101
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Breathing-in epigenetic change with vitamin C. EMBO Rep 2013; 14:337-46. [PMID: 23492828 PMCID: PMC3615655 DOI: 10.1038/embor.2013.29] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 02/19/2013] [Indexed: 01/01/2023] Open
Abstract
Vitamin C is an antioxidant that maintains the activity of iron and α-ketoglutarate-dependent dioxygenases. Despite these enzymes being implicated in a wide range of biological pathways, vitamin C is rarely included in common cell culture media. Recent studies show that reprogramming of pluripotent stem cells is enhanced when vitamin C is present, thereby illustrating previous limitations in reprogramming cultures. Here, we summarize understanding of dioxygenase function in reprogramming and epigenetic regulation. The available data suggest a link between dioxygenase function and stem cell differentiation, which is exposed to environmental influence and is relevant for human disease.
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102
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Wang X, Schröder HC, Feng Q, Draenert F, Müller WEG. The deep-sea natural products, biogenic polyphosphate (Bio-PolyP) and biogenic silica (Bio-Silica), as biomimetic scaffolds for bone tissue engineering: fabrication of a morphogenetically-active polymer. Mar Drugs 2013; 11:718-46. [PMID: 23528950 PMCID: PMC3705367 DOI: 10.3390/md11030718] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 02/04/2013] [Accepted: 02/06/2013] [Indexed: 12/12/2022] Open
Abstract
Bone defects in human, caused by fractures/nonunions or trauma, gain increasing impact and have become a medical challenge in the present-day aging population. Frequently, those fractures require surgical intervention which ideally relies on autografts or suboptimally on allografts. Therefore, it is pressing and likewise challenging to develop bone substitution materials to heal bone defects. During the differentiation of osteoblasts from their mesenchymal progenitor/stem cells and of osteoclasts from their hemopoietic precursor cells, a lineage-specific release of growth factors and a trans-lineage homeostatic cross-talk via signaling molecules take place. Hence, the major hurdle is to fabricate a template that is functioning in a way mimicking the morphogenetic, inductive role(s) of the native extracellular matrix. In the last few years, two naturally occurring polymers that are produced by deep-sea sponges, the biogenic polyphosphate (bio-polyP) and biogenic silica (bio-silica) have also been identified as promoting morphogenetic on both osteoblasts and osteoclasts. These polymers elicit cytokines that affect bone mineralization (hydroxyapatite formation). In this manner, bio-silica and bio-polyP cause an increased release of BMP-2, the key mediator activating the anabolic arm of the hydroxyapatite forming cells, and of RANKL. In addition, bio-polyP inhibits the progression of the pre-osteoclasts to functionally active osteoclasts. Based on these findings, new bioinspired strategies for the fabrication of bone biomimetic templates have been developed applying 3D-printing techniques. Finally, a strategy is outlined by which these two morphogenetically active polymers might be used to develop a novel functionally active polymer.
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Affiliation(s)
- Xiaohong Wang
- ERC Advanced Investigator Grant Research Group at Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, Duesbergweg 6, D-55128 Mainz, Germany; E-Mail:
- National Research Center for Geoanalysis, Chinese Academy of Geological Sciences, 26 Baiwanzhuang Dajie, 100037 Beijing, China
| | - Heinz C. Schröder
- ERC Advanced Investigator Grant Research Group at Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, Duesbergweg 6, D-55128 Mainz, Germany; E-Mail:
| | - Qingling Feng
- Department of Materials Science and Engineering, Tsinghua University, 100084 Beijing, China; E-Mail:
| | - Florian Draenert
- Department and Clinic for Oral and Maxillofacial Surgery, Baldingerstraße, D-35033 Marburg, Germany; E-Mail:
| | - Werner E. G. Müller
- ERC Advanced Investigator Grant Research Group at Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, Duesbergweg 6, D-55128 Mainz, Germany; E-Mail:
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103
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Identification and characterization of microRNAs controlled by the osteoblast-specific transcription factor Osterix. PLoS One 2013; 8:e58104. [PMID: 23472141 PMCID: PMC3589352 DOI: 10.1371/journal.pone.0058104] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Accepted: 02/03/2013] [Indexed: 01/08/2023] Open
Abstract
Osterix (Osx) is an osteoblast-specific transcription factor which is essential for bone formation. MicroRNAs (miRNAs) have been previously shown to be involved in osteogenesis. However, it is unclear whether Osx is involved in the regulation of miRNA expression. In this study, we have identified groups of miRNAs that are differentially expressed in calvaria of the E18.5 Osx(-/-) embryos compared to wild type embryos. The correlation between the levels of miRNAs and Osx expression was further verified in cultured M-Osx cells in which over-expression of Osx is inducible. Our results suggest that Osx down-regulates expression of a group of miRNAs including mir-133a and -204/211, but up-regulates expression of another group of miRNAs such as mir-141/200a. Mir-133a and -204/211 are known to target the master osteogenic transcription factor Runx2. Further assays suggest that Sost, which encodes the Wnt signaling antagonist Sclerostin, and alkaline phosphatase (ALP) are two additional targets of mir-204/211. Mir-141/200a has been known to target the transcription factor Dlx5. Thus, we postulate that during the process of Osx-controlled osteogenesis, Osx has the ability to coordinately modulate Runx2, Sclerostin, ALP and Dlx5 proteins at levels appropriate for optimal osteoblast differentiation and function, at least in part, through regulation of specific miRNAs. Our study shows a tight correlation between Osx and the miRNAs involved in bone formation, and provides new information about molecular mechanisms of Osx-controlled osteogenesis.
