytoplasm and transiently colocalizes with the C. elegans Apaf-1 homolog CED-4 at the nuclear periphery. SIR-2.1 translocation is an early event in germ cell apoptosis and is independent of apoptosis execution and cep-1, raising the possibility that SIR-2.1 translocation is linked to the induction of DNA damage-induced apoptosis.
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Affiliation(s)
- Sebastian Greiss
- Wellcome Trust Centre for Gene Regulation and Expression, University of Dundee, Dundee DD1 5EH, United Kingdom
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Jedrusik MA, Schulze E. Linker histone HIS-24 (H1.1) cytoplasmic retention promotes germ line development and influences histone H3 methylation in Caenorhabditis elegans. Mol Cell Biol 2007; 27:2229-39. [PMID: 17210650 PMCID: PMC1820517 DOI: 10.1128/mcb.01713-06] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
RNA interference with one of the eight Caenorhabditis elegans linker histone genes triggers desilencing of a repetitive transgene and developmental defects in the hermaphrodite germ line. These characteristics are similar to the phenotype of the C. elegans Polycomb group genes mes-2, mes-3, mes-4, and mes-6 (M. A. Jedrusik and E. Schulze, Development 128:1069-1080, 2001; I. Korf, Y. Fan, and S. Strome, Development 125:2469-2478, 1998). These Polycomb group proteins contribute to germ line-specific chromatin modifications. Using a his-24 deletion mutant and an isoform-specific antibody, we characterized the role of his-24 in C. elegans germ line development. We describe an unexpected cytoplasmic retention of HIS-24 in peculiar granular structures. This phenomenon is confined to the developing germ lines of both sexes. It is strictly dependent on the activities of the chromatin-modifying genes mes-2, mes-3, mes-4, and mes-6, as well as on the C. elegans sirtuin gene sir-2.1. A temperature shift experiment with a mes-3(ts) mutant revealed that mes gene activity is required in a time window ranging from L3 to the early L4 stage before the onset of meiosis. We find that the his-24(ok1024) mutant germ line is characterized by an increased level of the activating H3K4 methylation mark concomitant with a decrease of the repressive H3K9 methylation. In the germ line of his-24(ok1024) mes-3(bn35) double mutant animals, the repressive H3K27 methylation is more reduced than in the respective mes single mutant. These observations distinguish his-24 as an unusual element in the developmental regulation of germ line chromatin structure in C. elegans.
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Affiliation(s)
- Monika A Jedrusik
- Max Planck Institute for Biophysical Chemistry, Laboratory of Chromatin Biochemistry, Am Fassberg 11, D-37077 Göttingen, Germany.
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9
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Abstract
Sirtuins have been the focus of intense scrutiny since the discovery of Sir2 as a yeast longevity factor. Functioning as either deacetylases or ADP ribosylases, Sirtuins are regulated by the cofactor NAD and thus may serve as sensors of the metabolic state of the cell and organism. Here we examine the roles of Sirtuins in diverse eukaryotic species, with special emphasis on their links to aging and age-related diseases including cancer, diabetes, and neurodegenerative disorders.
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Affiliation(s)
- Valter D Longo
- Department of Molecular and Computational Biology, Andrus Gerontology Center, University of Southern California, Los Angeles, CA 90089, USA.
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10
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Ni JQ, Liu LP, Hess D, Rietdorf J, Sun FL. Drosophila ribosomal proteins are associated with linker histone H1 and suppress gene transcription. Genes Dev 2006; 20:1959-73. [PMID: 16816001 PMCID: PMC1522087 DOI: 10.1101/gad.390106] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2005] [Accepted: 05/08/2006] [Indexed: 11/24/2022]
Abstract
The dynamics and function of ribosomal proteins in the cell nucleus remain enigmatic. Here we provide evidence that specific components of Drosophila melanogaster ribosomes copurify with linker histone H1. Using various experimental approaches, we demonstrate that this association of nuclear ribosomal proteins with histone H1 is specific, and that colocalization occurs on condensed chromatin in vivo. Chromatin immunoprecipitation analysis confirmed that specific ribosomal proteins are associated with chromatin in a histone H1-dependent manner. Overexpression of either histone H1 or ribosomal protein L22 in Drosophila cells resulted in global suppression of the same set of genes, while depletion of H1 and L22 caused up-regulation of tested genes, suggesting that H1 and ribosomal proteins are essential for transcriptional gene repression. Overall, this study provides evidence for a previously undefined link between ribosomal proteins and chromatin, and suggests a role for this association in transcriptional regulation in higher eukaryotes.
