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Sample records for polycomb group target

  1. Polycomb group targeting through different binding partners of RING1B C-terminal domain.

    PubMed

    Wang, Renjing; Taylor, Alexander B; Leal, Belinda Z; Chadwell, Linda V; Ilangovan, Udayar; Robinson, Angela K; Schirf, Virgil; Hart, P John; Lafer, Eileen M; Demeler, Borries; Hinck, Andrew P; McEwen, Donald G; Kim, Chongwoo A

    2010-08-11

    RING1B, a Polycomb Group (PcG) protein, binds methylated chromatin through its association with another PcG protein called Polycomb (Pc). However, RING1B can associate with nonmethylated chromatin suggesting an alternate mechanism for RING1B interaction with chromatin. Here, we demonstrate that two proteins with little sequence identity between them, the Pc cbox domain and RYBP, bind the same surface on the C-terminal domain of RING1B (C-RING1B). Pc cbox and RYBP each fold into a nearly identical, intermolecular beta sheet with C-RING1B and a loop structure which are completely different in the two proteins. Both the beta sheet and loop are required for stable binding and transcription repression. Further, a mutation engineered to disrupt binding on the Drosophila dRING1 protein prevents chromatin association and PcG function in vivo. These results suggest that PcG targeting to different chromatin locations relies, in part, on binding partners of C-RING1B that are diverse in sequence and structure.

  2. Deregulated Expression of the Polycomb-Group Protein SUZ12 Target Genes Characterizes Mantle Cell Lymphoma

    PubMed Central

    Martín-Pérez, Daniel; Sánchez, Esther; Maestre, Lorena; Suela, Javier; Vargiu, Pierfrancesco; Di Lisio, Lorena; Martínez, Nerea; Alves, Javier; Piris, Miguel A.; Sánchez-Beato, Margarita

    2010-01-01

    Polycomb proteins are known to be of great importance in human cancer pathogenesis. SUZ12 is a component of the Polycomb PRC2 complex that, along with EZH2, is involved in embryonic stem cell differentiation. EZH2 plays an essential role in many cancer types, but an equivalent involvement of SUZ12 has not been as thoroughly demonstrated. Here we show that SUZ12 is anomalously expressed in human primary tumors, especially in mantle cell lymphoma (MCL), pulmonary carcinomas and melanoma, and is associated with gene locus amplification in some cases. Using MCL as a model, functional and genomic studies demonstrate that SUZ12 loss compromises cell viability, increases apoptosis, and targets genes involved in central oncogenic pathways associated with MCL pathogenesis. Our results support the hypothesis that the abnormal expression of SUZ12 accounts for some of the unexplained features of MCL, such as abnormal DNA repair and increased resistance to apoptosis. PMID:20558579

  3. Interactions with RNA direct the Polycomb group protein SCML2 to chromatin where it represses target genes

    PubMed Central

    Bonasio, Roberto; Lecona, Emilio; Narendra, Varun; Voigt, Philipp; Parisi, Fabio; Kluger, Yuval; Reinberg, Danny

    2014-01-01

    Polycomb repressive complex-1 (PRC1) is essential for the epigenetic regulation of gene expression. SCML2 is a mammalian homolog of Drosophila SCM, a Polycomb-group protein that associates with PRC1. In this study, we show that SCML2A, an SCML2 isoform tightly associated to chromatin, contributes to PRC1 localization and also directly enforces repression of certain Polycomb target genes. SCML2A binds to PRC1 via its SPM domain and interacts with ncRNAs through a novel RNA-binding region (RBR). Targeting of SCML2A to chromatin involves the coordinated action of the MBT domains, RNA binding, and interaction with PRC1 through the SPM domain. Deletion of the RBR reduces the occupancy of SCML2A at target genes and overexpression of a mutant SCML2A lacking the RBR causes defects in PRC1 recruitment. These observations point to a role for ncRNAs in regulating SCML2 function and suggest that SCML2 participates in the epigenetic control of transcription directly and in cooperation with PRC1. DOI: http://dx.doi.org/10.7554/eLife.02637.001 PMID:24986859

  4. Complementary Activities of TELOMERE REPEAT BINDING Proteins and Polycomb Group Complexes in Transcriptional Regulation of Target Genes[OPEN

    PubMed Central

    Hartwig, Benjamin; James, Geo Velikkakam

    2016-01-01

    In multicellular organisms, Polycomb Repressive Complex 1 (PRC1) and PRC2 repress target genes through histone modification and chromatin compaction. Arabidopsis thaliana mutants strongly compromised in the pathway cannot develop differentiated organs. LIKE HETEROCHROMATIN PROTEIN1 (LHP1) is so far the only known plant PRC1 component that directly binds to H3K27me3, the histone modification set by PRC2, and also associates genome-wide with trimethylation of lysine 27 of histone H3 (H3K27me3). Surprisingly, lhp1 mutants show relatively mild phenotypic alterations. To explain this paradox, we screened for genetic enhancers of lhp1 mutants to identify novel components repressing target genes together with, or in parallel to, LHP1. Two enhancing mutations were mapped to TELOMERE REPEAT BINDING PROTEIN1 (TRB1) and its paralog TRB3. We show that TRB1 binds to thousands of genomic sites containing telobox or related cis-elements with a significant increase of sites and strength of binding in the lhp1 background. Furthermore, in combination with lhp1, but not alone, trb1 mutants show increased transcription of LHP1 targets, such as floral meristem identity genes, which are more likely to be bound by TRB1 in the lhp1 background. By contrast, expression of a subset of LHP1-independent TRB1 target genes, many involved in primary metabolism, is decreased in the absence of TRB1 alone. Thus, TRB1 is a bivalent transcriptional modulator that maintains downregulation of Polycomb Group (PcG) target genes in lhp1 mutants, while it sustains high expression of targets that are regulated independently of PcG. PMID:26721861

  5. SUMOylation of the polycomb group protein L3MBTL2 facilitates repression of its target genes

    PubMed Central

    Stielow, Christina; Stielow, Bastian; Finkernagel, Florian; Scharfe, Maren; Jarek, Michael; Suske, Guntram

    2014-01-01

    Lethal(3) malignant brain tumour like 2 (L3MBTL2) is an integral component of the polycomb repressive complex 1.6 (PRC1.6) and has been implicated in transcriptional repression and chromatin compaction. Here, we show that L3MBTL2 is modified by SUMO2/3 at lysine residues 675 and 700 close to the C-terminus. SUMOylation of L3MBTL2 neither affected its repressive activity in reporter gene assays nor it’s binding to histone tails in vitro. In order to analyse whether SUMOylation affects binding of L3MBTL2 to chromatin, we performed ChIP-Seq analysis with chromatin of wild-type HEK293 cells and with chromatin of HEK293 cells stably expressing either FLAG-tagged SUMOylation-competent or SUMOylation-defective L3MBTL2. Wild-type FLAG-L3MBTL2 and the SUMOylation-defective FLAG-L3MBTL2 K675/700R mutant essentially occupied the same sites as endogenous L3MBTL2 suggesting that SUMOylation of L3MBTL2 does not affect chromatin binding. However, a subset of L3MBTL2-target genes, particularly those with low L3MBTL2 occupancy including pro-inflammatory genes, was de-repressed in cells expressing the FLAG-L3MBTL2 K675/700R mutant. Finally, we provide evidence that SUMOylation of L3MBTL2 facilitates repression of these PRC1.6-target genes by balancing the local H2Aub1 levels established by the ubiquitinating enzyme RING2 and the de-ubiquitinating PR–DUB complex. PMID:24369422

  6. Are we there yet? Initial targeting of the Male-Specific Lethal and Polycomb group chromatin complexes in Drosophila

    PubMed Central

    McElroy, Kyle A.; Kang, Hyuckjoon; Kuroda, Mitzi I.

    2014-01-01

    Chromatin-binding proteins must navigate the complex nuclear milieu to find their sites of action, and a constellation of protein factors and other properties are likely to influence targeting specificity. Despite considerable progress, the precise rules by which binding specificity is achieved have remained elusive. Here, we consider early targeting events for two groups of chromatin-binding complexes in Drosophila: the Male-Specific Lethal (MSL) and the Polycomb group (PcG) complexes. These two serve as models for understanding targeting, because they have been extensively studied and play vital roles in Drosophila, and their targets have been documented at high resolution. Furthermore, the proteins and biochemical properties of both complexes are largely conserved in multicellular organisms, including humans. While the MSL complex increases gene expression and PcG members repress genes, the two groups share many similarities such as the ability to modify their chromatin environment to create active or repressive domains, respectively. With legacies of in-depth genetic, biochemical and now genomic approaches, the MSL and PcG complexes will continue to provide tractable systems for understanding the recruitment of multiprotein chromatin complexes to their target loci. PMID:24671948

  7. Coordinated regulation of Myc trans-activation targets by Polycomb and the Trithorax group protein Ash1

    PubMed Central

    Goodliffe, Julie M; Cole, Michael D; Wieschaus, Eric

    2007-01-01

    Background The Myc oncoprotein is a transcriptional regulator whose function is essential for normal development. Myc is capable of binding to 10% of the mammalian genome, and it is unclear how a developing embryo controls the DNA binding of its abundant Myc proteins in order to avoid Myc's potential for inducing tumorigenesis. Results To identify chromatin binding proteins with a potential role in controlling Myc activity, we established a genetic assay for dMyc activity in Drosophila. We conducted a genome-wide screen using this assay, and identified the Trithorax Group protein Ash1 as a modifier of dMyc activity. Ash1 is a histone methyltransferase known for its role in opposing repression by Polycomb. Using RNAi in the embryo and Affymetrix microarrays, we show that ash1 RNAi causes the increased expression of many genes, suggesting that it is directly or indirectly required for repression in the embryo, in contrast to its known role in maintenance of activation. Many of these genes also respond similarly upon depletion of Pc and pho transcripts, as determined by concurrent microarray analysis of Pc and pho RNAi embryos, suggesting that the three are required for low levels of expression of a common set of targets. Further, many of these overlapping targets are also activated by Myc overexpression. We identify a second group of genes whose expression in the embryo requires Ash1, consistent with its previously established role in maintenance of activation. We find that this second group of Ash1 targets overlaps those activated by Myc and that ectopic Myc overcomes their requirement for Ash1. Conclusion Genetic, genomic and chromatin immunoprecipitation data suggest a model in which Pc, Ash1 and Pho are required to maintain a low level of expression of embryonic targets of activation by Myc, and that this occurs, directly or indirectly, by a combination of disparate chromatin modifications. PMID:17519021

  8. Transcriptional Silencing by Polycomb-Group Proteins

    PubMed Central

    Grossniklaus, Ueli; Paro, Renato

    2014-01-01

    Polycomb-group (PcG) genes encode chromatin proteins involved in stable and heritable transcriptional silencing. PcG proteins participate in distinct multimeric complexes that deposit, or bind to, specific histone modifications (e.g., H3K27me3 and H2AK119ub1) to prevent gene activation and maintain repressed chromatin domains. PcG proteins are evolutionary conserved and play a role in processes ranging from vernalization and seed development in plants, over X-chromosome inactivation in mammals, to the maintenance of stem cell identity. PcG silencing is medically relevant as it is often observed in human disorders, including cancer, and tissue regeneration, which involve the reprogramming of PcG-controlled target genes. PMID:25367972

  9. Selective Interactions between Vertebrate Polycomb Homologs and the SUV39H1 Histone Lysine Methyltransferase Suggest that Histone H3-K9 Methylation Contributes to Chromosomal Targeting of Polycomb Group Proteins

    PubMed Central

    Sewalt, Richard G. A. B.; Lachner, Monika; Vargas, Mark; Hamer, Karien M.; den Blaauwen, Jan L.; Hendrix, Thijs; Melcher, Martin; Schweizer, Dieter; Jenuwein, Thomas; Otte, Arie P.

    2002-01-01

    Polycomb group (PcG) proteins form multimeric chromatin-associated protein complexes that are involved in heritable repression of gene activity. Two distinct human PcG complexes have been characterized. The EED/EZH2 PcG complex utilizes histone deacetylation to repress gene activity. The HPC/HPH PcG complex contains the HPH, RING1, BMI1, and HPC proteins. Here we show that vertebrate Polycomb homologs HPC2 and XPc2, but not M33/MPc1, interact with the histone lysine methyltransferase (HMTase) SUV39H1 both in vitro and in vivo. We further find that overexpression of SUV39H1 induces selective nuclear relocalization of HPC/HPH PcG proteins but not of the EED/EZH2 PcG proteins. This SUV39H1-dependent relocalization concentrates the HPC/HPH PcG proteins to the large pericentromeric heterochromatin domains (1q12) on human chromosome 1. Within these PcG domains we observe increased H3-K9 methylation. Finally, we show that H3-K9 HMTase activity is associated with endogenous HPC2. Our findings suggest a role for the SUV39H1 HMTase and histone H3-K9 methylation in the targeting of human HPC/HPH PcG proteins to modified chromatin structures. PMID:12101246

  10. Genome-wide analysis of Polycomb targets in Drosophila

    SciTech Connect

    Schwartz, Yuri B.; Kahn, Tatyana G.; Nix, David A.; Li,Xiao-Yong; Bourgon, Richard; Biggin, Mark; Pirrotta, Vincenzo

    2006-04-01

    Polycomb Group (PcG) complexes are multiprotein assemblages that bind to chromatin and establish chromatin states leading to epigenetic silencing. PcG proteins regulate homeotic genes in flies and vertebrates but little is known about other PcG targets and the role of the PcG in development, differentiation and disease. We have determined the distribution of the PcG proteins PC, E(Z) and PSC and of histone H3K27 trimethylation in the Drosophila genome. At more than 200 PcG target genes, binding sites for the three PcG proteins colocalize to presumptive Polycomb Response Elements (PREs). In contrast, H3 me3K27 forms broad domains including the entire transcription unit and regulatory regions. PcG targets are highly enriched in genes encoding transcription factors but receptors, signaling proteins, morphogens and regulators representing all major developmental pathways are also included.

  11. Polycomb group protein bodybuilding: working out the routines.

    PubMed

    Sievers, Cem; Paro, Renato

    2013-09-30

    Polycomb group (PcG) proteins regulate gene expression by modifying chemical and structural properties of chromatin. Isono et al. (2013) now report in Developmental Cell a polymerization-dependent mechanism used by PcG proteins to form higher-order chromatin structures, referred to as Polycomb bodies, and demonstrate its necessity for gene silencing.

  12. Insulators, not Polycomb response elements, are required for long-range interactions between Polycomb targets in Drosophila melanogaster.

    PubMed

    Li, Hua-Bing; Müller, Martin; Bahechar, Ilham Anne; Kyrchanova, Olga; Ohno, Katsuhito; Georgiev, Pavel; Pirrotta, Vincenzo

    2011-02-01

    The genomic binding sites of Polycomb group (PcG) complexes have been found to cluster, forming Polycomb "bodies" or foci in mammalian or fly nuclei. These associations are thought to be driven by interactions between PcG complexes and result in enhanced repression. Here, we show that a Polycomb response element (PRE) with strong PcG binding and repressive activity cannot mediate trans interactions. In the case of the two best-studied interacting PcG targets in Drosophila, the Mcp and the Fab-7 regulatory elements, we find that these associations are not dependent on or caused by the Polycomb response elements they contain. Using functional assays and physical colocalization by in vivo fluorescence imaging or chromosome conformation capture (3C) methods, we show that the interactions between remote copies of Mcp or Fab-7 elements are dependent on the insulator activities present in these elements and not on their PREs. We conclude that insulator binding proteins rather than PcG complexes are likely to be the major determinants of the long-range higher-order organization of PcG targets in the nucleus. PMID:21135119

  13. The Trithorax-mimic allele of Enhancer of zeste renders active domains of target genes accessible to polycomb-group-dependent silencing in Drosophila melanogaster.

    PubMed Central

    Bajusz, I; Sipos, L; Györgypál, Z; Carrington, E A; Jones, R S; Gausz, J; Gyurkovics, H

    2001-01-01

    Two antagonistic groups of genes, the trithorax- and the Polycomb-group, are proposed to maintain the appropriate active or inactive state of homeotic genes set up earlier by transiently expressed segmentation genes. Although some details about the mechanism of maintenance are available, it is still unclear how the initially active or inactive chromatin domains are recognized by either the trithorax-group or the Polycomb-group proteins. We describe an unusual dominant allele of a Polycomb-group gene, Enhancer of zeste, which mimics the phenotype of loss-of-function mutations in trithorax-group genes. This mutation, named E(z)(Trithorax mimic) [E(z)(Trm)], contains a single-amino-acid substitution in the conserved SET domain. The strong dominant trithorax-like phenotypes elicited by this E(z) allele suggest that the mutated arginine-741 plays a critical role in distinguishing between active and inactive chromatin domains of the homeotic gene complexes. We have examined the modification of E(z)(Trm) phenotypes by mutant alleles of PcG and trxG genes and other mutations that alter the phosphorylation of nuclear proteins, covalent modifications of histones, or histone dosage. These data implicate some trxG genes in transcriptional repression as well as activation and provide genetic evidence for involvement of histone modifications in PcG/trxG-dependent transcriptional regulation. PMID:11729158

  14. miR-203 inhibits melanoma invasive and proliferative abilities by targeting the polycomb group gene BMI1

    SciTech Connect

    Chang, Xiao; Sun, Yong; Han, Siqi; Zhu, Wei; Zhang, Haiping; Lian, Shi

    2015-01-02

    Highlights: • First reported deregulation of miR-203 and up-regulation of BMI1 in metastatic melanoma. • miR-203 decreased BMI1 expression by directly binding to 3′UTR. • Further found miR-203 overexpression suppressed cell invasion and stemness. • Re-expression of BMI1 rescued miR-203-mediated suppression. • miR-203-BMI1 axis may be potential therapeutic targets of melanoma metastasis. - Abstract: Metastasis is the major problem in malignant melanoma, posing a therapeutic challenge to clinicians. The investigation of the underlying mechanism driving this progress remains a large unmet need. In this study, we revealed a miR-203-BMI1 axis that regulated melanoma metastasis. We found significantly deregulation of miR-203 and up-regulation of BMI1 in melanoma, particularly in metastatic melanoma. An inverse correlation between the levels of miR-203 and BMI1 was further observed in melanoma tissues and cell lines. We also identified BMI1 as a downstream target gene of miR-203, which bound to the 3′UTR of BMI1. Overexpression of miR-203 was associated with decreased BMI1 expression and impaired cell invasion and tumor sphere formation activities. Re-expression of BMI1 markedly rescued miR-203-mediated suppression of these events. Taken together, our results demonstrated that miR-203 regulated melanoma invasive and proliferative abilities in part by targeting BMI1, providing new insights into potential mechanisms of melanoma metastasis.

  15. MiR-203 inhibits melanoma invasive and proliferative abilities by targeting the polycomb group gene BMI1.

    PubMed

    Chang, Xiao; Sun, Yong; Han, Siqi; Zhu, Wei; Zhang, Haiping; Lian, Shi

    2015-01-01

    Metastasis is the major problem in malignant melanoma, posing a therapeutic challenge to clinicians. The investigation of the underlying mechanism driving this progress remains a large unmet need. In this study, we revealed a miR-203-BMI1 axis that regulated melanoma metastasis. We found significantly deregulation of miR-203 and up-regulation of BMI1 in melanoma, particularly in metastatic melanoma. An inverse correlation between the levels of miR-203 and BMI1 was further observed in melanoma tissues and cell lines. We also identified BMI1 as a downstream target gene of miR-203, which bound to the 3'UTR of BMI1. Overexpression of miR-203 was associated with decreased BMI1 expression and impaired cell invasion and tumor sphere formation activities. Re-expression of BMI1 markedly rescued miR-203-mediated suppression of these events. Taken together, our results demonstrated that miR-203 regulated melanoma invasive and proliferative abilities in part by targeting BMI1, providing new insights into potential mechanisms of melanoma metastasis.

  16. In Vivo Models to Address the Function of Polycomb Group Proteins.

    PubMed

    Bantignies, Frédéric

    2016-01-01

    Initially discovered as repressors of homeotic gene expression in Drosophila, Polycomb group (PcG) proteins have now been shown to be involved in a plethora of biological processes. Indeed, by repressing a large number of target genes, including specific lineage genes, these chromatin factors play major roles in a multitude of cellular functions, such as pluripotency, differentiation, reprogramming, tissue regeneration, and nuclear organization. In this book chapter are presented in vivo approaches and technologies, which have been used in both mammalian and Drosophila systems to study the cellular functions of Polycomb group proteins. PMID:27659991

  17. Polycomb Group (PcG) Proteins and Human Cancers: Multifaceted Functions and Therapeutic Implications

    PubMed Central

    Wang, Wei; Qin, Jiang-Jiang; Voruganti, Sukesh; Nag, Subhasree; Zhou, Jianwei; Zhang, Ruiwen

    2016-01-01

    Polycomb group (PcG) proteins are transcriptional repressors that regulate several crucial developmental and physiological processes in the cell. More recently, they have been found to play important roles in human carcinogenesis and cancer development and progression. The deregulation and dysfunction of PcG proteins often lead to blocking or inappropriate activation of developmental pathways, enhancing cellular proliferation, inhibiting apoptosis, and increasing the cancer stem cell population. Genetic and molecular investigations of PcG proteins have long been focused on their PcG functions. However, PcG proteins have recently been shown to exert non-polycomb functions, contributing to the regulation of diverse cellular functions. We and others have demonstrated that PcG proteins regulate the expression and function of several oncogenes and tumor suppressor genes in a PcG-independent manner, and PcG proteins are associated with the survival of patients with cancer. In this review, we summarize the recent advances in the research on PcG proteins, including both the polycomb-repressive and non-polycomb functions. We specifically focus on the mechanisms by which PcG proteins play roles in cancer initiation, development, and progression. Finally, we discuss the potential value of PcG proteins as molecular biomarkers for the diagnosis and prognosis of cancer, and as molecular targets for cancer therapy. PMID:26227500

  18. Nucleotide substitutions revealing specific functions of Polycomb group genes.

    PubMed

    Bajusz, Izabella; Sipos, László; Pirity, Melinda K

    2015-04-01

    POLYCOMB group (PCG) proteins belong to the family of epigenetic regulators of genes playing important roles in differentiation and development. Mutants of PcG genes were isolated first in the fruit fly, Drosophila melanogaster, resulting in spectacular segmental transformations due to the ectopic expression of homeotic genes. Homologs of Drosophila PcG genes were also identified in plants and in vertebrates and subsequent experiments revealed the general role of PCG proteins in the maintenance of the repressed state of chromatin through cell divisions. The past decades of gene targeting experiments have allowed us to make significant strides towards understanding how the network of PCG proteins influences multiple aspects of cellular fate determination during development. Being involved in the transmission of specific expression profiles of different cell lineages, PCG proteins were found to control wide spectra of unrelated epigenetic processes in vertebrates, such as stem cell plasticity and renewal, genomic imprinting and inactivation of X-chromosome. PCG proteins also affect regulation of metabolic genes being important for switching programs between pluripotency and differentiation. Insight into the precise roles of PCG proteins in normal physiological processes has emerged from studies employing cell culture-based systems and genetically modified animals. Here we summarize the findings obtained from PcG mutant fruit flies and mice generated to date with a focus on PRC1 and PRC2 members altered by nucleotide substitutions resulting in specific alleles. We also include a compilation of lessons learned from these models about the in vivo functions of this complex protein family. With multiple knockout lines, sophisticated approaches to study the consequences of peculiar missense point mutations, and insights from complementary gain-of-function systems in hand, we are now in a unique position to significantly advance our understanding of the molecular basis of

  19. Dynamic regulation of Polycomb group activity during plant development.

    PubMed

    Bemer, Marian; Grossniklaus, Ueli

    2012-11-01

    Polycomb group (PcG) complexes play important roles in phase transitions and cell fate determination in plants and animals, by epigenetically repressing sets of genes that promote either proliferation or differentiation. The continuous differentiation of new organs in plants, such as leaves or flowers, requires a highly dynamic PcG function, which can be induced, modulated, or repressed when necessary. In this review, we discuss the recent advance in understanding PcG function in plants and focus on the diverse molecular mechanisms that have been described to regulate and counteract PcG activity in Arabidopsis.

  20. Dynamic regulation of Polycomb group activity during plant development.

    PubMed

    Bemer, Marian; Grossniklaus, Ueli

    2012-11-01

    Polycomb group (PcG) complexes play important roles in phase transitions and cell fate determination in plants and animals, by epigenetically repressing sets of genes that promote either proliferation or differentiation. The continuous differentiation of new organs in plants, such as leaves or flowers, requires a highly dynamic PcG function, which can be induced, modulated, or repressed when necessary. In this review, we discuss the recent advance in understanding PcG function in plants and focus on the diverse molecular mechanisms that have been described to regulate and counteract PcG activity in Arabidopsis. PMID:22999383

  1. Epigenome changes in active and inactive Polycomb-group-controlled regions

    PubMed Central

    Breiling, Achim; O'Neill, Laura P; D'Eliseo, Donatella; Turner, Bryan M; Orlando, Valerio

    2004-01-01

    The Polycomb group (PcG) of proteins conveys epigenetic inheritance of repressed transcriptional states. In Drosophila, the Polycomb repressive complex 1 (PRC1) maintains the silent state by inhibiting the transcription machinery and chromatin remodelling at core promoters. Using immunoprecipitation of in vivo formaldehyde-fixed chromatin in phenotypically diverse cultured cell lines, we have mapped PRC1 components, the histone methyl transferase (HMT) Enhancer of zeste (E(z)) and histone H3 modifications in active and inactive PcG-controlled regions. We show that PRC1 components are present in both cases, but at different levels. In particular, active target promoters are nearly devoid of E(z) and Polycomb. Moreover, repressed regions are trimethylated at lysines 9 and 27, suggesting that these histone modifications represent a mark for inactive PcG-controlled regions. These PcG-specific repressive marks are maintained by the action of the E(z) HMT, an enzyme that has an important role not only in establishing but also in maintaining PcG repression. PMID:15448640

  2. Polycomb-group proteins in hematopoietic stem cell regulation and hematopoietic neoplasms.

    PubMed

    Radulović, V; de Haan, G; Klauke, K

    2013-03-01

    The equilibrium between self-renewal and differentiation of hematopoietic stem cells is regulated by epigenetic mechanisms. In particular, Polycomb-group (PcG) proteins have been shown to be involved in this process by repressing genes involved in cell-cycle regulation and differentiation. PcGs are histone modifiers that reside in two multi-protein complexes: Polycomb Repressive Complex 1 and 2 (PRC1 and PRC2). The existence of multiple orthologs for each Polycomb gene allows the formation of a multitude of distinct PRC1 and PRC2 sub-complexes. Changes in the expression of individual PcG genes are likely to cause perturbations in the composition of the PRC, which affect PRC enzymatic activity and target selectivity. An interesting recent development is that aberrant expression of, and mutations in, PcG genes have been shown to occur in hematopoietic neoplasms, where they display both tumor-suppressor and oncogenic activities. We therefore comprehensively reviewed the latest research on the role of PcG genes in normal and malignant blood cell development. We conclude that future research to elucidate the compositional changes of the PRCs and methods to intervene in PRC assembly will be of great therapeutic relevance to combat hematological malignancies.

  3. Polycomb group proteins in hematopoietic stem cell aging and malignancies.

    PubMed

    Klauke, Karin; de Haan, Gerald

    2011-07-01

    Protection of the transcriptional "stemness" network is important to maintain a healthy hematopoietic stem cells (HSCs) compartment during the lifetime of the organism. Recent evidence shows that fundamental changes in the epigenetic status of HSCs might be one of the driving forces behind many age-related HSC changes and might pave the way for HSC malignant transformation and subsequent leukemia development, the incidence of which increases exponentially with age. Polycomb group (PcG) proteins are key epigenetic regulators of HSC cellular fate decisions and are often found to be misregulated in human hematopoietic malignancies. In this review, we speculate that PcG proteins balance HSC aging against the risk of developing cancer, since a disturbance in PcG genes and proteins affects several important cellular processes such as cell fate decisions, senescence, apoptosis, and DNA damage repair.

  4. JARID2 regulates binding of the Polycomb repressive complex 2 to target genes in ES cells.

    PubMed

    Pasini, Diego; Cloos, Paul A C; Walfridsson, Julian; Olsson, Linda; Bukowski, John-Paul; Johansen, Jens V; Bak, Mads; Tommerup, Niels; Rappsilber, Juri; Helin, Kristian

    2010-03-11

    The Polycomb group (PcG) proteins have an important role in controlling the expression of genes essential for development, differentiation and maintenance of cell fates. The Polycomb repressive complex 2 (PRC2) is believed to regulate transcriptional repression by catalysing the di- and tri-methylation of lysine 27 on histone H3 (H3K27me2/3). At present, it is unknown how the PcG proteins are recruited to their target promoters in mammalian cells. Here we show that PRC2 forms a stable complex with the Jumonji- and ARID-domain-containing protein, JARID2 (ref. 4). Using genome-wide location analysis, we show that JARID2 binds to more than 90% of previously mapped PcG target genes. Notably, we show that JARID2 is sufficient to recruit PcG proteins to a heterologous promoter, and that inhibition of JARID2 expression leads to a major loss of PcG binding and to a reduction of H3K27me3 levels on target genes. Consistent with an essential role for PcG proteins in early development, we demonstrate that JARID2 is required for the differentiation of mouse embryonic stem cells. Thus, these results demonstrate that JARID2 is essential for the binding of PcG proteins to target genes and, consistent with this, for the proper differentiation of embryonic stem cells and normal development.

  5. Chromatin topology is coupled to Polycomb group protein subnuclear organization

    PubMed Central

    Wani, Ajazul H.; Boettiger, Alistair N.; Schorderet, Patrick; Ergun, Ayla; Münger, Christine; Sadreyev, Ruslan I.; Zhuang, Xiaowei; Kingston, Robert E.; Francis, Nicole J.

    2016-01-01

    The genomes of metazoa are organized at multiple scales. Many proteins that regulate genome architecture, including Polycomb group (PcG) proteins, form subnuclear structures. Deciphering mechanistic links between protein organization and chromatin architecture requires precise description and mechanistic perturbations of both. Using super-resolution microscopy, here we show that PcG proteins are organized into hundreds of nanoscale protein clusters. We manipulated PcG clusters by disrupting the polymerization activity of the sterile alpha motif (SAM) of the PcG protein Polyhomeotic (Ph) or by increasing Ph levels. Ph with mutant SAM disrupts clustering of endogenous PcG complexes and chromatin interactions while elevating Ph level increases cluster number and chromatin interactions. These effects can be captured by molecular simulations based on a previously described chromatin polymer model. Both perturbations also alter gene expression. Organization of PcG proteins into small, abundant clusters on chromatin through Ph SAM polymerization activity may shape genome architecture through chromatin interactions. PMID:26759081

  6. MK3 controls Polycomb target gene expression via negative feedback on ERK

    PubMed Central

    2012-01-01

    Background Gene-environment interactions are mediated by epigenetic mechanisms. Polycomb Group proteins constitute part of an epigenetic cellular transcriptional memory system that is subject to dynamic modulation during differentiation. Molecular insight in processes that control dynamic chromatin association and dissociation of Polycomb repressive complexes during and beyond development is limited. We recently showed that MK3 interacts with Polycomb repressive complex 1 (PRC1). The functional relevance of this interaction, however, remained poorly understood. MK3 is activated downstream of mitogen- and stress-activated protein kinases (M/SAPKs), all of which fulfill crucial roles during development. We here use activation of the immediate-early response gene ATF3, a bona fide PRC1 target gene, as a model to study how MK3 and its effector kinases MAPK/ERK and SAPK/P38 are involved in regulation of PRC1-dependent ATF3 transcription. Results Our current data show that mitogenic signaling through ERK, P38 and MK3 regulates ATF3 expression by PRC1/chromatin dissociation and epigenetic modulation. Mitogenic stimulation results in transient P38-dependent H3S28 phosphorylation and ERK-driven PRC1/chromatin dissociation at PRC1 targets. H3S28 phosphorylation by itself appears not sufficient to induce PRC1/chromatin dissociation, nor ATF3 transcription, as inhibition of MEK/ERK signaling blocks BMI1/chromatin dissociation and ATF3 expression, despite induced H3S28 phosphorylation. In addition, we establish that concomitant loss of local H3K27me3 promoter marking is not required for ATF3 activation. We identify pERK as a novel signaling-induced binding partner of PRC1, and provide evidence that MK3 controls ATF3 expression in cultured cells via negative regulatory feedback on M/SAPKs. Dramatically increased ectopic wing vein formation in the absence of Drosophila MK in a Drosophila ERK gain-of-function wing vein patterning model, supports the existence of MK

  7. Determination of Polycomb Group of Protein Compartmentalization Through Chromatin Fractionation Procedure.

    PubMed

    Marasca, Federica; Marullo, Fabrizia; Lanzuolo, Chiara

    2016-01-01

    Epigenetic mechanisms modulate and maintain the transcriptional state of the genome acting at various levels on chromatin. Emerging findings suggest that the position in the nuclear space and the cross talk between components of the nuclear architecture play a role in the regulation of epigenetic signatures. We recently described a cross talk between the Polycomb group of proteins (PcG) epigenetic repressors and the nuclear lamina. This interplay is important for the maintenance of transcriptional repression at muscle-specific genes and for the correct timing of muscle differentiation. To investigate the synergism between PcG factors and nuclear architecture we improved a chromatin fractionation protocol with the aim to analyze the PcG nuclear compartmentalization. We thus separated PcG proteins in different fractions depending on their solubility. We surprisingly found a consistent amount of PcG proteins in the matrix-associated fraction. In this chapter we describe the chromatin fractionation procedure, a method that can be used to study the nuclear compartmentalization of Polycomb group of proteins and/or PcG targets in murine and Drosophila cells. PMID:27659984

  8. Polycomb Group Protein PHF1 Regulates p53-dependent Cell Growth Arrest and Apoptosis*

    PubMed Central

    Yang, Yang; Wang, Chenji; Zhang, Pingzhao; Gao, Kun; Wang, Dejie; Yu, Hongxiu; Zhang, Ting; Jiang, Sirui; Hexige, Saiyin; Hong, Zehui; Yasui, Akira; Liu, Jun O.; Huang, Haojie; Yu, Long

    2013-01-01

    Polycomb group protein PHF1 is well known as a component of a novel EED-EZH2·Polycomb repressive complex 2 complex and plays important roles in H3K27 methylation and Hox gene silencing. PHF1 is also involved in the response to DNA double-strand breaks in human cells, promotes nonhomologous end-joining processes through interaction with Ku70/Ku80. Here, we identified another function of PHF1 as a potential p53 pathway activator in a pathway screen using luminescence reporter assay. Subsequent studies showed PHF1 directly interacts with p53 proteins both in vivo and in vitro and co-localized in nucleus. PHF1 binds to the C-terminal regulatory domain of p53. Overexpression of PHF1 elevated p53 protein level and prolonged its turnover. Knockdown of PHF1 reduced p53 protein level and its target gene expression both in normal state and DNA damage response. Mechanically, PHF1 protects p53 proteins from MDM2-mediated ubiquitination and degradation. Furthermore, we showed that PHF1 regulates cell growth arrest and etoposide-induced apoptosis in a p53-dependent manner. Finally, PHF1 expression was significantly down-regulated in human breast cancer samples. Taken together, we establish PHF1 as a novel positive regulator of the p53 pathway. These data shed light on the potential roles of PHF1 in tumorigenesis and/or tumor progression. PMID:23150668

  9. Redistribution of H3K27me3 upon DNA hypomethylation results in de-repression of Polycomb target genes

    PubMed Central

    2013-01-01

    Background DNA methylation and the Polycomb repression system are epigenetic mechanisms that play important roles in maintaining transcriptional repression. Recent evidence suggests that DNA methylation can attenuate the binding of Polycomb protein components to chromatin and thus plays a role in determining their genomic targeting. However, whether this role of DNA methylation is important in the context of transcriptional regulation is unclear. Results By genome-wide mapping of the Polycomb Repressive Complex 2-signature histone mark, H3K27me3, in severely DNA hypomethylated mouse somatic cells, we show that hypomethylation leads to widespread H3K27me3 redistribution, in a manner that reflects the local DNA methylation status in wild-type cells. Unexpectedly, we observe striking loss of H3K27me3 and Polycomb Repressive Complex 2 from Polycomb target gene promoters in DNA hypomethylated cells, including Hox gene clusters. Importantly, we show that many of these genes become ectopically expressed in DNA hypomethylated cells, consistent with loss of Polycomb-mediated repression. Conclusions An intact DNA methylome is required for appropriate Polycomb-mediated gene repression by constraining Polycomb Repressive Complex 2 targeting. These observations identify a previously unappreciated role for DNA methylation in gene regulation and therefore influence our understanding of how this epigenetic mechanism contributes to normal development and disease. PMID:23531360

  10. An E3 ligase complex regulates SET-domain polycomb group protein activity in Arabidopsis thaliana

    PubMed Central

    Jeong, Cheol Woong; Roh, Hyungmin; Dang, Tuong Vi; Choi, Yang Do; Fischer, Robert L.; Lee, Jong Seob; Choi, Yeonhee

    2011-01-01

    Transcriptional repression via methylation of histone H3 lysine 27 (H3K27) by the polycomb repressive complex 2 (PRC2) is conserved in higher eukaryotes. The Arabidopsis PRC2 controls homeotic gene expression, flowering time, and gene imprinting. Although downstream target genes and the regulatory mechanism of PRC2 are well understood, much less is known about the significance of posttranslational regulation of PRC2 protein activity. Here, we show the posttranslational regulation of CURLY LEAF (CLF) SET-domain polycomb group (PcG) protein by the F-box protein, UPWARD CURLY LEAF1 (UCL1). Overexpression of UCL1 generates mutant phenotypes similar to those observed in plants with a loss-of-function mutation in the CLF gene. Leaf curling and early flowering phenotypes of UCL1 overexpression mutants, like clf mutants, are rescued by mutations in the AGAMOUS and FLOWERING LOCUS T genes, which is consistent with UCL1 and CLF functioning in the same genetic pathway. Overexpression of UCL1 reduces the level of CLF protein and alters expression and H3K27 methylation of CLF-target genes in transgenic plants, suggesting that UCL1 negatively regulates CLF. Interaction of UCL1 with CLF was detected in plant nuclei and in the yeast two-hybrid system. The UCL1 F-box binds in vivo to components of the E3 ligase complex, which ubiquitylate proteins that are subsequently degraded via the ubiquitin-26S proteasome pathway. Taken together, these results demonstrate the posttranslational regulation of the CLF SET-domain PcG activity by the UCL1 F-box protein in the E3 ligase complex. PMID:21518870

  11. Piwi maintains germline stem cells and oogenesis in Drosophila through negative regulation of Polycomb group proteins.