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104
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Ortuño MJ, Susperregui ARG, Artigas N, Rosa JL, Ventura F. Osterix induces Col1a1 gene expression through binding to Sp1 sites in the bone enhancer and proximal promoter regions. Bone 2013; 52:548-56. [PMID: 23159876 DOI: 10.1016/j.bone.2012.11.007] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 10/10/2012] [Accepted: 11/07/2012] [Indexed: 01/24/2023]
Abstract
Bone-specific transcription factors promote differentiation of mesenchymal precursors toward the osteoblastic cell phenotype. Among them, Runx2 and Osterix have been widely accepted as master osteogenic factors, since neither Runx2 nor Osterix null mice form mature osteoblasts. Recruitment of Osterix to a number of promoters of bone-specific genes has been shown. However, little is known about the functional interactions between Osterix and the Col1a1 promoter. In this study we determined in several mesenchymal and osteoblastic cell types that either BMP-2 or Osterix overexpression increased Col1a1 transcription. We identified consensus Sp1 sequences, located in the proximal promoter and in the bone-enhancer, as Osterix binding regions in the Col1a1 promoter in vitro and in vivo. Furthermore, we show that p38 or Erk MAPK signaling is required for maximal transcriptional effects on Col1a1 expression. Runx2 has been shown to activate Col1a1 expression through binding to sites which are located close to the Sp1 sites where Osterix binds. Our data show that overexpression of Runx2 and Osterix leads to a cooperative effect on the expression of the Col1a1 endogenous gene and its promoter reporter construct. These effects mainly affect the long isoform of Osterix which suggest that the two Osterix isoforms might display some differential effects on the transactivation of bone-specific genes.
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Affiliation(s)
- Maria José Ortuño
- Departament de Ciències Fisiològiques II, Universitat de Barcelona, IDIBELL, L'Hospitalet de Llobregat, Spain
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105
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Inorganic polyphosphates: biologically active biopolymers for biomedical applications. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2013; 54:261-94. [PMID: 24420717 DOI: 10.1007/978-3-642-41004-8_10] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Inorganic polyphosphate (polyP) is a widely occurring but only rarely investigated biopolymer which exists in both prokaryotic and eukaryotic organisms. Only in the last few years, this polymer has been identified to cause morphogenetic activity on cells involved in human bone formation. The calcium complex of polyP was found to display a dual effect on bone-forming osteoblasts and bone-resorbing osteoclasts. Exposure of these cells to polyP (Ca(2+) complex) elicits the expression of cytokines that promote the mineralization process by osteoblasts and suppress the differentiation of osteoclast precursor cells to the functionally active mature osteoclasts dissolving bone minerals. The effect of polyP on bone formation is associated with an increased release of the bone morphogenetic protein 2 (BMP-2), a key mediator that activates the anabolic processes leading to bone formation. In addition, polyP has been shown to act as a hemostatic regulator that displays various effects on blood coagulation and fibrinolysis and might play an important role in platelet-dependent proinflammatory and procoagulant disorders.
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106
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Ge W, Wolf A, Feng T, Ho CH, Sekirnik R, Zayer A, Granatino N, Cockman ME, Loenarz C, Loik ND, Hardy AP, Claridge TD, Hamed RB, Chowdhury R, Gong L, Robinson CV, Trudgian DC, Jiang M, Mackeen MM, Mccullagh JS, Gordiyenko Y, Thalhammer A, Yamamoto A, Yang M, Liu-Yi P, Zhang Z, Schmidt-Zachmann M, Kessler BM, Ratcliffe PJ, Preston GM, Coleman ML, Schofield CJ. Oxygenase-catalyzed ribosome hydroxylation occurs in prokaryotes and humans. Nat Chem Biol 2012; 8:960-962. [PMID: 23103944 PMCID: PMC4972389 DOI: 10.1038/nchembio.1093] [Citation(s) in RCA: 121] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Accepted: 09/14/2012] [Indexed: 12/21/2022]
Abstract
The finding that oxygenase-catalyzed protein hydroxylation regulates animal transcription raises questions as to whether the translation machinery and prokaryotic proteins are analogously modified. Escherichia coli ycfD is a growth-regulating 2-oxoglutarate oxygenase catalyzing arginyl hydroxylation of the ribosomal protein Rpl16. Human ycfD homologs, Myc-induced nuclear antigen (MINA53) and NO66, are also linked to growth and catalyze histidyl hydroxylation of Rpl27a and Rpl8, respectively. This work reveals new therapeutic possibilities via oxygenase inhibition and by targeting modified over unmodified ribosomes.
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Affiliation(s)
- Wei Ge
- Chemistry Research Laboratory and Oxford Centre for Integrative Systems Biology, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Alexander Wolf
- Chemistry Research Laboratory and Oxford Centre for Integrative Systems Biology, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Tianshu Feng
- Henry Wellcome Building for Molecular Physiology, University of Oxford, Oxford, OX3 7BN, UK
| | - Chia-hua Ho
- Chemistry Research Laboratory and Oxford Centre for Integrative Systems Biology, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Rok Sekirnik
- Chemistry Research Laboratory and Oxford Centre for Integrative Systems Biology, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Adam Zayer
- Henry Wellcome Building for Molecular Physiology, University of Oxford, Oxford, OX3 7BN, UK
| | - Nicolas Granatino
- Chemistry Research Laboratory and Oxford Centre for Integrative Systems Biology, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Matthew E. Cockman
- Henry Wellcome Building for Molecular Physiology, University of Oxford, Oxford, OX3 7BN, UK
| | - Christoph Loenarz
- Chemistry Research Laboratory and Oxford Centre for Integrative Systems Biology, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Nikita D. Loik
- Chemistry Research Laboratory and Oxford Centre for Integrative Systems Biology, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Adam P. Hardy
- Chemistry Research Laboratory and Oxford Centre for Integrative Systems Biology, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Timothy D.W. Claridge
