851
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Hong W, Kim AY, Ky S, Rakowski C, Seo SB, Chakravarti D, Atchison M, Blobel GA. Inhibition of CBP-mediated protein acetylation by the Ets family oncoprotein PU.1. Mol Cell Biol 2002; 22:3729-43. [PMID: 11997509 PMCID: PMC133832 DOI: 10.1128/mcb.22.11.3729-3743.2002] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2001] [Revised: 01/30/2002] [Accepted: 02/28/2002] [Indexed: 01/09/2023] Open
Abstract
Aberrant expression of PU.1 inhibits erythroid cell differentiation and contributes to the formation of murine erythroleukemias (MEL). The molecular mechanism by which this occurs is poorly understood. Here we show that PU.1 specifically and efficiently inhibits CBP-mediated acetylation of several nuclear proteins, including the hematopoietic transcription factors GATA-1, NF-E2, and erythroid Krüppel-like factor. In addition, PU.1 blocks acetylation of histones and interferes with acetylation-dependent transcriptional events. CBP acetyltransferase activity increases during MEL cell differentiation as PU.1 levels decline and is inhibited by sustained PU.1 expression. Finally, PU.1 inhibits the differentiation-associated increase in histone acetylation at an erythroid-specific gene locus in vivo. Together, these findings suggest that aberrant expression of PU.1 and possibly other members of the Ets family of oncoproteins subverts normal cellular differentiation in part by inhibiting the acetylation of critical nuclear factors involved in balancing cellular proliferation and maturation.
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Affiliation(s)
- Wei Hong
- Division of Hematology, Children's Hospital of Philadelphia, Pennsylvania 19104, USA
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852
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Humbert S, Bryson EA, Cordelières FP, Connors NC, Datta SR, Finkbeiner S, Greenberg ME, Saudou F. The IGF-1/Akt pathway is neuroprotective in Huntington's disease and involves Huntingtin phosphorylation by Akt. Dev Cell 2002; 2:831-7. [PMID: 12062094 DOI: 10.1016/s1534-5807(02)00188-0] [Citation(s) in RCA: 388] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In the search for neuroprotective factors in Huntington's disease, we found that insulin growth factor 1 via activation of the serine/threonine kinase Akt/PKB is able to inhibit neuronal death specifically induced by mutant huntingtin containing an expanded polyglutamine stretch. The IGF-1/Akt pathway has a dual effect on huntingtin-induced toxicity, since activation of this pathway also results in a decrease in the formation of intranuclear inclusions of mutant huntingtin. We demonstrate that huntingtin is a substrate of Akt and that phosphorylation of huntingtin by Akt is crucial to mediate the neuroprotective effects of IGF-1. Finally, we show that Akt is altered in Huntington's disease patients. Taken together, these results support a potential role of the Akt pathway in Huntington's disease.
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Affiliation(s)
- Sandrine Humbert
- UMR 146 CNRS/Institut Curie, Centre Universitaire, 91405 Orsay Cedex, France
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853
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Okazawa H, Rich T, Chang A, Lin X, Waragai M, Kajikawa M, Enokido Y, Komuro A, Kato S, Shibata M, Hatanaka H, Mouradian MM, Sudol M, Kanazawa I. Interaction between mutant ataxin-1 and PQBP-1 affects transcription and cell death. Neuron 2002; 34:701-13. [PMID: 12062018 DOI: 10.1016/s0896-6273(02)00697-9] [Citation(s) in RCA: 146] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
PQBP-1 was isolated on the basis of its interaction with polyglutamine tracts. In this study, using in vitro and in vivo assays, we show that the association between ataxin-1 and PQBP-1 is positively influenced by expanded polyglutamine sequences. In cell lines, interaction between the two molecules induces apoptotic cell death. As a possible mechanism underlying this phenomenon, we found that mutant ataxin-1 enhances binding of PQBP-1 to the C-terminal domain of RNA polymerase II large subunit (Pol II). This reduces the level of phosphorylated Pol II and transcription. Our results suggest the involvement of PQBP-1 in the pathology of spinocerebellar ataxia type 1 (SCA1) and support the idea that modified transcription underlies polyglutamine-mediated pathology.
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Affiliation(s)
- Hitoshi Okazawa
- Department of Neurology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, 113-8655, Japan.