    PubMed

    Peng, Jamy C; Valouev, Anton; Liu, Na; Lin, Haifan

    2016-03-01

    The Drosophila melanogaster Piwi protein regulates both niche and intrinsic mechanisms to maintain germline stem cells, but its underlying mechanism remains unclear. Here we report that Piwi interacts with Polycomb group complexes PRC1 and PRC2 in niche and germline cells to regulate ovarian germline stem cells and oogenesis. Piwi physically interacts with the PRC2 subunits Su(z)12 and Esc in the ovary and in vitro. Chromatin coimmunoprecipitation of Piwi, the PRC2 enzymatic subunit E(z), histone H3 trimethylated at lysine 27 (H3K27me3) and RNA polymerase II in wild-type and piwi mutant ovaries demonstrates that Piwi binds a conserved DNA motif at ∼ 72 genomic sites and inhibits PRC2 binding to many non-Piwi-binding genomic targets and H3K27 trimethylation. Moreover, Piwi influences RNA polymerase II activities in Drosophila ovaries, likely via inhibiting PRC2. We hypothesize that Piwi negatively regulates PRC2 binding by sequestering PRC2 in the nucleoplasm, thus reducing PRC2 binding to many targets and influencing transcription during oogenesis. PMID:26780607

  12. Piwi maintains germline stem cells and oogenesis in Drosophila through negative regulation of Polycomb Group proteins

    PubMed Central

    Peng, Jamy C.; Valouev, Anton; Liu, Na; Lin, Haifan

    2015-01-01

    The Drosophila Piwi protein regulates both niche and intrinsic mechanisms to maintain germline stem cells, but its underlying mechanism remains unclear. Here we report that Piwi cooperates with Polycomb Group complexes PRC1 and PRC2 in niche and germline cells to regulate ovarian germline stem cells and oogenesis. Piwi physically interacts with PRC2 subunits Su(z)12 and Esc in the ovary and in vitro. Chromatin co-immunoprecipitation of Piwi, the PRC2 enzymatic subunit E(z), lysine-27-tri-methylated histone 3 (H3K27m3), and RNA polymerase II in wild-type and piwi mutant ovaries reveals that Piwi binds a conserved DNA motif at ~72 genomic sites, and inhibits PRC2 binding to many non-Piwi-binding genomic targets and H3K27 tri-methylation. Moreover, Piwi influences RNA Polymerase II activities in Drosophila ovaries likely via inhibiting PRC2. We hypothesize that Piwi negatively regulates PRC2 binding by sequestering PRC2 in the nucleoplasm, thus reducing PRC2 binding to many targets and influences transcription during oogenesis. PMID:26780607

  13. Kicking against the PRCs – A Domesticated Transposase Antagonises Silencing Mediated by Polycomb Group Proteins and Is an Accessory Component of Polycomb Repressive Complex 2

    PubMed Central

    Perera, Pumi; Mora-García, Santiago; de Leau, Erica; Thornton, Harry; de Alves, Flavia Lima; Rapsilber, Juri; Yang, Suxin; James, Geo Velikkakam; Schneeberger, Korbinian; Finnegan, E. Jean; Turck, Franziska; Goodrich, Justin

    2015-01-01

    The Polycomb group (PcG) and trithorax group (trxG) genes play crucial roles in development by regulating expression of homeotic and other genes controlling cell fate. Both groups catalyse modifications of chromatin, particularly histone methylation, leading to epigenetic changes that affect gene activity. The trxG antagonizes the function of PcG genes by activating PcG target genes, and consequently trxG mutants suppress PcG mutant phenotypes. We previously identified the ANTAGONIST OF LIKE HETEROCHROMATIN PROTEIN1 (ALP1) gene as a genetic suppressor of mutants in the Arabidopsis PcG gene LIKE HETEROCHROMATIN PROTEIN1 (LHP1). Here, we show that ALP1 interacts genetically with several other PcG and trxG components and that it antagonizes PcG silencing. Transcriptional profiling reveals that when PcG activity is compromised numerous target genes are hyper-activated in seedlings and that in most cases this requires ALP1. Furthermore, when PcG activity is present ALP1 is needed for full activation of several floral homeotic genes that are repressed by the PcG. Strikingly, ALP1 does not encode a known chromatin protein but rather a protein related to PIF/Harbinger class transposases. Phylogenetic analysis indicates that ALP1 is broadly conserved in land plants and likely lost transposase activity and acquired a novel function during angiosperm evolution. Consistent with this, immunoprecipitation and mass spectrometry (IP-MS) show that ALP1 associates, in vivo, with core components of POLYCOMB REPRESSIVE COMPLEX 2 (PRC2), a widely conserved PcG protein complex which functions as a H3K27me3 histone methyltransferase. Furthermore, in reciprocal pulldowns using the histone methyltransferase CURLY LEAF (CLF), we identify not only ALP1 and the core PRC2 components but also plant-specific accessory components including EMBRYONIC FLOWER 1 (EMF1), a transcriptional repressor previously associated with PRC1-like complexes. Taken together our data suggest that ALP1 inhibits Pc

  14. A cellular chemical probe targeting the chromodomains of Polycomb Repressive Complex 1

    PubMed Central

    Stuckey, Jacob I; Dickson, Bradley M; Cheng, Nancy; Liu, Yanli; Norris, Jacqueline L; Cholensky, Stephanie H; Tempel, Wolfram; Qin, Su; Huber, Katherine G; Sagum, Cari; Black, Karynne; Li, Fengling; Huang, Xi-Ping; Roth, Bryan L; Baughman, Brandi M; Senisterra, Guillermo; Pattenden, Samantha G; Vedadi, Masoud; Brown, Peter J; Bedford, Mark T; Min, Jinrong; Arrowsmith, Cheryl H

    2015-01-01

    We report the design and characterization of UNC3866, a potent antagonist of the methyl-lysine (Kme) reading function of the Polycomb CBX and CDY families of chromodomains. Polycomb CBX proteins regulate gene expression by targeting Polycomb Repressive Complex 1 to sites of H3K27me3 via their chromodomains. UNC3866 binds the chromodomains of CBX4 and CBX7 most potently with a Kd of ∼100 nM for each, and is 6- to 18-fold selective versus seven other CBX and CDY chromodomains while being highly selective versus >250 other protein targets. X-ray crystallography revealed that UNC3866 closely mimics the interactions of the methylated H3 tail with these chromodomains. UNC4195, a biotinylated derivative of UNC3866, was used to demonstrate that UNC3866 engages intact PRC1 and that EED incorporation into PRC1 is isoform-dependent in PC3 prostate cancer cells. Finally, UNC3866 inhibits PC3 cell proliferation, a known CBX7 phenotype, while UNC4219, a methylated negative control compound, has negligible effects. PMID:26807715

  15. The Immediate Early Gene Product EGR1 and Polycomb Group Proteins Interact in Epigenetic Programming during Chondrogenesis

    PubMed Central

    Caron, Marjolein M. J.; Prickaerts, Peggy; Rofel, Celine; Dahlmans, Vivian E. H.; Surtel, Don A. M.; Paulis, Yvette; Schweizer, Finja; Welting, Tim J. M.; Eijssen, Lars M.; Voncken, Jan Willem

    2013-01-01

    Initiation of and progression through chondrogenesis is driven by changes in the cellular microenvironment. At the onset of chondrogenesis, resting mesenchymal stem cells are mobilized in vivo and a complex, step-wise chondrogenic differentiation program is initiated. Differentiation requires coordinated transcriptomic reprogramming and increased progenitor proliferation; both processes require chromatin remodeling. The nature of early molecular responses that relay differentiation signals to chromatin is poorly understood. We here show that immediate early genes are rapidly and transiently induced in response to differentiation stimuli in vitro. Functional ablation of the immediate early factor EGR1 severely deregulates expression of key chondrogenic control genes at the onset of differentiation. In addition, differentiating cells accumulate DNA damage, activate a DNA damage response and undergo a cell cycle arrest and prevent differentiation associated hyper-proliferation. Failed differentiation in the absence of EGR1 affects global acetylation and terminates in overall histone hypermethylation. We report novel molecular connections between EGR1 and Polycomb Group function: Polycomb associated histone H3 lysine27 trimethylation (H3K27me3) blocks chromatin access of EGR1. In addition, EGR1 ablation results in abnormal Ezh2 and Bmi1 expression. Consistent with this functional interaction, we identify a number of co-regulated targets genes in a chondrogenic gene network. We here describe an important role for EGR1 in early chondrogenic epigenetic programming to accommodate early gene-environment interactions in chondrogenesis. PMID:23483971

  16. Local chromatin environment of a Polycomb target gene instructs its own epigenetic inheritance

    PubMed Central

    Berry, Scott; Hartley, Matthew; Olsson, Tjelvar S G; Dean, Caroline; Howard, Martin

    2015-01-01

    Inheritance of gene expression states is fundamental for cells to ‘remember’ past events, such as environmental or developmental cues. The conserved Polycomb Repressive Complex 2 (PRC2) maintains epigenetic repression of many genes in animals and plants and modifies chromatin at its targets. Histones modified by PRC2 can be inherited through cell division. However, it remains unclear whether this inheritance can direct long-term memory of individual gene expression states (cis memory) or instead if local chromatin states are dictated by the concentrations of diffusible factors (trans memory). By monitoring the expression of two copies of the Arabidopsis Polycomb target gene FLOWERING LOCUS C (FLC) in the same plants, we show that one copy can be repressed while the other is active. Furthermore, this ‘mixed’ expression state is inherited through many cell divisions as plants develop. These data demonstrate that epigenetic memory of FLC expression is stored not in trans but in cis. DOI: http://dx.doi.org/10.7554/eLife.07205.001 PMID:25955967

  17. Polycomb Group Protein Pcgf6 Acts as a Master Regulator to Maintain Embryonic Stem Cell Identity

    PubMed Central

    Yang, Chao-Shun; Chang, Kung-Yen; Dang, Jason; Rana, Tariq M.

    2016-01-01

    The polycomb repressive complex 1 (PRC1) is a multi-subunit complex that plays critical roles in the epigenetic modulation of gene expression. Here, we show that the PRC1 component polycomb group ring finger 6 (Pcgf6) is required to maintain embryonic stem cell (ESC) identity. In contrast to canonical PRC1, Pcgf6 acts as a positive regulator of transcription and binds predominantly to promoters bearing active chromatin marks. Pcgf6 is expressed at high levels in ESCs, and knockdown reduces the expression of the core ESC regulators Oct4, Sox2, and Nanog. Conversely, Pcgf6 overexpression prevents downregulation of these factors and impairs differentiation. In addition, Pcgf6 enhanced reprogramming in both mouse and human somatic cells. The genomic binding profile of Pcgf6 is highly similar to that of trithorax group proteins, but not of PRC1 or PRC2 complexes, suggesting that Pcgf6 functions atypically in ESCs. Our data reveal novel roles for Pcgf6 in directly regulating Oct4, Nanog, Sox2, and Lin28 expression to maintain ESC identity. PMID:27247273

  18. Polycomb dysregulation in gliomagenesis targets a Zfp423-dependent differentiation network

    PubMed Central

    Signaroldi, Elena; Laise, Pasquale; Cristofanon, Silvia; Brancaccio, Arianna; Reisoli, Elisa; Atashpaz, Sina; Terreni, Maria Rosa; Doglioni, Claudio; Pruneri, Giancarlo; Malatesta, Paolo; Testa, Giuseppe

    2016-01-01

    Malignant gliomas constitute one of the most significant areas of unmet medical need, owing to the invariable failure of surgical eradication and their marked molecular heterogeneity. Accumulating evidence has revealed a critical contribution by the Polycomb axis of epigenetic repression. However, a coherent understanding of the regulatory networks affected by Polycomb during gliomagenesis is still lacking. Here we integrate transcriptomic and epigenomic analyses to define Polycomb-dependent networks that promote gliomagenesis, validating them both in two independent mouse models and in a large cohort of human samples. We find that Polycomb dysregulation in gliomagenesis affects transcriptional networks associated with invasiveness and de-differentiation. The dissection of these networks uncovers Zfp423 as a critical Polycomb-dependent transcription factor whose silencing negatively impacts survival. The anti-gliomagenic activity of Zfp423 requires interaction with the SMAD proteins within the BMP signalling pathway, pointing to a novel synergic circuit through which Polycomb inhibits BMP signalling. PMID:26923714

  19. Genome-Wide Ultrabithorax Binding Analysis Reveals Highly Targeted Genomic Loci at Developmental Regulators and a Potential Connection to Polycomb-Mediated Regulation

    PubMed Central

    Meireles-Filho, Antonio C. A.; Pagani, Michaela; Stark, Alexander

    2016-01-01

    Hox homeodomain transcription factors are key regulators of animal development. They specify the identity of segments along the anterior-posterior body axis in metazoans by controlling the expression of diverse downstream targets, including transcription factors and signaling pathway components. The Drosophila melanogaster Hox factor Ultrabithorax (Ubx) directs the development of thoracic and abdominal segments and appendages, and loss of Ubx function can lead for example to the transformation of third thoracic segment appendages (e.g. halters) into second thoracic segment appendages (e.g. wings), resulting in a characteristic four-wing phenotype. Here we present a Drosophila melanogaster strain with a V5-epitope tagged Ubx allele, which we employed to obtain a high quality genome-wide map of Ubx binding sites using ChIP-seq. We confirm the sensitivity of the V5 ChIP-seq by recovering 7/8 of well-studied Ubx-dependent cis-regulatory regions. Moreover, we show that Ubx binding is predictive of enhancer activity as suggested by comparison with a genome-scale resource of in vivo tested enhancer candidates. We observed densely clustered Ubx binding sites at 12 extended genomic loci that included ANTP-C, BX-C, Polycomb complex genes, and other regulators and the clustered binding sites were frequently active enhancers. Furthermore, Ubx binding was detected at known Polycomb response elements (PREs) and was associated with significant enrichments of Pc and Pho ChIP signals in contrast to binding sites of other developmental TFs. Together, our results show that Ubx targets developmental regulators via strongly clustered binding sites and allow us to hypothesize that regulation by Ubx might involve Polycomb group proteins to maintain specific regulatory states in cooperative or mutually exclusive fashion, an attractive model that combines two groups of proteins with prominent gene regulatory roles during animal development. PMID:27575958

  20. Genome-Wide Ultrabithorax Binding Analysis Reveals Highly Targeted Genomic Loci at Developmental Regulators and a Potential Connection to Polycomb-Mediated Regulation.

    PubMed

    Shlyueva, Daria; Meireles-Filho, Antonio C A; Pagani, Michaela; Stark, Alexander

    2016-01-01

    Hox homeodomain transcription factors are key regulators of animal development. They specify the identity of segments along the anterior-posterior body axis in metazoans by controlling the expression of diverse downstream targets, including transcription factors and signaling pathway components. The Drosophila melanogaster Hox factor Ultrabithorax (Ubx) directs the development of thoracic and abdominal segments and appendages, and loss of Ubx function can lead for example to the transformation of third thoracic segment appendages (e.g. halters) into second thoracic segment appendages (e.g. wings), resulting in a characteristic four-wing phenotype. Here we present a Drosophila melanogaster strain with a V5-epitope tagged Ubx allele, which we employed to obtain a high quality genome-wide map of Ubx binding sites using ChIP-seq. We confirm the sensitivity of the V5 ChIP-seq by recovering 7/8 of well-studied Ubx-dependent cis-regulatory regions. Moreover, we show that Ubx binding is predictive of enhancer activity as suggested by comparison with a genome-scale resource of in vivo tested enhancer candidates. We observed densely clustered Ubx binding sites at 12 extended genomic loci that included ANTP-C, BX-C, Polycomb complex genes, and other regulators and the clustered binding sites were frequently active enhancers. Furthermore, Ubx binding was detected at known Polycomb response elements (PREs) and was associated with significant enrichments of Pc and Pho ChIP signals in contrast to binding sites of other developmental TFs. Together, our results show that Ubx targets developmental regulators via strongly clustered binding sites and allow us to hypothesize that regulation by Ubx might involve Polycomb group proteins to maintain specific regulatory states in cooperative or mutually exclusive fashion, an attractive model that combines two groups of proteins with prominent gene regulatory roles during animal development. PMID:27575958

  1. The Polycomb Group Protein EED Interacts with YY1, and Both Proteins Induce Neural Tissue in Xenopus Embryos

    PubMed Central

    Satijn, David P. E.; Hamer, Karien M.; den Blaauwen, Jan; Otte, Arie P.

    2001-01-01

    Polycomb group (PcG) proteins form multimeric protein complexes which are involved in the heritable stable repression of genes. Previously, we identified two distinct human PcG protein complexes. The EED-EZH protein complex contains the EED and EZH2 PcG proteins, and the HPC-HPH PcG complex contains the HPC, HPH, BMI1, and RING1 PcG proteins. Here we show that YY1, a homolog of the Drosophila PcG protein pleiohomeotic (Pho), interacts specificially with the human PcG protein EED but not with proteins of the HPC-HPH PcG complex. Since YY1 and Pho are DNA-binding proteins, the interaction between YY1 and EED provides a direct link between the chromatin-associated EED-EZH PcG complex and the DNA of target genes. To study the functional significance of the interaction, we expressed the Xenopus homologs of EED and YY1 in Xenopus embryos. Both Xeed and XYY1 induce an ectopic neural axis but do not induce mesodermal tissues. In contrast, members of the HPC-HPH PcG complex do not induce neural tissue. The exclusive, direct neuralizing activity of both the Xeed and XYY1 proteins underlines the significance of the interaction between the two proteins. Our data also indicate a role for chromatin-associated proteins, such as PcG proteins, in Xenopus neural induction. PMID:11158321

  2. AGAMOUS Terminates Floral Stem Cell Maintenance in Arabidopsis by Directly Repressing WUSCHEL through Recruitment of Polycomb Group Proteins[W

    PubMed Central

    Liu, Xigang; Kim, Yun Ju; Müller, Ralf; Yumul, Rae Eden; Liu, Chunyan; Pan, Yanyun; Cao, Xiaofeng; Goodrich, Justin; Chen, Xuemei

    2011-01-01

    Floral stem cells produce a defined number of floral organs before ceasing to be maintained as stem cells. Therefore, floral stem cells offer an ideal model to study the temporal control of stem cell maintenance within a developmental context. AGAMOUS (AG), a MADS domain transcription factor essential for the termination of floral stem cell fate, has long been thought to repress the stem cell maintenance gene WUSCHEL (WUS) indirectly. Here, we uncover a role of Polycomb Group (PcG) genes in the temporally precise repression of WUS expression and termination of floral stem cell fate. We show that AG directly represses WUS expression by binding to the WUS locus and recruiting, directly or indirectly, PcG that methylates histone H3 Lys-27 at WUS. We also show that PcG acts downstream of AG and probably in parallel with the known AG target KNUCKLES to terminate floral stem cell fate. Our studies identify core components of the network governing the temporal program of floral stem cells. PMID:22028461

  3. Nucleoplasmic Lamin A/C and Polycomb group of proteins: An evolutionarily conserved interplay

    PubMed Central

    Marullo, F.; Cesarini, E.; Antonelli, L.; Gregoretti, F.; Oliva, G.; Lanzuolo, C.

    2016-01-01

    ABSTRACT Nuclear lamins are the main components of the nuclear lamina at the nuclear periphery, providing mechanical support to the nucleus. However, recent findings suggest that lamins also reside in the nuclear interior, as a distinct and dynamic pool with critical roles in transcriptional regulation. In our work we found a functional and evolutionary conserved crosstalk between Lamin A/C and the Polycomb group (PcG) of proteins, this being required for the maintenance of the PcG repressive functions. Indeed, Lamin A/C knock-down causes PcG foci dispersion and defects in PcG-mediated higher order structures, thereby leading to impaired PcG mediated transcriptional repression. By using ad-hoc algorithms for image analysis and PLA approaches we hereby show that PcG proteins are preferentially located in the nuclear interior where they interact with nucleoplasmic Lamin A/C. Taken together, our findings suggest that nuclear components, such as Lamin A/C, functionally interact with epigenetic factors to ensure the correct transcriptional program maintenance. PMID:26930442

  4. Pluripotency factors and Polycomb Group proteins repress aryl hydrocarbon receptor expression in murine embryonic stem cells.

    PubMed

    Ko, Chia-I; Wang, Qin; Fan, Yunxia; Xia, Ying; Puga, Alvaro

    2014-01-01

    The aryl hydrocarbon receptor (AHR) is a transcription factor and environmental sensor that regulates expression of genes involved in drug-metabolism and cell cycle regulation. Chromatin immunoprecipitation analyses, Ahr ablation in mice and studies with orthologous genes in invertebrates suggest that AHR may also play a significant role in embryonic development. To address this hypothesis, we studied the regulation of Ahr expression in mouse embryonic stem cells and their differentiated progeny. In ES cells, interactions between OCT3/4, NANOG, SOX2 and Polycomb Group proteins at the Ahr promoter repress AHR expression, which can also be repressed by ectopic expression of reprogramming factors in hepatoma cells. In ES cells, unproductive RNA polymerase II binds at the Ahr transcription start site and drives the synthesis of short abortive transcripts. Activation of Ahr expression during differentiation follows from reversal of repressive marks in Ahr promoter chromatin, release of pluripotency factors and PcG proteins, binding of Sp factors, establishment of histone marks of open chromatin, and engagement of active RNAPII to drive full-length RNA transcript elongation. Our results suggest that reversible Ahr repression in ES cells holds the gene poised for expression and allows for a quick switch to activation during embryonic development.

  5. dBRWD3 Regulates Tissue Overgrowth and Ectopic Gene Expression Caused by Polycomb Group Mutations

    PubMed Central

    Shih, Hsueh-Tzu; Chen, Wei-Yu; Liu, Kwei-Yan; Shih, Zong-Siou; Chen, Yi-Jyun; Hsieh, Paul-Chen; Kuo, Kuan-Lin; Huang, Kuo-How; Hsu, Pang-Hung; Liu, Ya-Wen; Tsai, Yu-Chen; Wu, June-Tai

    2016-01-01

    To maintain a particular cell fate, a unique set of genes should be expressed while another set is repressed. One way to repress gene expression is through Polycomb group (PcG) proteins that compact chromatin into a silent configuration. In addition to cell fate maintenance, PcG proteins also maintain normal cell physiology, for example cell cycle. In the absence of PcG, ectopic activation of the PcG-repressed genes leads to developmental defects and malignant tumors. Little is known about the molecular nature of ectopic gene expression; especially what differentiates expression of a given gene in the orthotopic tissue (orthotopic expression) and the ectopic expression of the same gene due to PcG mutations. Here we present that ectopic gene expression in PcG mutant cells specifically requires dBRWD3, a negative regulator of HIRA/Yemanuclein (YEM)-mediated histone variant H3.3 deposition. dBRWD3 mutations suppress both the ectopic gene expression and aberrant tissue overgrowth in PcG mutants through a YEM-dependent mechanism. Our findings identified dBRWD3 as a critical regulator that is uniquely required for ectopic gene expression and aberrant tissue overgrowth caused by PcG mutations. PMID:27588417

  6. dBRWD3 Regulates Tissue Overgrowth and Ectopic Gene Expression Caused by Polycomb Group Mutations.

    PubMed

    Shih, Hsueh-Tzu; Chen, Wei-Yu; Liu, Kwei-Yan; Shih, Zong-Siou; Chen, Yi-Jyun; Hsieh, Paul-Chen; Kuo, Kuan-Lin; Huang, Kuo-How; Hsu, Pang-Hung; Liu, Ya-Wen; Chan, Shih-Peng; Lee, Hsiu-Hsiang; Tsai, Yu-Chen; Wu, June-Tai

    2016-09-01

    To maintain a particular cell fate, a unique set of genes should be expressed while another set is repressed. One way to repress gene expression is through Polycomb group (PcG) proteins that compact chromatin into a silent configuration. In addition to cell fate maintenance, PcG proteins also maintain normal cell physiology, for example cell cycle. In the absence of PcG, ectopic activation of the PcG-repressed genes leads to developmental defects and malignant tumors. Little is known about the molecular nature of ectopic gene expression; especially what differentiates expression of a given gene in the orthotopic tissue (orthotopic expression) and the ectopic expression of the same gene due to PcG mutations. Here we present that ectopic gene expression in PcG mutant cells specifically requires dBRWD3, a negative regulator of HIRA/Yemanuclein (YEM)-mediated histone variant H3.3 deposition. dBRWD3 mutations suppress both the ectopic gene expression and aberrant tissue overgrowth in PcG mutants through a YEM-dependent mechanism. Our findings identified dBRWD3 as a critical regulator that is uniquely required for ectopic gene expression and aberrant tissue overgrowth caused by PcG mutations. PMID:27588417

  7. Nucleoplasmic Lamin A/C and Polycomb group of proteins: An evolutionarily conserved interplay.

    PubMed

    Marullo, F; Cesarini, E; Antonelli, L; Gregoretti, F; Oliva, G; Lanzuolo, C

    2016-04-25

    Nuclear lamins are the main components of the nuclear lamina at the nuclear periphery, providing mechanical support to the nucleus. However, recent findings suggest that lamins also reside in the nuclear interior, as a distinct and dynamic pool with critical roles in transcriptional regulation. In our work we found a functional and evolutionary conserved crosstalk between Lamin A/C and the Polycomb group (PcG) of proteins, this being required for the maintenance of the PcG repressive functions. Indeed, Lamin A/C knock-down causes PcG foci dispersion and defects in PcG-mediated higher order structures, thereby leading to impaired PcG mediated transcriptional repression. By using ad-hoc algorithms for image analysis and PLA approaches we hereby show that PcG proteins are preferentially located in the nuclear interior where they interact with nucleoplasmic Lamin A/C. Taken together, our findings suggest that nuclear components, such as Lamin A/C, functionally interact with epigenetic factors to ensure the correct transcriptional program maintenance. PMID:26930442

  8. The Human Polycomb Group Complex Associates with Pericentromeric Heterochromatin to Form a Novel Nuclear Domain

    PubMed Central

    Saurin, Andrew J.; Shiels, Carol; Williamson, Jill; Satijn, David P.E.; Otte, Arie P.; Sheer, Denise; Freemont, Paul S.

    1998-01-01

    The Polycomb group (PcG) complex is a chromatin-associated multiprotein complex, involved in the stable repression of homeotic gene activity in Drosophila. Recently, a mammalian PcG complex has been identified with several PcG proteins implicated in the regulation of Hox gene expression. Although the mammalian PcG complex appears analogous to the complex in Drosophila, the molecular mechanisms and functions for the mammalian PcG complex remain unknown. Here we describe a detailed characterization of the human PcG complex in terms of cellular localization and chromosomal association. By using antibodies that specifically recognize three human PcG proteins— RING1, BMI1, and hPc2—we demonstrate in a number of human cell lines that the PcG complex forms a unique discrete nuclear structure that we term PcG bodies. PcG bodies are prominent novel nuclear structures with the larger PcG foci generally localized near the centromeres, as visualized with a kinetochore antibody marker. In both normal fetal and adult fibroblasts, PcG bodies are not randomly dispersed, but appear clustered into defined areas within the nucleus. We show in three different human cell lines that the PcG complex can tightly associate with large pericentromeric heterochromatin regions (1q12) on chromosome 1, and with related pericentromeric sequences on different chromosomes, providing evidence for a mammalian PcG–heterochromatin association. Furthermore, these heterochromatin-bound PcG complexes remain stably associated throughout mitosis, thereby allowing the potential inheritance of the PcG complex through successive cell divisions. We discuss these results in terms of the known function of the PcG complex as a transcriptional repression complex. PMID:9722603

  9. The impact of Polycomb group (PcG) and Trithorax group (TrxG) epigenetic factors in plant plasticity.

    PubMed

    de la Paz Sanchez, Maria; Aceves-García, Pamela; Petrone, Emilio; Steckenborn, Stefan; Vega-León, Rosario; Álvarez-Buylla, Elena R; Garay-Arroyo, Adriana; García-Ponce, Berenice

    2015-11-01

    Current advances indicate that epigenetic mechanisms play important roles in the regulatory networks involved in plant developmental responses to environmental conditions. Hence, understanding the role of such components becomes crucial to understanding the mechanisms underlying the plasticity and variability of plant traits, and thus the ecology and evolution of plant development. We now know that important components of phenotypic variation may result from heritable and reversible epigenetic mechanisms without genetic alterations. The epigenetic factors Polycomb group (PcG) and Trithorax group (TrxG) are involved in developmental processes that respond to environmental signals, playing important roles in plant plasticity. In this review, we discuss current knowledge of TrxG and PcG functions in different developmental processes in response to internal and environmental cues and we also integrate the emerging evidence concerning their function in plant plasticity. Many such plastic responses rely on meristematic cell behavior, including stem cell niche maintenance, cellular reprogramming, flowering and dormancy as well as stress memory. This information will help to determine how to integrate the role of epigenetic regulation into models of gene regulatory networks, which have mostly included transcriptional interactions underlying various aspects of plant development and its plastic response to environmental conditions.

  10. Integrative epigenome analysis identifies a Polycomb-targeted differentiation program as a tumor-suppressor event epigenetically inactivated in colorectal cancer.

    PubMed

    Tan, J; Yang, X; Jiang, X; Zhou, J; Li, Z; Lee, P L; Li, B; Robson, P; Yu, Q

    2014-07-17

    Aberrant DNA hypermethylation in human cancer has been associated with Polycomb target genes in embryonic stem (ES) cells, but a functional link of the Polycomb-targeted differentiation program to tumorigenesis remains to be established. Here, through epigenome analysis correlating DNA hypermethylation in colon cancer with ES cell pluripotency and differentiation, we identified a set of DNA hypermethylated genes in cancer cells that are Polycomb targets strongly associated with ES cell differentiation, including HAND1, a developmental regulator. Intriguingly, HAND1 is silenced in over 90% of human primary colorectal tumors, and re-expression of HAND1 in colon cancer cells induces terminal differentiation, inhibits proliferation and prevents xenograft tumor formation. Moreover, hypermethylated HAND1 has a minimum enrichment of EZH2-H3K27me3 in cancer cells, but becomes EZH2 bound and bivalent upon the loss of DNA methylation, suggesting a sequential gene silencing event during oncogenesis. These findings established a functional role of Polycomb-targeted differentiation program as a tumor-suppressor event epigenetically inactivated in human cancer.

  11. A Drosophila ESC-E(Z) protein complex is distinct from other polycomb group complexes and contains covalently modified ESC.

    PubMed

    Ng, J; Hart, C M; Morgan, K; Simon, J A

    2000-05-01

    The extra sex combs (ESC) and Enhancer of zeste [E(Z)] proteins, members of the Polycomb group (PcG) of transcriptional repressors, interact directly and are coassociated in fly embryos. We report that these two proteins are components of a 600-kDa complex in embryos. Using gel filtration and affinity chromatography, we show that this complex is biochemically distinct from previously described complexes containing the PcG proteins Polyhomeotic, Polycomb, and Sex comb on midleg. In addition, we present evidence that ESC is phosphorylated in vivo and that this modified ESC is preferentially associated in the complex with E(Z). Modified ESC accumulates between 2 and 6 h of embryogenesis, which is the developmental time when esc function is first required. We find that mutations in E(z) reduce the ratio of modified to unmodified ESC in vivo. We have also generated germ line transformants that express ESC proteins bearing site-directed mutations that disrupt ESC-E(Z) binding in vitro. These mutant ESC proteins fail to provide esc function, show reduced levels of modification in vivo, and are still assembled into complexes. Taken together, these results suggest that ESC phosphorylation normally occurs after assembly into ESC-E(Z) complexes and that it contributes to the function or regulation of these complexes. We discuss how biochemically separable ESC-E(Z) and PC-PH complexes might work together to provide PcG repression. PMID:10757791

  12. Prenatal alcohol exposure and cellular differentiation: a role for Polycomb and Trithorax group proteins in FAS phenotypes?