- Chemistry Research Laboratory and Oxford Centre for Integrative Systems Biology, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Refaat B. Hamed
- Chemistry Research Laboratory and Oxford Centre for Integrative Systems Biology, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Rasheduzzaman Chowdhury
- Chemistry Research Laboratory and Oxford Centre for Integrative Systems Biology, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Lingzhi Gong
- Chemistry Research Laboratory and Oxford Centre for Integrative Systems Biology, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | | | - David C. Trudgian
- Biochemistry Dept and Proteomics Core, UT Southwestern Medical Center at Dallas, 6001 Forest Park Rd, Dallas, TX 75390-8816, USA
| | - Miao Jiang
- Chemistry Research Laboratory and Oxford Centre for Integrative Systems Biology, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Mukram M. Mackeen
- Chemistry Research Laboratory and Oxford Centre for Integrative Systems Biology, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - James S. Mccullagh
- Chemistry Research Laboratory and Oxford Centre for Integrative Systems Biology, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Yuliya Gordiyenko
- Chemistry Research Laboratory and Oxford Centre for Integrative Systems Biology, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Armin Thalhammer
- Chemistry Research Laboratory and Oxford Centre for Integrative Systems Biology, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Atsushi Yamamoto
- Henry Wellcome Building for Molecular Physiology, University of Oxford, Oxford, OX3 7BN, UK
| | - Ming Yang
- Henry Wellcome Building for Molecular Physiology, University of Oxford, Oxford, OX3 7BN, UK
| | - Phebee Liu-Yi
- Henry Wellcome Building for Molecular Physiology, University of Oxford, Oxford, OX3 7BN, UK
| | - Zhihong Zhang
- Chemistry Research Laboratory and Oxford Centre for Integrative Systems Biology, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Marion Schmidt-Zachmann
- Clinical Cooperation Unit Molecular Hematology/Oncology, German Cancer Research Center, 69120 Heidelberg, Germany
| | - Benedikt M. Kessler
- Henry Wellcome Building for Molecular Physiology, University of Oxford, Oxford, OX3 7BN, UK
| | - Peter J. Ratcliffe
- Henry Wellcome Building for Molecular Physiology, University of Oxford, Oxford, OX3 7BN, UK
| | - Gail M. Preston
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK
| | - Mathew L. Coleman
- Henry Wellcome Building for Molecular Physiology, University of Oxford, Oxford, OX3 7BN, UK
| | - Christopher J. Schofield
- Chemistry Research Laboratory and Oxford Centre for Integrative Systems Biology, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
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107
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Brien GL, Gambero G, O'Connell DJ, Jerman E, Turner SA, Egan CM, Dunne EJ, Jurgens MC, Wynne K, Piao L, Lohan AJ, Ferguson N, Shi X, Sinha KM, Loftus BJ, Cagney G, Bracken AP. Polycomb PHF19 binds H3K36me3 and recruits PRC2 and demethylase NO66 to embryonic stem cell genes during differentiation. Nat Struct Mol Biol 2012; 19:1273-81. [DOI: 10.1038/nsmb.2449] [Citation(s) in RCA: 201] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2012] [Accepted: 10/17/2012] [Indexed: 12/21/2022]
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108
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Zhou X, Tao Y, Wu M, Zhang D, Zang J. Purification, crystallization and preliminary crystallographic analysis of histone lysine demethylase NO66 from Homo sapiens. Acta Crystallogr Sect F Struct Biol Cryst Commun 2012; 68:764-6. [PMID: 22750859 DOI: 10.1107/s174430911201740x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Accepted: 04/19/2012] [Indexed: 11/10/2022]
Abstract
NO66 is a JmjC domain-containing histone demethylase with specificity towards histone H3 methylated on both Lys4 and Lys36 in vitro and in vivo. A fragment of NO66 lacking the N-terminal 167 amino-acid residues was overexpressed in Escherichia coli, purified and crystallized using the sitting-drop vapour-diffusion method. X-ray diffraction data were collected to a resolution of 2.29 Å. NO66 crystallized in space group P3(1) or P3(2), with unit-cell parameters a = 89.35, b = 89.35, c = 304.86 Å, α = β = 90, γ = 120°, and the crystal is likely to contain four molecules in the asymmetric unit.
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Affiliation(s)
- Xing Zhou
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, People's Republic of China
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109
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Wang X, Schröder HC, Diehl-Seifert B, Kropf K, Schlossmacher U, Wiens M, Müller WEG. Dual effect of inorganic polymeric phosphate/polyphosphate on osteoblasts and osteoclasts in vitro. J Tissue Eng Regen Med 2012; 7:767-76. [PMID: 22411908 DOI: 10.1002/term.1465] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Revised: 11/12/2011] [Accepted: 01/05/2012] [Indexed: 11/09/2022]
Abstract
Inorganic polymeric phosphate/polyphosphate (polyP) is a natural polymer existing in both pro- and eukaryotic systems. In the present study the effect of polyP as well as of polyP supplied in a stoichiometric ratio of 2 m polyP:1 m CaCl2 [polyP (Ca(2+) complex)] on the osteoblast-like SaOS-2 cells and the osteoclast-like RAW 264.7 cells was determined. Both polymers are non-toxic for these cells up to a concentration of 100 µm. In contrast to polyP, polyP (Ca(2+) complex) significantly induced hydroxyapatite formation at a concentration > 10 µm, as documented by alizarin red S staining and scanning electron microscopic (SEM) inspection. Furthermore, polyP (Ca(2+) complex) triggered in SaOS-2 cells transcription of BMP2 (bone morphogenetic protein 2), a cytokine involved in maturation of hydroxyapatite-forming cells. An additional activity of polyP (Ca(2+) complex) is described by showing that this polymer impairs osteoclastogenesis. At concentrations > 10 µm polyP (Ca(2+) complex) slows down the progression of RAW 264.7 cells to functional osteoclasts, as measured by the expression of TRAP (tartrate-resistant acid phosphatase). Finally, it is shown that 10-100 µm polyP (Ca(2+) complex) inhibited phosphorylation of IκBα by the respective kinase in RAW 264.7 cells. We concluded that polyP (Ca(2+) complex) displays a dual effect on bone metabolizing cells. It promotes hydroxyapatite formation in SaOS-2 cells (osteoblasts) and impairs maturation of the osteoclast-related RAW 264.7 cells.