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854
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Taylor JP, Fischbeck KH. Altered acetylation in polyglutamine disease: an opportunity for therapeutic intervention? Trends Mol Med 2002; 8:195-7. [PMID: 12067622 DOI: 10.1016/s1471-4914(02)02332-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Recent investigations into polyglutamine diseases suggest that aberrant transcriptional regulation might be central to the molecular pathogenesis, perhaps because of inappropriate interaction between mutant proteins and important nuclear factors. Several groups have reported an interaction of mutant polyglutamine with histone acetylases, implicating defective acetylation as a cause of abnormal transcription. An important recent observation is that reversal of the acetylation defect with histone deacetylase inhibitors ameliorates polyglutamine toxicity in yeast, mammalian cell culture, and animal models. These encouraging findings suggest that a novel strategy--pharmacological restoration of histone acetylation-- could prove effective in treating this group of devastating illnesses.
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Affiliation(s)
- J Paul Taylor
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, 10 Center Drive, Building 10, Room 3B-14, Bethesda, MD 20892-1250, USA.
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855
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856
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Abstract
Huntington's disease (HD) is an autosomal-dominant neurodegenerative disorder caused by a CAG trinucleotide repeat expansion in the HD gene. The expanded repeats are translated into an abnormally long polyglutamine tract close to the N-terminus of the HD gene product, huntingtin. Studies in mouse models and human suggest that the mutation is associated with a deleterious gain of function. There is now a wide range of mouse models for HD, providing important insights into processes associated with disease pathogenesis. These models have been complemented by studies in Drosophila and Caenorhabditis elegans that have allowed the identification of possible modifier loci through suppressor screens.
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Affiliation(s)
- David C Rubinsztein
- Dept of Medical Genetics, Cambridge Institute of Medical Research, Wellcome/MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 2XY, UK.
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857
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Abstract
Covalent modifications of the amino termini of the core histones in nucleosomes have important roles in gene regulation. Research in the past two years reveals these modifications to consist of phosphorylation, methylation and ubiquitination, in addition to the better-characterized acetylation. This multiplicity of modifications, and their occurrence in patterns and dependent sequences, argues persuasively for the existence of a histone code.
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Affiliation(s)
- Shelley L Berger
- The Wistar Institute, 3601 Spruce Street, Philadelphia, Pennsylvania 19104, USA.
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858
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Kazantsev A, Walker HA, Slepko N, Bear JE, Preisinger E, Steffan JS, Zhu YZ, Gertler FB, Housman DE, Marsh JL, Thompson LM. A bivalent Huntingtin binding peptide suppresses polyglutamine aggregation and pathogenesis in Drosophila. Nat Genet 2002; 30:367-76. [PMID: 11925563 DOI: 10.1038/ng864] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Huntington disease is caused by the expansion of a polyglutamine repeat in the Huntingtin protein (Htt) that leads to degeneration of neurons in the central nervous system and the appearance of visible aggregates within neurons. We have developed and tested suppressor polypeptides that bind mutant Htt and interfere with the process of aggregation in cell culture. In a Drosophila model, the most potent suppressor inhibits both adult lethality and photoreceptor neuron degeneration. The appearance of aggregates in photoreceptor neurons correlates strongly with the occurrence of pathology, and expression of suppressor polypeptides delays and limits the appearance of aggregates and protects photoreceptor neurons. These results suggest that targeting the protein interactions leading to aggregate formation may be beneficial for the design and development of therapeutic agents for Huntington disease.
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Affiliation(s)
- Aleksey Kazantsev
- Department of Biology, Center for Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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859
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Abstract
As alterations in gene expression underlie a considerable proportion of human diseases, correcting such aberrant transcription in vivo is expected to provide therapeutic benefit to the patient. Attempts to control endogenous mammalian genes, however, face a significant obstacle in the form of chromatin. Aberrant gene repression can be alleviated by using small-molecule inhibitors that exert nucleus-wide effects on chromatin-based repressors. Genome-wide chromatin remodeling also occurs during cloning via nuclear transfer, and causes the deregulation of epigenetically controlled genes. Regulation of genes in vivo can be accomplished via the use of designed transcription factors - these result from a fusion of a designed DNA-binding domain based on the zinc finger protein motif to a functional domain of choice.