    PubMed

    Veazey, Kylee J; Muller, Daria; Golding, Michael C

    2013-01-01

    Exposure to alcohol significantly alters the developmental trajectory of progenitor cells and fundamentally compromises tissue formation (i.e., histogenesis). Emerging research suggests that ethanol can impair mammalian development by interfering with the execution of molecular programs governing differentiation. For example, ethanol exposure disrupts cellular migration, changes cell-cell interactions, and alters growth factor signaling pathways. Additionally, ethanol can alter epigenetic mechanisms controlling gene expression. Normally, lineage-specific regulatory factors (i.e., transcription factors) establish the transcriptional networks of each new cell type; the cell's identity then is maintained through epigenetic alterations in the way in which the DNA encoding each gene becomes packaged within the chromatin. Ethanol exposure can induce epigenetic changes that do not induce genetic mutations but nonetheless alter the course of fetal development and result in a large array of patterning defects. Two crucial enzyme complexes--the Polycomb and Trithorax proteins--are central to the epigenetic programs controlling the intricate balance between self-renewal and the execution of cellular differentiation, with diametrically opposed functions. Prenatal ethanol exposure may disrupt the functions of these two enzyme complexes, altering a crucial aspect of mammalian differentiation. Characterizing the involvement of Polycomb and Trithorax group complexes in the etiology of fetal alcohol spectrum disorders will undoubtedly enhance understanding of the role that epigenetic programming plays in this complex disorder.

  13. The Polycomb Group Protein Pcgf1 Is Dispensable in Zebrafish but Involved in Early Growth and Aging.

    PubMed

    Dupret, Barbara; Völkel, Pamela; Le Bourhis, Xuefen; Angrand, Pierre-Olivier

    2016-01-01

    Polycomb Repressive Complex (PRC) 1 regulates the control of gene expression programs via chromatin structure reorganization. Through mutual exclusion, different PCGF members generate a variety of PRC1 complexes with potentially distinct cellular functions. In this context, the molecular function of each of the PCGF family members remains elusive. The study of PCGF family member expression in zebrafish development and during caudal fin regeneration reveals that the zebrafish pcgf genes are subjected to different regulations and that all PRC1 complexes in terms of Pcgf subunit composition are not always present in the same tissues. To unveil the function of Pcgf1 in zebrafish, a mutant line was generated using the TALEN technology. Mutant pcgf1-/- fish are viable and fertile, but the growth rate at early developmental stages is reduced in absence of pcgf1 gene function and a significant number of pcgf1-/- fish show signs of premature aging. This first vertebrate model lacking Pcgf1 function shows that this Polycomb Group protein is involved in cell proliferation during early embryogenesis and establishes a link between epigenetics and aging. PMID:27442247

  14. The Polycomb Group Protein Pcgf1 Is Dispensable in Zebrafish but Involved in Early Growth and Aging

    PubMed Central

    Le Bourhis, Xuefen; Angrand, Pierre-Olivier

    2016-01-01

    Polycomb Repressive Complex (PRC) 1 regulates the control of gene expression programs via chromatin structure reorganization. Through mutual exclusion, different PCGF members generate a variety of PRC1 complexes with potentially distinct cellular functions. In this context, the molecular function of each of the PCGF family members remains elusive. The study of PCGF family member expression in zebrafish development and during caudal fin regeneration reveals that the zebrafish pcgf genes are subjected to different regulations and that all PRC1 complexes in terms of Pcgf subunit composition are not always present in the same tissues. To unveil the function of Pcgf1 in zebrafish, a mutant line was generated using the TALEN technology. Mutant pcgf1-/- fish are viable and fertile, but the growth rate at early developmental stages is reduced in absence of pcgf1 gene function and a significant number of pcgf1-/- fish show signs of premature aging. This first vertebrate model lacking Pcgf1 function shows that this Polycomb Group protein is involved in cell proliferation during early embryogenesis and establishes a link between epigenetics and aging. PMID:27442247

  15. Role of polycomb group protein cbx2/m33 in meiosis onset and maintenance of chromosome stability in the Mammalian germline.

    PubMed

    Baumann, Claudia; De La Fuente, Rabindranath

    2011-01-01

    Polycomb group proteins (PcG) are major epigenetic regulators, essential for establishing heritable expression patterns of developmental control genes. The mouse PcG family member M33/Cbx2 (Chromobox homolog protein 2) is a component of the Polycomb-Repressive Complex 1 (PRC1). Targeted deletion of Cbx2/M33 in mice results in homeotic transformations of the axial skeleton, growth retardation and male-to-female sex reversal. In this study, we tested whether Cbx2 is involved in the control of chromatin remodeling processes during meiosis. Our analysis revealed sex reversal in 28.6% of XY(-/-) embryos, in which a hypoplastic testis and a contralateral ovary were observed in close proximity to the kidney, while the remaining male mutant fetuses exhibited bilateral testicular hypoplasia. Notably, germ cells recovered from Cbx2((XY-/-)) testes on day 18.5 of fetal development exhibited premature meiosis onset with synaptonemal complex formation suggesting a role for Cbx2 in the control of meiotic entry in male germ cells. Mutant females exhibited small ovaries with significant germ cell loss and a high proportion of oocytes with abnormal synapsis and non-homologous interactions at the pachytene stage as well as formation of univalents at diplotene. These defects were associated with failure to resolve DNA double strand breaks marked by persistent γH2AX and Rad51 foci at the late pachytene stage. Importantly, two factors required for meiotic silencing of asynapsed chromatin, ubiquitinated histone H2A (ubH2A) and the chromatin remodeling protein BRCA1, co-localized with fully synapsed chromosome axes in the majority of Cbx2((-/-)) oocytes. These results provide novel evidence that Cbx2 plays a critical and previously unrecognized role in germ cell viability, meiosis onset and homologous chromosome synapsis in the mammalian germline. PMID:22200029

  16. batman Interacts with polycomb and trithorax group genes and encodes a BTB/POZ protein that is included in a complex containing GAGA factor.

    PubMed

    Faucheux, M; Roignant, J-Y; Netter, S; Charollais, J; Antoniewski, C; Théodore, L

    2003-02-01

    Polycomb and trithorax group genes maintain the appropriate repressed or activated state of homeotic gene expression throughout Drosophila melanogaster development. We have previously identified the batman gene as a Polycomb group candidate since its function is necessary for the repression of Sex combs reduced. However, our present genetic analysis indicates functions of batman in both activation and repression of homeotic genes. The 127-amino-acid Batman protein is almost reduced to a BTB/POZ domain, an evolutionary conserved protein-protein interaction domain found in a large protein family. We show that this domain is involved in the interaction between Batman and the DNA binding GAGA factor encoded by the Trithorax-like gene. The GAGA factor and Batman codistribute on polytene chromosomes, coimmunoprecipitate from nuclear embryonic and larval extracts, and interact in the yeast two-hybrid assay. Batman, together with the GAGA factor, binds to MHS-70, a 70-bp fragment of the bithoraxoid Polycomb response element. This binding, like that of the GAGA factor, requires the presence of d(GA)n sequences. Together, our results suggest that batman belongs to a subset of the Polycomb/trithorax group of genes that includes Trithorax-like, whose products are involved in both activation and repression of homeotic genes.

  17. Segregating Variation in the Polycomb Group Gene cramped Alters the Effect of Temperature on Multiple Traits

    PubMed Central

    Gibert, Jean-Michel; Karch, François; Schlötterer, Christian

    2011-01-01

    The phenotype produced by a given genotype can be strongly modulated by environmental conditions. Therefore, natural populations continuously adapt to environment heterogeneity to maintain optimal phenotypes. It generates a high genetic variation in environment-sensitive gene networks, which is thought to facilitate evolution. Here we analyze the chromatin regulator crm, identified as a candidate for adaptation of Drosophila melanogaster to northern latitudes. We show that crm contributes to environmental canalization. In particular, crm modulates the effect of temperature on a genomic region encoding Hedgehog and Wingless signaling effectors. crm affects this region through both constitutive heterochromatin and Polycomb silencing. Furthermore, we show that crm European and African natural variants shift the reaction norms of plastic traits. Interestingly, traits modulated by crm natural variants can differ markedly between Drosophila species, suggesting that temperature adaptation facilitates their evolution. PMID:21283785

  18. A view of nuclear Polycomb bodies

    PubMed Central

    Pirrotta, Vincenzo; Li, Hua-Bing

    2012-01-01

    Polycomb Group (PcG) proteins are concentrated in nuclear foci called PcG bodies. Although the some of these foci are due to the tendency of PcG binding sites in the genome to occur in linear clusters, distant PcG sites can contact one another and in some cases congregate in the same PcG body when they are repressed. Experiments using transgenes containing PcG binding sites reveal that co-localization depends on the presence of insulator elements rather than of Polycomb Response Elements (PREs) and that it can occur also when the transgenes are in the active state. A model is proposed according to which insulator proteins mediate shuttling of PcG target genes between PcG bodies when repressed to transcription factories when transcriptionally active. PMID:22178420

  19. The Transcriptional Repressor Polycomb Group Factor 6, PCGF6, Negatively Regulates Dendritic Cell Activation and Promotes Quiescence.

    PubMed

    Boukhaled, Giselle M; Cordeiro, Brendan; Deblois, Genevieve; Dimitrov, Vassil; Bailey, Swneke D; Holowka, Thomas; Domi, Anisa; Guak, Hannah; Chiu, Huai-Hsuan Clare; Everts, Bart; Pearce, Edward J; Lupien, Mathieu; White, John H; Krawczyk, Connie M

    2016-08-16

    Pro-inflammatory signals provided by the microenvironment are critical to activate dendritic cells (DCs), components of the innate immune system that shape both innate and adaptive immunity. However, to prevent inappropriate immune activation, mechanisms must be in place to restrain DC activation to ensure DCs are activated only once sufficient stimuli have been received. Here, we report that DC activation and immunogenicity are regulated by the transcriptional repressor Polycomb group factor 6 (PCGF6). Pcgf6 is rapidly downregulated upon stimulation, and this downregulation is necessary to permit full DC activation. Silencing PCGF6 expression enhanced both spontaneous and stimulated DC activation. We show that PCGF6 associates with the H3K4me3 demethylase JARID1c, and together, they negatively regulate H3K4me3 levels in DCs. Our results identify two key regulators, PCGF6 and JARID1c that temper DC activation and implicate active transcriptional silencing via histone demethylation as a previously unappreciated mechanism for regulating DC activation and quiescence.

  20. O-GlcNAcylation, an Epigenetic Mark. Focus on the Histone Code, TET Family Proteins, and Polycomb Group Proteins

    PubMed Central

    Dehennaut, Vanessa; Leprince, Dominique; Lefebvre, Tony

    2014-01-01

    There are increasing evidences that dietary components and metabolic disorders affect gene expression through epigenetic mechanisms. These observations support the notion that epigenetic reprograming-linked nutrition is connected to the etiology of metabolic diseases and cancer. During the last 5 years, accumulating data revealed that the nutrient-sensing O-GlcNAc glycosylation (O-GlcNAcylation) may be pivotal in the modulation of chromatin remodeling and in the regulation of gene expression by being part of the “histone code,” and by identifying OGT (O-GlcNAc transferase) as an interacting partner of the TET family proteins of DNA hydroxylases and as a member of the polycomb group proteins. Thus, it is suggested that O-GlcNAcylation is a post-translational modification that links nutrition to epigenetic. This review summarizes recent findings about the interplay between O-GlcNAcylation and the epigenome and enlightens the contribution of the glycosylation to epigenetic reprograming. PMID:25309514

  1. The Transcriptional Repressor Polycomb Group Factor 6, PCGF6, Negatively Regulates Dendritic Cell Activation and Promotes Quiescence.

    PubMed

    Boukhaled, Giselle M; Cordeiro, Brendan; Deblois, Genevieve; Dimitrov, Vassil; Bailey, Swneke D; Holowka, Thomas; Domi, Anisa; Guak, Hannah; Chiu, Huai-Hsuan Clare; Everts, Bart; Pearce, Edward J; Lupien, Mathieu; White, John H; Krawczyk, Connie M

    2016-08-16

    Pro-inflammatory signals provided by the microenvironment are critical to activate dendritic cells (DCs), components of the innate immune system that shape both innate and adaptive immunity. However, to prevent inappropriate immune activation, mechanisms must be in place to restrain DC activation to ensure DCs are activated only once sufficient stimuli have been received. Here, we report that DC activation and immunogenicity are regulated by the transcriptional repressor Polycomb group factor 6 (PCGF6). Pcgf6 is rapidly downregulated upon stimulation, and this downregulation is necessary to permit full DC activation. Silencing PCGF6 expression enhanced both spontaneous and stimulated DC activation. We show that PCGF6 associates with the H3K4me3 demethylase JARID1c, and together, they negatively regulate H3K4me3 levels in DCs. Our results identify two key regulators, PCGF6 and JARID1c that temper DC activation and implicate active transcriptional silencing via histone demethylation as a previously unappreciated mechanism for regulating DC activation and quiescence. PMID:27498878

  2. Trans-silencing by P elements inserted in subtelomeric heterochromatin involves the Drosophila Polycomb group gene, Enhancer of zeste.

    PubMed Central

    Roche, S E; Rio, D C

    1998-01-01

    Drosophila P-element transposition is regulated by a maternally inherited state known as P cytotype. An important aspect of P cytotype is transcriptional repression of the P-element promoter. P cytotype can also repress non-P-element promoters within P-element ends, suggesting that P cytotype repression might involve chromatin-based transcriptional silencing. To learn more about the role of chromatin in P cytotype repression, we have been studying the P strain Lk-P(1A). This strain contains two full-length P elements inserted in the heterochromatic telomere-associated sequences (TAS elements) at cytological location 1A. Mutations in the Polycomb group gene (Pc-G gene), Enhancer of zeste (E(z)), whose protein product binds at 1A, resulted in a loss of Lk-P(1A) cytotype control. E(z) mutations also affected the trans-silencing of heterologous promoters between P-element termini by P-element transgenes inserted in the TAS repeats. These data suggest that pairing interactions between P elements, resulting in exchange of chromatin structures, may be a mechanism for controlling the expression and activity of P elements. PMID:9691041

  3. RING1B O-GlcNAcylation regulates gene targeting of polycomb repressive complex 1 in human embryonic stem cells.

    PubMed

    Maury, Julien Jean Pierre; El Farran, Chadi A; Ng, Daniel; Loh, Yuin-Han; Bi, Xuezhi; Bardor, Muriel; Choo, Andre Boon-Hwa

    2015-07-01

    O-linked-N-acetylglucosamine (O-GlcNAc) post-translationally modifies and regulates thousands of proteins involved in various cellular mechanisms. Recently, O-GlcNAc has been linked to human embryonic stem cells (hESC) differentiation, however the identity and function of O-GlcNAc proteins regulating hESC remain unknown. Here, we firstly identified O-GlcNAc modified human stem cell regulators such as hnRNP K, HP1γ, and especially RING1B/RNF2. Thereafter, we focused our work on RING1B which is the catalytic subunit of the polycomb repressive complex 1 (PRC1) a major epigenetic repressor essential for pluripotency maintenance and differentiation. By point-mutation, we show that T(250)/S(251) and S(278) RING1B residues are bearing O-GlcNAc, and that T(250)/S(251) O-GlcNAcylation decreases during differentiation. O-GlcNAc seems to regulate RING1B-DNA binding as suggested by our ChIP-sequencing results. Non-O-GlcNAcylated RING1B is found to be enriched near cell cycle genes whereas O-GlcNAcylated RING1B seems preferentially enriched near neuronal genes. Our data suggest that during hESC differentiation, the decrease of RING1B O-GlcNAcylation might enable PRC1 to switch its target to induce neuron differentiation. Overall, we demonstrate that O-GlcNAc modifies and regulates an essential epigenetic tool, RING1B, which may contribute to hESC pluripotency maintenance and differentiation. PMID:26100231

  4. Short germ insects utilize both the ancestral and derived mode of Polycomb group-mediated epigenetic silencing of Hox genes

    PubMed Central

    Matsuoka, Yuji; Bando, Tetsuya; Watanabe, Takahito; Ishimaru, Yoshiyasu; Noji, Sumihare; Popadić, Aleksandar; Mito, Taro

    2015-01-01

    In insect species that undergo long germ segmentation, such as Drosophila, all segments are specified simultaneously at the early blastoderm stage. As embryogenesis progresses, the expression boundaries of Hox genes are established by repression of gap genes, which is subsequently replaced by Polycomb group (PcG) silencing. At present, however, it is not known whether patterning occurs this way in a more ancestral (short germ) mode of embryogenesis, where segments are added gradually during posterior elongation. In this study, two members of the PcG family, Enhancer of zeste (E(z)) and Suppressor of zeste 12 (Su(z)12), were analyzed in the short germ cricket, Gryllus bimaculatus. Results suggest that although stepwise negative regulation by gap and PcG genes is present in anterior members of the Hox cluster, it does not account for regulation of two posterior Hox genes, abdominal-A (abd-A) and Abdominal-B (Abd-B). Instead, abd-A and Abd-B are predominantly regulated by PcG genes, which is the mode present in vertebrates. These findings suggest that an intriguing transition of the PcG-mediated silencing of Hox genes may have occurred during animal evolution. The ancestral bilaterian state may have resembled the current vertebrate mode of regulation, where PcG-mediated silencing of Hox genes occurs before their expression is initiated and is responsible for the establishment of individual expression domains. Then, during insect evolution, the repression by transcription factors may have been acquired in anterior Hox genes of short germ insects, while PcG silencing was maintained in posterior Hox genes. PMID:25948756

  5. Short germ insects utilize both the ancestral and derived mode of Polycomb group-mediated epigenetic silencing of Hox genes.

    PubMed

    Matsuoka, Yuji; Bando, Tetsuya; Watanabe, Takahito; Ishimaru, Yoshiyasu; Noji, Sumihare; Popadić, Aleksandar; Mito, Taro

    2015-01-01

    In insect species that undergo long germ segmentation, such as Drosophila, all segments are specified simultaneously at the early blastoderm stage. As embryogenesis progresses, the expression boundaries of Hox genes are established by repression of gap genes, which is subsequently replaced by Polycomb group (PcG) silencing. At present, however, it is not known whether patterning occurs this way in a more ancestral (short germ) mode of embryogenesis, where segments are added gradually during posterior elongation. In this study, two members of the PcG family, Enhancer of zeste (E(z)) and Suppressor of zeste 12 (Su(z)12), were analyzed in the short germ cricket, Gryllus bimaculatus. Results suggest that although stepwise negative regulation by gap and PcG genes is present in anterior members of the Hox cluster, it does not account for regulation of two posterior Hox genes, abdominal-A (abd-A) and Abdominal-B (Abd-B). Instead, abd-A and Abd-B are predominantly regulated by PcG genes, which is the mode present in vertebrates. These findings suggest that an intriguing transition of the PcG-mediated silencing of Hox genes may have occurred during animal evolution. The ancestral bilaterian state may have resembled the current vertebrate mode of regulation, where PcG-mediated silencing of Hox genes occurs before their expression is initiated and is responsible for the establishment of individual expression domains. Then, during insect evolution, the repression by transcription factors may have been acquired in anterior Hox genes of short germ insects, while PcG silencing was maintained in posterior Hox genes. PMID:25948756

  6. white+ transgene insertions presenting a dorsal/ventral pattern define a single cluster of homeobox genes that is silenced by the polycomb-group proteins in Drosophila melanogaster.

    PubMed

    Netter, S; Fauvarque, M O; Diez del Corral, R; Dura, J M; Coen, D

    1998-05-01

    We used the white gene as an enhancer trap and reporter of chromatin structure. We collected white+ transgene insertions presenting a peculiar pigmentation pattern in the eye: white expression is restricted to the dorsal half of the eye, with a clear-cut dorsal/ventral (D/V) border. This D/V pattern is stable and heritable, indicating that phenotypic expression of the white reporter reflects positional information in the developing eye. Localization of these transgenes led us to identify a unique genomic region encompassing 140 kb in 69D1-3 subject to this D/V effect. This region contains at least three closely related homeobox-containing genes that are constituents of the iroquois complex (IRO-C). IRO-C genes are coordinately regulated and implicated in similar developmental processes. Expression of these genes in the eye is regulated by the products of the Polycomb-group (Pc-G) and trithorax-group (trx-G) genes but is not modified by classical modifiers of position-effect variegation. Our results, together with the report of a Pc-G binding site in 69D, suggest that we have identified a novel cluster of target genes for the Pc-G and trx-G products. We thus propose that ventral silencing of the whole IRO-C in the eye occurs at the level of chromatin structure in a manner similar to that of the homeotic gene complexes, perhaps by local compaction of the region into a heterochromatin-like structure involving the Pc-G products.

  7. white+ transgene insertions presenting a dorsal/ventral pattern define a single cluster of homeobox genes that is silenced by the polycomb-group proteins in Drosophila melanogaster.

    PubMed Central

    Netter, S; Fauvarque, M O; Diez del Corral, R; Dura, J M; Coen, D

    1998-01-01

    We used the white gene as an enhancer trap and reporter of chromatin structure. We collected white+ transgene insertions presenting a peculiar pigmentation pattern in the eye: white expression is restricted to the dorsal half of the eye, with a clear-cut dorsal/ventral (D/V) border. This D/V pattern is stable and heritable, indicating that phenotypic expression of the white reporter reflects positional information in the developing eye. Localization of these transgenes led us to identify a unique genomic region encompassing 140 kb in 69D1-3 subject to this D/V effect. This region contains at least three closely related homeobox-containing genes that are constituents of the iroquois complex (IRO-C). IRO-C genes are coordinately regulated and implicated in similar developmental processes. Expression of these genes in the eye is regulated by the products of the Polycomb-group (Pc-G) and trithorax-group (trx-G) genes but is not modified by classical modifiers of position-effect variegation. Our results, together with the report of a Pc-G binding site in 69D, suggest that we have identified a novel cluster of target genes for the Pc-G and trx-G products. We thus propose that ventral silencing of the whole IRO-C in the eye occurs at the level of chromatin structure in a manner similar to that of the homeotic gene complexes, perhaps by local compaction of the region into a heterochromatin-like structure involving the Pc-G products. PMID:9584101

  8. The Polycomb Group Protein EZH2 Impairs DNA Damage Repair Gene Expression in Human Uterine Fibroids.

    PubMed

    Yang, Qiwei; Nair, Sangeeta; Laknaur, Archana; Ismail, Nahed; Diamond, Michael P; Al-Hendy, Ayman

    2016-03-01

    Uterine fibroids are benign, smooth muscle tumors that occur in approximately 70%-80% of women by age 50 yr. The cellular and molecular mechanism(s) by which uterine fibroids (UFs) develop are not fully understood. Accumulating evidence demonstrates that several genetic abnormalities, including deletions, rearrangements, translocations, as well as mutations, have been found in UFs. These genetic anomalies suggest that low DNA damage repair capacity may be involved in UF formation. The objective of this study was to determine whether expression levels of DNA damage repair-related genes were altered, and how they were regulated in the pathogenesis of UFs. Expression levels of DNA repair-related genes RAD51 and BRCA1 were deregulated in fibroid tissues as compared to adjacent myometrial tissues. Expression levels of chromatin protein enhancer of zeste homolog 2 (EZH2) were higher in a subset of fibroids as compared to adjacent myometrial tissues by both immunohistochemistry and Western blot analysis. Treatment with an inhibitor of EZH2 markedly increased expression levels of RAD51 and BRCA1 in fibroid cells and inhibited cell proliferation paired with cell cycle arrest. Restoring the expression of RAD51 and BRCA1 by treatment with EZH2 inhibitor was dependent on reducing the enrichment of trimethylation of histone 3 lysine 27 epigenetic mark in their promoter regions. This study reveals the important role of EZH2-regulated DNA damage-repair genes via histone methylation in fibroid biology, and may provide novel therapeutic targets for the medical treatment of women with symptomatic UFs. PMID:26888970

  9. Adhesive pad differentiation in Drosophila melanogaster depends on the Polycomb group gene Su(z)2.

    PubMed

    Hüsken, Mirko; Hufnagel, Kim; Mende, Katharina; Appel, Esther; Meyer, Heiko; Peisker, Henrik; Tögel, Markus; Wang, Shuoshuo; Wolff, Jonas; Gorb, Stanislav N; Paululat, Achim

    2015-04-15

    The ability of many insects to walk on vertical smooth surfaces such as glass or even on the ceiling has fascinated biologists for a long time, and has led to the discovery of highly specialized adhesive organs located at the distal end of the animals' legs. So far, research has primarily focused on structural and ultrastructural investigations leading to a deeper understanding of adhesive organ functionality and to the development of new bioinspired materials. Genetic approaches, e.g. the analysis of mutants, to achieve a better understanding of adhesive organ differentiation have not been used so far. Here, we describe the first Drosophila melanogaster mutant that develops malformed adhesive organs, resulting in a complete loss of climbing ability on vertical smooth surfaces. Interestingly, these mutants fail to make close contact between the setal tips and the smooth surface, a crucial condition for wet adhesion mediated by capillary forces. Instead, these flies walk solely on their claws. Moreover, we were able to show that the mutation is caused by a P-element insertion into the Su(z)2 gene locus. Remobilization of the P-element restores climbing ability. Furthermore, we provide evidence that the P-element insertion results in an artificial Su(z)2 transcript, which most likely causes a gain-of-function mutation. We presume that this transcript causes deregulation of yet unknown target genes involved in pulvilli differentiation. Our results nicely demonstrate that the genetically treatable model organism Drosophila is highly suitable for future investigations on adhesive organ differentiation.

  10. MLL repression domain interacts with histone deacetylases, the polycomb group proteins HPC2 and BMI-1, and the corepressor C-terminal-binding protein

    PubMed Central

    Xia, Zhen-Biao; Anderson, Melanie; Diaz, Manuel O.; Zeleznik-Le, Nancy J.

    2003-01-01

    The MLL (mixed-lineage leukemia) gene is involved in many chromosomal translocations associated with acute myeloid and lymphoid leukemia. We previously identified a transcriptional repression domain in MLL, which contains a region with homology to DNA methyltransferase. In chromosomal translocations, the MLL repression domain is retained in the leukemogenic fusion protein and is required for transforming activity of MLL fusion proteins. We explored the mechanism of action of the MLL repression domain. Histone deacetylase 1 interacts with the MLL repression domain, partially mediating its activity; binding of Cyp33 to the adjacent MLL-PHD domain potentiates this binding. Because the MLL repression domain activity was only partially relieved with the histone deacetylase inhibitor trichostatin A, we explored other protein interactions with this domain. Polycomb group proteins HPC2 and BMI-1 and the corepressor C-terminal-binding protein also bind the MLL repression domain. Expression of exogenous BMI-1 potentiates MLL repression domain activity. Functional antagonism between Mll and Bmi-1 has been shown genetically in murine knockout models for Mll and Bmi-1. Our new data suggest a model whereby recruitment of BMI-1 to the MLL protein may be able to modulate its function. Furthermore, repression mediated by histone deacetylases and that mediated by polycomb group proteins may act either independently or together for MLL function in vivo. PMID:12829790

  11. PLK1 Inhibition Down-regulates Polycomb Group Protein BMI1 via Modulation of the miR-200c/141 Cluster*

    PubMed Central

    Dimri, Manjari; Cho, Joon-Ho; Kang, Mingu; Dimri, Goberdhan P.

    2015-01-01

    The polycomb group protein BMI1 is an important regulator of cancer stem cell (CSC) phenotype and is often overexpressed in cancer cells. Its overexpression leads to increase in CSC fraction and therapy resistance in tumors. BMI1 functions via polycomb repressive complex 1 (PRC1)-mediated gene silencing and also via PRC1-independent transcriptional activities. At present, very little is known about the therapy reagents that can efficiently inhibit BMI1 expression, and the CSC phenotype. Here, we report that the polo-like kinase 1 (PLK1) regulates BMI1 expression, and that its inhibition can efficiently down-regulate BMI1 expression and PRC1 activity, and induce premature senescence in breast cancer cells. We also show that the exogenous BMI1 overexpression mitigates anti-oncogenic effects of PLK1 inhibition and overcomes senescence induction by PLK1 inhibitors. We further show that PLK1 inhibition down-regulates BMI1 by upregulating the miRNA-200c/141 cluster, which encodes miR-200c and miR-141, both of which are known to post-transcriptionally downregulate BMI1 expression. Thus, our data suggest that PLK1 inhibitors can be successfully used to inhibit growth of tumors in which PcG protein BMI1 is overexpressed or the PRC1 activity is deregulated. PMID:25505268

  12. Polycomb repressive complex 2 in embryonic stem cells: an overview.

    PubMed

    Jones, Amanda; Wang, Hengbin

    2010-12-01

    Polycomb Group Proteins (PcG) are a family of epigenetic regulators responsible for the repression of an array of genes important in development and cell fate specification. PcG proteins complex to form two types of epigenetic regulators: Polycomb Repressive Complex 1 and 2 (PRC1 and PRC2). Although the mechanisms regulating PRC2 recruitment and activity in mammals remain poorly understood, recent work has identified a non-canonical PRC2 in mouse embryonic stem cells (mESC) with unique activities required for repression of PRC2 target genes and necessary for mESC differentiation and somatic cell reprogramming. Here we review the functions of PRC2 in embryonic stem cells and explore the role of the newly identified mESC specific PRC2 regulatory subunits Jarid2 (jumonji, AT rich interactive domain 2), Mtf2 (metal response element binding transcription factor 2) and esPRC2p48.

  13. Live-cell single-molecule tracking reveals co-recognition of H3K27me3 and DNA targets polycomb Cbx7-PRC1 to chromatin

    PubMed Central

    Zhen, Chao Yu; Tatavosian, Roubina; Huynh, Thao Ngoc; Duc, Huy Nguyen; Das, Raibatak; Kokotovic, Marko; Grimm, Jonathan B; Lavis, Luke D; Lee, Jun; Mejia, Frances J; Li, Yang; Yao, Tingting; Ren, Xiaojun

    2016-01-01

    The Polycomb PRC1 plays essential roles in development and disease pathogenesis. Targeting of PRC1 to chromatin is thought to be mediated by the Cbx family proteins (Cbx2/4/6/7/8) binding to histone H3 with a K27me3 modification (H3K27me3). Despite this prevailing view, the molecular mechanisms of targeting remain poorly understood. Here, by combining live-cell single-molecule tracking (SMT) and genetic engineering, we reveal that H3K27me3 contributes significantly to the targeting of Cbx7 and Cbx8 to chromatin, but less to Cbx2, Cbx4, and Cbx6. Genetic disruption of the complex formation of PRC1 facilitates the targeting of Cbx7 to chromatin. Biochemical analyses uncover that the CD and AT-hook-like (ATL) motif of Cbx7 constitute a functional DNA-binding unit. Live-cell SMT of Cbx7 mutants demonstrates that Cbx7 is targeted to chromatin by co-recognizing of H3K27me3 and DNA. Our data suggest a novel hierarchical cooperation mechanism by which histone modifications and DNA coordinate to target chromatin regulatory complexes. DOI: http://dx.doi.org/10.7554/eLife.17667.001 PMID:27723458

  14. An Automatic Segmentation Method Combining an Active Contour Model and a Classification Technique for Detecting Polycomb-group Proteinsin High-Throughput Microscopy Images.