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Affiliation(s)
- Xiaohong Wang
- National Research Centre for Geoanalysis, Chinese Academy of Geological Sciences, Beijing, People's Republic of China; ERC Advanced Investigator Grant Research Group, Institute for Physiological Chemistry, University Medical Centre, Johannes Gutenberg University, Mainz, Germany
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110
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Youn MY, Yokoyama A, Fujiyama-Nakamura S, Ohtake F, Minehata KI, Yasuda H, Suzuki T, Kato S, Imai Y. JMJD5, a Jumonji C (JmjC) domain-containing protein, negatively regulates osteoclastogenesis by facilitating NFATc1 protein degradation. J Biol Chem 2012; 287:12994-3004. [PMID: 22375008 DOI: 10.1074/jbc.m111.323105] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Osteoclastogenesis is a highly regulated process governed by diverse classes of regulators. Among them, nuclear factor of activated T-cells calcineurin-dependent 1 (NFATc1) is the primary osteoclastogenic transcription factor, and its expression is transcriptionally induced during early osteoclastogenesis by receptor activation of nuclear factor κB ligand (RANKL), an osteoclastogenic cytokine. Here, we report the novel enzymatic function of JMJD5, which regulates NFATc1 protein stability. Among the tested Jumonji C (JmjC) domain-containing proteins, decreased mRNA expression levels during osteoclastogenesis were found for JMJD5 in RAW264 cells stimulated by RANKL. To examine the functional role of JMJD5 in osteoclast differentiation, we established stable JMJD5 knockdown cells, and osteoclast formation was assessed. Down-regulated expression of JMJD5 led to accelerated osteoclast formation together with induction of several osteoclast-specific genes such as Ctsk and DC-STAMP, suggesting that JMJD5 is a negative regulator in osteoclast differentiation. Although JMJD5 was recently reported as a histone demethylase for histone H3K36me2, no histone demethylase activity was detected in JMJD5 in vitro or in living cells, even for other methylated histone residues. Instead, JMJD5 co-repressed transcriptional activity by destabilizing NFATc1 protein. Protein hydroxylase activity mediated by the JmjC domain in JMJD5 was required for the observed functions of JMJD5. JMJD5 induced the association of hydroxylated NFATc1 with the E3 ubiquitin ligase Von Hippel-Lindau tumor suppressor (VHL), thereby presumably facilitating proteasomal degradation of NFATc1 via ubiquitination. Taken together, the present study demonstrated that JMJD5 is a post-translational co-repressor for NFATc1 that attenuates osteoclastogenesis.
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Affiliation(s)
- Min-Young Youn
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-0032, Japan
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111
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Xu F, Flowers S, Moran E. Essential role of ARID2 protein-containing SWI/SNF complex in tissue-specific gene expression. J Biol Chem 2011; 287:5033-41. [PMID: 22184115 DOI: 10.1074/jbc.m111.279968] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Unfolding of the gene expression program that converts precursor cells to their terminally differentiated counterparts is critically dependent on the nucleosome-remodeling activity of the mammalian SWI/SNF complex. The complex can be powered by either of two alternative ATPases, BRM or BRG1. BRG1 is critical for development and the activation of tissue specific genes and is found in two major stable configurations. The complex of BRG1-associated factors termed BAF is the originally characterized form of mammalian SWI/SNF. A more recently recognized configuration shares many of the same subunits but is termed PBAF in recognition of a unique subunit, the polybromo protein (PBRM1). Two other unique subunits, BRD7 and ARID2, are also diagnostic of PBAF. PBAF plays an essential role in development, apparent from the embryonic lethality of Pbmr1-null mice, but very little is known about the role of PBAF, or its signature subunits, in tissue-specific gene expression in individual differentiation programs. Osteoblast differentiation is an attractive model for tissue-specific gene expression because the process is highly regulated and remains tightly synchronized over a period of several weeks. This model was used here, with a stable shRNA-mediated depletion approach, to examine the role of the signature PBAF subunit, ARID2, during differentiation. This analysis identifies a critical role for ARID2-containing complexes in promoting osteoblast differentiation and supports a view that the PBAF subset of SWI/SNF contributes importantly to maintaining cellular identity and activating tissue-specific gene expression.
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Affiliation(s)
- Fuhua Xu
- Department of Orthopaedics, New Jersey Medical School-University Hospital Cancer Center, University of Medicine and Dentistry of New Jersey, Newark, New Jersey 07103, USA
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112
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Goldring MB, Marcu KB. Epigenomic and microRNA-mediated regulation in cartilage development, homeostasis, and osteoarthritis. Trends Mol Med 2011; 18:109-18. [PMID: 22178468 DOI: 10.1016/j.molmed.2011.11.005] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Revised: 11/11/2011] [Accepted: 11/18/2011] [Indexed: 12/21/2022]
Abstract
Osteoarthritis (OA) is a multifactorial disease subject to the effects of many genes and environmental factors. Alterations in the normal pattern of chondrocyte gene control in cartilage facilitate the onset and progression of OA. Stable changes in patterns of gene expression, not associated with alterations in DNA sequences, occur through epigenetic changes, including DNA methylation, histone modifications, and alterations in chromatin structure, as well as by microRNA (miRNA)-mediated mechanisms. Moreover, the ability of the host to repair damaged cartilage is reflected in alterations in gene control circuits, suggestive of an epigenetic and miRNA-dependent tug-of-war between tissue homeostasis and OA disease pathogenesis. Herein, we summarize epigenetic and miRNA-mediated mechanisms impacting on OA progression and in this context offer potential therapeutic strategies for OA treatment.
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Affiliation(s)
- Mary B Goldring
- Research Division, The Hospital for Special Surgery, Weill Cornell Medical College, New York, NY 10021, USA.
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113
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Lie KK, Moren M. Retinoic acid induces two osteocalcin isoforms and inhibits markers of osteoclast activity in Atlantic cod (Gadus morhua) ex vivo cultured craniofacial tissues. Comp Biochem Physiol A Mol Integr Physiol 2011; 161:174-84. [PMID: 22075542 DOI: 10.1016/j.cbpa.2011.10.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Revised: 10/24/2011] [Accepted: 10/24/2011] [Indexed: 11/19/2022]
Abstract
Nutritional status including vitamin A could explain some of the developmental deformities observed in cultivated teleosts, including Atlantic cod (Gadus morhua). In the present study we aimed to investigate the transcriptional effect of retinoic acid (RA) on bone related genes using Atlantic cod craniofacial explants tissue cultures. Two different osteoblast specific osteocalcin/bone gla protein isoforms were discovered in cod. Transcription of both isoforms was up-regulated following RA treatment of 65 dph cod lower jaw explants. In contrast, transcripts coding for genes related to bone resorption and osteoclast activity, matrix metalloproteinase 9 and cathepsin K were down-regulated following RA treatment. This could be linked to the decreased transcriptional ratio between receptor activator of nuclear factor kappa-B ligand rankl and osteoprotegerin observed in the same tissue samples. RA treatment of juvenile explants had no effect on runt-related transcription factor 2 and osterix mRNA levels. However, osterix was significantly down-regulated in 25 dph cod head explants following RA treatment. In situ hybridizations revealed differential spatial distribution of the two isoforms and the predominant expression of cathepsin K in bone surrounding tissues. The present study indicates that RA causes a shift in the balance between osteoclast activity and osteoblast activity in favor of the latter.