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Affiliation(s)
- Jian-Quan Ni
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
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11
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Abstract
Two allelic isoforms (H1.a1 and H1.a2) of histone H1.a were identified within two conservative flocks (R11 and R55) of Rhode Island Red chickens. These proteins form three phenotypes: a1, a2 and a1a2. Birds with phenotype a1 were most common (frequency 0.825-0.980) while the a1a2 chickens appeared relatively rarely (0.017-0.175). The third phenotype a2, not detected in the tested populations, has only been revealed in progeny of the purpose-mated a1a2 birds. The polymorphism of histone H1.a was observed in all examined chicken tissues, so that the H1 preparations isolated from the lung, spleen, kidney and testis from the same individual exhibited identical phenotypes (a1, a2, or a1a2). This finding, together with inheritance data, supports the genetic nature of the H1.a polymorphism. As indicated by cleavages with alpha-chymotrypsin and protease V8, the H1.a1 and H1.a2 are two highly related proteins which differ within N-terminal part of their C-terminal tails. Only a single nonconservative amino acid substitution between both H1.a allelic isoforms was detected by Edman degradation: glutamic acid present at position 117 in histone H1.a1 was replaced by lysine in histone H1.a2. Furthermore, using microsequencing techniques we have found a sequence homology between the N- and C-terminal parts of an unknown minor protein H1.y, present in the phenotype a2, and similar regions of histone H1.b.
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Robert VJP, Sijen T, van Wolfswinkel J, Plasterk RHA. Chromatin and RNAi factors protect the C. elegans germline against repetitive sequences. Genes Dev 2005; 19:782-7. [PMID: 15774721 PMCID: PMC1074315 DOI: 10.1101/gad.332305] [Citation(s) in RCA: 124] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Protection of genomes against invasion by repetitive sequences, such as transposons, viruses, and repetitive transgenes, involves strong and selective silencing of these sequences. During silencing of repetitive transgenes, a trans effect ("cosuppression") occurs that results in silencing of cognate endogenous genes. Here we report RNA interference (RNAi) screens performed to catalog genes required for cosuppression in the Caenorhabditis elegans germline. We find factors with a putative role in chromatin remodeling and factors involved in RNAi. Together with molecular data also presented in this study, these results suggest that in C. elegans repetitive sequences trigger transcriptional gene silencing using RNAi and chromatin factors.
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Chen D, Dundr M, Wang C, Leung A, Lamond A, Misteli T, Huang S. Condensed mitotic chromatin is accessible to transcription factors and chromatin structural proteins. ACTA ACUST UNITED AC 2004; 168:41-54. [PMID: 15623580 PMCID: PMC2171683 DOI: 10.1083/jcb.200407182] [Citation(s) in RCA: 153] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
During mitosis, chromosomes are highly condensed and transcription is silenced globally. One explanation for transcriptional repression is the reduced accessibility of transcription factors. To directly test this hypothesis and to investigate the dynamics of mitotic chromatin, we evaluate the exchange kinetics of several RNA polymerase I transcription factors and nucleosome components on mitotic chromatin in living cells. We demonstrate that these factors rapidly exchange on and off ribosomal DNA clusters and that the kinetics of exchange varies at different phases of mitosis. In addition, the nucleosome component H1c-GFP also shows phase-specific exchange rates with mitotic chromatin. Furthermore, core histone components exchange at detectable levels that are elevated during anaphase and telophase, temporally correlating with H3-K9 acetylation and recruitment of RNA polymerase II before the onset of bulk RNA synthesis at mitotic exit. Our findings indicate that mitotic chromosomes in general and ribosomal genes in particular, although highly condensed, are accessible to transcription factors and chromatin proteins. The phase-specific exchanges of nucleosome components during late mitotic phases are consistent with an emerging model of replication independent core histone replacement.