    PubMed

    Gregoretti, Francesco; Cesarini, Elisa; Lanzuolo, Chiara; Oliva, Gennaro; Antonelli, Laura

    2016-01-01

    The large amount of data generated in biological experiments that rely on advanced microscopy can be handled only with automated image analysis. Most analyses require a reliable cell image segmentation eventually capable of detecting subcellular structures.We present an automatic segmentation method to detect Polycomb group (PcG) proteins areas isolated from nuclei regions in high-resolution fluorescent cell image stacks. It combines two segmentation algorithms that use an active contour model and a classification technique serving as a tool to better understand the subcellular three-dimensional distribution of PcG proteins in live cell image sequences. We obtained accurate results throughout several cell image datasets, coming from different cell types and corresponding to different fluorescent labels, without requiring elaborate adjustments to each dataset. PMID:27659985

  15. Mapping the Function of Polycomb Proteins.

    PubMed

    Pasini, Diego

    2016-01-01

    Polycomb group (PcG) proteins are master regulators of proliferation and development that play essential roles in human pathologies including cancers. PcGs act as gatekeepers of cellular identity, maintaining repression of a multitude of target genes. However, these properties have only been recently uncovered thanks to technological advances, first of all chromatin immunoprecipitations (ChIP), that allowed a systematic characterization of the activity of these factors in an unbiased manner at a genome-wide level. Using PcG protein as example, this chapter introduces the readers to the use of chromatin analysis (ChIP assays and replication timing) and how to move these approaches to a level of genome-wide interpretation. PMID:27659970

  16. Regulation of gene transcription by Polycomb proteins

    PubMed Central

    Aranda, Sergi; Mas, Gloria; Di Croce, Luciano

    2015-01-01

    The Polycomb group (PcG) of proteins defines a subset of factors that physically associate and function to maintain the positional identity of cells from the embryo to adult stages. PcG has long been considered a paradigmatic model for epigenetic maintenance of gene transcription programs. Despite intensive research efforts to unveil the molecular mechanisms of action of PcG proteins, several fundamental questions remain unresolved: How many different PcG complexes exist in mammalian cells? How are PcG complexes targeted to specific loci? How does PcG regulate transcription? In this review, we discuss the diversity of PcG complexes in mammalian cells, examine newly identified modes of recruitment to chromatin, and highlight the latest insights into the molecular mechanisms underlying the function of PcGs in transcription regulation and three-dimensional chromatin conformation. PMID:26665172

  17. Arabidopsis Flower and Embryo Developmental Genes are Repressed in Seedlings by Different Combinations of Polycomb Group Proteins in Association with Distinct Sets of Cis-regulatory Elements

    PubMed Central

    Liu, Jian; Zhang, Lei; He, Chongsheng; Shen, Wen-Hui; Jin, Hong; Xu, Lin; Zhang, Yijing

    2016-01-01

    Polycomb repressive complexes (PRCs) play crucial roles in transcriptional repression and developmental regulation in both plants and animals. In plants, depletion of different members of PRCs causes both overlapping and unique phenotypic defects. However, the underlying molecular mechanism determining the target specificity and functional diversity is not sufficiently characterized. Here, we quantitatively compared changes of tri-methylation at H3K27 in Arabidopsis mutants deprived of various key PRC components. We show that CURLY LEAF (CLF), a major catalytic subunit of PRC2, coordinates with different members of PRC1 in suppression of distinct plant developmental programs. We found that expression of flower development genes is repressed in seedlings preferentially via non-redundant role of CLF, which specifically associated with LIKE HETEROCHROMATIN PROTEIN1 (LHP1). In contrast, expression of embryo development genes is repressed by PRC1-catalytic core subunits AtBMI1 and AtRING1 in common with PRC2-catalytic enzymes CLF or SWINGER (SWN). This context-dependent role of CLF corresponds well with the change in H3K27me3 profiles, and is remarkably associated with differential co-occupancy of binding motifs of transcription factors (TFs), including MADS box and ABA-related factors. We propose that different combinations of PRC members distinctively regulate different developmental programs, and their target specificity is modulated by specific TFs. PMID:26760036

  18. RYBP stimulates PRC1 to shape chromatin-based communication between Polycomb repressive complexes

    PubMed Central

    Rose, Nathan R; King, Hamish W; Blackledge, Neil P; Fursova, Nadezda A; Ember, Katherine JI; Fischer, Roman; Kessler, Benedikt M; Klose, Robert J

    2016-01-01

    Polycomb group (PcG) proteins function as chromatin-based transcriptional repressors that are essential for normal gene regulation during development. However, how these systems function to achieve transcriptional regulation remains very poorly understood. Here, we discover that the histone H2AK119 E3 ubiquitin ligase activity of Polycomb repressive complex 1 (PRC1) is defined by the composition of its catalytic subunits and is highly regulated by RYBP/YAF2-dependent stimulation. In mouse embryonic stem cells, RYBP plays a central role in shaping H2AK119 mono-ubiquitylation at PcG targets and underpins an activity-based communication between PRC1 and Polycomb repressive complex 2 (PRC2) which is required for normal histone H3 lysine 27 trimethylation (H3K27me3). Without normal histone modification-dependent communication between PRC1 and PRC2, repressive Polycomb chromatin domains can erode, rendering target genes susceptible to inappropriate gene expression signals. This suggests that activity-based communication and histone modification-dependent thresholds create a localized form of epigenetic memory required for normal PcG chromatin domain function in gene regulation. DOI: http://dx.doi.org/10.7554/eLife.18591.001 PMID:27705745

  19. The Polycomb group protein RING1B is overexpressed in ductal breast carcinoma and is required to sustain FAK steady state levels in breast cancer epithelial cells

    PubMed Central

    Bosch, Almudena; Panoutsopoulou, Konstantina; Corominas, Josep Maria; Gimeno, Ramón; Moreno-Bueno, Gema; Martín-Caballero, Juan; Morales, Saleta; Lobato, Tania; Martínez-Romero, Carles; Farias, Eduardo F.; Mayol, Xavier; Cano, Amparo; Hernández-Muáoz, Inmaculada

    2014-01-01

    In early stages of metastasis malignant cells must acquire phenotypic changes to enhance their migratory behavior and their ability to breach the matrix surrounding tumors and blood vessel walls. Epigenetic regulation of gene expression allows the acquisition of these features that, once tumoral cells have escape from the primary tumor, can be reverted. Here we report that the expression of the Polycomb epigenetic repressor Ring1B is enhanced in tumoral cells that invade the stroma in human ductal breast carcinoma and its expression is coincident with that of Fak in these tumors. Ring1B knockdown in breast cancer cell lines revealed that Ring1B is required to sustain Fak expression in basal conditions as well as in Tgfβ-treated cells. Functionally, endogenous Ring1B is required for cell migration and invasion in vitro and for in vivo invasion of the mammary fat pad by tumoral cells. Finally we identify p63 as a target of Ring1B to regulate Fak expression: Ring1B depletion results in enhanced p63 expression, which in turns represses Fak expression. Importantly, Fak downregulation upon Ring1B depletion is dependent on p63 expression. Our findings provide new insights in the biology of the breast carcinoma and open new avenues for breast cancer prognosis and therapy. PMID:24742605

  20. Polycomb-group protein SlMSI1 represses the expression of fruit-ripening genes to prolong shelf life in tomato.

    PubMed

    Liu, Dan-Dan; Zhou, Li-Jie; Fang, Mou-Jing; Dong, Qing-Long; An, Xiu-Hong; You, Chun-Xiang; Hao, Yu-Jin

    2016-01-01

    Polycomb-group (PcG) protein MULTICOPY SUPPRESSOR OF IRA1 (MSI1) protein is an evolutionarily conserved developmental suppressor and plays a crucial role in regulating epigenetic modulations. However, the potential role and function of MSI1 in fleshy fruits remain unknown. In this study, SlMSI1 was cloned and transformed into tomato to explore its function. The quantitative real-time PCR results showed that SlMSI1 was highly expressed in flowers and fruits and that its transcript and protein levels were significantly decreased in fruits after the breaker stage. Additionally, SlMSI1-overexpressing transgenic tomatoes displayed abnormal non-ripening fruit formation, whereas its suppression promoted fruit ripening in transgenic tomatoes. Quantitative real-time PCR assays also showed that RIN and its regulons were decreased in SlMSI1 overexpression transgenic tomato fruits. Furthermore, RNA-seq analysis demonstrated that SlMSI1 inhibits fruit ripening by negatively regulating a large set of fruit-ripening genes in addition to RIN and its regulons. Finally, genetic manipulation of SlMSI1 and RIN successfully prolonged the fruit shelf life by regulating the fruit-ripening genes in tomato. Our findings reveal a novel regulatory function of SlMSI1 in fruit ripening and provide a new regulator that may be useful for genetic engineering and modification of fruit shelf life. PMID:27558543

  1. Polycomb-group protein SlMSI1 represses the expression of fruit-ripening genes to prolong shelf life in tomato

    PubMed Central

    Liu, Dan-Dan; Zhou, Li-Jie; Fang, Mou-Jing; Dong, Qing-Long; An, Xiu-Hong; You, Chun-Xiang; Hao, Yu-Jin

    2016-01-01

    Polycomb-group (PcG) protein MULTICOPY SUPPRESSOR OF IRA1 (MSI1) protein is an evolutionarily conserved developmental suppressor and plays a crucial role in regulating epigenetic modulations. However, the potential role and function of MSI1 in fleshy fruits remain unknown. In this study, SlMSI1 was cloned and transformed into tomato to explore its function. The quantitative real-time PCR results showed that SlMSI1 was highly expressed in flowers and fruits and that its transcript and protein levels were significantly decreased in fruits after the breaker stage. Additionally, SlMSI1-overexpressing transgenic tomatoes displayed abnormal non-ripening fruit formation, whereas its suppression promoted fruit ripening in transgenic tomatoes. Quantitative real-time PCR assays also showed that RIN and its regulons were decreased in SlMSI1 overexpression transgenic tomato fruits. Furthermore, RNA-seq analysis demonstrated that SlMSI1 inhibits fruit ripening by negatively regulating a large set of fruit-ripening genes in addition to RIN and its regulons. Finally, genetic manipulation of SlMSI1 and RIN successfully prolonged the fruit shelf life by regulating the fruit-ripening genes in tomato. Our findings reveal a novel regulatory function of SlMSI1 in fruit ripening and provide a new regulator that may be useful for genetic engineering and modification of fruit shelf life. PMID:27558543

  2. Polycomb-group protein SlMSI1 represses the expression of fruit-ripening genes to prolong shelf life in tomato.

    PubMed

    Liu, Dan-Dan; Zhou, Li-Jie; Fang, Mou-Jing; Dong, Qing-Long; An, Xiu-Hong; You, Chun-Xiang; Hao, Yu-Jin

    2016-08-25

    Polycomb-group (PcG) protein MULTICOPY SUPPRESSOR OF IRA1 (MSI1) protein is an evolutionarily conserved developmental suppressor and plays a crucial role in regulating epigenetic modulations. However, the potential role and function of MSI1 in fleshy fruits remain unknown. In this study, SlMSI1 was cloned and transformed into tomato to explore its function. The quantitative real-time PCR results showed that SlMSI1 was highly expressed in flowers and fruits and that its transcript and protein levels were significantly decreased in fruits after the breaker stage. Additionally, SlMSI1-overexpressing transgenic tomatoes displayed abnormal non-ripening fruit formation, whereas its suppression promoted fruit ripening in transgenic tomatoes. Quantitative real-time PCR assays also showed that RIN and its regulons were decreased in SlMSI1 overexpression transgenic tomato fruits. Furthermore, RNA-seq analysis demonstrated that SlMSI1 inhibits fruit ripening by negatively regulating a large set of fruit-ripening genes in addition to RIN and its regulons. Finally, genetic manipulation of SlMSI1 and RIN successfully prolonged the fruit shelf life by regulating the fruit-ripening genes in tomato. Our findings reveal a novel regulatory function of SlMSI1 in fruit ripening and provide a new regulator that may be useful for genetic engineering and modification of fruit shelf life.

  3. Drosophila O-GlcNAc transferase (OGT) is encoded by the Polycomb group (PcG) gene, super sex combs (sxc)

    PubMed Central

    Sinclair, Donald A. R.; Syrzycka, Monika; Macauley, Matthew S.; Rastgardani, Tara; Komljenovic, Ivana; Vocadlo, David J.; Brock, Hugh W.; Honda, Barry M.

    2009-01-01

    O-linked N-acetylglucosamine transferase (OGT) reversibly modifies serine and threonine residues of many intracellular proteins with a single β-O-linked N-acetylglucosamine residue (O-GlcNAc), and has been implicated in insulin signaling, neurodegenerative disease, cellular stress response, and other important processes in mammals. OGT also glycosylates RNA polymerase II and various transcription factors, which suggests that it might be directly involved in transcriptional regulation. We report here that the Drosophila OGT is encoded by the Polycomb group (PcG) gene, super sex combs (sxc). Furthermore, major sites of O-GlcNAc modification on polytene chromosomes correspond to PcG protein binding sites. Our results thus suggest a direct role for O-linked glycosylation by OGT in PcG-mediated epigenetic gene silencing, which is important in developmental regulation, stem cell maintenance, genomic imprinting, and cancer. In addition, we observe rescue of sxc lethality by a human Ogt cDNA transgene; thus Drosophila may provide an ideal model to study important functional roles of OGT in mammals. PMID:19666537

  4. Drosophila O-GlcNAc transferase (OGT) is encoded by the Polycomb group (PcG) gene, super sex combs (sxc).

    PubMed

    Sinclair, Donald A R; Syrzycka, Monika; Macauley, Matthew S; Rastgardani, Tara; Komljenovic, Ivana; Vocadlo, David J; Brock, Hugh W; Honda, Barry M

    2009-08-11

    O-linked N-acetylglucosamine transferase (OGT) reversibly modifies serine and threonine residues of many intracellular proteins with a single beta-O-linked N-acetylglucosamine residue (O-GlcNAc), and has been implicated in insulin signaling, neurodegenerative disease, cellular stress response, and other important processes in mammals. OGT also glycosylates RNA polymerase II and various transcription factors, which suggests that it might be directly involved in transcriptional regulation. We report here that the Drosophila OGT is encoded by the Polycomb group (PcG) gene, super sex combs (sxc). Furthermore, major sites of O-GlcNAc modification on polytene chromosomes correspond to PcG protein binding sites. Our results thus suggest a direct role for O-linked glycosylation by OGT in PcG-mediated epigenetic gene silencing, which is important in developmental regulation, stem cell maintenance, genomic imprinting, and cancer. In addition, we observe rescue of sxc lethality by a human Ogt cDNA transgene; thus Drosophila may provide an ideal model to study important functional roles of OGT in mammals. PMID:19666537

  5. The polycomb group protein Bmi-1 represses the tumor suppressor PTEN and induces epithelial-mesenchymal transition in human nasopharyngeal epithelial cells

    PubMed Central

    Song, Li-Bing; Li, Jun; Liao, Wen-Ting; Feng, Yan; Yu, Chun-Ping; Hu, Li-Juan; Kong, Qing-Li; Xu, Li-Hua; Zhang, Xing; Liu, Wan-Li; Li, Man-Zhi; Zhang, Ling; Kang, Tie-Bang; Fu, Li-Wu; Huang, Wen-Lin; Xia, Yun-Fei; Tsao, Sai Wah; Li, Mengfeng; Band, Vimla; Band, Hamid; Shi, Qing-Hua; Zeng, Yi-Xin; Zeng, Mu-Sheng

    2009-01-01

    The polycomb group protein B lymphoma Mo-MLV insertion region 1 homolog (Bmi-1) is dysregulated in various cancers, and its upregulation strongly correlates with an invasive phenotype and poor prognosis in patients with nasopharyngeal carcinomas. However, the underlying mechanism of Bmi-1–mediated invasiveness remains unknown. In the current study, we found that upregulation of Bmi-1 induced epithelial-mesenchymal transition (EMT) and enhanced the motility and invasiveness of human nasopharyngeal epithelial cells, whereas silencing endogenous Bmi-1 expression reversed EMT and reduced motility. Furthermore, upregulation of Bmi-1 led to the stabilization of Snail, a transcriptional repressor associated with EMT, via modulation of PI3K/Akt/GSK-3β signaling. Chromatin immunoprecipitation assays revealed that Bmi-1 transcriptionally downregulated expression of the tumor suppressor PTEN in tumor cells through direct association with the PTEN locus. This in vitro analysis was consistent with the statistical inverse correlation detected between Bmi-1 and PTEN expression in a cohort of human nasopharyngeal carcinoma biopsies. Moreover, ablation of PTEN expression partially rescued the migratory/invasive phenotype of Bmi-1–silenced cells, indicating that PTEN might be a major mediator of Bmi-1–induced EMT. Our results provide functional and mechanistic links between the oncoprotein Bmi-1 and the tumor suppressor PTEN in the development and progression of cancer. PMID:19884659

  6. Zeste maintains repression of Ubx transgenes: Support for a new model of polycomb repression

    SciTech Connect

    Hur, Man-Wook; Laney, Jeffrey D.; Jeon, Sang-Hack; Ali, Janann; Biggin, Mark D.

    2001-09-01

    During late embryogenesis, the expression domains of homeotic genes are maintained by two groups of ubiquitously expressed regulators: the Polycomb repressors and the Trithorax activators. It is not known how the activities of the two maintenance systems are initially targeted to the correct genes. Zeste and GAGA are sequence specific DNA binding proteins previously shown to be Trithorax group activators of the homeotic gene Ultrabithorax (Ubx). Here we demonstrate that Zeste and GAGA DNA binding sites at the proximal promoter are also required to maintain, but not to initiate, repression of Ubx. Further, the repression mediated by Zeste DNA binding site is abolished in zeste null embryos. These data imply that Zeste and probably GAGA mediate Polycomb repression. We present a model in which the dual transcriptional activities of Zeste and GAGA are an essential component of the mechanism that chooses which maintenance system is to be targeted to a given promoter.

  7. Mapping polycomb response elements at the Drosophilla melanogaster giant locus.

    PubMed

    Abed, Jumana AlHaj; Cheng, Connie L; Crowell, Chase R; Madigan, Laura L; Onwuegbuchu, Erica; Desai, Siddhi; Benes, Judith; Jones, Richard S

    2013-12-01

    Polycomb-group (PcG) proteins are highly conserved epigenetic transcriptional regulators. They are capable of either maintaining the transcriptional silence of target genes through many cell cycles or enabling a dynamic regulation of gene expression in stem cells. In Drosophila melanogaster, recruitment of PcG proteins to targets requires the presence of at least one polycomb response element (PRE). Although the sequence requirements for PREs are not well-defined, the presence of Pho, a PRE-binding PcG protein, is a very good PRE indicator. In this study, we identify two PRE-containing regions at the PcG target gene, giant, one at the promoter, and another approximately 6 kb upstream. PRE-containing fragments, which coincide with localized presence of Pho in chromatin immunoprecipitations, were shown to maintain restricted expression of a lacZ reporter gene in embryos and to cause pairing-sensitive silencing of the mini-white gene in eyes. Our results also reinforce previous observations that although PRE maintenance and pairing-sensitive silencing activities are closely linked, the sequence requirements for these functions are not identical. PMID:24170735

  8. The Polycomb group protein CLF emerges as a specific tri-methylase of H3K27 regulating gene expression and development in Physcomitrella patens.

    PubMed

    Pereman, Idan; Mosquna, Assaf; Katz, Aviva; Wiedemann, Gertrud; Lang, Daniel; Decker, Eva L; Tamada, Yosuke; Ishikawa, Takaaki; Nishiyama, Tomoaki; Hasebe, Mitsuyasu; Reski, Ralf; Ohad, Nir

    2016-07-01

    Packaging of eukaryotic DNA largely depends on histone modifications that affect the accessibility of DNA to transcriptional regulators, thus controlling gene expression. The Polycomb group (PcG) chromatin remodeling complex deposits a methyl group on lysine 27 of histone 3 leading to repressed gene expression. Plants encode homologs of the Enhancer of zeste (E(z)), a component of the PcG complex from Drosophila, one of which is a SET domain protein designated CURLY LEAF (CLF). Although this SET domain protein exhibits a strong correlation with the presence of the H3K27me3 mark in plants, the methyl-transferase activity and specificity of its SET domain have not been directly tested in-vivo. Using the evolutionary early-diverged land plant model species Physcomitrella patens we show that abolishment of a single copy gene PpCLF, as well as an additional member of the PcG complex, FERTILIZATION-INDEPENDENT ENDOSPERM (PpFIE), results in a specific loss of tri-methylation of H3K27. Using site-directed mutagenesis of key residues, we revealed that H3K27 tri-methylation is mediated by the SET domain of the CLF protein. Moreover, the abolishment of H3K27me3 led to enhanced expression of transcription factor genes. This in turn led to the development of fertilization-independent sporophyte-like structures, as observed in PpCLF and PpFIE null mutants. Overall, our results demonstrate the role of PpCLF as a SET protein in tri-methylation of H3K27 in-vivo and the importance of this modification in regulating the expression of transcription factor genes involved in developmental programs of P. patens.

  9. The Polycomb group protein CLF emerges as a specific tri-methylase of H3K27 regulating gene expression and development in Physcomitrella patens.

    PubMed

    Pereman, Idan; Mosquna, Assaf; Katz, Aviva; Wiedemann, Gertrud; Lang, Daniel; Decker, Eva L; Tamada, Yosuke; Ishikawa, Takaaki; Nishiyama, Tomoaki; Hasebe, Mitsuyasu; Reski, Ralf; Ohad, Nir

    2016-07-01

    Packaging of eukaryotic DNA largely depends on histone modifications that affect the accessibility of DNA to transcriptional regulators, thus controlling gene expression. The Polycomb group (PcG) chromatin remodeling complex deposits a methyl group on lysine 27 of histone 3 leading to repressed gene expression. Plants encode homologs of the Enhancer of zeste (E(z)), a component of the PcG complex from Drosophila, one of which is a SET domain protein designated CURLY LEAF (CLF). Although this SET domain protein exhibits a strong correlation with the presence of the H3K27me3 mark in plants, the methyl-transferase activity and specificity of its SET domain have not been directly tested in-vivo. Using the evolutionary early-diverged land plant model species Physcomitrella patens we show that abolishment of a single copy gene PpCLF, as well as an additional member of the PcG complex, FERTILIZATION-INDEPENDENT ENDOSPERM (PpFIE), results in a specific loss of tri-methylation of H3K27. Using site-directed mutagenesis of key residues, we revealed that H3K27 tri-methylation is mediated by the SET domain of the CLF protein. Moreover, the abolishment of H3K27me3 led to enhanced expression of transcription factor genes. This in turn led to the development of fertilization-independent sporophyte-like structures, as observed in PpCLF and PpFIE null mutants. Overall, our results demonstrate the role of PpCLF as a SET protein in tri-methylation of H3K27 in-vivo and the importance of this modification in regulating the expression of transcription factor genes involved in developmental programs of P. patens. PMID:27179444

  10. The Dynamics of Polycomb Complexes.

    PubMed

    Palacios, Daniela

    2016-01-01

    Polycomb complexes are essential regulators of embryonic and adult stem cells, highly conserved from flies to mammals. Traditionally, their study was based on biochemical and genetic approaches. More recently, the development of novel technologies and the improvement and standardization of existing ones has allowed to address previously unexplored aspects of Polycomb biology, such as dynamics and regulation. In this chapter, relevant researchers in the field discuss novel technologies aimed at dissecting the dynamics of Polycomb complexes in normal and pathological conditions. PMID:27659981

  11. Mechanism of Polycomb recruitment to CpG islands revealed by inherited disease-associated mutation.

    PubMed

    Caputo, Valentina S; Costa, Joana R; Makarona, Kalliopi; Georgiou, Elisabeth; Layton, D Mark; Roberts, Irene; Karadimitris, Anastasios

    2013-08-15

    How the transcription repressing complex Polycomb interacts with transcriptional regulators at housekeeping genes in somatic cells is not well understood. By exploiting a CpG island (CGI) point mutation causing a Mendelian disease, we show that DNA binding of activating transcription factor (TF) determines histone acetylation and nucleosomal depletion commensurate with Polycomb exclusion from the target promoter. Lack of TF binding leads to reversible transcriptional repression imposed by nucleosomal compaction and consolidated by Polycomb recruitment and establishment of bivalent chromatin status. Thus, within a functional hierarchy of transcriptional regulators, TF binding is the main determinant of Polycomb recruitment to the CGI of a housekeeping gene in somatic cells. PMID:23591993

  12. Polycomb group gene OsFIE2 regulates rice (Oryza sativa) seed development and grain filling via a mechanism distinct from Arabidopsis.

    PubMed

    Nallamilli, Babi Ramesh Reddy; Zhang, Jian; Mujahid, Hana; Malone, Brandon M; Bridges, Susan M; Peng, Zhaohua

    2013-01-01

    Cereal endosperm represents 60% of the calories consumed by human beings worldwide. In addition, cereals also serve as the primary feedstock for livestock. However, the regulatory mechanism of cereal endosperm and seed development is largely unknown. Polycomb complex has been shown to play a key role in the regulation of endosperm development in Arabidopsis, but its role in cereal endosperm development remains obscure. Additionally, the enzyme activities of the polycomb complexes have not been demonstrated in plants. Here we purified the rice OsFIE2-polycomb complex using tandem affinity purification and demonstrated its specific H3 methyltransferase activity. We found that the OsFIE2 gene product was responsible for H3K27me3 production specifically in vivo. Genetic studies showed that a reduction of OsFIE2 expression led to smaller seeds, partially filled seeds, and partial loss of seed dormancy. Gene expression and proteomics analyses found that the starch synthesis rate limiting step enzyme and multiple storage proteins are down-regulated in OsFIE2 reduction lines. Genome wide ChIP-Seq data analysis shows that H3K27me3 is associated with many genes in the young seeds. The H3K27me3 modification and gene expression in a key helix-loop-helix transcription factor is shown to be regulated by OsFIE2. Our results suggest that OsFIE2-polycomb complex positively regulates rice endosperm development and grain filling via a mechanism highly different from that in Arabidopsis.

  13. A repetitive elements perspective in Polycomb epigenetics.

    PubMed

    Casa, Valentina; Gabellini, Davide

    2012-01-01

    Repetitive elements comprise over two-thirds of the human genome. For a long time, these elements have received little attention since they were considered non-functional. On the contrary, recent evidence indicates that they play central roles in genome integrity, gene expression, and disease. Indeed, repeats display meiotic instability associated with disease and are located within common fragile sites, which are hotspots of chromosome re-arrangements in tumors. Moreover, a variety of diseases have been associated with aberrant transcription of repetitive elements. Overall this indicates that appropriate regulation of repetitive elements' activity is fundamental. Polycomb group (PcG) proteins are epigenetic regulators that are essential for the normal development of multicellular organisms. Mammalian PcG proteins are involved in fundamental processes, such as cellular memory, cell proliferation, genomic imprinting, X-inactivation, and cancer development. PcG proteins can convey their activity through long-distance interactions also on different chromosomes. This indicates that the 3D organization of PcG proteins contributes significantly to their function. However, it is still unclear how these complex mechanisms are orchestrated and which role PcG proteins play in the multi-level organization of gene regulation. Intriguingly, the greatest proportion of Polycomb-mediated chromatin modifications is located in genomic repeats and it has been suggested that they could provide a binding platform for Polycomb proteins. Here, these lines of evidence are woven together to discuss how repetitive elements could contribute to chromatin organization in the 3D nuclear space.

  14. Polycomb silencing of the Drosophila 4E-BP gene regulates imaginal disc cell growth.

    PubMed

    Mason-Suares, Heather; Tie, Feng; Yan, Christopher M; Harte, Peter J

    2013-08-01

    Polycomb group (PcG) proteins are best known for their role in maintaining stable, mitotically heritable silencing of the homeotic (HOX) genes during development. In addition to loss of homeotic gene silencing, some PcG mutants also have small imaginal discs. These include mutations in E(z), Su(z)12, esc and escl, which encode Polycomb repressive complex 2 (PRC2) subunits. The cause of this phenotype is not known, but the human homologs of PRC2 subunits have been shown to play a role in cell proliferation, are over-expressed in many tumors, and appear to be required for tumor proliferation. Here we show that the small imaginal disc phenotype arises, at least in part, from a cell growth defect. In homozygous E(z) mutants, imaginal disc cells are smaller than cells in normally proliferating discs. We show that the Thor gene, which encodes eIF4E-binding protein (4E-BP), the evolutionarily conserved inhibitor of cap-dependent translation and potent inhibitor of cell growth, is involved in the development of this phenotype. The Thor promoter region contains DNA binding motifs for transcription factors found in well-characterized Polycomb response elements (PREs), including PHO/PHOL, GAGA factor, and others, suggesting that Thor may be a direct target of Polycomb silencing. We present chromatin immunoprecipitation evidence that PcG proteins are bound to the Thor 5' region in vivo. The Thor gene is normally repressed in imaginal discs, but Thor mRNA and 4E-BP protein levels are elevated in imaginal discs of PRC2 subunit mutant larvae. Deletion of the Thor gene in E(z) mutants partially restores imaginal disc size toward wild-type and results in an increase in the fraction of larvae that pupariate. These results thus suggest that PcG proteins can directly modulate cell growth in Drosophila, in part by regulating Thor expression.

  15. Polycomb enables primitive endoderm lineage priming in embryonic stem cells

    PubMed Central

    Illingworth, Robert S; Hölzenspies, Jurriaan J; Roske, Fabian V; Bickmore, Wendy A; Brickman, Joshua M

    2016-01-01

    Mouse embryonic stem cells (ESCs), like the blastocyst from which they are derived, contain precursors of the epiblast (Epi) and primitive endoderm (PrEn) lineages. While transient in vivo, these precursor populations readily interconvert in vitro. We show that altered transcription is the driver of these coordinated changes, known as lineage priming, in a process that exploits novel polycomb activities. We find that intragenic levels of the polycomb mark H3K27me3 anti-correlate with changes in transcription, irrespective of the gene’s developmental trajectory or identity as a polycomb target. In contrast, promoter proximal H3K27me3 is markedly higher for PrEn priming genes. Consequently, depletion of this modification stimulates the degree to which ESCs are primed towards PrEn when challenged to differentiate, but has little effect on gene expression in self-renewing ESC culture. These observations link polycomb with dynamic changes in transcription and stalled lineage commitment, allowing cells to explore alternative choices prior to a definitive decision. DOI: http://dx.doi.org/10.7554/eLife.14926.001 PMID:27723457

  16. One, Two, Three: Polycomb Proteins Hit All Dimensions of Gene Regulation

    PubMed Central

    del Prete, Stefania; Mikulski, Pawel; Schubert, Daniel; Gaudin, Valérie

    2015-01-01

    Polycomb group (PcG) proteins contribute to the formation and maintenance of a specific repressive chromatin state that prevents the expression of genes in a particular space and time. Polycomb repressive complexes (PRCs) consist of several PcG proteins with specific regulatory or catalytic properties. PRCs are recruited to thousands of target genes, and various recruitment factors, including DNA-binding proteins and non-coding RNAs, are involved in the targeting. PcG proteins contribute to a multitude of biological processes by altering chromatin features at different scales. PcG proteins mediate both biochemical modifications of histone tails and biophysical modifications (e.g., chromatin fiber compaction and three-dimensional (3D) chromatin conformation). Here, we review the role of PcG proteins in nuclear architecture, describing their impact on the structure of the chromatin fiber, on chromatin interactions, and on the spatial organization of the genome in nuclei. Although little is known about the role of plant PcG proteins in nuclear organization, much is known in the animal field, and we highlight similarities and differences in the roles of PcG proteins in 3D gene regulation in plants and animals. PMID:26184319

  17. Stuxnet Facilitates the Degradation of Polycomb Protein during Development.

    PubMed

    Du, Juan; Zhang, Junzheng; He, Tao; Li, Yajuan; Su, Ying; Tie, Feng; Liu, Min; Harte, Peter J; Zhu, Alan Jian

    2016-06-20

    Polycomb-group (PcG) proteins function to ensure correct deployment of developmental programs by epigenetically repressing target gene expression. Despite the importance, few studies have been focused on the regulation of PcG activity itself. Here, we report a Drosophila gene, stuxnet (stx), that controls Pc protein stability. We find that heightened stx activity leads to homeotic transformation, reduced Pc activity, and de-repression of PcG targets. Conversely, stx mutants, which can be rescued by decreased Pc expression, display developmental defects resembling hyperactivation of Pc. Our biochemical analyses provide a mechanistic basis for the interaction between stx and Pc; Stx facilitates Pc degradation in the proteasome, independent of ubiquitin modification. Furthermore, this mode of regulation is conserved in vertebrates. Mouse stx promotes degradation of Cbx4, an orthologous Pc protein, in vertebrate cells and induces homeotic transformation in Drosophila. Our results highlight an evolutionarily conserved mechanism of regulated protein degradation on PcG homeostasis and epigenetic activity. PMID:27326929

  18. Polycomb mediates Myc autorepression and its transcriptional control of many loci in Drosophila

    PubMed Central

    Goodliffe, Julie M.; Wieschaus, Eric; Cole, Michael D.

    2005-01-01

    Aberrant accumulation of the Myc oncoprotein propels proliferation and induces carcinogenesis. In normal cells, however, an abundance of Myc protein represses transcription at the c-myc locus. Cancer cells often lose this autorepression. We examined the control of myc in Drosophila and show here that the Drosophila ortholog, dmyc, also undergoes autorepression. We find that the developmental repressor Polycomb (Pc) is required for dmyc autorepression, and that this Pc-dMyc-mediated repression spreads across an 875-kb region encompassing the dmyc gene. To further investigate the relationship between Myc and Polycomb, we used microarrays to identify genes regulated by each, and identify a striking relationship between the two: A large set of dMyc activation targets is normally repressed by Pc, and 73% of dMyc repression targets require Pc for this repression. Chromatin immunoprecipitation confirmed that many dMyc-Pc-repressed loci have an epigenetic mark recognized by Pc. Our results suggest a novel relationship between Myc and Polycomb, wherein Myc enhances Polycomb repression in order to repress targets, and Myc suppresses Polycomb repression in order to activate targets. PMID:16357214

  19. Following the Motion of Polycomb Bodies in Living Drosophila Embryos.

    PubMed

    Cheutin, Thierry; Cavalli, Giacomo

    2016-01-01

    During the last two decades, observation of cell nuclei in live microscopy evidences motion of nuclear compartments. Drosophila embryos constitute a good model to study nuclear dynamic during cell differentiation because they can easily be observed in live microscopy. Inside the cell nucleus, Polycomb group proteins accumulate in foci named Pc bodies. Here, we describe a method to visualize and analyze the motion of these nuclear compartments inside cell nuclei of Drosophila embryos. PMID:27659993

  20. Phf19 links methylated Lys36 of histone H3 to regulation of Polycomb activity

    PubMed Central

    Ballaré, Cecilia; Lange, Martin; Lapinaite, Audrone; Martin, Gloria Mas; Morey, Lluis; Pascual, Gloria; Liefke, Robert; Simon, Bernd; Shi, Yang; Gozani, Or; Carlomagno, Teresa; Benitah, Salvador Aznar; Croce, Luciano Di

    2013-01-01

    Polycomb-group proteins are transcriptional repressors with essential roles in embryonic development. Polycomb repressive complex 2 (PRC2) contains the methyltransferase activity for Lys27. However, the role of other histone modifications in regulating PRC2 activity is just beginning to be understood. Here we show that direct recognition of methylated histone H3 Lys36 (H3K36me), a mark associated with activation, by the PRC2 subunit Phf19 is required for the full enzymatic activity of the PRC2 complex. Using NMR spectroscopy, we provide structural evidence for this interaction. Furthermore, we show that Phf19 binds to a subset of PRC2 targets in mouse embryonic stem cells and that this is required for their repression and for H3K27me3 deposition. These findings show that the interaction of Phf19 with H3K36me2 and H3K36me3 is essential for PRC2 complex activity and for proper regulation of gene repression in embryonic stem cells. PMID:23104054

  1. Polycomb Repressive Complex 2 (PRC2) Restricts Hematopoietic Stem Cell Activity

    PubMed Central

    Majewski, Ian J; Blewitt, Marnie E; de Graaf, Carolyn A; McManus, Edward J; Bahlo, Melanie; Hilton, Adrienne A; Hyland, Craig D; Smyth, Gordon K; Corbin, Jason E; Metcalf, Donald; Alexander, Warren S; Hilton, Douglas J

    2008-01-01

    Polycomb group proteins are transcriptional repressors that play a central role in the establishment and maintenance of gene expression patterns during development. Using mice with an N-ethyl-N-nitrosourea (ENU)-induced mutation in Suppressor of Zeste 12 (Suz12), a core component of Polycomb Repressive Complex 2 (PRC2), we show here that loss of Suz12 function enhances hematopoietic stem cell (HSC) activity. In addition to these effects on a wild-type genetic background, mutations in Suz12 are sufficient to ameliorate the stem cell defect and thrombocytopenia present in mice that lack the thrombopoietin receptor (c-Mpl). To investigate the molecular targets of the PRC2 complex in the HSC compartment, we examined changes in global patterns of gene expression in cells deficient in Suz12. We identified a distinct set of genes that are regulated by Suz12 in hematopoietic cells, including eight genes that appear to be highly responsive to PRC2 function within this compartment. These data suggest that PRC2 is required to maintain a specific gene expression pattern in hematopoiesis that is indispensable to normal stem cell function. PMID:18416604

  2. MicroRNA-323-3p Regulates the Activity of Polycomb Repressive Complex 2 (PRC2) via Targeting the mRNA of Embryonic Ectoderm Development (Eed) Gene in Mouse Embryonic Stem Cells*

    PubMed Central

    Zhang, Ying; Teng, Fei; Luo, Guan-Zheng; Wang, Meng; Tong, Man; Zhao, Xiaoyang; Wang, Liu; Wang, Xiu-Jie; Zhou, Qi

    2013-01-01

    PRC2 (Polycomb repressive complex 2) mediates epigenetic gene silencing by catalyzing the triple methylation of histone H3 Lys-27 (H3K27me3) to establish a repressive epigenetic state. PRC2 is involved in the regulation of many fundamental biological processes and is especially essential for embryonic stem cells. However, how the formation and function of PRC2 are regulated is largely unknown. Here, we show that a microRNA encoded by the imprinted Dlk1-Dio3 region of mouse chromosome 12, miR-323-3p, targets Eed (embryonic ectoderm development) mRNA, which encodes one of the core components of PRC2, the EED protein. Binding of miR-323-3p to Eed mRNA resulted in reduced EED protein abundance and cellular H3K27me3 levels, indicating decreased PRC2 activity. Such regulation seems to be conserved among mammals, at least between mice and humans. We demonstrate that induced pluripotent stem cells with varied developmental abilities had different miR-323-3p as well as EED and H3K27me3 levels, indicating that miR-323-3p may be involved in the regulation of stem cell pluripotency through affecting PRC2 activity. Mouse embryonic fibroblast cells had much higher miR-323-3p expression and nearly undetectable H3K27me3 levels. These findings identify miR-323-3p as a new regulator for PRC2 and provide a new approach for regulating PRC2 activity via microRNAs. PMID:23821546

  3. Formation of a Polycomb-Domain in the Absence of Strong Polycomb Response Elements

    PubMed Central

    De, Sandip; Mitra, Apratim; Cheng, Yuzhong; Pfeifer, Karl; Kassis, Judith A.