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Affiliation(s)
- Kai Kristoffer Lie
- National Institute of Nutrition and Seafood Research, Nordnesboder 1-2, N-5005 Bergen, Norway.
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114
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Sengoku T, Yokoyama S. Structural basis for histone H3 Lys 27 demethylation by UTX/KDM6A. Genes Dev 2011; 25:2266-77. [PMID: 22002947 DOI: 10.1101/gad.172296.111] [Citation(s) in RCA: 110] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Tri- and dimethylations of histone H3K9 (H3K9me3/2) and H3K27 (H3K27me3/2), both situated in the "A-R-Kme-S" sequence motif, mediate transcriptional repression of distinct genomic regions. H3K9me3/2 mainly governs constitutive heterochromatin formation, while H3K27me3/2 represses key developmental genes. The mechanisms by which histone-modifying enzymes selectively regulate the methylation states of H3K9 and H3K27 are poorly understood. Here we report the crystal structures of the catalytic fragment of UTX/KDM6A, an H3K27me3/2-specific demethylase, in the free and H3 peptide-bound forms. The catalytic jumonji domain binds H3 residues 25-33, recognizing H3R26, H3A29, and H3P30 in a sequence-specific manner, in addition to H3K27me3 in the catalytic pocket. A novel zinc-binding domain, conserved within the KDM6 family, binds residues 17-21 of H3. The zinc-binding domain changes its conformation upon H3 binding, and thereby recognizes the H3L20 side chain via a hydrophobic patch on its surface, which is inaccessible in the H3-free form. Mutational analyses showed that H3R17, H3L20, H3R26, H3A29, H3P30, and H3T32 are each important for demethylation. No other methyllysines in the histone tails have the same set of residues at the corresponding positions. Thus, we clarified how UTX discriminates H3K27me3/2 from the other methyllysines with distinct roles, including the near-cognate H3K9me3/2, in histones.
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Affiliation(s)
- Toru Sengoku
- RIKEN Systems and Structural Biology Center, Tsurumi, Yokohama, Japan
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115
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Affiliation(s)
- Takayoshi Suzuki
- Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 13 Taishogun Nishitakatsukasa-Cho, Kita-ku, Kyoto 403-8334, Japan.
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Niger C, Lima F, Yoo DJ, Gupta RR, Buo AM, Hebert C, Stains JP. The transcriptional activity of osterix requires the recruitment of Sp1 to the osteocalcin proximal promoter. Bone 2011; 49:683-92. [PMID: 21820092 PMCID: PMC3170016 DOI: 10.1016/j.bone.2011.07.027] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Revised: 07/13/2011] [Accepted: 07/16/2011] [Indexed: 12/11/2022]
Abstract
The transcription factor osterix (Osx/Sp7) is required for osteogenic differentiation and bone formation in vivo. While Osx can act at canonical Sp1 DNA-binding sites and/or interact with NFATc1 to cooperatively regulate transcription in some osteoblast promoters, little is known about the molecular details by which Osx regulates osteocalcin (OCN) transcription. We previously identified in the OCN proximal promoter a minimal C/T-rich motif, termed OCN-CxRE (connexin-response element) that binds Sp1 and Sp3 in a gap junction-dependent manner. In the present study, we hypothesized that Osx could act via this non-canonical Sp1/Sp3-binding element to regulate OCN transcription. OCN promoter luciferase reporter assays show that Osx alone is an insufficient activator that requires Sp1, but not Sp3, to synergistically stimulate OCN promoter activity. Moreover, promoter deletion analyses demonstrate that both the Sp1/Sp3-binding OCN-CxRE (-70 to -57) and the -92 to -87 region of the OCN proximal promoter are critical for Osx/Sp1 synergistic activities. Our data show that Sp1 influences Osx activity by enhancing Osx occupancy on the OCN promoter, perhaps via physical interactions between the two transcription factors. Finally, alteration of the expression of the gap junction protein connexin43 modulates the recruitment of both Sp1 and Osx to the OCN promoter. In total, our data are strongly in support of Sp1 as an essential transcription factor required for Osx recruitment and transactivation of the OCN promoter. Further, these data lend insight into a mechanism by which alteration of connexin43 impacts osteogenesis in vitro and in vivo.
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Affiliation(s)
- Corinne Niger
- Department of Orthopaedics, University of Maryland, School of Medicine, Baltimore, MD, USA.