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Affiliation(s)
- Danyang Chen
- Department of Cell and Molecular Biology, The Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
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Vaquero A, Scher M, Lee D, Erdjument-Bromage H, Tempst P, Reinberg D. Human SirT1 interacts with histone H1 and promotes formation of facultative heterochromatin. Mol Cell 2004; 16:93-105. [PMID: 15469825 DOI: 10.1016/j.molcel.2004.08.031] [Citation(s) in RCA: 670] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2004] [Revised: 08/11/2004] [Accepted: 08/13/2004] [Indexed: 11/30/2022]
Abstract
We characterized human SirT1, one of the human homologs of the budding yeast Sir2p, an NAD+-dependent histone deacetylase involved in establishing repressive chromatin and increased life span. SirT1 deacetylates histone polypeptides with a preference for histone H4 lysine 16 (H4-K16Ac) and H3 lysine 9 (H3-K9Ac) in vitro. RNAi-mediated decreased expression of SirT1 in human cells causes hyperacetylation of H4-K16 and H3-K9 in vivo. SirT1 interacts with and deacetylates histone H1 at lysine 26. Using an inducible system directing expression of SirT1 fused to the Gal4-DNA binding domain and a Gal4-reporter integrated in euchromatin, Gal4-SirT1 expression resulted in the deacetylation of H4-K16 and H3-K9, recruitment of H1 within the promoter vicinity, drastically reduced reporter expression, and loss of H3-K79 methylation, a mark restricting silenced chromatin. We propose a model for SirT1-mediated heterochromatin formation that includes deacetylation of histone tails, recruitment and deacetylation of histone H1, and spreading of hypomethylated H3-K79 with resultant silencing.
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Affiliation(s)
- Alejandro Vaquero
- Howard Hughes Medical Institute, Division of Nucleic Acids Enzymology, Department of Biochemistry, Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA
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Hendzel MJ, Lever MA, Crawford E, Th'ng JPH. The C-terminal domain is the primary determinant of histone H1 binding to chromatin in vivo. J Biol Chem 2004; 279:20028-34. [PMID: 14985337 DOI: 10.1074/jbc.m400070200] [Citation(s) in RCA: 168] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have used a combination of kinetic measurements and targeted mutations to show that the C-terminal domain is required for high-affinity binding of histone H1 to chromatin, and phosphorylations can disrupt binding by affecting the secondary structure of the C terminus. By measuring the fluorescence recovery after photo-bleaching profiles of green fluorescent protein-histone H1 proteins in living cells, we find that the deletion of the N terminus only modestly reduces binding affinity. Deletion of the C terminus, however, almost completely eliminates histone H1.1 binding. Specific mutations of the C-terminal domain identified Thr-152 and Ser-183 as novel regulatory switches that control the binding of histone H1.1 in vivo. It is remarkable that the single amino acid substitution of Thr-152 with glutamic acid was almost as effective as the truncation of the C terminus to amino acid 151 in destabilizing histone H1.1 binding in vivo. We found that modifications to the C terminus can affect histone H1 binding dramatically but have little or no influence on the charge distribution or the overall net charge of this domain. A comparison of individual point mutations and deletion mutants, when reviewed collectively, cannot be reconciled with simple charge-dependent mechanisms of C-terminal domain function of linker histones.
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Affiliation(s)
- Michael J Hendzel
- Cross Cancer Institute and Department of Oncology, University of Alberta, Edmonton, Alberta T6G 1Z2, Canada
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16
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Current awareness on yeast. Yeast 2003; 20:1151-8. [PMID: 14598808 DOI: 10.1002/yea.949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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