    2016-01-01

    Polycomb group response elements (PREs) in Drosophila are DNA-elements that recruit Polycomb proteins (PcG) to chromatin and regulate gene expression. PREs are easily recognizable in the Drosophila genome as strong peaks of PcG-protein binding over discrete DNA fragments; many small but statistically significant PcG peaks are also observed in PcG domains. Surprisingly, in vivo deletion of the four characterized strong PREs from the PcG regulated invected-engrailed (inv-en) gene complex did not disrupt the formation of the H3K27me3 domain and did not affect inv-en expression in embryos or larvae suggesting the presence of redundant PcG recruitment mechanism. Further, the 3D-structure of the inv-en domain was only minimally altered by the deletion of the strong PREs. A reporter construct containing a 7.5kb en fragment that contains three weak peaks but no large PcG peaks forms an H3K27me3 domain and is PcG-regulated. Our data suggests a model for the recruitment of PcG-complexes to Drosophila genes via interactions with multiple, weak PREs spread throughout an H3K27me3 domain. PMID:27466807

  4. Repressing the Keratinocyte Genome: How the Polycomb Complex Subunits Operate in Concert to Control Skin and Hair Follicle Development.

    PubMed

    Botchkarev, Vladimir A; Mardaryev, Andrei N

    2016-08-01

    The Polycomb group proteins are transcriptional repressors that are critically important in the control of stem cell activity and maintenance of the identity of differentiated cells. Polycomb proteins interact with each other to form chromatin-associated repressive complexes (Polycomb repressive complexes 1 and 2) leading to chromatin compaction and gene silencing. However, the roles of the distinct components of the Polycomb repressive complex 2 in the control of skin development and keratinocyte differentiation remain obscure. Dauber et al. demonstrate the conditional ablations of three essential Polycomb repressive complex 2 subunits (EED, Suz12, or Ezh1/2) in the epidermal progenitors result in quite similar skin phenotypes including premature acquisition of a functional epidermal barrier, formation of ectopic Merkel cells, and defective postnatal hair follicle development. The reported data demonstrate that in skin epithelia, EED, Suz12, and Ezh1/2 function largely as subunits of the Polycomb repressive complex 2, which is important in the context of data demonstrating their independent activities in other cell types. The report provides an important platform for further analyses of the role of distinct Polycomb components in the control of gene expression programs in the disorders of epidermal differentiation, such as psoriasis and epidermal cancer. PMID:27450498

  5. Arabidopsis transcriptional repressor VAL1 triggers Polycomb silencing at FLC during vernalization.

    PubMed

    Qüesta, Julia I; Song, Jie; Geraldo, Nuno; An, Hailong; Dean, Caroline

    2016-07-29

    The determinants that specify the genomic targets of Polycomb silencing complexes are still unclear. Polycomb silencing of Arabidopsis FLOWERING LOCUS C (FLC) accelerates flowering and involves a cold-dependent epigenetic switch. Here we identify a single point mutation at an intragenic nucleation site within FLC that prevents this epigenetic switch from taking place. The mutation blocks nucleation of plant homeodomain-Polycomb repressive complex 2 (PHD-PRC2) and indicates a role for the transcriptional repressor VAL1 in the silencing mechanism. VAL1 localizes to the nucleation region in vivo, promoting histone deacetylation and FLC transcriptional silencing, and interacts with components of the conserved apoptosis- and splicing-associated protein (ASAP) complex. Sequence-specific targeting of transcriptional repressors thus recruits the machinery for PHD-PRC2 nucleation and epigenetic silencing.

  6. Arabidopsis transcriptional repressor VAL1 triggers Polycomb silencing at FLC during vernalization.

    PubMed

    Qüesta, Julia I; Song, Jie; Geraldo, Nuno; An, Hailong; Dean, Caroline

    2016-07-29

    The determinants that specify the genomic targets of Polycomb silencing complexes are still unclear. Polycomb silencing of Arabidopsis FLOWERING LOCUS C (FLC) accelerates flowering and involves a cold-dependent epigenetic switch. Here we identify a single point mutation at an intragenic nucleation site within FLC that prevents this epigenetic switch from taking place. The mutation blocks nucleation of plant homeodomain-Polycomb repressive complex 2 (PHD-PRC2) and indicates a role for the transcriptional repressor VAL1 in the silencing mechanism. VAL1 localizes to the nucleation region in vivo, promoting histone deacetylation and FLC transcriptional silencing, and interacts with components of the conserved apoptosis- and splicing-associated protein (ASAP) complex. Sequence-specific targeting of transcriptional repressors thus recruits the machinery for PHD-PRC2 nucleation and epigenetic silencing. PMID:27471304

  7. Identification of regulators of the three-dimensional polycomb organization by a microscopy-based genome-wide RNAi screen.

    PubMed

    Gonzalez, Inma; Mateos-Langerak, Julio; Thomas, Aubin; Cheutin, Thierry; Cavalli, Giacomo

    2014-05-01

    Polycomb group (PcG) proteins dynamically define cellular identities through epigenetic repression of key developmental genes. PcG target gene repression can be stabilized through the interaction in the nucleus at PcG foci. Here, we report the results of a high-resolution microscopy genome-wide RNAi screen that identifies 129 genes that regulate the nuclear organization of Pc foci. Candidate genes include PcG components and chromatin factors, as well as many protein-modifying enzymes, including components of the SUMOylation pathway. In the absence of SUMO, Pc foci coagulate into larger aggregates. Conversely, loss of function of the SUMO peptidase Velo disperses Pc foci. Moreover, SUMO and Velo colocalize with PcG proteins at PREs, and Pc SUMOylation affects its chromatin targeting, suggesting that the dynamic regulation of Pc SUMOylation regulates PcG-mediated silencing by modulating the kinetics of Pc binding to chromatin as well as its ability to form Polycomb foci. PMID:24703951

  8. Functional analysis of AEBP2, a PRC2 Polycomb protein, reveals a Trithorax phenotype in embryonic development and in ESCs

    PubMed Central

    Grijzenhout, Anne; Godwin, Jonathan; Koseki, Haruhiko; Gdula, Michal Ryszard; Szumska, Dorota; McGouran, Joanna F.; Bhattacharya, Shoumo; Kessler, Benedikt M.; Brockdorff, Neil

    2016-01-01

    The Polycomb repressive complexes PRC1 and PRC2 are key mediators of heritable gene silencing in multicellular organisms. Here, we characterise AEBP2, a known PRC2 co-factor which, in vitro, has been shown to stimulate PRC2 activity. We show that AEBP2 localises specifically to PRC2 target loci, including the inactive X chromosome. Proteomic analysis confirms that AEBP2 associates exclusively with PRC2 complexes. However, analysis of embryos homozygous for a targeted mutation of Aebp2 unexpectedly revealed a Trithorax phenotype, normally linked to antagonism of Polycomb function. Consistent with this, we observe elevated levels of PRC2-mediated histone H3K27 methylation at target loci in Aebp2 mutant embryonic stem cells (ESCs). We further demonstrate that mutant ESCs assemble atypical hybrid PRC2 subcomplexes, potentially accounting for enhancement of Polycomb activity, and suggesting that AEBP2 normally plays a role in defining the mutually exclusive composition of PRC2 subcomplexes. PMID:27317809

  9. Polycomb repressive complex 1 controls uterine decidualization

    PubMed Central

    Bian, Fenghua; Gao, Fei; Kartashov, Andrey V.; Jegga, Anil G.; Barski, Artem; Das, Sanjoy K.

    2016-01-01

    Uterine stromal cell decidualization is an essential part of the reproductive process. Decidual tissue development requires a highly regulated control of the extracellular tissue remodeling; however the mechanism of this regulation remains unknown. Through systematic expression studies, we detected that Cbx4/2, Rybp, and Ring1B [components of polycomb repressive complex 1 (PRC1)] are predominantly utilized in antimesometrial decidualization with polyploidy. Immunofluorescence analyses revealed that PRC1 members are co-localized with its functional histone modifier H2AK119ub1 (mono ubiquitination of histone-H2A at lysine-119) in polyploid cell. A potent small-molecule inhibitor of Ring1A/B E3-ubiquitin ligase or siRNA-mediated suppression of Cbx4 caused inhibition of H2AK119ub1, in conjunction with perturbation of decidualization and polyploidy development, suggesting a role for Cbx4/Ring1B-containing PRC1 in these processes. Analyses of genetic signatures by RNA-seq studies showed that the inhibition of PRC1 function affects 238 genes (154 up and 84 down) during decidualization. Functional enrichment analyses identified that about 38% genes primarily involved in extracellular processes are specifically targeted by PRC1. Furthermore, ~15% of upregulated genes exhibited a significant overlap with the upregulated Bmp2 null-induced genes in mice. Overall, Cbx4/Ring1B-containing PRC1 controls decidualization via regulation of extracellular gene remodeling functions and sheds new insights into underlying molecular mechanism(s) through transcriptional repression regulation. PMID:27181215

  10. Polycomb Repressed Genes have Permissive Enhancers that Initiate Reprogramming

    PubMed Central

    Taberlay, Phillippa C.; Kelly, Theresa K.; Liu, Chun-Chi; You, Jueng Soo; de Carvalho, Daniel D.; Miranda, Tina B.; Zhou, Xianghong J.; Liang, Gangning; Jones, Peter A.

    2011-01-01

    SUMMARY Key regulatory genes, suppressed by Polycomb and H3K27me3, become active during normal differentiation and induced reprogramming. Using the well-characterized enhancer/promoter pair of MYOD1 as a model, we have identified a critical role for enhancers in reprogramming. We observed an unexpected nucleosome depleted region (NDR) at the H3K4me1-enriched enhancer at which transcriptional regulators initially bind, leading to subsequent changes in the chromatin at the cognate promoter. Exogenous Myod1 activates its own transcription by binding first at the enhancer leading to an NDR and transcription-permissive chromatin at the associated MYOD1 promoter. Exogenous OCT4 also binds first to the permissive MYOD1 enhancer, but has a different effect on the cognate promoter, where the monovalent H3K27me3-marks are converted to the bivalent state characteristic of stem cells. Genome-wide, a high percentage of Polycomb targets are associated with putative enhancers in permissive states, suggesting they may provide a widespread avenue for the initiation of cell-fate reprogramming. PMID:22153073

  11. Animal Rights Groups Target High School Dissection.

    ERIC Educational Resources Information Center

    Trotter, Andrew

    1992-01-01

    Two groups leading the charge against dissection are People for the Ethical Treatment of Animals (PETA) and the Student Action Corps for Animals (SACA). Protests by student and community members remain the movement's strongest weapon. (MLF)

  12. New Group Targets Political Bias on Campus.

    ERIC Educational Resources Information Center

    Marshall, Eliot

    1985-01-01

    "Accuracy in Academia" (AIA) is a new lobby organized for recruiting student volunteers to monitor university courses and expose anti-American teaching. Hard science and journalism courses will be omitted from scrutiny with emphasis on political science, economics, history, and sociology courses. University groups feel that AIA's tactics threaten…

  13. An Evolutionary Conserved Epigenetic Mark of Polycomb Response Elements Implemented by Trx/MLL/COMPASS.

    PubMed

    Rickels, Ryan; Hu, Deqing; Collings, Clayton K; Woodfin, Ashley R; Piunti, Andrea; Mohan, Man; Herz, Hans-Martin; Kvon, Evgeny; Shilatifard, Ali

    2016-07-21

    Polycomb response elements (PREs) are specific DNA sequences that stably maintain the developmental pattern of gene expression. Drosophila PREs are well characterized, whereas the existence of PREs in mammals remains debated. Accumulating evidence supports a model in which CpG islands recruit Polycomb group (PcG) complexes; however, which subset of CGIs is selected to serve as PREs is unclear. Trithorax (Trx) positively regulates gene expression in Drosophila and co-occupies PREs to antagonize Polycomb-dependent silencing. Here we demonstrate that Trx-dependent H3K4 dimethylation (H3K4me2) marks Drosophila PREs and maintains the developmental expression pattern of nearby genes. Similarly, the mammalian Trx homolog, MLL1, deposits H3K4me2 at CpG-dense regions that could serve as PREs. In the absence of MLL1 and H3K4me2, H3K27me3 levels, a mark of Polycomb repressive complex 2 (PRC2), increase at these loci. By inhibiting PRC2-dependent H3K27me3 in the absence of MLL1, we can rescue expression of these loci, demonstrating a functional balance between MLL1 and PRC2 activities at these sites. Thus, our study provides rules for identifying cell-type-specific functional mammalian PREs within the human genome. PMID:27447986

  14. Transcription factors that convert adult cell identity are differentially polycomb repressed.

    PubMed

    Davis, Fred P; Eddy, Sean R

    2013-01-01

    Transcription factors that can convert adult cells of one type to another are usually discovered empirically by testing factors with a known developmental role in the target cell. Here we show that standard genomic methods (RNA-seq and ChIP-seq) can help identify these factors, as most are more strongly Polycomb repressed in the source cell and more highly expressed in the target cell. This criterion is an effective genome-wide screen that significantly enriches for factors that can transdifferentiate several mammalian cell types including neural stem cells, neurons, pancreatic islets, and hepatocytes. These results suggest that barriers between adult cell types, as depicted in Waddington's "epigenetic landscape", consist in part of differentially Polycomb-repressed transcription factors. This genomic model of cell identity helps rationalize a growing number of transdifferentiation protocols and may help facilitate the engineering of cell identity for regenerative medicine.

  15. Reduction in maternal Polycomb levels contributes to transgenerational inheritance of a response to toxic stress in flies

    PubMed Central

    Stern, Shay; Snir, Orli; Mizrachi, Eran; Galili, Matana; Zaltsman, Inbal; Soen, Yoav

    2014-01-01

    Transgenerational persistence of parental responses to environmental stimuli has been reported in various organisms, but the underlying mechanisms remain underexplored. In one of these reported examples, we have shown that exposure of fly larvae to G418 antibiotic leads to non-Mendelian inheritance of ectopic induction of certain developmental genes. Here we investigate if this inheritance involves changes in mRNA composition within the early, maternal-stage offspring embryos of exposed flies. Exposure to G418 in F1 modified the maternal RNA levels of many genes in their early (F2) embryos. This includes reduction of maternal Polycomb group genes which persisted in the following generation of embryos (F3). To investigate the functional meaning of this reduction, we compared genetically normal embryos of Polycomb mutant females to normal embryos of normal females. Analysis with two different alleles of Polycomb, Pc1 and Pc3, revealed that maternal reduction in Polycomb gene dosage has a positive influence on the inheritance of induced expression. Together, this shows that exposure to G418 stress reduces the maternal levels of Polycomb in the offspring embryos and this reduction contributes to the inheritance of induced expression. PMID:24535443

  16. Epigenetic balance of gene expression by Polycomb and COMPASS families.

    PubMed

    Piunti, Andrea; Shilatifard, Ali

    2016-06-01

    Epigenetic regulation of gene expression in metazoans is central for establishing cellular diversity, and its deregulation can result in pathological conditions. Although transcription factors are essential for implementing gene expression programs, they do not function in isolation and require the recruitment of various chromatin-modifying and -remodeling machineries. A classic example of developmental chromatin regulation is the balanced activities of the Polycomb group (PcG) proteins within the PRC1 and PRC2 complexes, and the Trithorax group (TrxG) proteins within the COMPASS family, which are highly mutated in a large number of human diseases. In this review, we will discuss the latest findings regarding the properties of the PcG and COMPASS families and the insight they provide into the epigenetic control of transcription under physiological and pathological settings. PMID:27257261

  17. The Arabidopsis GAGA-Binding Factor BASIC PENTACYSTEINE6 Recruits the POLYCOMB-REPRESSIVE COMPLEX1 Component LIKE HETEROCHROMATIN PROTEIN1 to GAGA DNA Motifs1

    PubMed Central

    Hecker, Andreas; Brand, Luise H.; Peter, Sébastien; Simoncello, Nathalie; Kilian, Joachim; Gaudin, Valérie

    2015-01-01

    Polycomb-repressive complexes (PRCs) play key roles in development by repressing a large number of genes involved in various functions. Much, however, remains to be discovered about PRC-silencing mechanisms as well as their targeting to specific genomic regions. Besides other mechanisms, GAGA-binding factors in animals can guide PRC members in a sequence-specific manner to Polycomb-responsive DNA elements. Here, we show that the Arabidopsis (Arabidopsis thaliana) GAGA-motif binding factor protein BASIC PENTACYSTEINE6 (BPC6) interacts with LIKE HETEROCHROMATIN PROTEIN1 (LHP1), a PRC1 component, and associates with VERNALIZATION2 (VRN2), a PRC2 component, in vivo. By using a modified DNA-protein interaction enzyme-linked immunosorbant assay, we could show that BPC6 was required and sufficient to recruit LHP1 to GAGA motif-containing DNA probes in vitro. We also found that LHP1 interacts with VRN2 and, therefore, can function as a possible scaffold between BPC6 and VRN2. The lhp1-4 bpc4 bpc6 triple mutant displayed a pleiotropic phenotype, extreme dwarfism and early flowering, which disclosed synergistic functions of LHP1 and group II plant BPC members. Transcriptome analyses supported this synergy and suggested a possible function in the concerted repression of homeotic genes, probably through histone H3 lysine-27 trimethylation. Hence, our findings suggest striking similarities between animal and plant GAGA-binding factors in the recruitment of PRC1 and PRC2 components to Polycomb-responsive DNA element-like GAGA motifs, which must have evolved through convergent evolution. PMID:26025051

  18. Expansion of the polycomb system and evolution of complexity.

    PubMed

    Sowpati, Divya Tej; Ramamoorthy, Senthilkumar; Mishra, Rakesh K

    2015-11-01

    Polycomb group (PcG) proteins regulate and maintain expression pattern of genes set early during development. Although originally isolated as regulators of homeotic genes, PcG members play a key role in epigenetic mechanisms that maintain the expression state of a large number of genes. All members of the two polycomb repressive complexes (PRC1 and PRC2) are conserved during evolution and while invertebrates generally have one gene for each of these, vertebrates have multiple homologues of them. It remains unclear, however, if different vertebrate PcG homologues have distinct or overlapping functions. We have identified and compared the sequence of PcG homologues in various organisms to analyze similarities and differences that shaped the evolutionary history of these proteins. Comparative analysis of the sequences led to the identification of several novel and signature motifs in the vertebrate homologues of these proteins, which can be directly used to pick respective homologues. Our analysis shows that PcG is an ancient gene group dating back to pre-bilaterian origin that has not only been conserved but also expanded during the evolution of complexity. The presence of unique motifs in each paralogue and its conservation for more than 500 Ma indicates their functional relevance and probable unique role. Although this does not rule out completely any overlapping function, our finding that these homologues only minimally overlap in their nuclear localization suggests that each PcG homologue has distinct function. We further propose distinct complex formation by the PcG members. Taken together, our studies suggest non-redundant and specific role of multiple homologues of PcG proteins in vertebrates and indicate major expansion event preceded by emergence of vertebrates that contributed as enhanced epigenetic resource to the evolution of complexity. PMID:26259680

  19. A functionally conserved Polycomb response element from mouse HoxD complex responds to heterochromatin factors

    NASA Astrophysics Data System (ADS)

    Vasanthi, Dasari; Nagabhushan, A.; Matharu, Navneet Kaur; Mishra, Rakesh K.

    2013-10-01

    Anterior-posterior body axis in all bilaterians is determined by the Hox gene clusters that are activated in a spatio-temporal order. This expression pattern of Hox genes is established and maintained by regulatory mechanisms that involve higher order chromatin structure and Polycomb group (PcG) and trithorax group (trxG) proteins. We identified earlier a Polycomb response element (PRE) in the mouse HoxD complex that is functionally conserved in flies. We analyzed the molecular and genetic interactions of mouse PRE using Drosophila melanogaster and vertebrate cell culture as the model systems. We demonstrate that the repressive activity of this PRE depends on PcG/trxG genes as well as the heterochromatin components. Our findings indicate that a wide range of factors interact with the HoxD PRE that can contribute to establishing the expression pattern of homeotic genes in the complex early during development and maintain that pattern at subsequent stages.

  20. Polycomb Mediated Epigenetic Silencing and Replication Timing at the INK4a/ARF Locus during Senescence

    PubMed Central

    Verthuy, Christophe; Chasson, Lionel; Serrano, Manuel; Djabali, Malek

    2009-01-01

    Background The INK4/ARF locus encodes three tumor suppressor genes (p15Ink4b, Arf and p16Ink4a) and is frequently inactivated in a large number of human cancers. Mechanisms regulating INK4/ARF expression are not fully characterized. Principal Findings Here we show that in young proliferating embryonic fibroblasts (MEFs) the Polycomb Repressive Complex 2 (PRC2) member EZH2 together with PRC1 members BMI1 and M33 are strongly expressed and localized at the INK4/ARF regulatory domain (RD) identified as a DNA replication origin. When cells enter senescence the binding to RD of both PRC1 and PRC2 complexes is lost leading to a decreased level of histone H3K27 trimethylation (H3K27me3). This loss is accompanied with an increased expression of the histone demethylase Jmjd3 and with the recruitment of the MLL1 protein, and correlates with the expression of the Ink4a/Arf genes. Moreover, we show that the Polycomb protein BMI1 interacts with CDC6, an essential regulator of DNA replication in eukaryotic cells. Finally, we demonstrate that Polycomb proteins and associated epigenetic marks are crucial for the control of the replication timing of the INK4a/ARF locus during senescence. Conclusions We identified the replication licencing factor CDC6 as a new partner of the Polycomb group member BMI1. Our results suggest that in young cells Polycomb proteins are recruited to the INK4/ARF locus through CDC6 and the resulting silent locus is replicated during late S-phase. Upon senescence, Jmjd3 is overexpressed and the MLL1 protein is recruited to the locus provoking the dissociation of Polycomb from the INK4/ARF locus, its transcriptional activation and its replication during early S-phase. Together, these results provide a unified model that integrates replication, transcription and epigenetics at the INK4/ARF locus. PMID:19462008

  1. Genome-wide co-localization of Polycomb orthologs and their effects on gene expression in human fibroblasts

    PubMed Central

    2014-01-01

    Background Polycomb group proteins form multicomponent complexes that are important for establishing lineage-specific patterns of gene expression. Mammalian cells encode multiple permutations of the prototypic Polycomb repressive complex 1 (PRC1) with little evidence for functional specialization. An aim of this study is to determine whether the multiple orthologs that are co-expressed in human fibroblasts act on different target genes and whether their genomic location changes during cellular senescence. Results Deep sequencing of chromatin immunoprecipitated with antibodies against CBX6, CBX7, CBX8, RING1 and RING2 reveals that the orthologs co-localize at multiple sites. PCR-based validation at representative loci suggests that a further six PRC1 proteins have similar binding patterns. Importantly, sequential chromatin immunoprecipitation with antibodies against different orthologs implies that multiple variants of PRC1 associate with the same DNA. At many loci, the binding profiles have a distinctive architecture that is preserved in two different types of fibroblast. Conversely, there are several hundred loci at which PRC1 binding is cell type-specific and, contrary to expectations, the presence of PRC1 does not necessarily equate with transcriptional silencing. Interestingly, the PRC1 binding profiles are preserved in senescent cells despite changes in gene expression. Conclusions The multiple permutations of PRC1 in human fibroblasts congregate at common rather than specific sites in the genome and with overlapping but distinctive binding profiles in different fibroblasts. The data imply that the effects of PRC1 complexes on gene expression are more subtle than simply repressing the loci at which they bind. PMID:24485159

  2. Timing matters: sonar call groups facilitate target localization in bats

    PubMed Central

    Kothari, Ninad B.; Wohlgemuth, Melville J.; Hulgard, Katrine; Surlykke, Annemarie; Moss, Cynthia F.

    2014-01-01

    To successfully negotiate a cluttered environment, an echolocating bat must control the timing of motor behaviors in response to dynamic sensory information. Here we detail the big brown bat's adaptive temporal control over sonar call production for tracking prey, moving predictably or unpredictably, under different experimental conditions. We studied the adaptive control of vocal-motor behaviors in free-flying big brown bats, Eptesicus fuscus, as they captured tethered and free-flying insects, in open and cluttered environments. We also studied adaptive sonar behavior in bats trained to track moving targets from a resting position. In each of these experiments, bats adjusted the features of their calls to separate target and clutter. Under many task conditions, flying bats produced prominent sonar sound groups identified as clusters of echolocation pulses with relatively stable intervals, surrounded by longer pulse intervals. In experiments where bats tracked approaching targets from a resting position, bats also produced sonar sound groups, and the prevalence of these sonar sound groups increased when motion of the target was unpredictable. We hypothesize that sonar sound groups produced during flight, and the sonar call doublets produced by a bat tracking a target from a resting position, help the animal resolve dynamic target location and represent the echo scene in greater detail. Collectively, our data reveal adaptive temporal control over sonar call production that allows the bat to negotiate a complex and dynamic environment. PMID:24860509

  3. Timing matters: sonar call groups facilitate target localization in bats.

    PubMed

    Kothari, Ninad B; Wohlgemuth, Melville J; Hulgard, Katrine; Surlykke, Annemarie; Moss, Cynthia F

    2014-01-01

    To successfully negotiate a cluttered environment, an echolocating bat must control the timing of motor behaviors in response to dynamic sensory information. Here we detail the big brown bat's adaptive temporal control over sonar call production for tracking prey, moving predictably or unpredictably, under different experimental conditions. We studied the adaptive control of vocal-motor behaviors in free-flying big brown bats, Eptesicus fuscus, as they captured tethered and free-flying insects, in open and cluttered environments. We also studied adaptive sonar behavior in bats trained to track moving targets from a resting position. In each of these experiments, bats adjusted the features of their calls to separate target and clutter. Under many task conditions, flying bats produced prominent sonar sound groups identified as clusters of echolocation pulses with relatively stable intervals, surrounded by longer pulse intervals. In experiments where bats tracked approaching targets from a resting position, bats also produced sonar sound groups, and the prevalence of these sonar sound groups increased when motion of the target was unpredictable. We hypothesize that sonar sound groups produced during flight, and the sonar call doublets produced by a bat tracking a target from a resting position, help the animal resolve dynamic target location and represent the echo scene in greater detail. Collectively, our data reveal adaptive temporal control over sonar call production that allows the bat to negotiate a complex and dynamic environment.

  4. Regulatory interactions between RNA and polycomb repressive complex 2.

    PubMed

    Cifuentes-Rojas, Catherine; Hernandez, Alfredo J; Sarma, Kavitha; Lee, Jeannie T

    2014-07-17

    Polycomb repressive complex 2 (PRC2) is a histone methyltransferase that is localized to thousands of mammalian genes. Though important to human disease and as a drug target, how PRC2 is recruited remains unclear. One model invokes cis-regulatory RNA. Herein, we biochemically and functionally probe PRC2's recognition of RNA using the X-inactivation model. We observe surprisingly high discriminatory capabilities. While SUZ12 and JARID2 subunits can bind RNA, EZH2 has highest affinity and is somewhat promiscuous. EED regulates the affinity of EZH2 for RNA, lending greater specificity to PRC2-RNA interactions. Intriguingly, while RNA is crucial for targeting, RNA inhibits EZH2's catalytic activity. JARID2 weakens PRC2's binding to RNA and relieves catalytic inhibition. We propose that RNA guides PRC2 to its target but inhibits its enzymatic activity until PRC2 associates with JARID2 on chromatin. Our study provides a molecular view of regulatory interactions between RNA and PRC2 at the chromatin interface.

  5. Polycomb Cbx family members mediate the balance between haematopoietic stem cell self-renewal and differentiation.

    PubMed

    Klauke, Karin; Radulović, Višnja; Broekhuis, Mathilde; Weersing, Ellen; Zwart, Erik; Olthof, Sandra; Ritsema, Martha; Bruggeman, Sophia; Wu, Xudong; Helin, Kristian; Bystrykh, Leonid; de Haan, Gerald

    2013-04-01

    The balance between self-renewal and differentiation of adult stem cells is essential for tissue homeostasis. Here we show that in the haematopoietic system this process is governed by polycomb chromobox (Cbx) proteins. Cbx7 is specifically expressed in haematopoietic stem cells (HSCs), and its overexpression enhances self-renewal and induces leukaemia. This effect is dependent on integration into polycomb repressive complex-1 (PRC1) and requires H3K27me3 binding. In contrast, overexpression of Cbx2, Cbx4 or Cbx8 results in differentiation and exhaustion of HSCs. ChIP-sequencing analysis shows that Cbx7 and Cbx8 share most of their targets; we identified approximately 200 differential targets. Whereas genes targeted by Cbx8 are highly expressed in HSCs and become repressed in progenitors, Cbx7 targets show the opposite expression pattern. Thus, Cbx7 preserves HSC self-renewal by repressing progenitor-specific genes. Taken together, the presence of distinct Cbx proteins confers target selectivity to PRC1 and provides a molecular balance between self-renewal and differentiation of HSCs.

  6. A positive role for polycomb in transcriptional regulation via H4K20me1

    PubMed Central

    Lv, Xiangdong; Han, Zhijun; Chen, Hao; Yang, Bo; Yang, Xiaofeng; Xia, Yuanxin; Pan, Chenyu; Fu, Lin; Zhang, Shuo; Han, Hui; Wu, Min; Zhou, Zhaocai; Zhang, Lei; Li, Lin; Wei, Gang; Zhao, Yun

    2016-01-01

    The highly conserved polycomb group (PcG) proteins maintain heritable transcription repression of the genes essential for development from fly to mammals. However, sporadic reports imply a potential role of PcGs in positive regulation of gene transcription, although systematic investigation of such function and the underlying mechanism has rarely been reported. Here, we report a Pc-mediated, H3K27me3-dependent positive transcriptional regulation of Senseless (Sens), a key transcription factor required for development. Mechanistic studies show that Pc regulates Sens expression by promoting H4K20me1 at the Sens locus. Further bioinformatic analysis at genome-wide level indicates that the existence of H4K20me1 acts as a selective mark for positive transcriptional regulation by Pc/H3K27me3. Both the intensities and specific patterns of Pc and H3K27me3 are important for the fates of target gene transcription. Moreover, binding of transcription factor Broad (Br), which physically interacts with Pc and positively regulates the transcription of Sens, is observed in Pc+H3K27me3+H4K20me1+ genes, but not in Pc+H3K27me3+H4K20me1− genes. Taken together, our study reveals that, coupling with the transcription factor Br, Pc positively regulates transcription of Pc+H3K27me3+H4K20me1+ genes in developing Drosophila wing disc. PMID:27002220

  7. Cohort Profile: The Applied Research Group for Kids (TARGet Kids!).

    PubMed

    Carsley, Sarah; Borkhoff, Cornelia M; Maguire, Jonathon L; Birken, Catherine S; Khovratovich, Marina; McCrindle, Brian; Macarthur, Colin; Parkin, Patricia C

    2015-06-01

    The Applied Research Group for Kids (TARGet Kids!) is an ongoing open longitudinal cohort study enrolling healthy children (from birth to 5 years of age) and following them into adolescence. The aim of the TARGet Kids! cohort is to link early life exposures to health problems including obesity, micronutrient deficiencies and developmental problems. The overarching goal is to improve the health of Canadians by optimizing growth and developmental trajectories through preventive interventions in early childhood. TARGet Kids!, the only child health research network embedded in primary care practices in Canada, leverages the unique relationship between children and families and their trusted primary care practitioners, with whom they have at least seven health supervision visits in the first 5 years of life. Children are enrolled during regularly scheduled well-child visits. To date, we have enrolled 5062 children. In addition to demographic information, we collect physical measurements (e.g. height, weight), lifestyle factors (nutrition, screen time and physical activity), child behaviour and developmental screening and a blood sample (providing measures of cardiometabolic, iron and vitamin D status, and trace metals). All data are collected at each well-child visit: twice a year until age 2 and every year until age 10. Information can be found at: http://www.targetkids.ca/contact-us/.

  8. Automatic target recognition using group-structured sparse representation

    NASA Astrophysics Data System (ADS)

    Sun, Bo; Wu, Xuewen; He, Jun; Zhu, Xiaoming; Chen, Chao

    2014-06-01

    Sparse representation classification method has been increasingly used in the fields of computer vision and pattern analysis, due to its high recognition rate, little dependence on the features, robustness to corruption and occlusion, and etc. However, most of these existing methods aim to find the sparsest representations of the test sample y in an overcomplete dictionary, which do not particularly consider the relevant structure between the atoms in the dictionary. Moreover, sufficient training samples are always required by the sparse representation method for effective recognition. In this paper we formulate the classification as a group-structured sparse representation problem using a sparsity-inducing norm minimization optimization and propose a novel sparse representation-based automatic target recognition (ATR) framework for the practical applications in which the training samples are drawn from the simulation models of real targets. The experimental results show that the proposed approach improves the recognition rate of standard sparse models, and our system can effectively and efficiently recognize targets under real environments, especially, where the good characteristics of the sparse representation based classification method are kept.

  9. Wilms Tumor Suppressor, WT1, Cooperates with MicroRNA-26a and MicroRNA-101 to Suppress Translation of the Polycomb Protein, EZH2, in Mesenchymal Stem Cells.

    PubMed

    Akpa, Murielle M; Iglesias, Diana; Chu, LeeLee; Thiébaut, Antonin; Jentoft, Ida; Hammond, Leah; Torban, Elena; Goodyer, Paul R

    2016-02-19

    Hereditary forms of Wilms arise from developmentally arrested clones of renal progenitor cells with biallelic mutations of WT1; recently, it has been found that Wilms tumors may also be associated with biallelic mutations in DICER1 or DROSHA, crucial for miRNA biogenesis. We have previously shown that a critical role for WT1 during normal nephrogenesis is to suppress transcription of the Polycomb group protein, EZH2, thereby de-repressing genes in the differentiation cascade. Here we show that WT1 also suppresses translation of EZH2. All major WT1 isoforms induce an array of miRNAs, which target the 3' UTR of EZH2 and other Polycomb-associated transcripts. We show that the WT1(+KTS) isoform binds to the 5' UTR of EZH2 and interacts directly with the miRNA-containing RISC to enhance post-transcriptional inhibition. These observations suggest a novel mechanism through which WT1 regulates the transition from resting stem cell to activated progenitor cell during nephrogenesis. Our findings also offer a plausible explanation for the fact that Wilms tumors can arise either from loss of WT1 or loss of miRNA processing enzymes. PMID:26655220

  10. Huntingtin facilitates polycomb repressive complex 2

    PubMed Central

    Seong, Ihn Sik; Woda, Juliana M.; Song, Ji-Joon; Lloret, Alejandro; Abeyrathne, Priyanka D.; Woo, Caroline J.; Gregory, Gillian; Lee, Jong-Min; Wheeler, Vanessa C.; Walz, Thomas; Kingston, Robert E.; Gusella, James F.; Conlon, Ronald A.; MacDonald, Marcy E.