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117
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Chen F, Zhang X, Sun S, Zara JN, Zou X, Chiu R, Culiat CT, Ting K, Soo C. NELL-1, an osteoinductive factor, is a direct transcriptional target of Osterix. PLoS One 2011; 6:e24638. [PMID: 21931789 PMCID: PMC3172249 DOI: 10.1371/journal.pone.0024638] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2010] [Accepted: 08/17/2011] [Indexed: 11/24/2022] Open
Abstract
NELL-1 is a novel secreted protein associated with premature fusion of cranial sutures in craniosynostosis that has been found to promote osteoblast cell differentiation and mineralization. Our previous study showed that Runx2, the key transcription factor in osteoblast differentiation, transactivates the NELL-1 promoter. In this study, we evaluated the regulatory involvement and mechanisms of Osterix, an essential transcription factor of osteoblasts, in NELL-1 gene expression and function. Promoter analysis showed a cluster of potential Sp1 sites (Sp1/Osterix binding sites) within approximately 70 bp (from -71 to -142) of the 5' flanking region of the human NELL-1 transcriptional start site. Luciferase activity in our NELL-1 promoter reporter systems was significantly decreased in Saos-2 cells when Osterix was overexpressed. Mutagenesis study demonstrated that this suppression is mediated by the Sp1 sites. The binding specificity of Osterix to these Sp1 sites was confirmed in Saos-2 cells and primary human osteoblasts by EMSA in vitro and ChIP assay in vivo. ChIP assay also showed that Osterix downregulated NELL-1 by affecting binding of RNA polymerase II to the NELL-1 promoter, but not by competing with Runx2 binding to the OSE2 sites. Moreover, NELL-1 mRNA levels were significantly decreased when Osterix was overexpressed in Saos-2, U2OS, Hela and Glioma cells. Correspondingly, knockdown of Osterix increased NELL-1 transcription and osteoblastic differentiation in both Saos-2 cells and primary human osteoblasts. These results suggest that Osterix is a direct transcriptional regulator with repressive effect on NELL-1 gene expression, contributing to a delicate balance of regulatory effects on NELL-1 transcription with Runx2, and may play a crucial role in osteoblast differentiation and mineralization. These findings also extend our understanding of the molecular mechanism of Runx2, Osterix, and NELL-1 and demonstrate their crosstalk during osteogenesis.
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Affiliation(s)
- Feng Chen
- Dental and Craniofacial Research Institute, University of California Los Angeles, Los Angeles, United States of America
- School and Hospital of Stomatology, Peking University, Beijing, China
| | - Xinli Zhang
- Dental and Craniofacial Research Institute, University of California Los Angeles, Los Angeles, United States of America
| | - Shan Sun
- School of Dentistry, University of California Los Angeles, Los Angeles, United States of America
| | - Janette N. Zara
- Department of Bioengineering, University of California Los Angeles, Los Angeles, United States of America
| | - Xuan Zou
- Dental and Craniofacial Research Institute, University of California Los Angeles, Los Angeles, United States of America
| | - Robert Chiu
- School of Dentistry, University of California Los Angeles, Los Angeles, United States of America
| | - Cymbelin T. Culiat
- Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
| | - Kang Ting
- Dental and Craniofacial Research Institute, University of California Los Angeles, Los Angeles, United States of America
- School of Dentistry, University of California Los Angeles, Los Angeles, United States of America
| | - Chia Soo
- Orthopaedic Hospital, Department of Orthopaedic Surgery and the Orthopaedic Hospital Research Center, University of California Los Angeles, Los Angeles, United States of America
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118
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Affiliation(s)
- Diane E. Handy
- Cardiovascular Division, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA
| | - Rita Castro
- Cardiovascular Division, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA
- Metabolism & Genetics Group, Research Institute for Medicines and Pharmaceutical Sciences (iMed.UL), Faculty of Pharmacy, University of Lisbon, Portugal
| | - Joseph Loscalzo
- Cardiovascular Division, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA
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Rose NR, McDonough MA, King ONF, Kawamura A, Schofield CJ. Inhibition of 2-oxoglutarate dependent oxygenases. Chem Soc Rev 2011; 40:4364-97. [PMID: 21390379 DOI: 10.1039/c0cs00203h] [Citation(s) in RCA: 307] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
2-Oxoglutarate (2OG) dependent oxygenases are ubiquitous iron enzymes that couple substrate oxidation to the conversion of 2OG to succinate and carbon dioxide. In humans their roles include collagen biosynthesis, fatty acid metabolism, DNA repair, RNA and chromatin modifications, and hypoxic sensing. Commercial applications of 2OG oxygenase inhibitors began with plant growth retardants, and now extend to a clinically used pharmaceutical compound for cardioprotection. Several 2OG oxygenases are now being targeted for therapeutic intervention for diseases including anaemia, inflammation and cancer. In this critical review, we describe studies on the inhibition of 2OG oxygenases, focusing on small molecules, and discuss the potential of 2OG oxygenases as therapeutic targets (295 references).
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Affiliation(s)
- Nathan R Rose
- Department of Chemistry and the Oxford Centre for Integrative Systems Biology, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
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120
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Aravind L, Abhiman S, Iyer LM. Natural history of the eukaryotic chromatin protein methylation system. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2011; 101:105-76. [PMID: 21507350 DOI: 10.1016/b978-0-12-387685-0.00004-4] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In eukaryotes, methylation of nucleosomal histones and other nuclear proteins is a central aspect of chromatin structure and dynamics. The past 15 years have seen an enormous advance in our understanding of the biochemistry of these modifications, and of their role in establishing the epigenetic code. We provide a synthetic overview, from an evolutionary perspective, of the main players in the eukaryotic chromatin protein methylation system, with an emphasis on catalytic domains. Several components of the eukaryotic protein methylation system had their origins in bacteria. In particular, the Rossmann fold protein methylases (PRMTs and DOT1), and the LSD1 and jumonji-related demethylases and oxidases, appear to have emerged in the context of bacterial peptide methylation and hydroxylation systems. These systems were originally involved in synthesis of peptide secondary metabolites, such as antibiotics, toxins, and siderophores. The peptidylarginine deiminases appear to have been acquired by animals from bacterial enzymes that modify cell-surface proteins. SET domain methylases, which display the β-clip fold, apparently first emerged in prokaryotes from the SAF superfamily of carbohydrate-binding domains. However, even in bacteria, a subset of the SET domains might have evolved a chromatin-related role in conjunction with a BAF60a/b-like SWIB domain protein and topoisomerases. By the time of the last eukaryotic common ancestor, multiple SET and PRMT methylases were already in place and are likely to have mediated methylation at the H3K4, H3K9, H3K36, and H4K20 positions, and carried out both asymmetric and symmetric arginine dimethylation. Inference of H3K27 methylation in the ancestral eukaryote appears uncertain, though it was certainly in place a little later in eukaryotic evolution. Current data suggest that unlike SET methylases, which are universally present in eukaryotes, demethylases are not. They appear to be absent in the earliest-branching eukaryotic lineages, and emerged later along with several other chromatin proteins, such as the Dot1-methylase, prior to divergence of the kinetoplastid-heterolobosean lineage from the remaining eukaryotes. This period also corresponds to the point of origin of DNA cytosine methylation by DNMT1. Origin of major lineages of SET domains such as the Trithorax, Su(var)3-9, Ash1, SMYD, and TTLL12 and E(Z) might have played the initial role in the establishment of multiple distinct heterochromatic and euchromatic states that are likely to have been present, in some form, through much of eukaryotic evolution. Elaboration of these chromatin states might have gone hand-in-hand with acquisition of multiple jumonji-related and LSD1-like demethylases, and functional linkages with the DNA methylation and RNAi systems. Throughout eukaryotic evolution, there were several lineage-specific expansions of SET domain proteins, which might be related to a special transcription regulation process in trypanosomes, acquisition of new meiotic recombination hotspots in animals, and methylation and associated modifications of the diatom silaffin proteins involved in silica biomineralization. The use of specific domains to "read" the methylation marks appears to have been present in the ancestral eukaryote itself. Of these the chromo-like domains appear to have been acquired from bacterial secreted proteins that might have a role in binding cell-surface peptides or peptidoglycan. Domain architectures of the primary enzymes involved in the eukaryotic protein methylation system indicate key features relating to interactions with each other and other modifications in chromatin, such as acetylation. They also emphasize the profound functional distinction between the role of demethylation and deacetylation in regulation of chromatin dynamics.