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Affiliation(s)
- Andreas Reik
- Sangamo Biosciences, Pt Richmond Tech Center, 501 Canal Blvd, Suite A100, Richmond, California 94804, USA
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860
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861
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Tong JJ, Liu J, Bertos NR, Yang XJ. Identification of HDAC10, a novel class II human histone deacetylase containing a leucine-rich domain. Nucleic Acids Res 2002; 30:1114-23. [PMID: 11861901 PMCID: PMC101247 DOI: 10.1093/nar/30.5.1114] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2001] [Revised: 01/10/2002] [Accepted: 01/10/2002] [Indexed: 11/14/2022] Open
Abstract
Histone acetylation is important for regulating chromatin structure and gene expression. Three classes of mammalian histone deacetylases have been identified. Among class II, there are five known members, namely HDAC4, HDAC5, HDAC6, HDAC7 and HDAC9. Here we describe the identification and characterization of a novel class II member termed HDAC10. It is a 669 residue polypeptide with a bipartite modular structure consisting of an N-terminal Hda1p-related putative deacetylase domain and a C-terminal leucine-rich domain. HDAC10 is widely expressed in adult human tissues and cultured mammalian cells. It is enriched in the cytoplasm and this enrichment is not sensitive to leptomycin B, a specific inhibitor known to block the nuclear export of other class II members. The leucine-rich domain of HDAC10 is responsible for its cytoplasmic enrichment. Recombinant HDAC10 protein possesses histone deacetylase activity, which is sensitive to trichostatin A, a specific inhibitor for known class I and class II histone deacetylases. When tethered to a promoter, HDAC10 is able to repress transcription. Furthermore, HDAC10 interacts with HDAC3 but not with HDAC4 or HDAC6. These results indicate that HDAC10 is a novel class II histone deacetylase possessing a unique leucine-rich domain.
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Affiliation(s)
- Jenny J Tong
- Molecular Oncology Group, Department of Medicine, McGill University Health Center, 687 Pine Avenue West, Montreal, Quebec H3A 1A1, Canada
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862
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Muqit MMK, Feany MB. Modelling neurodegenerative diseases in Drosophila: a fruitful approach? Nat Rev Neurosci 2002; 3:237-43. [PMID: 11994755 DOI: 10.1038/nrn751] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Human neurodegenerative diseases are characterized by the progressive loss of specific neuronal populations, resulting in substantial disability and early death. The identification of causative single-gene mutations in families with inherited neurodegenerative disorders has facilitated the modelling of these diseases in experimental organisms, including the fruitfly Drosophila melanogaster. Many neurodegenerative diseases have now been successfully modelled in Drosophila, and genetic analysis is under way in each of these models. Using fruitfly genetics to define the molecular pathways that underlie the neurodegenerative process is likely to improve substantially our understanding of the pathogenesis of the human diseases, and to provide new therapeutic targets.
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Affiliation(s)
- Miratul M K Muqit
- Department of Pathology, Division of Neuropathy, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
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863
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Abstract
Recent developments in live-cell imaging are challenging our stereotyped view of the fixed cell nucleus. The emerging picture is that nuclear processes may rely on a constant flow of molecules between dynamic compartments created by relatively immobile binding or assembly sites. This article discusses current views on the origins of nuclear compartments and their roles in gene expression.
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Affiliation(s)
- Maria Carmo-Fonseca
- Institute of Molecular Medicine, Faculty of Medicine, University of Lisbon, Av. Prof. Egas Moniz, 1649-028 Lisbon, Portugal.
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864
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Abstract
Recent evidence indicates that inhibition of histone acetyltransferases may be a primary cause of cellular pathogenesis in polyglutamine diseases such as Huntington disease; the results raise the possibility that pharmacologic manipulation of protein acetylation levels could be of therapeutic benefit.
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Affiliation(s)
- Robert E Hughes
- Division of Medical Genetics, Box 357720, University of Washington, Seattle, Washington 98195, USA. rehughes.u.washington.edu
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865
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Abstract
Transcriptional repression, which plays a crucial role in diverse biological processes, is mediated in part by non-DNA-binding co-repressors. The closely related co-repressor proteins N-CoR and SMRT, although originally identified on the basis of their ability to associate with and confer transcriptional repression through nuclear receptors, have been shown to be recruited to many classes of transcription factor and are in fact components of multiple protein complexes containing histone deacetylase proteins. This association with histone deacetylase activity provides an important component of the mechanism that allows DNA-binding proteins interacting with N-CoR or SMRT to repress transcription of specific target genes. Both N-CoR and SMRT are important targets for cell signaling pathways, which influence their expression levels, subcellular localization and association with other proteins. Recently, the biological importance of these proteins has been revealed by studies of genetically engineered mice and human diseases such as acute promyelocytic leukemia (APL) and resistance to thyroid hormone(RTH).