    2010-01-01

    Huntington's disease (HD) is caused by expansion of the polymorphic polyglutamine segment in the huntingtin protein. Full-length huntingtin is thought to be a predominant HEAT repeat α-solenoid, implying a role as a facilitator of macromolecular complexes. Here we have investigated huntingtin's domain structure and potential intersection with epigenetic silencer polycomb repressive complex 2 (PRC2), suggested by shared embryonic deficiency phenotypes. Analysis of a set of full-length recombinant huntingtins, with different polyglutamine regions, demonstrated dramatic conformational flexibility, with an accessible hinge separating two large α-helical domains. Moreover, embryos lacking huntingtin exhibited impaired PRC2 regulation of Hox gene expression, trophoblast giant cell differentiation, paternal X chromosome inactivation and histone H3K27 tri-methylation, while full-length endogenous nuclear huntingtin in wild-type embryoid bodies (EBs) was associated with PRC2 subunits and was detected with trimethylated histone H3K27 at Hoxb9. Supporting a direct stimulatory role, full-length recombinant huntingtin significantly increased the histone H3K27 tri-methylase activity of reconstituted PRC2 in vitro, and structure–function analysis demonstrated that the polyglutamine region augmented full-length huntingtin PRC2 stimulation, both in HdhQ111 EBs and in vitro, with reconstituted PRC2. Knowledge of full-length huntingtin's α-helical organization and role as a facilitator of the multi-subunit PRC2 complex provides a novel starting point for studying PRC2 regulation, implicates this chromatin repressive complex in a neurodegenerative disorder and sets the stage for further study of huntingtin's molecular function and the impact of its modulatory polyglutamine region. PMID:19933700

  11. Variable requirements for DNA-binding proteins at polycomb-dependent repressive regions in human HOX clusters.

    PubMed

    Woo, Caroline J; Kharchenko, Peter V; Daheron, Laurence; Park, Peter J; Kingston, Robert E

    2013-08-01

    Polycomb group (PcG)-mediated repression is an evolutionarily conserved process critical for cell fate determination and maintenance of gene expression during embryonic development. However, the mechanisms underlying PcG recruitment in mammals remain unclear since few regulatory sites have been identified. We report two novel prospective PcG-dependent regulatory elements within the human HOXB and HOXC clusters and compare their repressive activities to a previously identified element in the HOXD cluster. These regions recruited the PcG proteins BMI1 and SUZ12 to a reporter construct in mesenchymal stem cells and conferred repression that was dependent upon PcG expression. Furthermore, we examined the potential of two DNA-binding proteins, JARID2 and YY1, to regulate PcG activity at these three elements. JARID2 has differential requirements, whereas YY1 appears to be required for repressive activity at all 3 sites. We conclude that distinct elements of the mammalian HOX clusters can recruit components of the PcG complexes and confer repression, similar to what has been seen in Drosophila. These elements, however, have diverse requirements for binding factors, which, combined with previous data on other loci, speaks to the complexity of PcG targeting in mammals.

  12. RET finger protein is a transcriptional repressor and interacts with enhancer of polycomb that has dual transcriptional functions.

    PubMed

    Shimono, Y; Murakami, H; Hasegawa, Y; Takahashi, M

    2000-12-15

    RET finger protein (RFP) belongs to the large B-box RING finger protein family and is known to become oncogenic by fusion with RET tyrosine kinase. Although RFP is reported to be a nuclear protein that is present in the nuclear matrix, its function is largely unknown. Here we show that RFP interacts with Enhancer of Polycomb (EPC) and strongly represses the gene transcription. Yeast two-hybrid assays revealed that the coiled-coil domain of RFP was associated with the EPcA domain and the carboxyl-terminal region of EPC. In addition, both proteins were co-precipitated from the lysates of human cells and mostly colocalized in the nucleus. Using the luciferase reporter-gene assay, we found that they repress the gene transcription activity independent of the differences of enhancers and promoters used, although the repressive activity of RFP was much stronger than that of EPC. The coiled-coil domain of RFP and the carboxyl-terminal region of EPC were most important for the repressive activity of each protein, whereas the EPcA domain had the transcription activating ability that is unique as the Polycomb group protein function. These results suggested that RFP may be involved in the epigenetic gene silencing mechanism cooperating with Polycomb group proteins and that EPC is a unique molecule with both repressive and transactivating activities.

  13. Polycomb- and REST-associated histone deacetylases are independent pathways toward a mature neuronal phenotype

    PubMed Central

    McGann, James C; Oyer, Jon A; Garg, Saurabh; Yao, Huilan; Liu, Jun; Feng, Xin; Liao, Lujian; Yates, John R; Mandel, Gail

    2014-01-01

    The bivalent hypothesis posits that genes encoding developmental regulators required for early lineage decisions are poised in stem/progenitor cells by the balance between a repressor histone modification (H3K27me3), mediated by the Polycomb Repressor Complex 2 (PRC2), and an activator modification (H3K4me3). In this study, we test whether this mechanism applies equally to genes that are not required until terminal differentiation. We focus on the RE1 Silencing Transcription Factor (REST) because it is expressed highly in stem cells and is an established global repressor of terminal neuronal genes. Elucidation of the REST complex, and comparison of chromatin marks and gene expression levels in control and REST-deficient stem cells, shows that REST target genes are poised by a mechanism independent of Polycomb, even at promoters which bear the H3K27me3 mark. Specifically, genes under REST control are actively repressed in stem cells by a balance of the H3K4me3 mark and a repressor complex that relies on histone deacetylase activity. Thus, chromatin distinctions between pro-neural and terminal neuronal genes are established at the embryonic stem cell stage by two parallel, but distinct, repressor pathways. DOI: http://dx.doi.org/10.7554/eLife.04235.001 PMID:25250711

  14. Jumonji modulates polycomb activity and self-renewal versus differentiation of stem cells.

    PubMed

    Shen, Xiaohua; Kim, Woojin; Fujiwara, Yuko; Simon, Matthew D; Liu, Yingchun; Mysliwiec, Matthew R; Yuan, Guo-Cheng; Lee, Youngsook; Orkin, Stuart H

    2009-12-24

    Trimethylation on histone H3 lysine 27 (H3K27me3) by Polycomb repressive complex 2 (PRC2) regulates the balance between self-renewal and differentiation of embryonic stem cells (ESCs). The mechanisms controlling the activity and recruitment of PRC2 are largely unknown. Here we demonstrate that the founding member of the Jumonji family, JMJ (JUMONJI or JARID2), is associated with PRC2, colocalizes with PRC2 and H3K27me3 on chromatin, and modulates PRC2 function. In vitro JMJ inhibits PRC2 methyltransferase activity, consistent with increased H3K27me3 marks at PRC2 targets in Jmj(-/-) ESCs. Paradoxically, JMJ is required for efficient binding of PRC2, indicating that the interplay of PRC2 and JMJ fine-tunes deposition of the H3K27me3 mark. During differentiation, activation of genes marked by H3K27me3 and lineage commitments are delayed in Jmj(-/-) ESCs. Our results demonstrate that dynamic regulation of Polycomb complex activity orchestrated by JMJ balances self-renewal and differentiation, highlighting the involvement of chromatin dynamics in cell-fate transitions.

  15. Homoeosis in Drosophila. II. a Genetic Analysis of Polycomb.

    PubMed

    Denell, R E

    1978-10-01

    Three dominant mutant alleles of the Polycomb locus of Drosophila melanogaster are associated with homoeotic transformations of meso- and metathoracic to prothoracic legs, a homoeotic transformation of antennae to legs, and abnormalities of wings and some thoracic bristles. Puro and Nygrén (1975) localized Polycomb in the proximal left arm of chromosome 3 within salivary gland chromosome interval 77E,F-80. In the present study, the location and dosage relationships of this locus were examined, using translocation-generated segmental aneuploidy. The results indicate that Polycomb lies within interval 78C,D-79D, and that the locus is haplo-insufficient. Males hypoploid for this interval show meso- and metathoracic leg transformations, and both males and females show wing abnormalities. In addition, the legs of hypoploids of both sexes are shorter than those of wild-type flies, and show aberrancies of segmentation, chaetal number and distribution, and other morphological characteristics. Hypoploid flies do not express a homoeotic antennal-leg transformation, but the deficiency is associated with a Minute phenotype that is known to suppress this transformation in Polycomb flies; thus it cannot be ascertained whether the antennal-leg transformation is a haplo-insufficient phenotype. It is suggested that the expression of non-homoeotic pleiotropic effects provides a criterion for identifying homoeotic mutations that do not function directly in the establishment of determined states, but rather cause homoeosis indirectly. Polycomb is interpreted in this fashion, and it is suggested that the mutant syndrome may result from localized cell death.

  16. Adaptive selection and coevolution at the proteins of the Polycomb repressive complexes in Drosophila.

    PubMed

    Calvo-Martín, J M; Librado, P; Aguadé, M; Papaceit, M; Segarra, C

    2016-02-01

    Polycomb group (PcG) proteins are important epigenetic regulatory proteins that modulate the chromatin state through posttranslational histone modifications. These interacting proteins form multimeric complexes that repress gene expression. Thus, PcG proteins are expected to evolve coordinately, which might be reflected in their phylogenetic trees by concordant episodes of positive selection and by a correlation in evolutionary rates. In order to detect these signals of coevolution, the molecular evolution of 17 genes encoding the subunits of five Polycomb repressive complexes has been analyzed in the Drosophila genus. The observed distribution of divergence differs substantially among and along proteins. Indeed, CAF1 is uniformly conserved, whereas only the established protein domains are conserved in other proteins, such as PHO, PHOL, PSC, PH-P and ASX. Moreover, regions with a low divergence not yet described as protein domains are present, for instance, in SFMBT and SU(Z)12. Maximum likelihood methods indicate an acceleration in the nonsynonymous substitution rate at the lineage ancestral to the obscura group species in most genes encoding subunits of the Pcl-PRC2 complex and in genes Sfmbt, Psc and Kdm2. These methods also allow inferring the action of positive selection in this lineage at genes E(z) and Sfmbt. Finally, the protein interaction network predicted from the complete proteomes of 12 Drosophila species using a coevolutionary approach shows two tight PcG clusters. These clusters include well-established binary interactions among PcG proteins as well as new putative interactions.

  17. Clarifying the impact of polycomb complex component disruption in human cancers.

    PubMed

    Yamamoto, Yukiya; Abe, Akihiro; Emi, Nobuhiko

    2014-04-01

    The dysregulation of proper transcriptional control is a major cause of developmental diseases and cancers. Polycomb proteins form chromatin-modifying complexes that transcriptionally silence genome regions in higher eukaryotes. The BCL6 corepressor (BCOR) complex comprises ring finger protein 1B (RNF2/RING1B), polycomb group ring finger 1 (PCGF1), and lysine-specific demethylase 2B (KDM2B) and is uniquely recruited to nonmethylated CpG islands, where it removes histone H3K36me2 and induces repressive histone H2A monoubiquitylation. Germline BCOR mutations have been detected in patients with oculofaciocardiodental and Lenz microphthalmia syndromes, which are inherited conditions. Recently, several variants of BCOR and BCOR-like 1 (BCORL1) chimeric fusion transcripts were reported in human cancers, including acute promyelocytic leukemia, bone sarcoma, and hepatocellular carcinoma. In addition, massively parallel sequencing has identified inactivating somatic BCOR and BCORL1 mutations in patients with acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), chronic myelomonocytic leukemia, medulloblastoma, and retinoblastoma. More importantly, patients with AML and MDS with BCOR mutations exhibit poor prognosis. This perspective highlights the detection of BCOR mutations and fusion transcripts of BCOR and BCORL1 and discusses their importance for diagnosing cancer subtypes and estimating the treatment responses of patients. Furthermore, this perspective proposes the need for additional functional studies to clarify the oncogenic mechanism by which BCOR and BCORL1 are disrupted in cancers, and how this may lead to the development of novel therapeutics. PMID:24515802

  18. Anti-choice groups target reproductive rights in Congress.

    PubMed

    1995-06-16

    In a May 3 memo, the GOP "Family Caucus" presented its legislative agenda for the remainder of the 104th Congress. Chaired by Representative Tom Coburn (R-OK), the anti-choice caucus promotes family and social issues, and emphasizes religious liberty and parental rights. It is seeking to eliminate funding for Title X of the Public Health Service Act, which provides grants to domestic family planning providers; repeal the Freedom of Access to Clinic Entrances Act (FACE); curtail fetal tissue research; restrict the production and sale of RU486; reduce funding for the US Agency for International Development (USAID); and hinder US representation at the UN Fourth World Conference on Women. On May 17, the Virginia-based Christian Coalition unveiled a ten-point "Contract with the American Family," which targets reproductive health care by restricting late-term abortions, reversing the Medicaid requirement that states cover abortions in cases of rape or incest, and eliminating funding for Title X and international family planning. Director Ralph Reed was joined at the group's press conference in the Capitol by Speaker of the House Newt Gingrich (R-GA) and Senator Phil Gramm (R-TX), both of whom are anti-abortion. Senate Majority Leader Robert Dole (R-KS), who is also anti-choice, met with Reed in his office later that day. Anti-choice representatives and senators met with some success in the last month in restricting US funding for family planning programs abroad, US participation in international meetings, and the performance of abortions at military facilities. Representative Charles Canady (R-FL) has introduced a bill banning modified dilation and evacuation abortions, and Representative Robert Dornan (R-CA) has introduced the "Family Planning Programs Repeal Act" (HR 1623).

  19. Polycomb complex PRC1 as gatekeeper of intestinal stem cell identity.

    PubMed

    Léveillé, Nicolas; Vermeulen, Louis

    2016-01-01

    Intestinal stem cells (ISCs) are adult multipotent cells essential for the maintenance of intestinal epithelial homeostasis. Wnt signaling activity ensures that the pool of ISCs at the basis of the intestinal crypts is preserved. Dysregulation of the Wnt pathway is often observed in cancer and supports malignant progression. Chiacchiera and colleagues recently demonstrated the implication of the polycomb complex PRC1 in the regulation of the Wnt pathway in adult ISCs. The authors show that PRC1 maintains intestinal homeostasis by repressing the expression of ZICs, a family of transcription factors inactivating the β-catenin/TCF complex. Importantly, interfering with PRC1 activity completely inhibits the formation of Wnt-dependent tumors. These findings reveal a new layer of epigenetic regulation of the Wnt pathway and open novel opportunities for cancer stem cell targeted therapy. PMID:27488310

  20. Polycomb complex PRC1 as gatekeeper of intestinal stem cell identity

    PubMed Central

    Léveillé, Nicolas

    2016-01-01

    Intestinal stem cells (ISCs) are adult multipotent cells essential for the maintenance of intestinal epithelial homeostasis. Wnt signaling activity ensures that the pool of ISCs at the basis of the intestinal crypts is preserved. Dysregulation of the Wnt pathway is often observed in cancer and supports malignant progression. Chiacchiera and colleagues recently demonstrated the implication of the polycomb complex PRC1 in the regulation of the Wnt pathway in adult ISCs. The authors show that PRC1 maintains intestinal homeostasis by repressing the expression of ZICs, a family of transcription factors inactivating the β-catenin/TCF complex. Importantly, interfering with PRC1 activity completely inhibits the formation of Wnt-dependent tumors. These findings reveal a new layer of epigenetic regulation of the Wnt pathway and open novel opportunities for cancer stem cell targeted therapy. PMID:27488310

  1. Stop Shouting. Use Writing to Keep Group Decisions on Target.

    ERIC Educational Resources Information Center

    Erickson, Lawrence G.

    1983-01-01

    Suggests combining the Delphi technique and the nominal group process technique to improve the collective decision-making of school curriculum and other committees. Both methods require group members to respond in writing. A five-step agenda with sample questions illustrates the approach. (MLF)

  2. The Enhancer of Trithorax and Polycomb Corto Interacts with Cyclin G in Drosophila

    PubMed Central

    Salvaing, Juliette; Nagel, Anja C.; Mouchel-Vielh, Emmanuèle; Bloyer, Sébastien; Maier, Dieter; Preiss, Anette; Peronnet, Frédérique

    2008-01-01

    Background Polycomb (PcG) and trithorax (trxG) genes encode proteins involved in the maintenance of gene expression patterns, notably Hox genes, throughout development. PcG proteins are required for long-term gene repression whereas TrxG proteins are positive regulators that counteract PcG action. PcG and TrxG proteins form large complexes that bind chromatin at overlapping sites called Polycomb and Trithorax Response Elements (PRE/TRE). A third class of proteins, so-called “Enhancers of Trithorax and Polycomb” (ETP), interacts with either complexes, behaving sometimes as repressors and sometimes as activators. The role of ETP proteins is largely unknown. Methodology/Principal Findings In a two-hybrid screen, we identified Cyclin G (CycG) as a partner of the Drosophila ETP Corto. Inactivation of CycG by RNA interference highlights its essential role during development. We show here that Corto and CycG directly interact and bind to each other in embryos and S2 cells. Moreover, CycG is targeted to polytene chromosomes where it co-localizes at multiple sites with Corto and with the PcG factor Polyhomeotic (PH). We observed that corto is involved in maintaining Abd-B repression outside its normal expression domain in embryos. This could be achieved by association between Corto and CycG since both proteins bind the regulatory element iab-7 PRE and the promoter of the Abd-B gene. Conclusions/Significance Our results suggest that CycG could regulate the activity of Corto at chromatin and thus be involved in changing Corto from an Enhancer of TrxG into an Enhancer of PcG. PMID:18286205

  3. Collaboration of MLLT1/ENL, Polycomb and ATM for transcription and genome integrity.

    PubMed

    Ui, Ayako; Yasui, Akira

    2016-04-25

    Polycomb group (PcG) repress, whereas Trithorax group (TrxG) activate transcription for tissue development and cellular proliferation, and misregulation of these factors is often associated with cancer. ENL (MLLT1) and AF9 (MLLT3) are fusion partners of Mixed Lineage Leukemia (MLL), TrxG proteins, and are factors in Super Elongation Complex (SEC). SEC controls transcriptional elongation to release RNA polymerase II, paused around transcription start site. In MLL rearranged leukemia, several components of SEC have been found as MLL-fusion partners and the control of transcriptional elongation is misregulated leading to tumorigenesis in MLL-SEC fused Leukemia. It has been suggested that unexpected collaboration of ENL/AF9-MLL and PcG are involved in tumorigenesis in leukemia. Recently, we found that the collaboration of ENL/AF9 and PcG led to a novel mechanism of transcriptional switch from elongation to repression under ATM-signaling for genome integrity. Activated ATM phosphorylates ENL/AF9 in SEC, and the phosphorylated ENL/AF9 binds BMI1 and RING1B, a heterodimeric E3-ubiquitin-ligase complex in Polycomb Repressive complex 1 (PRC1), and recruits PRC1 at transcriptional elongation sites to rapidly repress transcription. The ENL/AF9 in SEC- and PcG-mediated transcriptional repression promotes DSB repair near transcription sites. The implication of this is that the collaboration of ENL/AF9 in SEC and PcG ensures a rapid response of transcriptional switching from elongation to repression to neighboring genotoxic stresses for DSB repair. Therefore, these results suggested that the collaboration of ENL/AF9 and PcG in transcriptional control is required to maintain genome integrity and may be link to the MLL-ENL/AF9 leukemia. PMID:27310306

  4. 7 CFR 761.208 - Target participation rates for socially disadvantaged groups.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 7 2014-01-01 2014-01-01 false Target participation rates for socially disadvantaged... ADMINISTRATION Allocation of Farm Loan Programs Funds to State Offices § 761.208 Target participation rates for socially disadvantaged groups. (a) General. (1) The Agency establishes target participation rates...

  5. 7 CFR 761.208 - Target participation rates for socially disadvantaged groups.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 7 2013-01-01 2013-01-01 false Target participation rates for socially disadvantaged... ADMINISTRATION Allocation of Farm Loan Programs Funds to State Offices § 761.208 Target participation rates for socially disadvantaged groups. (a) General. (1) The Agency establishes target participation rates...

  6. 7 CFR 761.208 - Target participation rates for socially disadvantaged groups.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Target participation rates for socially disadvantaged... Farm Loan Programs Funds to State Offices § 761.208 Target participation rates for socially disadvantaged groups. (a) General. (1) The Agency establishes target participation rates for providing FO and...

  7. 7 CFR 761.208 - Target participation rates for socially disadvantaged groups.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 7 2011-01-01 2011-01-01 false Target participation rates for socially disadvantaged... Farm Loan Programs Funds to State Offices § 761.208 Target participation rates for socially disadvantaged groups. (a) General. (1) The Agency establishes target participation rates for providing FO,...

  8. 7 CFR 761.208 - Target participation rates for socially disadvantaged groups.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 7 2012-01-01 2012-01-01 false Target participation rates for socially disadvantaged... ADMINISTRATION Allocation of Farm Loan Programs Funds to State Offices § 761.208 Target participation rates for socially disadvantaged groups. (a) General. (1) The Agency establishes target participation rates...

  9. Polycomb Protein SCML2 Associates with USP7 and Counteracts Histone H2A Ubiquitination in the XY Chromatin during Male Meiosis

    PubMed Central

    Luo, Mengcheng; Zhou, Jian; Leu, N. Adrian; Abreu, Carla M.; Wang, Jianle; Anguera, Montserrat C.; de Rooij, Dirk G.; Jasin, Maria; Wang, P. Jeremy

    2015-01-01

    Polycomb group proteins mediate transcriptional silencing in diverse developmental processes. Sex chromosomes undergo chromosome-wide transcription silencing during male meiosis. Here we report that mouse SCML2 (Sex comb on midleg-like 2), an X chromosome-encoded polycomb protein, is specifically expressed in germ cells, including spermatogonia, spermatocytes, and round spermatids. SCML2 associates with phosphorylated H2AX and localizes to the XY body in spermatocytes. Loss of SCML2 in mice causes defective spermatogenesis, resulting in sharply reduced sperm production. SCML2 interacts with and recruits a deubiquitinase, USP7, to the XY body in spermatocytes. In the absence of SCML2, USP7 fails to accumulate on the XY body, whereas H2A monoubiquitination is dramatically augmented in the XY chromatin. Our results demonstrate that the SCML2/USP7 complex constitutes a novel molecular pathway in modulating the epigenetic state of sex chromosomes during male meiosis. PMID:25634095

  10. Global Comparison of Warring Groups in 2002–2007: Fatalities from Targeting Civilians vs. Fighting Battles

    PubMed Central

    Hicks, Madelyn Hsiao-Rei; Lee, Uih Ran; Sundberg, Ralph; Spagat, Michael

    2011-01-01

    Background Warring groups that compete to dominate a civilian population confront contending behavioral options: target civilians or battle the enemy. We aimed to describe degrees to which combatant groups concentrated lethal behavior into intentionally targeting civilians as opposed to engaging in battle with opponents in contemporary armed conflict. Methodology/Principal Findings We identified all 226 formally organized state and non-state groups (i.e. actors) that engaged in lethal armed conflict during 2002–2007: 43 state and 183 non-state. We summed civilians killed by an actor's intentional targeting with civilians and combatants killed in battles in which the actor was involved for total fatalities associated with each actor, indicating overall scale of armed conflict. We used a Civilian Targeting Index (CTI), defined as the proportion of total fatalities caused by intentional targeting of civilians, to measure the concentration of lethal behavior into civilian targeting. We report actor-specific findings and four significant trends: 1.) 61% of all 226 actors (95% CI 55% to 67%) refrained from targeting civilians. 2.) Logistic regression showed actors were more likely to have targeted civilians if conflict duration was three or more years rather than one year. 3.) In the 88 actors that targeted civilians, multiple regressions showed an inverse correlation between CTI values and the total number of fatalities. Conflict duration of three or more years was associated with lower CTI values than conflict duration of one year. 4.) When conflict scale and duration were accounted for, state and non-state actors did not differ. We describe civilian targeting by actors in prolonged conflict. We discuss comparable patterns found in nature and interdisciplinary research. Conclusions/Significance Most warring groups in 2002–2007 did not target civilians. Warring groups that targeted civilians in small-scale, brief conflict concentrated more lethal behavior into

  11. The Polycomb complex PRC2 supports aberrant self-renewal in a mouse model of MLL-AF9;NrasG12D acute myeloid leukemia

    PubMed Central

    Shi, Junwei; Wang, Eric; Zuber, Johannes; Rappaport, Amy; Taylor, Meredith; Johns, Christopher

    2014-01-01

    The Trithorax and Polycomb groups of chromatin regulators are critical for cell-lineage specification during normal development; functions that often become deregulated during tumorigenesis. As an example, oncogenic fusions of the Trithorax-related protein MLL can initiate aggressive leukemias by altering the transcriptional circuitry governing hematopoietic cell differentiation, a process that is known to require additional epigenetic pathways to implement. Here we used shRNA screening to identify chromatin regulators uniquely required in a mouse model of MLL-fusion acute myeloid leukemia, which revealed a role for the Polycomb Repressive Complex 2 (PRC2) in maintenance of this disease. shRNA-mediated suppression of PRC2 subunits Eed, Suz12, or Ezh1/Ezh2 led to proliferation-arrest and differentiation of leukemia cells, with a minimal impact on growth of several non-transformed hematopoietic cell lines. The requirement for PRC2 in leukemia is partly due to its role in direct transcriptional repression of genes that limit the self-renewal potential of hematopoietic cells, including Cdkn2a. In addition to implicating a role for PRC2 in the pathogenesis of MLL-fusion leukemia, our results suggest, more generally, that Trithorax and Polycomb group proteins can cooperate with one another to maintain aberrant lineage programs in cancer. PMID:22469984

  12. The FBXL10/KDM2B Scaffolding Protein Associates with Novel Polycomb Repressive Complex-1 to Regulate Adipogenesis*

    PubMed Central

    Inagaki, Takeshi; Iwasaki, Satoshi; Matsumura, Yoshihiro; Kawamura, Takeshi; Tanaka, Toshiya; Abe, Yohei; Yamasaki, Ayumu; Tsurutani, Yuya; Yoshida, Ayano; Chikaoka, Yoko; Nakamura, Kanako; Magoori, Kenta; Nakaki, Ryo; Osborne, Timothy F.; Fukami, Kiyoko; Aburatani, Hiroyuki; Kodama, Tatsuhiko; Sakai, Juro

    2015-01-01

    Polycomb repressive complex 1 (PRC1) plays an essential role in the epigenetic repression of gene expression during development and cellular differentiation via multiple effector mechanisms, including ubiquitination of H2A and chromatin compaction. However, whether it regulates the stepwise progression of adipogenesis is unknown. Here, we show that FBXL10/KDM2B is an anti-adipogenic factor that is up-regulated during the early phase of 3T3-L1 preadipocyte differentiation and in adipose tissue in a diet-induced model of obesity. Interestingly, inhibition of adipogenesis does not require the JmjC demethylase domain of FBXL10, but it does require the F-box and leucine-rich repeat domains, which we show recruit a noncanonical polycomb repressive complex 1 (PRC1) containing RING1B, SKP1, PCGF1, and BCOR. Knockdown of either RING1B or SKP1 prevented FBXL10-mediated repression of 3T3-L1 preadipocyte differentiation indicating that PRC1 formation mediates the inhibitory effect of FBXL10 on adipogenesis. Using ChIP-seq, we show that FBXL10 recruits RING1B to key specific genomic loci surrounding the key cell cycle and the adipogenic genes Cdk1, Uhrf1, Pparg1, and Pparg2 to repress adipogenesis. These results suggest that FBXL10 represses adipogenesis by targeting a noncanonical PRC1 complex to repress key genes (e.g. Pparg) that control conversion of pluripotent cells into the adipogenic lineage. PMID:25533466

  13. MDM2 Associates with Polycomb Repressor Complex 2 and Enhances Stemness-Promoting Chromatin Modifications Independent of p53.

    PubMed

    Wienken, Magdalena; Dickmanns, Antje; Nemajerova, Alice; Kramer, Daniela; Najafova, Zeynab; Weiss, Miriam; Karpiuk, Oleksandra; Kassem, Moustapha; Zhang, Yanping; Lozano, Guillermina; Johnsen, Steven A; Moll, Ute M; Zhang, Xin; Dobbelstein, Matthias

    2016-01-01

    The MDM2 oncoprotein ubiquitinates and antagonizes p53 but may also carry out p53-independent functions. Here we report that MDM2 is required for the efficient generation of induced pluripotent stem cells (iPSCs) from murine embryonic fibroblasts, in the absence of p53. Similarly, MDM2 depletion in the context of p53 deficiency also promoted the differentiation of human mesenchymal stem cells and diminished clonogenic survival of cancer cells. Most of the MDM2-controlled genes also responded to the inactivation of the Polycomb Repressor Complex 2 (PRC2) and its catalytic component EZH2. MDM2 physically associated with EZH2 on chromatin, enhancing the trimethylation of histone 3 at lysine 27 and the ubiquitination of histone 2A at lysine 119 (H2AK119) at its target genes. Removing MDM2 simultaneously with the H2AK119 E3 ligase Ring1B/RNF2 further induced these genes and synthetically arrested cell proliferation. In conclusion, MDM2 supports the Polycomb-mediated repression of lineage-specific genes, independent of p53. PMID:26748827

  14. Clustering of mammalian Hox genes with other H3K27me3 targets within an active nuclear domain.

    PubMed

    Vieux-Rochas, Maxence; Fabre, Pierre J; Leleu, Marion; Duboule, Denis; Noordermeer, Daan

    2015-04-14

    Embryogenesis requires the precise activation and repression of many transcriptional regulators. The Polycomb group proteins and the associated H3K27me3 histone mark are essential to maintain the inactive state of many of these genes. Mammalian Hox genes are targets of Polycomb proteins and form local 3D clusters centered on the H3K27me3 mark. More distal contacts have also been described, yet their selectivity, dynamics, and relation to other layers of chromatin organization remained elusive. We report that repressed Hox genes form mutual intra- and interchromosomal interactions with other genes located in strong domains labeled by H3K27me3. These interactions occur in a central and active nuclear environment that consists of the HiC compartment A, away from peripheral lamina-associated domains. Interactions are independent of nearby H3K27me3-marked loci and determined by chromosomal distance and cell-type-specific scaling factors, thus inducing a moderate reorganization during embryogenesis. These results provide a simplified view of nuclear organization whereby Polycomb proteins may have evolved to repress genes located in gene-dense regions whose position is restricted to central, active, nuclear environments.

  15. Clustering of mammalian Hox genes with other H3K27me3 targets within an active nuclear domain

    PubMed Central

    Vieux-Rochas, Maxence; Fabre, Pierre J.; Leleu, Marion; Duboule, Denis; Noordermeer, Daan

    2015-01-01

    Embryogenesis requires the precise activation and repression of many transcriptional regulators. The Polycomb group proteins and the associated H3K27me3 histone mark are essential to maintain the inactive state of many of these genes. Mammalian Hox genes are targets of Polycomb proteins and form local 3D clusters centered on the H3K27me3 mark. More distal contacts have also been described, yet their selectivity, dynamics, and relation to other layers of chromatin organization remained elusive. We report that repressed Hox genes form mutual intra- and interchromosomal interactions with other genes located in strong domains labeled by H3K27me3. These interactions occur in a central and active nuclear environment that consists of the HiC compartment A, away from peripheral lamina-associated domains. Interactions are independent of nearby H3K27me3-marked loci and determined by chromosomal distance and cell-type–specific scaling factors, thus inducing a moderate reorganization during embryogenesis. These results provide a simplified view of nuclear organization whereby Polycomb proteins may have evolved to repress genes located in gene-dense regions whose position is restricted to central, active, nuclear environments. PMID:25825760

  16. The iab-7 polycomb response element maps to a nucleosome-free region of chromatin and requires both GAGA and pleiohomeotic for silencing activity.

    PubMed

    Mishra, R K; Mihaly, J; Barges, S; Spierer, A; Karch, F; Hagstrom, K; Schweinsberg, S E; Schedl, P

    2001-02-01

    In the work reported here we have undertaken a functional dissection of a Polycomb response element (PRE) from the iab-7 cis-regulatory domain of the Drosophila melanogaster bithorax complex (BX-C). Previous studies mapped the iab-7 PRE to an 860-bp fragment located just distal to the Fab-7 boundary. Located within this fragment is an approximately 230-bp chromatin-specific nuclease-hypersensitive region called HS3. We have shown that HS3 is capable of functioning as a Polycomb-dependent silencer in vivo, inducing pairing-dependent silencing of a mini-white reporter. The HS3 sequence contains consensus binding sites for the GAGA factor, a protein implicated in the formation of nucleosome-free regions of chromatin, and Pleiohomeotic (Pho), a Polycomb group protein that is related to the mammalian transcription factor YY1. We show that GAGA and Pho interact with these sequences in vitro and that the consensus binding sites for the two proteins are critical for the silencing activity of the iab-7 PRE in vivo. PMID:11158316

  17. Jarid2 regulates hematopoietic stem cell function by acting with polycomb repressive complex 2

    PubMed Central

    Kinkel, Sarah A.; Galeev, Roman; Flensburg, Christoffer; Keniry, Andrew; Breslin, Kelsey; Gilan, Omer; Lee, Stanley; Liu, Joy; Chen, Kelan; Gearing, Linden J.; Moore, Darcy L.; Alexander, Warren S.; Dawson, Mark; Majewski, Ian J.; Oshlack, Alicia; Larsson, Jonas

    2015-01-01

    Polycomb repressive complex 2 (PRC2) plays a key role in hematopoietic stem and progenitor cell (HSPC) function. Analyses of mouse mutants harboring deletions of core components have implicated PRC2 in fine-tuning multiple pathways that instruct HSPC behavior, yet how PRC2 is targeted to specific genomic loci within HSPCs remains unknown. Here we use short hairpin RNA–mediated knockdown to survey the function of PRC2 accessory factors that were defined in embryonic stem cells (ESCs) by testing the competitive reconstitution capacity of transduced murine HSPCs. We find that, similar to the phenotype observed upon depletion of core subunit Suz12, depleting Jarid2 enhances the competitive transplantation capacity of both fetal and adult mouse HSPCs. Furthermore, we demonstrate that depletion of JARID2 enhances the in vitro expansion and in vivo reconstitution capacity of human HSPCs. Gene expression profiling revealed common Suz12 and Jarid2 target genes that are enriched for the H3K27me3 mark established by PRC2. These data implicate Jarid2 as an important component of PRC2 that has a central role in coordinating HSPC function. PMID:25645357

  18. Jarid2 regulates hematopoietic stem cell function by acting with polycomb repressive complex 2.

    PubMed

    Kinkel, Sarah A; Galeev, Roman; Flensburg, Christoffer; Keniry, Andrew; Breslin, Kelsey; Gilan, Omer; Lee, Stanley; Liu, Joy; Chen, Kelan; Gearing, Linden J; Moore, Darcy L; Alexander, Warren S; Dawson, Mark; Majewski, Ian J; Oshlack, Alicia; Larsson, Jonas; Blewitt, Marnie E

    2015-03-19

    Polycomb repressive complex 2 (PRC2) plays a key role in hematopoietic stem and progenitor cell (HSPC) function. Analyses of mouse mutants harboring deletions of core components have implicated PRC2 in fine-tuning multiple pathways that instruct HSPC behavior, yet how PRC2 is targeted to specific genomic loci within HSPCs remains unknown. Here we use short hairpin RNA-mediated knockdown to survey the function of PRC2 accessory factors that were defined in embryonic stem cells (ESCs) by testing the competitive reconstitution capacity of transduced murine HSPCs. We find that, similar to the phenotype observed upon depletion of core subunit Suz12, depleting Jarid2 enhances the competitive transplantation capacity of both fetal and adult mouse HSPCs. Furthermore, we demonstrate that depletion of JARID2 enhances the in vitro expansion and in vivo reconstitution capacity of human HSPCs. Gene expression profiling revealed common Suz12 and Jarid2 target genes that are enriched for the H3K27me3 mark established by PRC2. These data implicate Jarid2 as an important component of PRC2 that has a central role in coordinating HSPC function. PMID:25645357

  19. Jarid2 regulates hematopoietic stem cell function by acting with polycomb repressive complex 2.

    PubMed

    Kinkel, Sarah A; Galeev, Roman; Flensburg, Christoffer; Keniry, Andrew; Breslin, Kelsey; Gilan, Omer; Lee, Stanley; Liu, Joy; Chen, Kelan; Gearing, Linden J; Moore, Darcy L; Alexander, Warren S; Dawson, Mark; Majewski, Ian J; Oshlack, Alicia; Larsson, Jonas; Blewitt, Marnie E

    2015-03-19

    Polycomb repressive complex 2 (PRC2) plays a key role in hematopoietic stem and progenitor cell (HSPC) function. Analyses of mouse mutants harboring deletions of core components have implicated PRC2 in fine-tuning multiple pathways that instruct HSPC behavior, yet how PRC2 is targeted to specific genomic loci within HSPCs remains unknown. Here we use short hairpin RNA-mediated knockdown to survey the function of PRC2 accessory factors that were defined in embryonic stem cells (ESCs) by testing the competitive reconstitution capacity of transduced murine HSPCs. We find that, similar to the phenotype observed upon depletion of core subunit Suz12, depleting Jarid2 enhances the competitive transplantation capacity of both fetal and adult mouse HSPCs. Furthermore, we demonstrate that depletion of JARID2 enhances the in vitro expansion and in vivo reconstitution capacity of human HSPCs. Gene expression profiling revealed common Suz12 and Jarid2 target genes that are enriched for the H3K27me3 mark established by PRC2. These data implicate Jarid2 as an important component of PRC2 that has a central role in coordinating HSPC function.