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Affiliation(s)
- L Aravind
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, USA
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121
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Landeira D, Fisher AG. Inactive yet indispensable: the tale of Jarid2. Trends Cell Biol 2010; 21:74-80. [PMID: 21074441 PMCID: PMC3034028 DOI: 10.1016/j.tcb.2010.10.004] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Revised: 10/05/2010] [Accepted: 10/08/2010] [Indexed: 12/03/2022]
Abstract
Methylation of histone tails is believed to be important for the establishment and inheritance of gene expression programs during development. Jarid2/Jumonji is the founding member of a family of chromatin modifiers with histone demethylase activity. Although Jarid2 contains amino acid substitutions that are thought to abolish its catalytic activity, it is essential for the development of multiple organs in mice. Recent studies have shown that Jarid2 is a component of the polycomb repressive complex 2 and is required for embryonic stem (ES) cell differentiation. Here, we discuss current literature on the function of Jarid2 and hypothesize that defects resulting from Jarid2 deficiency arise from a failure to correctly prime genes in ES cells that are required for later stages in development.
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Affiliation(s)
- David Landeira
- Lymphocyte Development Group, MRC Clinical Sciences Centre, Imperial College School of Medicine, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK
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122
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Nordstrand LM, Svärd J, Larsen E, Nilsen A, Ougland R, Furu K, Lien GF, Rognes T, Namekawa SH, Lee JT, Klungland A. Mice lacking Alkbh1 display sex-ratio distortion and unilateral eye defects. PLoS One 2010; 5:e13827. [PMID: 21072209 PMCID: PMC2972218 DOI: 10.1371/journal.pone.0013827] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Accepted: 10/14/2010] [Indexed: 11/26/2022] Open
Abstract
Background Eschericia coli AlkB is a 2-oxoglutarate- and iron-dependent dioxygenase that reverses alkylated DNA damage by oxidative demethylation. Mouse AlkB homolog 1 (Alkbh1) is one of eight members of the newly discovered family of mammalian dioxygenases. Methods and Findings In the present study we show non-Mendelian inheritance of the Alkbh1 targeted allele in mice. Both Alkbh1−/− and heterozygous Alkbh1+/− offspring are born at a greatly reduced frequency. Additionally, the sex-ratio is considerably skewed against female offspring, with one female born for every three to four males. Most mechanisms that cause segregation distortion, act in the male gametes and affect male fertility. The skewing of the sexes appears to be of paternal origin, and might be set in the pachythene stage of meiosis during spermatogenesis, in which Alkbh1 is upregulated more than 10-fold. In testes, apoptotic spermatids were revealed in 5–10% of the tubules in Alkbh1−/− adults. The deficiency of Alkbh1 also causes misexpression of Bmp2, 4 and 7 at E11.5 during embryonic development. This is consistent with the incompletely penetrant phenotypes observed, particularly recurrent unilateral eye defects and craniofacial malformations. Conclusions Genetic and phenotypic assessment suggests that Alkbh1 mediates gene regulation in spermatogenesis, and that Alkbh1 is essential for normal sex-ratio distribution and embryonic development in mice.
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Affiliation(s)
- Line M. Nordstrand
- Centre for Molecular Biology and Neuroscience, Institute of Medical Microbiology, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Jessica Svärd
- Centre for Molecular Biology and Neuroscience, Institute of Medical Microbiology, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Elisabeth Larsen
- Centre for Molecular Biology and Neuroscience, Institute of Medical Microbiology, Oslo University Hospital and University of Oslo, Oslo, Norway
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Anja Nilsen
- Centre for Molecular Biology and Neuroscience, Institute of Medical Microbiology, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Rune Ougland
- Centre for Molecular Biology and Neuroscience, Institute of Medical Microbiology, Oslo University Hospital and University of Oslo, Oslo, Norway
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Kari Furu
- Centre for Molecular Biology and Neuroscience, Institute of Medical Microbiology, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Guro F. Lien
- Centre for Molecular Biology and Neuroscience, Institute of Medical Microbiology, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Torbjørn Rognes
- Centre for Molecular Biology and Neuroscience, Institute of Medical Microbiology, Oslo University Hospital and University of Oslo, Oslo, Norway
- Department of Informatics, University of Oslo, Oslo, Norway
| | - Satoshi H. Namekawa
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Jeannie T. Lee
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Arne Klungland
- Centre for Molecular Biology and Neuroscience, Institute of Medical Microbiology, Oslo University Hospital and University of Oslo, Oslo, Norway
- Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
- * E-mail:
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Ortuño MJ, Ruiz-Gaspà S, Rodríguez-Carballo E, Susperregui ARG, Bartrons R, Rosa JL, Ventura F. p38 regulates expression of osteoblast-specific genes by phosphorylation of osterix. J Biol Chem 2010; 285:31985-94. [PMID: 20682789 DOI: 10.1074/jbc.m110.123612] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Osterix, a zinc finger transcription factor, is specifically expressed in osteoblasts and osteocytes of all developing bones. Because no bone formation occurs in Osx-null mice, Osterix is thought to be an essential regulator of osteoblast differentiation. We report that, in several mesenchymal and osteoblastic cell types, BMP-2 induces an increase in expression of the two isoforms of Osterix arising from two alternative promoters. We identified a consensus Sp1 sequence (GGGCGG) as Osterix binding regions in the fibromodulin and the bone sialoprotein promoters in vitro and in vivo. Furthermore, we show that Osterix is a novel substrate for p38 MAPK in vitro and in vivo and that Ser-73 and Ser-77 are the regulatory sites phosphorylated by p38. Our data also demonstrate that Osterix is able to increase recruitment of p300 and Brg1 to the promoters of its target genes fibromodulin and bone sialoprotein in vivo and that it directly associates with these cofactors through protein-protein interactions. Phosphorylation of Osterix at Ser-73/77 increased its ability to recruit p300 and SWI/SNF to either fibromodulin or bone sialoprotein promoters. We therefore propose that Osterix binds to Sp1 sequences on target gene promoters and that its phosphorylation by p38 enhances recruitment of coactivators to form transcriptionally active complexes.