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Affiliation(s)
- Kristen Jepsen
- Howard Hughes Medical Institute, Department and School of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 920393-0648, USA
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866
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867
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Abstract
We report that feeding Drosophila throughout adulthood with 4-phenylbutyrate (PBA) can significantly increase lifespan, without diminution of locomotor vigor, resistance to stress, or reproductive ability. Treatment for a limited period, either early or late in adult life, is also effective. Flies fed PBA show a global increase in histone acetylation as well as a dramatically altered pattern of gene expression, including induction or repression of numerous genes. The delay in aging may result from the altered physiological state.
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Affiliation(s)
- Hyung-Lyun Kang
- Neurogenetics Branch, MSC1250, 10/3B12, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
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868
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Zhang S, Xu L, Lee J, Xu T. Drosophila atrophin homolog functions as a transcriptional corepressor in multiple developmental processes. Cell 2002; 108:45-56. [PMID: 11792320 DOI: 10.1016/s0092-8674(01)00630-4] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Dentatorubral-pallidoluysian atrophy is a progressive neurodegenerative disease caused by the expansion of a polyglutamine repeats within the Atrophin-1 protein. The in vivo function of Atrophin-1 is unknown. We have characterized a Drosophila gene encoding an Atrophin family protein. Analysis of mutant phenotypes indicates that Drosophila Atrophin is required in diverse developmental processes including early embryonic patterning. Drosophila Atrophin genetically interacts with the transcription repressor even-skipped and is required for its repressive function in vivo. Drosophila Atrophin directly binds to Even-skipped in vitro. Furthermore, both human Atrophin-1 and Drosophila Atrophin repress transcription in vivo when tethered to DNA, and poly-Q expansion in Atrophin-1 reduces this repressive activity. We propose that Atrophin proteins function as versatile transcriptional corepressors and discuss a model that deregulation of transcription may contribute to the pathogenesis of neurodegeneration.
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Affiliation(s)
- Sheng Zhang
- Howard Hughes Medical Institute, Department of Genetics, Yale University School of Medicine, 295 Congress Avenue, New Haven, CT 06535, USA
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869
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Allsopp TE. An open and shut case of neurodegeneration. Trends Neurosci 2002. [DOI: 10.1016/s0166-2236(00)02100-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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870
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McCampbell A, Taye AA, Whitty L, Penney E, Steffan JS, Fischbeck KH. Histone deacetylase inhibitors reduce polyglutamine toxicity. Proc Natl Acad Sci U S A 2001; 98:15179-84. [PMID: 11742087 PMCID: PMC65003 DOI: 10.1073/pnas.261400698] [Citation(s) in RCA: 189] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Polyglutamine diseases include at least nine neurodegenerative disorders, each caused by a CAG repeat expansion in a different gene. Accumulation of mutant polyglutamine-containing proteins occurs in patients, and evidence from cell culture and animal experiments suggests the nucleus as a site of pathogenesis. To understand the consequences of nuclear accumulation, we created a cell culture system with nuclear-targeted polyglutamine. In our system, cell death can be mitigated by overexpression of full-length cAMP response element binding protein (CREB)-binding protein (CBP) or its amino-terminal portion alone. CBP is one of several histone acetyltransferases sequestered by polyglutamine inclusions. We found histone acetylation to be reduced in cells expressing mutant polyglutamine. Reversal of this hypoacetylation, which can be achieved either by overexpression of CBP or its amino terminus or by treatment with deacetylase inhibitors, reduced cell loss. These findings suggest that nuclear accumulation of polyglutamine can lead to altered protein acetylation in neurons and indicate a novel therapeutic strategy for polyglutamine disease.
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Affiliation(s)
- A McCampbell
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Building 10, Room 3B14, 10 Center Drive, Bethesda, MD 20892, USA
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871
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Baderman N, Clough J, Milburn J, Owens J. News in brief. Drug Discov Today 2001. [DOI: 10.1016/s1359-6446(01)02064-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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872
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