  20. Transcriptional read-through is not sufficient to induce an epigenetic switch in the silencing activity of Polycomb response elements

    PubMed Central

    Erokhin, Maksim; Elizar’ev, Pavel; Parshikov, Aleksander; Schedl, Paul; Georgiev, Pavel; Chetverina, Darya

    2015-01-01

    In Drosophila, Polycomb (PcG) and Trithorax (TrxG) group proteins are assembled on Polycomb response elements (PREs) to maintain tissue and stage-specific patterns of gene expression. Critical to coordinating gene expression with the process of differentiation, the activity of PREs can be switched “on” and “off.” When on, the PRE imposes a silenced state on the genes in the same domain that is stably inherited through multiple rounds of cell division. When the PRE is switched off, the domain is in a state permissive for gene expression that can be stably inherited. Previous studies have suggested that a burst of transcription through a PRE sequence displaces PcG proteins and provides a universal mechanism for inducing a heritable switch in PRE activity from on to off; however, the evidence favoring this model is indirect. Here, we have directly tested the transcriptional read-through mechanism. Contrary to previous suggestions, we show that transcription through the PRE is not sufficient for inducing an epigenetic switch in PRE activity. In fact, even high levels of continuous transcription through a PRE fails to dislodge the PcG proteins, nor does it remove repressive histone marks. Our results indicate that other mechanisms involving adjacent DNA regulatory elements must be implicated in heritable switch of PRE activity. PMID:26504232

  1. Deciphering the Role of POLYCOMB REPRESSIVE COMPLEX1 Variants in Regulating the Acquisition of Flowering Competence in Arabidopsis1

    PubMed Central

    Picó, Sara; Ortiz-Marchena, M. Isabel; Merini, Wiam; Calonje, Myriam

    2015-01-01

    Polycomb group (PcG) proteins play important roles in regulating developmental phase transitions in plants; however, little is known about the role of the PcG machinery in regulating the transition from juvenile to adult phase. Here, we show that Arabidopsis (Arabidopsis thaliana) B lymphoma Moloney murine leukemia virus insertion region1 homolog (BMI1) POLYCOMB REPRESSIVE COMPLEX1 (PRC1) components participate in the repression of microRNA156 (miR156). Loss of AtBMI1 function leads to the up-regulation of the primary transcript of MIR156A and MIR156C at the time the levels of miR156 should decline, resulting in an extended juvenile phase and delayed flowering. Conversely, the PRC1 component EMBRYONIC FLOWER (EMF1) participates in the regulation of SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE and MIR172 genes. Accordingly, plants impaired in EMF1 function displayed misexpression of these genes early in development, which contributes to a CONSTANS-independent up-regulation of FLOWERING LOCUS T (FT) leading to the earliest flowering phenotype described in Arabidopsis. Our findings show how the different regulatory roles of two functional PRC1 variants coordinate the acquisition of flowering competence and help to reach the threshold of FT necessary to flower. Furthermore, we show how two central regulatory mechanisms, such as PcG and microRNA, assemble to achieve a developmental outcome. PMID:25897002

  2. Deciphering the Role of POLYCOMB REPRESSIVE COMPLEX1 Variants in Regulating the Acquisition of Flowering Competence in Arabidopsis.

    PubMed

    Picó, Sara; Ortiz-Marchena, M Isabel; Merini, Wiam; Calonje, Myriam

    2015-08-01

    Polycomb group (PcG) proteins play important roles in regulating developmental phase transitions in plants; however, little is known about the role of the PcG machinery in regulating the transition from juvenile to adult phase. Here, we show that Arabidopsis (Arabidopsis thaliana) B lymphoma Moloney murine leukemia virus insertion region1 homolog (BMI1) POLYCOMB REPRESSIVE COMPLEX1 (PRC1) components participate in the repression of microRNA156 (miR156). Loss of AtBMI1 function leads to the up-regulation of the primary transcript of MIR156A and MIR156C at the time the levels of miR156 should decline, resulting in an extended juvenile phase and delayed flowering. Conversely, the PRC1 component EMBRYONIC FLOWER (EMF1) participates in the regulation of SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE and MIR172 genes. Accordingly, plants impaired in EMF1 function displayed misexpression of these genes early in development, which contributes to a CONSTANS-independent up-regulation of FLOWERING LOCUS T (FT) leading to the earliest flowering phenotype described in Arabidopsis. Our findings show how the different regulatory roles of two functional PRC1 variants coordinate the acquisition of flowering competence and help to reach the threshold of FT necessary to flower. Furthermore, we show how two central regulatory mechanisms, such as PcG and microRNA, assemble to achieve a developmental outcome.

  3. Deciphering the Role of POLYCOMB REPRESSIVE COMPLEX1 Variants in Regulating the Acquisition of Flowering Competence in Arabidopsis.

    PubMed

    Picó, Sara; Ortiz-Marchena, M Isabel; Merini, Wiam; Calonje, Myriam

    2015-08-01

    Polycomb group (PcG) proteins play important roles in regulating developmental phase transitions in plants; however, little is known about the role of the PcG machinery in regulating the transition from juvenile to adult phase. Here, we show that Arabidopsis (Arabidopsis thaliana) B lymphoma Moloney murine leukemia virus insertion region1 homolog (BMI1) POLYCOMB REPRESSIVE COMPLEX1 (PRC1) components participate in the repression of microRNA156 (miR156). Loss of AtBMI1 function leads to the up-regulation of the primary transcript of MIR156A and MIR156C at the time the levels of miR156 should decline, resulting in an extended juvenile phase and delayed flowering. Conversely, the PRC1 component EMBRYONIC FLOWER (EMF1) participates in the regulation of SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE and MIR172 genes. Accordingly, plants impaired in EMF1 function displayed misexpression of these genes early in development, which contributes to a CONSTANS-independent up-regulation of FLOWERING LOCUS T (FT) leading to the earliest flowering phenotype described in Arabidopsis. Our findings show how the different regulatory roles of two functional PRC1 variants coordinate the acquisition of flowering competence and help to reach the threshold of FT necessary to flower. Furthermore, we show how two central regulatory mechanisms, such as PcG and microRNA, assemble to achieve a developmental outcome. PMID:25897002

  4. A target group tracking algorithm for wireless sensor networks using azimuthal angle of arrival information

    NASA Astrophysics Data System (ADS)

    Zhang, Chun; Fei, Shu-Min; Zhou, Xing-Peng

    2012-12-01

    In this paper, we explore the technology of tracking a group of targets with correlated motions in a wireless sensor network. Since a group of targets moves collectively and is restricted within a limited region, it is not worth consuming scarce resources of sensors in computing the trajectory of each single target. Hence, in this paper, the problem is modeled as tracking a geographical continuous region covered by all targets. A tracking algorithm is proposed to estimate the region covered by the target group in each sampling period. Based on the locations of sensors and the azimuthal angle of arrival (AOA) information, the estimated region covering all the group members is obtained. Algorithm analysis provides the fundamental limits to the accuracy of localizing a target group. Simulation results show that the proposed algorithm is superior to the existing hull algorithm due to the reduction in estimation error, which is between 10% and 40% of the hull algorithm, with a similar density of sensors. And when the density of sensors increases, the localization accuracy of the proposed algorithm improves dramatically.

  5. Acting Diverse: Target Group Orientation as Key Competence in Engineering Education

    ERIC Educational Resources Information Center

    Ihsen, S.; Buschmeyer, A.

    2007-01-01

    International companies are recognised by equity between men and women as well as between other different groups (Diversity) as an economic factor and incorporate it into their company visions. Mixed teams are set up to design target group-oriented products, for example in automotive engineering. Therefore they need employees who represent the…

  6. Appropriately Targeting Group Interventions for Academic Success Adopting the Clinical Model and PAR Profiles

    ERIC Educational Resources Information Center

    Johnson, Craig W.; Johnson, Ronald; Steigman, Michael; Odo, Chioma; Vijayan, Suvendra; Tata, Devadatta V.

    2016-01-01

    Prevalence of academic risk (PAR) group profiles provide data enabling empirically based group-specialized prescriptions for targeted academic success interventions to increase student retention, completion, and graduation rates, while improving allocation of institutional resources. Postsecondary student attrition engenders student debt,…

  7. Cooperative enclosing control for multiple moving targets by a group of agents

    NASA Astrophysics Data System (ADS)

    Shi, Y. J.; Li, R.; Teo, K. L.

    2015-01-01

    In this paper, the enclosing control problem of second-order multi-agent systems is considered, where the targets can be either stationary or moving. The objective is to achieve an equidistant circular formation for a group of agents to enclose a team of targets. In order to do so, we first introduce a formal definition explaining certain basic properties of the exploring relation between the agents and the targets. We then construct the estimator of the centre of the targets, which is used to build the control protocol to achieve equidistant circular enclosing. Using a Lyapunov function and Lasalle's Invariance Principle, the convergency of the estimator and control protocol are, respectively, established. We then construct a smooth function to approximate the discontinuous term in the estimator. Finally, the simulations for stationary targets and moving targets are given to verify the validity of the results obtained.

  8. Population and single-cell genomics reveal the Aire dependency, relief from Polycomb silencing, and distribution of self-antigen expression in thymic epithelia

    PubMed Central

    Shikama-Dorn, Noriko; Zhanybekova, Saule; Nusspaumer, Gretel; Macaulay, Iain C.; Deadman, Mary E.; Heger, Andreas; Ponting, Chris P.; Holländer, Georg A.

    2014-01-01

    Promiscuous gene expression (PGE) by thymic epithelial cells (TEC) is essential for generating a diverse T cell antigen receptor repertoire tolerant to self-antigens, and thus for avoiding autoimmunity. Nevertheless, the extent and nature of this unusual expression program within TEC populations and single cells are unknown. Using deep transcriptome sequencing of carefully identified mouse TEC subpopulations, we discovered a program of PGE that is common between medullary (m) and cortical TEC, further elaborated in mTEC, and completed in mature mTEC expressing the autoimmune regulator gene (Aire). TEC populations are capable of expressing up to 19,293 protein-coding genes, the highest number of genes known to be expressed in any cell type. Remarkably, in mouse mTEC, Aire expression alone positively regulates 3980 tissue-restricted genes. Notably, the tissue specificities of these genes include known targets of autoimmunity in human AIRE deficiency. Led by the observation that genes induced by Aire expression are generally characterized by a repressive chromatin state in somatic tissues, we found these genes to be strongly associated with H3K27me3 marks in mTEC. Our findings are consistent with AIRE targeting and inducing the promiscuous expression of genes previously epigenetically silenced by Polycomb group proteins. Comparison of the transcriptomes of 174 single mTEC indicates that genes induced by Aire expression are transcribed stochastically at low cell frequency. Furthermore, when present, Aire expression-dependent transcript levels were 16-fold higher, on average, in individual TEC than in the mTEC population. PMID:25224068

  9. Population and single-cell genomics reveal the Aire dependency, relief from Polycomb silencing, and distribution of self-antigen expression in thymic epithelia.

    PubMed

    Sansom, Stephen N; Shikama-Dorn, Noriko; Zhanybekova, Saule; Nusspaumer, Gretel; Macaulay, Iain C; Deadman, Mary E; Heger, Andreas; Ponting, Chris P; Holländer, Georg A

    2014-12-01

    Promiscuous gene expression (PGE) by thymic epithelial cells (TEC) is essential for generating a diverse T cell antigen receptor repertoire tolerant to self-antigens, and thus for avoiding autoimmunity. Nevertheless, the extent and nature of this unusual expression program within TEC populations and single cells are unknown. Using deep transcriptome sequencing of carefully identified mouse TEC subpopulations, we discovered a program of PGE that is common between medullary (m) and cortical TEC, further elaborated in mTEC, and completed in mature mTEC expressing the autoimmune regulator gene (Aire). TEC populations are capable of expressing up to 19,293 protein-coding genes, the highest number of genes known to be expressed in any cell type. Remarkably, in mouse mTEC, Aire expression alone positively regulates 3980 tissue-restricted genes. Notably, the tissue specificities of these genes include known targets of autoimmunity in human AIRE deficiency. Led by the observation that genes induced by Aire expression are generally characterized by a repressive chromatin state in somatic tissues, we found these genes to be strongly associated with H3K27me3 marks in mTEC. Our findings are consistent with AIRE targeting and inducing the promiscuous expression of genes previously epigenetically silenced by Polycomb group proteins. Comparison of the transcriptomes of 174 single mTEC indicates that genes induced by Aire expression are transcribed stochastically at low cell frequency. Furthermore, when present, Aire expression-dependent transcript levels were 16-fold higher, on average, in individual TEC than in the mTEC population.

  10. Identification of alsterpaullone as a novel small molecule inhibitor to target group 3 medulloblastoma

    PubMed Central

    Faria, Claudia C.; Agnihotri, Sameer; Mack, Stephen C.; Golbourn, Brian J.; Diaz, Roberto J.; Olsen, Samantha; Bryant, Melissa; Bebenek, Matthew; Wang, Xin; Bertrand, Kelsey C.; Kushida, Michelle; Head, Renee; Clark, Ian; Dirks, Peter; Smith, Christian A.; Taylor, Michael D.; Rutka, James T.

    2015-01-01

    Advances in the molecular biology of medulloblastoma revealed four genetically and clinically distinct subgroups. Group 3 medulloblastomas are characterized by frequent amplifications of the oncogene MYC, a high incidence of metastasis, and poor prognosis despite aggressive therapy. We investigated several potential small molecule inhibitors to target Group 3 medulloblastomas based on gene expression data using an in silico drug screen. The Connectivity Map (C-MAP) analysis identified piperlongumine as the top candidate drug for non-WNT medulloblastomas and the cyclin-dependent kinase (CDK) inhibitor alsterpaullone as the compound predicted to have specific antitumor activity against Group 3 medulloblastomas. To validate our findings we used these inhibitors against established Group 3 medulloblastoma cell lines. The C-MAP predicted drugs reduced cell proliferation in vitro and increased survival in Group 3 medulloblastoma xenografts. Alsterpaullone had the highest efficacy in Group 3 medulloblastoma cells. Genomic profiling of Group 3 medulloblastoma cells treated with alsterpaullone confirmed inhibition of cell cycle-related genes, and down-regulation of MYC. Our results demonstrate the preclinical efficacy of using a targeted therapy approach for Group 3 medulloblastomas. Specifically, we provide rationale for advancing alsterpaullone as a targeted therapy in Group 3 medulloblastoma. PMID:26061748

  11. Polycomb Repressive Complex 2 Regulates Lineage Fidelity during Embryonic Stem Cell Differentiation

    PubMed Central

    Thornton, Seraphim R.; Butty, Vincent L.; Levine, Stuart S.; Boyer, Laurie A.

    2014-01-01

    Polycomb Repressive Complex 2 (PRC2) catalyzes histone H3 lysine 27 tri-methylation (H3K27me3), an epigenetic modification associated with gene repression. H3K27me3 is enriched at the promoters of a large cohort of developmental genes in embryonic stem cells (ESCs). Loss of H3K27me3 leads to a failure of ESCs to properly differentiate, making it difficult to determine the precise roles of PRC2 during lineage commitment. Moreover, while studies suggest that PRC2 prevents DNA methylation, how these two epigenetic regulators coordinate to regulate lineage programs is poorly understood. Using several PRC2 mutant ESC lines that maintain varying levels of H3K27me3, we found that partial maintenance of H3K27me3 allowed for proper temporal activation of lineage genes during directed differentiation of ESCs to spinal motor neurons (SMNs). In contrast, genes that function to specify other lineages failed to be repressed in these cells, suggesting that PRC2 is also necessary for lineage fidelity. We also found that loss of H3K27me3 leads to a modest gain in DNA methylation at PRC2 target regions in both ESCs and in SMNs. Our study demonstrates a critical role for PRC2 in safeguarding lineage decisions and in protecting genes against inappropriate DNA methylation. PMID:25333635

  12. Polycomb PRC2 complex mediates epigenetic silencing of a critical osteogenic master regulator in the hippocampus.

    PubMed

    Aguilar, Rodrigo; Bustos, Fernando J; Saez, Mauricio; Rojas, Adriana; Allende, Miguel L; van Wijnen, Andre J; van Zundert, Brigitte; Montecino, Martin

    2016-08-01

    During hippocampal neuron differentiation, the expression of critical inducers of non-neuronal cell lineages must be efficiently silenced. Runx2 transcription factor is the master regulator of mesenchymal cells responsible for intramembranous osteoblast differentiation and formation of the craniofacial bone tissue that surrounds and protects the central nervous system (CNS) in mammalian embryos. The molecular mechanisms that mediate silencing of the Runx2 gene and its downstream target osteogenic-related genes in neuronal cells have not been explored. Here, we assess the epigenetic mechanisms that mediate silencing of osteoblast-specific genes in CNS neurons. In particular, we address the contribution of histone epigenetic marks and histone modifiers on the silencing of the Runx2/p57 bone-related isoform in rat hippocampal tissues at embryonic to adult stages. Our results indicate enrichment of repressive chromatin histone marks and of the Polycomb PRC2 complex at the Runx2/p57 promoter region. Knockdown of PRC2 H3K27-methyltransferases Ezh2 and Ezh1, or forced expression of the Trithorax/COMPASS subunit Wdr5 activates Runx2/p57 mRNA expression in both immature and mature hippocampal cells. Together these results indicate that complementary epigenetic mechanisms progressively and efficiently silence critical osteoblastic genes during hippocampal neuron differentiation. PMID:27216774

  13. Inactivation of polycomb repressive complex 2 components in myeloproliferative and myelodysplastic/myeloproliferative neoplasms.

    PubMed

    Score, Joannah; Hidalgo-Curtis, Claire; Jones, Amy V; Winkelmann, Nils; Skinner, Alison; Ward, Daniel; Zoi, Katerina; Ernst, Thomas; Stegelmann, Frank; Döhner, Konstanze; Chase, Andrew; Cross, Nicholas C P

    2012-02-01

    The polycomb repressive complex 2 (PRC2) is a highly conserved histone H3 lysine 27 methyltransferase that regulates the expression of developmental genes. Inactivating mutations of the catalytic component of PRC2, EZH2, are seen in myeloid disorders. We reasoned that the other 2 core PRC2 components, SUZ12 and EED, may also be mutational targets in these diseases, as well as associated factors such as JARID2. SUZ12 mutations were identified in 1 of 2 patients with myelodysplastic syndrome/myeloproliferative neoplasms with 17q acquired uniparental disomy and in 2 of 2 myelofibrosis cases with focal 17q11 deletions. All 3 were missense mutations affecting the highly conserved VEFS domain. Analysis of a further 146 myelodysplastic syndrome/myeloproliferative neoplasm patients revealed an additional VEFS domain mutant, yielding a total mutation frequency of 1.4% (2 of 148). We did not find mutations of JARID2 or EED in association with acquired uniparental disomy for chromosome 6p or 11q, respectively; however, screening unselected cases identified missense mutations in EED (1 of 148; 1%) and JARID2 (3 of 148; 2%). All 3 SUZ12 mutations tested and the EED mutation reduced PRC2 histone methyltransferase activity in vitro, demonstrating that PRC2 function may be compromised in myeloid disorders by mutation of distinct genes.

  14. Group II p21-activated kinases as therapeutic targets in gastrointestinal cancer

    PubMed Central

    Shao, Yang-Guang; Ning, Ke; Li, Feng

    2016-01-01

    P21-activated kinases (PAKs) are central players in various oncogenic signaling pathways. The six PAK family members are classified into group I (PAK1-3) and group II (PAK4-6). Focus is currently shifting from group I PAKs to group II PAKs. Group II PAKs play important roles in many fundamental cellular processes, some of which have particular significance in the development and progression of cancer. Because of their important functions, group II PAKs have become popular potential drug target candidates. However, few group II PAKs inhibitors have been reported, and most do not exhibit satisfactory kinase selectivity and “drug-like” properties. Isoform- and kinase-selective PAK inhibitors remain to be developed. This review describes the biological activities of group II PAKs, the importance of group II PAKs in the development and progression of gastrointestinal cancer, and small-molecule inhibitors of group II PAKs for the treatment of cancer. PMID:26811660

  15. The Arabidopsis SWI2/SNF2 chromatin Remodeler BRAHMA regulates polycomb function during vegetative development and directly activates the flowering repressor gene SVP.

    PubMed

    Li, Chenlong; Chen, Chen; Gao, Lei; Yang, Songguang; Nguyen, Vi; Shi, Xuejiang; Siminovitch, Katherine; Kohalmi, Susanne E; Huang, Shangzhi; Wu, Keqiang; Chen, Xuemei; Cui, Yuhai

    2015-01-01

    The chromatin remodeler BRAHMA (BRM) is a Trithorax Group (TrxG) protein that antagonizes the functions of Polycomb Group (PcG) proteins in fly and mammals. Recent studies also implicate such a role for Arabidopsis (Arabidopsis thaliana) BRM but the molecular mechanisms underlying the antagonism are unclear. To understand the interplay between BRM and PcG during plant development, we performed a genome-wide analysis of trimethylated histone H3 lysine 27 (H3K27me3) in brm mutant seedlings by chromatin immunoprecipitation followed by next generation sequencing (ChIP-seq). Increased H3K27me3 deposition at several hundred genes was observed in brm mutants and this increase was partially supressed by removal of the H3K27 methyltransferase CURLY LEAF (CLF) or SWINGER (SWN). ChIP experiments demonstrated that BRM directly binds to a subset of the genes and prevents the inappropriate association and/or activity of PcG proteins at these loci. Together, these results indicate a crucial role of BRM in restricting the inappropriate activity of PcG during plant development. The key flowering repressor gene SHORT VEGETATIVE PHASE (SVP) is such a BRM target. In brm mutants, elevated PcG occupancy at SVP accompanies a dramatic increase in H3K27me3 levels at this locus and a concomitant reduction of SVP expression. Further, our gain- and loss-of-function genetic evidence establishes that BRM controls flowering time by directly activating SVP expression. This work reveals a genome-wide functional interplay between BRM and PcG and provides new insights into the impacts of these proteins in plant growth and development.

  16. Spreading of X chromosome inactivation via a hierarchy of defined Polycomb stations

    PubMed Central

    Pinter, Stefan F.; Sadreyev, Ruslan I.; Yildirim, Eda; Jeon, Yesu; Ohsumi, Toshiro K.; Borowsky, Mark; Lee, Jeannie T.

    2012-01-01

    X chromosome inactivation (XCI) achieves dosage balance in mammals by repressing one of two X chromosomes in females. During XCI, the long noncoding Xist RNA and Polycomb proteins spread along the inactive X (Xi) to initiate chromosome-wide silencing. Although inactivation is known to commence at the X-inactivation center (Xic), how it propagates remains unknown. Here, we examine allele-specific binding of Polycomb repressive complex 2 (PRC2) and chromatin composition during XCI and generate a chromosome-wide profile of Xi and Xa (active X) at nucleosome-resolution. Initially, Polycomb proteins are localized to ∼150 strong sites along the X and concentrated predominantly within bivalent domains coinciding with CpG islands (“canonical sites”). As XCI proceeds, ∼4000 noncanonical sites are recruited, most of which are intergenic, nonbivalent, and lack CpG islands. Polycomb sites are depleted of LINE repeats but enriched for SINEs and simple repeats. Noncanonical sites cluster around the ∼150 strong sites, and their H3K27me3 levels reflect a graded concentration originating from strong sites. This suggests that PRC2 and H3K27 methylation spread along a gradient unique to XCI. We propose that XCI is governed by a hierarchy of defined Polycomb stations that spread H3K27 methylation in cis. PMID:22948768

  17. A Polycomb and Gaga Dependent Silencer Adjoins the Fab-7 Boundary in the Drosophila Bithorax Complex

    PubMed Central

    Hagstrom, K.; Muller, M.; Schedl, P.

    1997-01-01

    The homeotic genes of the Drosophila bithorax complex are controlled by a large cis-regulatory region that ensures their segmentally restricted pattern of expression. A deletion that removes the Frontabdominal-7 cis-regulatory region (Fab-7(1)) dominantly transforms parasegment 11 into parasegment 12. Previous studies suggested that removal of a domain boundary element on the proximal side of Fab-7(1) is responsible for this gain-of-function phenotype. In this article we demonstrate that the Fab-7(1) deletion also removes a silencer element, the iab-7 PRE, which maps to a different DNA segment and plays a different role in regulating parasegment-specific expression patterns of the Abd-B gene. The iab-7 PRE mediates pairing-sensitive silencing of mini-white, and can maintain the segmentally restricted expression pattern of a BXD, Ubx/lacZ reporter transgene. Both silencing activities depend upon Polycomb Group proteins. Pairing-sensitive silencing is relieved by removing the transvection protein Zeste, but is enhanced in a novel pairing-independent manner by the zeste(1) allele. The iab-7 PRE silencer is contained within a 0.8-kb fragment that spans a nuclease hypersensitive site, and silencing appears to depend on the chromatin remodeling protein, the GAGA factor. PMID:9258680

  18. LATS2 Positively Regulates Polycomb Repressive Complex 2.

    PubMed

    Torigata, Kosuke; Daisuke, Okuzaki; Mukai, Satomi; Hatanaka, Akira; Ohka, Fumiharu; Motooka, Daisuke; Nakamura, Shota; Ohkawa, Yasuyuki; Yabuta, Norikazu; Kondo, Yutaka; Nojima, Hiroshi

    2016-01-01

    LATS2, a pivotal Ser/Thr kinase of the Hippo pathway, plays important roles in many biological processes. LATS2 also function in Hippo-independent pathway, including mitosis, DNA damage response and epithelial to mesenchymal transition. However, the physiological relevance and molecular basis of these LATS2 functions remain obscure. To understand novel functions of LATS2, we constructed a LATS2 knockout HeLa-S3 cell line using TAL-effector nuclease (TALEN). Integrated omics profiling of this cell line revealed that LATS2 knockout caused genome-wide downregulation of Polycomb repressive complex 2 (PRC2) and H3K27me3. Cell-cycle analysis revealed that downregulation of PRC2 was not due to cell cycle aberrations caused by LATS2 knockout. Not LATS1, a homolog of LATS2, but LATS2 bound PRC2 on chromatin and phosphorylated it. LATS2 positively regulates histone methyltransferase activity of PRC2 and their expression at both the mRNA and protein levels. Our findings reveal a novel signal upstream of PRC2, and provide insight into the crucial role of LATS2 in coordinating the epigenome through regulation of PRC2. PMID:27434182

  19. LATS2 Positively Regulates Polycomb Repressive Complex 2

    PubMed Central

    Torigata, Kosuke; Daisuke, Okuzaki; Mukai, Satomi; Hatanaka, Akira; Ohka, Fumiharu; Motooka, Daisuke; Nakamura, Shota; Ohkawa, Yasuyuki; Yabuta, Norikazu; Kondo, Yutaka; Nojima, Hiroshi

    2016-01-01

    LATS2, a pivotal Ser/Thr kinase of the Hippo pathway, plays important roles in many biological processes. LATS2 also function in Hippo-independent pathway, including mitosis, DNA damage response and epithelial to mesenchymal transition. However, the physiological relevance and molecular basis of these LATS2 functions remain obscure. To understand novel functions of LATS2, we constructed a LATS2 knockout HeLa-S3 cell line using TAL-effector nuclease (TALEN). Integrated omics profiling of this cell line revealed that LATS2 knockout caused genome-wide downregulation of Polycomb repressive complex 2 (PRC2) and H3K27me3. Cell-cycle analysis revealed that downregulation of PRC2 was not due to cell cycle aberrations caused by LATS2 knockout. Not LATS1, a homolog of LATS2, but LATS2 bound PRC2 on chromatin and phosphorylated it. LATS2 positively regulates histone methyltransferase activity of PRC2 and their expression at both the mRNA and protein levels. Our findings reveal a novel signal upstream of PRC2, and provide insight into the crucial role of LATS2 in coordinating the epigenome through regulation of PRC2. PMID:27434182

  20. 48 CFR 952.226-73 - Energy Policy Act target group certification.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... is: (1) __ An institution of higher education that meets the requirements of 34 CFR 600.4(a), and has... and University by the Secretary of Education pursuant to 34 CFR 608.2; or (3) __ A small business....226-73 Energy Policy Act target group certification. As prescribed in 926.7007(d), insert...

  1. 48 CFR 952.226-73 - Energy Policy Act target group certification.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... is: (1) __ An institution of higher education that meets the requirements of 34 CFR 600.4(a), and has... and University by the Secretary of Education pursuant to 34 CFR 608.2; or (3) __ A small business....226-73 Energy Policy Act target group certification. As prescribed in 926.7007(d), insert...

  2. Role of polycomb proteins Ring1A and Ring1B in the epigenetic regulation of gene expression.

    PubMed

    Vidal, Miguel

    2009-01-01

    Generation of cell diversity depends on epigenetic regulatory mechanisms. Polycomb group (PcG) proteins are central components of epigenetic regulation in metazoans. The system, initially associated with transcriptional program stability during development, is also involved in the regulation of other processes, such as maintenance of stem cell pluripotency and cell proliferation. PcG regulation involves chromatin modifications through covalent histone modifications. One of these modifications, the monoubiquitylation of the H2A histone, depends on Ring1 proteins, which are essential for development in insects and mammals. In murine embryonic stem cells, Ring1A and Ring1B-dependent ubiquitylation of H2A is linked to repression of transcriptional initiation. Studies in mammalian cells have found a multiplicity of protein complexes containing Ring1A and Ring1B, suggesting an expanded regulatory role for Ring1A, Ring1B proteins in the epigenetic regulation of gene expression.

  3. New approaches to targeting RNA with oligonucleotides: inhibition of group I intron self-splicing.

    PubMed

    Disney, Matthew D; Childs, Jessica L; Turner, Douglas H

    2004-01-01

    RNA is one class of relatively unexplored drug targets. Since RNAs play a myriad of essential roles, it is likely that new drugs can be developed that target RNA. There are several factors that make targeting RNA particularly attractive. First, the amount of information about the roles of RNA in essential biological processes is currently being expanded. Second, sequence information about targetable RNA is pouring out of genome sequencing efforts at unprecedented levels. Third, designing and screening potential oligonucleotide therapeutics to target RNA is relatively simple. The use of oligonucleotides in cell culture, however, presents several challenges such as oligonucleotide uptake and stability, and selective targeting of genes of interest. Here, we review investigations aimed at targeting RNA with oligonucleotides that can circumvent several of these potential problems. The hallmark of the strategies discussed is the use of short oligonucleotides, which may have the advantage of higher cellular uptake and improved binding selectivity compared to longer oligonucleotides. These strategies have been applied to Group I introns from the mammalian pathogens Pneumocystis carinii and Candida albicans. Both are examples of fungal infections that are increasing in number and prevalence. PMID:14691946

  4. Lysis of typhus-group rickettsia-infected targets by lymphokine activated killers

    SciTech Connect

    Carl, M.; Dasch, G.A.

    1986-03-01

    The authors recently described a subset of OKT8, OKT3-positive lymphocytes from typhus-group rickettsia immune individuals which were capable of lysing autologous PHA-blasts or Epstein-Barr virus transformed B cells (LCL) infected with typhus-group rickettsiae. In order to determine if killing by these effectors was HLA-restricted, they stimulated peripheral blood mononuclear cells (PBMC) from typhus-group rickettsia immune individuals in vitro with typhus-group rickettsia-derived antigen for one week and then measured lysis of autologous LCL or HLA-mismatched LCL in a 4-6 hour Cr/sup 51/-release assay. There was significant lysis of both the autologous and the HLA-mismatched infected targets as compared to the corresponding uninfected targets. Since this suggested that the effectors were lymphokine activated killers (LAK) rather than cytotoxic T lymphocytes, they then tested this hypothesis by stimulating PBMC from both immune and non-immune individuals in vitro for one week with purified interleukin 2 and measuring lysis of infected, autologous LCL. PBMC thus treated, from both immune and non-immune individuals, were capable of significantly lysing autologous, infected LCL as compared to the non-infected control. They therefore conclude that targets infected with typhus-group rickettsiae are susceptible to lysis to LAK.