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Affiliation(s)
- María José Ortuño
- Departament de Ciències Fisiològiques II, Universitat de Barcelona, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), E-08907 L'Hospitalet de Llobregat, Spain
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124
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The chromosome peripheral proteins play an active role in chromosome dynamics. Biomol Concepts 2010; 1:157-64. [DOI: 10.1515/bmc.2010.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
AbstractThe chromosome periphery is a chromosomal structure that covers the surface of mitotic chromosomes. The structure and function of the chromosome periphery has been poorly understood since its first description in 1882. It has, however, been proposed to be an insulator or barrier to protect chromosomes from subcellular substances and to act as a carrier of nuclear and nucleolar components to direct their equal distribution to daughter cells because most chromosome peripheral proteins (CPPs) are derived from the nucleolus or nucleus. Until now, more than 30 CPPs were identified in mammalians. Recent immunostaining analyses of CPPs have revealed that the chromosome periphery covers the centromeric region of mitotic chromosomes in addition to telomeres and regions between two sister chromatids. Knockdown analyses of CPPs using RNAi have revealed functions in chromosome dynamics, including cohesion of sister chromatids, kinetochore-microtubule attachments, spindle assembly and chromosome segregation. Because most CPPs are involved in various subcellular events in the nucleolus or nuclear at interphase, a temporal and spatial-specific knockdown method of CPPs in the chromosome periphery will be useful to understand the function of chromosome periphery in cell division.
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125
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Iyer LM, Abhiman S, de Souza RF, Aravind L. Origin and evolution of peptide-modifying dioxygenases and identification of the wybutosine hydroxylase/hydroperoxidase. Nucleic Acids Res 2010; 38:5261-79. [PMID: 20423905 PMCID: PMC2938197 DOI: 10.1093/nar/gkq265] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Unlike classical 2-oxoglutarate and iron-dependent dioxygenases, which include several nucleic acid modifiers, the structurally similar jumonji-related dioxygenase superfamily was only known to catalyze peptide modifications. Using comparative genomics methods, we predict that a family of jumonji-related enzymes catalyzes wybutosine hydroxylation/peroxidation at position 37 of eukaryotic tRNAPhe. Identification of this enzyme raised questions regarding the emergence of protein- and nucleic acid-modifying activities among jumonji-related domains. We addressed these with a natural classification of DSBH domains and reconstructed the precursor of the dioxygenases as a sugar-binding domain. This precursor gave rise to sugar epimerases and metal-binding sugar isomerases. The sugar isomerase active site was exapted for catalysis of oxygenation, with a radiation of these enzymes in bacteria, probably due to impetus from the primary oxygenation event in Earth’s history. 2-Oxoglutarate-dependent versions appear to have further expanded with rise of the tricarboxylic acid cycle. We identify previously under-appreciated aspects of their active site and multiple independent innovations of 2-oxoacid-binding basic residues among these superfamilies. We show that double-stranded β-helix dioxygenases diversified extensively in biosynthesis and modification of halogenated siderophores, antibiotics, peptide secondary metabolites and glycine-rich collagen-like proteins in bacteria. Jumonji-related domains diversified into three distinct lineages in bacterial secondary metabolism systems and these were precursors of the three major clades of eukaryotic enzymes. The specificity of wybutosine hydroxylase/peroxidase probably relates to the structural similarity of the modified moiety to the ancestral amino acid substrate of this superfamily.
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Affiliation(s)
- Lakshminarayan M Iyer
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
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Abstract
Vertebrate skeletogenesis consists in elaborating an edifice of more than 200 pieces of bone and cartilage. Each skeletal piece is crafted at a distinct location in the body, is articulated with others, and reaches a specific size, shape, and tissue composition according to both species instructions and individual determinants. This complex, customized body frame fulfills multiple essential tasks. It confers morphological features, allows controlled postures and movements, protects vital organs, houses hematopoiesis, stores minerals, and adsorbs toxins. This review provides an overview of the multiple facets of this ingenious process for experts as well as nonexperts of skeletogenesis. We explain how the developing vertebrate uses both specific and ubiquitously expressed genes to generate multipotent mesenchymal cells, specify them to a skeletogenic fate, control their survival and proliferation, and direct their differentiation into cartilage, bone, and joint cells. We review milestone discoveries made toward uncovering the intricate networks of regulatory factors that are involved in these processes, with an emphasis on signaling pathways and transcription factors. We describe numerous skeletal malformation and degeneration diseases that occur in humans as a result of mutations in regulatory genes, and explain how these diseases both help and motivate us to further decipher skeletogenic processes. Upon discussing current knowledge and gaps in knowledge in the control of skeletogenesis, we highlight ultimate research goals and propose research priorities and approaches for future endeavors.
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Affiliation(s)
- Véronique Lefebvre
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
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