  5. Structure-Guided Discovery of Selective Antagonists for the Chromodomain of Polycomb Repressive Protein CBX7.

    PubMed

    Ren, Chunyan; Smith, Steven G; Yap, Kyoko; Li, SiDe; Li, Jiaojie; Mezei, Mihaly; Rodriguez, Yoel; Vincek, Adam; Aguilo, Francesca; Walsh, Martin J; Zhou, Ming-Ming

    2016-06-01

    The chromobox 7 (CBX7) protein of the polycomb repressive complex 1 (PRC1) functions to repress transcription of tumor suppressor p16 (INK4a) through long noncoding RNA, ANRIL (antisense noncoding RNA in the INK4 locus) directed chromodomain (ChD) binding to trimethylated lysine 27 of histone H3 (H3K27me3), resulting in chromatin compaction at the INK4a/ARF locus. In this study, we report structure-guided discovery of two distinct classes of small-molecule antagonists for the CBX7ChD. Our Class A compounds, a series including analogues of the previously reported MS452, inhibit CBX7ChD/methyl-lysine binding by occupying the H3K27me3 peptide binding site, whereas our Class B compound, the newly discovered MS351, appears to inhibit H3K27me3 binding when CBX7ChD is bound to RNA. Our crystal structure of the CBX7ChD/MS351 complex reveals the molecular details of ligand recognition by the aromatic cage residues that typically engage in methyl-lysine binding. We further demonstrate that MS351 effectively induces transcriptional derepression of CBX7 target genes, including p16 (INK4a) in mouse embryonic stem cells and human prostate cancer PC3 cells. Thus, MS351 represents a new class of ChD antagonists that selectively targets the biologically active form of CBX7 of the PRC1 in long noncoding RNA- and H3K27me3-directed gene transcriptional repression. PMID:27326334

  6. Long noncoding RNA, polycomb, and the ghosts haunting INK4b-ARF-INK4a expression.

    PubMed

    Aguilo, Francesca; Zhou, Ming-Ming; Walsh, Martin J

    2011-08-15

    Polycomb group proteins (PcG) function as transcriptional repressors of gene expression. The important role of PcG in mediating repression of the INK4b-ARF-INK4a locus, by directly binding to the long noncoding RNA (lncRNA) transcript antisense noncoding RNA in the INK4 locus (ANRIL), was recently shown. INK4b-ARF-INK4a encodes 3 tumor-suppressor proteins, p15(INK4b), p14(ARF), and p16(INK4a), and its transcription is a key requirement for replicative or oncogene-induced senescence and constitutes an important barrier for tumor growth. ANRIL gene is transcribed in the antisense orientation of the INK4b-ARF-INK4a gene cluster, and different single-nucleotide polymorphisms are associated with increased susceptibility to several diseases. Although lncRNA-mediated regulation of INK4b-ARF-INK4a gene is not restricted to ANRIL, both polycomb repressive complex-1 (PRC1) and -2 (PRC2) interact with ANRIL to form heterochromatin surrounding the INK4b-ARF-INK4a locus, leading to its repression. This mechanism would provide an increased advantage for bypassing senescence, sustaining the requirements for the proliferation of stem and/or progenitor cell populations or inappropriately leading to oncogenesis through the aberrant saturation of the INK4b-ARF-INK4a locus by PcG complexes. In this review, we summarize recent findings on the underlying epigenetic mechanisms that link PcG function with ANRIL, which impose gene silencing to control cellular homeostasis as well as cancer development. PMID:21828241

  7. Long Noncoding RNA, Polycomb, and the Ghosts Haunting INK4b-ARF-INK4a Expression

    PubMed Central

    Aguilo, Francesca; Zhou, Ming-Ming; Walsh, Martin J.

    2012-01-01

    Polycomb group proteins (PcG) function as transcriptional repressors of gene expression. The important role of PcG in mediating repression of the INK4b-ARF-INK4a locus, by directly binding to the long noncoding RNA (lncRNA) transcript antisense noncoding RNA in the INK4 locus (ANRIL), was recently shown. INK4b-ARF-INK4a encodes 3 tumor-suppressor proteins, p15INK4b, p14ARF, and p16INK4a, and its transcription is a key requirement for replicative or oncogene-induced senescence and constitutes an important barrier for tumor growth. ANRIL gene is transcribed in the antisense orientation of the INK4b-ARF-INK4a gene cluster, and different single-nucleotide polymorphisms are associated with increased susceptibility to several diseases. Although lncRNA-mediated regulation of INK4b-ARF-INK4a gene is not restricted to ANRIL, both polycomb repressive complex-1 (PRC1) and -2 (PRC2) interact with ANRIL to form heterochromatin surrounding the INK4b-ARF-INK4a locus, leading to its repression. This mechanism would provide an increased advantage for bypassing senescence, sustaining the requirements for the proliferation of stem and/or progenitor cell populations or inappropriately leading to oncogenesis through the aberrant saturation of the INK4b-ARF-INK4a locus by PcG complexes. In this review, we summarize recent findings on the underlying epigenetic mechanisms that link PcG function with ANRIL, which impose gene silencing to control cellular homeostasis as well as cancer development. PMID:21828241

  8. Imprinting of the MEDEA polycomb gene in the Arabidopsis endosperm.

    PubMed Central

    Kinoshita, T; Yadegari, R; Harada, J J; Goldberg, R B; Fischer, R L

    1999-01-01

    In flowering plants, two cells are fertilized in the haploid female gametophyte. Egg and sperm nuclei fuse to form the embryo. A second sperm nucleus fuses with the central cell nucleus that replicates to generate the endosperm, which is a tissue that supports embryo development. MEDEA (MEA) encodes an Arabidopsis SET domain Polycomb protein. Inheritance of a maternal loss-of-function mea allele results in embryo abortion and prolonged endosperm production, irrespective of the genotype of the paternal allele. Thus, only the maternal wild-type MEA allele is required for proper embryo and endosperm development. To understand the molecular mechanism responsible for the parent-of-origin effects of mea mutations on seed development, we compared the expression of maternal and paternal MEA alleles in the progeny of crosses between two Arabidopsis ecotypes. Only the maternal MEA mRNA was detected in the endosperm from seeds at the torpedo stage and later. By contrast, expression of both maternal and paternal MEA alleles was observed in the embryo from seeds at the torpedo stage and later, in seedling, leaf, stem, and root. Thus, MEA is an imprinted gene that displays parent-of-origin-dependent monoallelic expression specifically in the endosperm. These results suggest that the embryo abortion observed in mutant mea seeds is due, at least in part, to a defect in endosperm function. Silencing of the paternal MEA allele in the endosperm and the phenotype of mutant mea seeds supports the parental conflict theory for the evolution of imprinting in plants and mammals. PMID:10521524

  9. Polycomb recruitment at the Class II transactivator gene.

    PubMed

    Boyd, Nathaniel H; Morgan, Julie E; Greer, Susanna F

    2015-10-01

    The Class II Transactivator (CIITA) is the master regulator of Major Histocompatibility Class II (MHC II) genes. Transcription of CIITA through the IFN-γ inducible CIITA promoter IV (CIITA pIV) during activation is characterized by a decrease in trimethylation of histone H3 lysine 27 (H3K27me3), catalyzed by the histone methyltransferase Enhancer of Zeste Homolog 2 (EZH2). While EZH2 is the known catalytic subunit of the Polycomb Repressive Complex 2 (PRC2) and is present at the inactive CIITA pIV, the mechanism of PRC2 recruitment to mammalian promoters remains unknown. Here we identify two DNA-binding proteins, which interact with and regulate PRC2 recruitment to CIITA pIV. We demonstrate Yin Yang 1 (YY1) and Jumonji domain containing protein 2 (JARID2) are binding partners along with EZH2 in mammalian cells. Upon IFN-γ stimulation, YY1 dissociates from CIITA pIV while JARID2 binding to CIITA pIV increases, suggesting novel roles for these proteins in regulating expression of CIITA pIV. Knockdown of YY1 and JARID2 yields decreased binding of EZH2 and H3K27me3 at CIITA pIV, suggesting important roles for YY1 and JARID2 at CIITA pIV. JARID2 knockdown also results in significantly elevated levels of CIITA mRNA upon IFN-γ stimulation. This study is the first to identify novel roles of YY1 and JARID2 in the epigenetic regulation of the CIITA pIV by recruitment of PRC2. Our observations indicate the importance of JARID2 in CIITA pIV silencing, and also provide a novel YY1-JARID2-PRC2 regulatory complex as a possible explanation of differential PRC2 recruitment at inducible versus permanently silenced genes.

  10. Fear extinction to an out-group face: the role of target gender.

    PubMed

    Navarrete, Carlos David; Olsson, Andreas; Ho, Arnold K; Mendes, Wendy Berry; Thomsen, Lotte; Sidanius, James

    2009-02-01

    Conditioning studies on humans and other primates show that fear responses acquired toward danger-relevant stimuli, such as snakes, resist extinction, whereas responses toward danger-irrelevant stimuli, such as birds, are more readily extinguished. Similar evolved biases may extend to human groups, as recent research demonstrates that a conditioned fear response to faces of persons of a social out-group resists extinction, whereas fear toward a social in-group is more readily extinguished. Here, we provide an important extension to previous work by demonstrating that this fear-extinction bias occurs solely when the exemplars are male. These results underscore the importance of considering how gender of the target stimulus affects psychological and physiological responses to out-group threat.

  11. Astemizole arrests the proliferation of cancer cells by disrupting the EZH2-EED interaction of polycomb repressive complex 2.

    PubMed

    Kong, Xiangqian; Chen, Limin; Jiao, Lianying; Jiang, Xiangrui; Lian, Fulin; Lu, Junyan; Zhu, Kongkai; Du, Daohai; Liu, Jingqiu; Ding, Hong; Zhang, Naixia; Shen, Jingshan; Zheng, Mingyue; Chen, Kaixian; Liu, Xin; Jiang, Hualiang; Luo, Cheng

    2014-11-26

    Polycomb Repressive Complex 2 (PRC2) modulates the chromatin structure and transcriptional repression by trimethylation lysine 27 of histone H3 (H3K27me3), a process that necessitates the protein-protein interaction (PPI) between the catalytic subunit EZH2 and EED. Deregulated PRC2 is intimately involved in tumorigenesis and progression, making it an invaluable target for epigenetic cancer therapy. However, until now, there have been no reported small molecule compounds targeting the EZH2-EED interactions. In the present study, we identified astemizole, an FDA-approved drug, as a small molecule inhibitor of the EZH2-EED interaction of PRC2. The disruption of the EZH2-EED interaction by astemizole destabilizes the PRC2 complex and inhibits its methyltransferase activity in cancer cells. Multiple lines of evidence have demonstrated that astemizole arrests the proliferation of PRC2-driven lymphomas primarily by disabling the PRC2 complex. Our findings demonstrate the chemical tractability of the difficult PPI target by a small molecule compound, highlighting the therapeutic promise for PRC2-driven human cancers via targeted destruction of the EZH2-EED complex. PMID:25369470

  12. Social Grouping for Multi-Target Tracking and Head Pose Estimation in Video.

    PubMed

    Qin, Zhen; Shelton, Christian R

    2016-10-01

    Many computer vision tasks are more difficult when tackled without contextual information. For example, in multi-camera tracking, pedestrians may look very different in different cameras with varying pose and lighting conditions. Similarly, head direction estimation in high-angle surveillance video in which human head images are low resolution is challenging. Even humans can have trouble without contextual information. In this work, we couple novel contextual information, social grouping, with two important computer vision tasks: multi-target tracking and head pose/direction estimation in surveillance video. These three components are modeled in a probabilistic formulation and we provide effective solvers.We show that social grouping effectively helps to mitigate visual ambiguities in multi-camera tracking and head pose estimation. We further notice that in single-camera multi-target tracking, social grouping provides a natural high-order association cue that avoids existing complex algorithms for high-order track association. In experiments, we demonstrate improvements with our model over models without social grouping context and several state-of-art approaches on a number of publicly available datasets on tracking, head pose estimation, and group discovery.

  13. Targeting radiosensitizers to DNA by attachment of an intercalating group: Nitroimidazole-linked phenanthridines

    SciTech Connect

    Cowan, D.S.; Panicucci, R.; McClelland, R.A.; Rauth, A.M. )

    1991-07-01

    The nitroimidazole-linked phenanthridine series of compounds (NLP-1, 2, and 3) were synthesized under the assumption that it should be possible to enhance the molar efficiency of 2-nitroimidazoles as hypoxic cell radiosensitizers and cytotoxins by targeting them to their likely site of action, DNA. The targeting group chosen was the phenanthridine moiety, the major component of the classical DNA intercalating compound, ethidium bromide. The sole difference between the compounds is the length of the hydrocarbon chain linking the nitroimidazole to the phenanthridine. The phenanthridine group with a three-carbon side chain, P-1, was also synthesized to allow studies on the effect of the targeting group by itself. The ability of the compounds to bind to DNA is inversely proportional to their linker chain length with binding constant values ranging from approximately 1 {times} 10(5) mol-1 for NLP-2 to 6 {times} 10(5) mol-1 for NLP-3. The NLP compounds show selective toxicity to hypoxic cells at 37 degrees C at external drug concentrations 10-40 times lower than would be required for untargeted 2-nitroimidazoles such as misonidazole in vitro. Toxicity to both hypoxic and aerobic cells is dependent on the linker chain: the shorter the chain, the greater the toxicity. In addition, the NLP compounds radiosensitize hypoxic cells at external drug concentrations as low as 0.05 mM with almost the full oxygen effect being observed at a concentration of 0.5 mM. These concentrations are 10-100 times lower than would be required for similar radiosensitization using misonidazole. Radiosensitizing ability is independent of linker chain length. The present compounds represent prototypes for further studies of the efficacy and mechanism of action of 2-nitroimidazoles targeted to DNA by linkage to an intercalating group.

  14. UAHuntsville-NASA MSFC Heliophysics REU: A Model for Recruiting Targeted Groups

    NASA Astrophysics Data System (ADS)

    Farid, S.; Heerikhuisen, J.; Winebarger, A. R.

    2014-12-01

    In 2011, researchers from the University of Alabama-Huntsville Center for Space Plasma and Aeronomic Research Center (CSPAR) and NASA Marshall Space Fight Center (MSFC) received a 3-year NSF award to create a REU site specifically designed to increase the participation of underrepresented groups in the Geo-sciences, specifically Heliophysics, and to reduce the attrition rate of sophomores by engaging them in research. This program has been highly successful. In three years of operation, we have increased in the diversity of applicant pool and selected participants, increased the number of inexperienced participants and made measurable impacts on the students' perceptions of graduate school and Heliophysics careers, and produced research with significant scientific merit. We attribute the success of the program to our proactive recruitment of first and second year students, underrepresented groups, and students from small universities. Key factors in our efforts include: 1) In person school visits of targeted schools 2.) Establishing relationships with faculty at targeted schools. 3.) An inclusive selection process that considers the availability of research at the students home institution 4.) A reduced focus on GPA and more focus on recommendation letters as indicators of success 5.) A successful cohort of experienced and inexperienced students 6.) The unique learning environment fostered by UAH-CSPAR and NASA-MSFC scientists. In this presentation, we review our strategies and suggest techniques to recruit targeted groups to similar REU programs.

  15. Th22 cells control colon tumorigenesis through STAT3 and Polycomb Repression complex 2 signaling

    PubMed Central

    Sun, Danfeng; Lin, Yanwei; Hong, Jie; Chen, Haoyan; Nagarsheth, Nisha; Peng, Dongjun; Wei, Shuang; Huang, Emina; Fang, Jingyuan; Kryczek, Ilona; Zou, Weiping

    2016-01-01

    ABSTRACT Th22 cells traffic to and retain in the colon cancer microenvironment, and target core stem cell genes and promote colon cancer stemness via STAT3 and H3K79me2 signaling pathway and contribute to colon carcinogenesis. However, whether Th22 cells affect colon cancer cell proliferation and apoptosis remains unknown. We studied the interaction between Th22 cells and colon cancer cells in the colon cancer microenvironment. Colon cancer proliferation was examined by flow cytometry analysis and H3 thymidine incorporation. Cell cycle related genes were quantified by real-time PCR and Western blotting. We transfected colon cancer cells with lentiviral vector encoding specific gene shRNAs and used chromatin immunoprecipitation (ChIP) assay to determine the genetic signaling involved in interleukin (IL)-22-mediated colon cancer cell proliferation. We showed that Th22 cells released IL-22 and stimulated colon cancer proliferation. Mechanistically, IL-22 activated STAT3, and subsequently STAT3 bound to the promoter areas of the Polycomb Repression complex 2 (PRC2) components SUZ12 and EED, and stimulated the expression of PRC2. Consequently, the activated PRC2 catalyzed the promoters of the cell cycle check-point genes p16 and p21, and inhibited their expression through H3K27me3-mediated histone methylation, and ultimately caused colon cancer cell proliferation. Bioinformatics analysis revealed that the levels of IL-22 expression positively correlated with the levels of genes controlling cancer proliferation and cell cycling in colon cancer. In addition to controlling colon cancer stemness, Th22 cells support colon carcinogenesis via affecting colon cancer cell proliferation through a distinct histone modification. PMID:27622053

  16. Th22 cells control colon tumorigenesis through STAT3 and Polycomb Repression complex 2 signaling.

    PubMed

    Sun, Danfeng; Lin, Yanwei; Hong, Jie; Chen, Haoyan; Nagarsheth, Nisha; Peng, Dongjun; Wei, Shuang; Huang, Emina; Fang, Jingyuan; Kryczek, Ilona; Zou, Weiping

    2016-08-01

    Th22 cells traffic to and retain in the colon cancer microenvironment, and target core stem cell genes and promote colon cancer stemness via STAT3 and H3K79me2 signaling pathway and contribute to colon carcinogenesis. However, whether Th22 cells affect colon cancer cell proliferation and apoptosis remains unknown. We studied the interaction between Th22 cells and colon cancer cells in the colon cancer microenvironment. Colon cancer proliferation was examined by flow cytometry analysis and H(3) thymidine incorporation. Cell cycle related genes were quantified by real-time PCR and Western blotting. We transfected colon cancer cells with lentiviral vector encoding specific gene shRNAs and used chromatin immunoprecipitation (ChIP) assay to determine the genetic signaling involved in interleukin (IL)-22-mediated colon cancer cell proliferation. We showed that Th22 cells released IL-22 and stimulated colon cancer proliferation. Mechanistically, IL-22 activated STAT3, and subsequently STAT3 bound to the promoter areas of the Polycomb Repression complex 2 (PRC2) components SUZ12 and EED, and stimulated the expression of PRC2. Consequently, the activated PRC2 catalyzed the promoters of the cell cycle check-point genes p16 and p21, and inhibited their expression through H3K27me3-mediated histone methylation, and ultimately caused colon cancer cell proliferation. Bioinformatics analysis revealed that the levels of IL-22 expression positively correlated with the levels of genes controlling cancer proliferation and cell cycling in colon cancer. In addition to controlling colon cancer stemness, Th22 cells support colon carcinogenesis via affecting colon cancer cell proliferation through a distinct histone modification. PMID:27622053

  17. Polycomb-dependent epigenetic landscape in adult T-cell leukemia.

    PubMed

    Fujikawa, Dai; Nakagawa, Shota; Hori, Makoto; Kurokawa, Naoya; Soejima, Ai; Nakano, Kazumi; Yamochi, Tadanori; Nakashima, Makoto; Kobayashi, Seiichiro; Tanaka, Yuetsu; Iwanaga, Masako; Utsunomiya, Atae; Uchimaru, Kaoru; Yamagishi, Makoto; Watanabe, Toshiki

    2016-04-01

    Adult T-cell leukemia-lymphoma (ATL) shows global gene expression alterations that confer cellular characteristics and unfavorable prognosis. However, molecular mechanisms of the sustained expression changes are largely unknown, because there is no study addressing the relationship between landscapes of the gene expression and epigenetic modifications. Here, we analyzed ATL epigenome and integrated it with transcriptome from primary ATL cells and those from corresponding normal CD4(+)T cells to decipher ATL-specific "epigenetic code" that was critical for cell identity. We found that polycomb-repressive complex 2 (PRC2)-mediated trimethylation at histone H3Lys27 (H3K27me3) was significantly and frequently reprogrammed at half of genes in ATL cells. A large proportion of the abnormal gene downregulation was detected at the early stage of disease progression and was explained by H3K27me3 accumulation. The global H3K27me3 alterations involved ATL-specific gene expression changes that included several tumor suppressors, transcription factors, epigenetic modifiers, miRNAs, and developmental genes, suggesting diverse outcomes by the PRC2-dependent hierarchical regulation. Interestingly, a key enzyme, EZH2, was sensitive to promiscuous signaling network including the NF-κB pathway and was functionally affected by human T-cell leukemia virus type I (HTLV-1) Tax. The Tax-dependent immortalized cells showed H3K27me3 reprogramming that was significantly similar to that of ATL cells. Of note, a majority of the epigenetic silencing has occurred in leukemic cells from indolent ATL and also in HTLV-1-infected T cells from asymptomatic HTLV-1 carriers. Because pharmacologic inhibition of EZH2 reversed epigenetic disruption and selectively eliminated leukemic and HTLV-1-infected cells, targeting the epigenetic elements will hold great promise in treatment and prevention of the onset of ATL and HTLV-1-related diseases. PMID:26773042

  18. Group IIC Intron with an Unusual Target of Integration in Enterobacter cloacae

    PubMed Central

    Rodríguez-Martínez, José-Manuel; Poirel, Laurent

    2012-01-01

    A potential role of group IIC-attC introns in integron gene cassette formation, that is, the way in which they could provide the attC sequence essential for recombination, has been proposed. Group IIC introns usually target the attC site of gene cassettes and more specifically their inverse core. Here we characterized a novel group IIC intron targeting the core site of the aadA1 gene cassette attC site (aadA1-qacEΔ1 gene cassette junction) from enterobacterial isolates. Intron mobility (retrohoming) was analyzed using a two-plasmid assay performed in Escherichia coli. Intron mobility assays confirmed the mobilization-integration of the group II intron into the core site of the aadA2, blaVIM-2, blaCARB-2, aac(6′)-Ib, dfrXVb, arr2, cmlA4, and aadB gene cassettes but not into the attI site. This mobility was dependent on maturase activity. Reverse transcriptase PCR showed that this intron was transcriptionally active, and an intermediate circular form was detected by inverse PCR. This element was linked to the blaVEB-1 extended-spectrum β-lactamase gene in a high number of enterobacterial isolates. A phylogenetic tree showed that the identified element was located in a branch separate from group IIC-attC introns, being an IIC intron possessing the ability to integrate using the core site of the attC sites as target. PMID:22020643

  19. What works best for worksite cholesterol education? Answers from targeted focus groups.

    PubMed

    McCarthy, P R; Lansing, D; Hartman, T J; Himes, J H

    1992-08-01

    Focus group discussions are an effective way to determine the needs and interests of a target population. In August 1989, eight focus group discussions were conducted with municipal employees in Phoenix, Ariz, to determine the needs and interests of potential participants in a worksite cholesterol education program. Employees were selected for the focus groups on the basis of an initial screening that determined their motivation to change customary eating habits. Individuals categorized as "somewhat motivated" were invited to participate in the focus groups because researchers thought they would best represent the motivation level of the majority of potential participants in the cholesterol education program. The focus group participants indicated that they preferred educational formats and approaches that appealed to diverse learning styles and recognized individual differences. Several of the program features identified by the focus groups are consistent with principles of adult education, especially active participation in the learning activity. The focus group participants wanted information presented in a simple, easy-to-understand manner, and they asked for behavioral directives rather than background information or medical jargon. Release time from work and employer commitment to the program were viewed as important to the success of the program. We conclude that employees respond best to worksite wellness programs that are simple, practical, and relevant and that allow them to participate actively in the learning activity during work time.

  20. Spy: a new group of eukaryotic DNA transposons without target site duplications.

    PubMed

    Han, Min-Jin; Xu, Hong-En; Zhang, Hua-Hao; Feschotte, Cédric; Zhang, Ze

    2014-06-24

    Class 2 or DNA transposons populate the genomes of most eukaryotes and like other mobile genetic elements have a profound impact on genome evolution. Most DNA transposons belong to the cut-and-paste types, which are relatively simple elements characterized by terminal-inverted repeats (TIRs) flanking a single gene encoding a transposase. All eukaryotic cut-and-paste transposons so far described are also characterized by target site duplications (TSDs) of host DNA generated upon chromosomal insertion. Here, we report a new group of evolutionarily related DNA transposons called Spy, which also include TIRs and DDE motif-containing transposase but surprisingly do not create TSDs upon insertion. Instead, Spy transposons appear to transpose precisely between 5'-AAA and TTT-3' host nucleotides, without duplication or modification of the AAATTT target sites. Spy transposons were identified in the genomes of diverse invertebrate species based on transposase homology searches and structure-based approaches. Phylogenetic analyses indicate that Spy transposases are distantly related to IS5, ISL2EU, and PIF/Harbinger transposases. However, Spy transposons are distinct from these and other DNA transposon superfamilies by their lack of TSD and their target site preference. Our findings expand the known diversity of DNA transposons and reveal a new group of eukaryotic DDE transposases with unusual catalytic properties.

  1. Spy: a new group of eukaryotic DNA transposons without target site duplications.

    PubMed

    Han, Min-Jin; Xu, Hong-En; Zhang, Hua-Hao; Feschotte, Cédric; Zhang, Ze

    2014-07-01

    Class 2 or DNA transposons populate the genomes of most eukaryotes and like other mobile genetic elements have a profound impact on genome evolution. Most DNA transposons belong to the cut-and-paste types, which are relatively simple elements characterized by terminal-inverted repeats (TIRs) flanking a single gene encoding a transposase. All eukaryotic cut-and-paste transposons so far described are also characterized by target site duplications (TSDs) of host DNA generated upon chromosomal insertion. Here, we report a new group of evolutionarily related DNA transposons called Spy, which also include TIRs and DDE motif-containing transposase but surprisingly do not create TSDs upon insertion. Instead, Spy transposons appear to transpose precisely between 5'-AAA and TTT-3' host nucleotides, without duplication or modification of the AAATTT target sites. Spy transposons were identified in the genomes of diverse invertebrate species based on transposase homology searches and structure-based approaches. Phylogenetic analyses indicate that Spy transposases are distantly related to IS5, ISL2EU, and PIF/Harbinger transposases. However, Spy transposons are distinct from these and other DNA transposon superfamilies by their lack of TSD and their target site preference. Our findings expand the known diversity of DNA transposons and reveal a new group of eukaryotic DDE transposases with unusual catalytic properties. PMID:24966181

  2. Polycomb Protein OsFIE2 Affects Plant Height and Grain Yield in Rice

    PubMed Central

    Sheng, Zhonghua; Jiao, Guiai; Tang, Shaoqing; Luo, Ju; Hu, Peisong

    2016-01-01

    Polycomb group (PcG) proteins have been shown to affect growth and development in plants. To further elucidate their role in these processes in rice, we isolated and characterized a rice mutant which exhibits dwarfism, reduced seed setting rate, defective floral organ, and small grains. Map-based cloning revealed that abnormal phenotypes were attributed to a mutation of the Fertilization Independent Endosperm 2 (OsFIE2) protein, which belongs to the PcG protein family. So we named the mutant as osfie2-1. Histological analysis revealed that the number of longitudinal cells in the internodes decreased in osfie2-1, and that lateral cell layer of the internodes was markedly thinner than wild-type. In addition, compared to wild-type, the number of large and small vascular bundles decreased in osfie2-1, as well as cell number and cell size in spikelet hulls. OsFIE2 is expressed in most tissues and the coded protein localizes in both nucleus and cytoplasm. Yeast two-hybrid and bimolecular fluorescence complementation assays demonstrated that OsFIE2 interacts with OsiEZ1 which encodes an enhancer of zeste protein previously identified as a histone methylation enzyme. RNA sequencing-based transcriptome profiling and qRT-PCR analysis revealed that some homeotic genes and genes involved in endosperm starch synthesis, cell division/expansion and hormone synthesis and signaling are differentially expressed between osfie2-1 and wild-type. In addition, the contents of IAA, GA3, ABA, JA and SA in osfie2-1 are significantly different from those in wild-type. Taken together, these results indicate that OsFIE2 plays an important role in the regulation of plant height and grain yield in rice. PMID:27764161

  3. Potential and Dunkelfeld offenders: two neglected target groups for prevention of child sexual abuse.

    PubMed

    Schaefer, Gerard A; Mundt, Ingrid A; Feelgood, Steven; Hupp, Elena; Neutze, Janina; Ahlers, Christoph J; Goecker, David; Beier, Klaus M

    2010-01-01

    Little is known about men who have not yet committed child sexual abuse but may be at risk of doing so (potential offenders) and the factors that distinguish these men from undetected child sexual abuse offenders with a sexual interest in children (Dunkelfeld offenders). The present study describes and compares potential and Dunkelfeld offenders, which can be viewed as ideal target groups for (primary) prevention efforts with respect to child sexual abuse. Also, this study seeks to demonstrate the feasibility of using a telephone screening procedure to conduct research with these groups. Using a computer assisted telephone interview (CATI), data on demographics, mental health, sexuality, criminal history, and victim characteristics were collected from respondents in a nation-wide media campaign, which informed potential (re-)offenders of child sexual abuse of a research and treatment project. Many participants reported recurrent sexual fantasies involving minors, as well as related distress, suggesting a high prevalence of pedophilia and hebephilia. More than half feared they would sexually abuse a minor, and Dunkelfeld offenders reported 3.2 victims on average. Group comparisons revealed that Dunkelfeld offenders were, for example, more likely to perceive themselves being at risk of offending, compared to potential offenders. The results suggest that targeting potential and Dunkelfeld offenders could prove a worthwhile approach in the prevention of child sexual abuse. PMID:20466423

  4. Act-Up, other AIDS groups targeted for FBI surveillance. Federal Bureau of Investigations.

    PubMed

    1995-06-01

    Documents obtained by a civil rights group, the Center for Constitutional Rights, showed that the Federal Bureau of Investigations (FBI) monitored the activities of Act-Up, Gay Men's Health Crisis (GMHC), the Coalition for Lesbian and Gay Rights, and Senior Action in a Gay Environment. Act-Up was the main target from 1988 through 1992, the years it staged its most conspicuous demonstrations against the Federal government's policy on AIDS. According to one of the documents, George Bush, then president, complained about Act-Up holding protests and tossing condoms outside his summer home in Maine in 1992. The documents showed that the organization posed little threat of harm.

  5. Crystallization of the Focal Adhesion Kinase Targeting (FAT) Domain in a Primitive Orthorhombic Space Group

    SciTech Connect

    Magis,A.; Bailey, K.; Kurenova, E.; Hernandez Prada, J.; Cance, W.; Ostrov, D.

    2008-01-01

    X-ray diffraction data from the targeting (FAT) domain of focal adhesion kinase (FAK) were collected from a single crystal that diffracted to 1.99 Angstroms resolution and reduced to the primitive orthorhombic lattice. A single molecule was predicted to be present in the asymmetric unit based on the Matthews coefficient. The data were phased using molecular-replacement methods using an existing model of the FAK FAT domain. All structures of human focal adhesion kinase FAT domains solved to date have been solved in a C-centered orthorhombic space group.

  6. Identifying target groups for a potential vaccination program during a hepatitis A communitywide outbreak.

    PubMed Central

    Hutin, Y J; Bell, B P; Marshall, K L; Schaben, C P; Dart, M; Quinlisk, M P; Shapiro, C N

    1999-01-01

    OBJECTIVES: This study sought to identify groups for targeted vaccination during a communitywide hepatitis A outbreak in 1996. METHODS: Residents of the Sioux City, Iowa, metropolitan area reported with hepatitis A between September 1995 and August 1996 were sampled and compared with population-based controls. RESULTS: In comparison with 51 controls, the 40 case patients were more likely to inject methamphetamine, to attend emergency rooms more often than other health care facilities, and to have a family member who used the Special Supplemental Nutrition Program for Women, Infants, and Children. CONCLUSIONS: Groups at increased risk of hepatitis A can be identified that might be [corrected] accessed for vaccination during communitywide outbreaks. PMID:10358687

  7. Group II Metabotropic Glutamate Receptors as Targets for Novel Antipsychotic Drugs

    PubMed Central

    Muguruza, Carolina; Meana, J. Javier; Callado, Luis F.

    2016-01-01

    Schizophrenia is a chronic psychiatric disorder which substantially impairs patients’ quality of life. Despite the extensive research in this field, the pathophysiology and etiology of schizophrenia remain unknown. Different neurotransmitter systems and functional networks have been found to be affected in the brain of patients with schizophrenia. In this context, postmortem brain studies as well as genetic assays have suggested alterations in Group II metabotropic glutamate receptors (mGluRs) in schizophrenia. Despite many years of drug research, several needs in the treatment of schizophrenia have not been addressed sufficiently. In fact, only 5–10% of patients with schizophrenia successfully achieve a full recovery after treatment. In recent years mGluRs have turned up as novel targets for the design of new antipsychotic medications for schizophrenia. Concretely, Group II mGluRs are of particular interest due to their regulatory role in neurotransmission modulating glutamatergic activity in brain synapses. Preclinical studies have demonstrated that orthosteric Group II mGluR agonists exhibit antipsychotic-like properties in animal models of schizophrenia. However, when these compounds have been tested in human clinical studies with schizophrenic patients results have been inconclusive. Nevertheless, it has been recently suggested that this apparent lack of efficacy in schizophrenic patients may be related to previous exposure to atypical antipsychotics. Moreover, the role of the functional heterocomplex formed by 5-HT2A and mGlu2 receptors in the clinical response to Group II mGluR agonists is currently under study. PMID:27242534

  8. BMI-1, a promising therapeutic target for human cancer

    PubMed Central

    WANG, MIN-CONG; LI, CHUN-LI; CUI, JIE; JIAO, MIN; WU, TAO; JING, LI; NAN, KE-JUN

    2015-01-01

    BMI-1 oncogene is a member of the polycomb-group gene family and a transcriptional repressor. Overexpression of BMI-1 has been identified in various human cancer tissues and is known to be involved in cancer cell proliferation, cell invasion, distant metastasis, chemosensitivity and patient survival. Accumulating evidence has revealed that BMI-1 is also involved in the regulation of self-renewal, differentiation and tumor initiation of cancer stem cells (CSCs). However, the molecular mechanisms underlying these biological processes remain unclear. The present review summarized the function of BMI-1 in different human cancer types and CSCs, and discussed the signaling pathways in which BMI-1 is potentially involved. In conclusion, BMI-1 may represent a promising target for the prevention and therapy of various cancer types. PMID:26622537

  9. Targeting the Psychosexual Challenges Faced by Couples with Breast Cancer: Can Couples Group Psychotherapy Help?

    PubMed Central

    Lagana, Luciana; Fobair, Patricia; Spiegel, David

    2016-01-01

    The need for the psychosexual rehabilitation of breast cancer survivors and their intimate partners is underscored by the high prevalence of multiple psychosexual difficulties encountered by this patient population. Concerns about health, sexuality, and emotional distress are common among women with breast cancer and are often related to the side effects of cancer treatment. Additionally, both intimate relationship problems and partners’ distress are likely to influence patients’ psychosexual health. A clearer understanding of these complex clinical issues is needed in order to implement effective psychosexual rehabilitation interventions. In this article, we extended the use of the manualized and empirically validated Supportive-Expressive Group Therapy (SEGT) model to target the specific psychosexual needs of couples with breast (as well as other types of) cancer. In view of the pertinent literature in this area and based on our clinical experience utilizing this group therapy model with different patient populations, we have discussed how clinicians involved in the psychosexual care of oncology patients could apply such a model within a couples group therapy format. PMID:27239398

  10. Target Group Segmentation in the Horse Buyers' Market against the Background of Equestrian Experience.

    PubMed

    Gille, Claudia; Kayser, Maike; Spiller, Achim

    2010-01-01

    Whereas in former times horses were reserved primarily for people involved in agriculture, elite equestrians or the military, nowadays equestrian sport has become an activity for people with a wide variety of backgrounds. However, as more and more people become involved with equestrian sport today, the knowledge concerning animal husbandry in general is diminishing due to an alienation from agricultural themes in modern societies. As a consequence, this development affects both riding ability and the appraisal of horses, especially with respect to the purchase of horses. In order to analyse which factors influence purchase decisions in the horse market in conjunction with equestrian experience, 739 horse riders were surveyed on their purchase behaviour in this study. Using cluster analysis, a typology was generated that provides a differentiated picture of the preferences of the various rider groups. Three clusters were distinguished: the "amateurs", the "experienced" and the "experts". Taking personal horse riding proficiency into account, it could be concluded that especially the "amateur" group required objective criteria for the evaluation of a horse they are considering purchasing. Alongside "measureable" qualities, such as previous showing success or the level of training of the horse, also other attributes such as the simple handling of the horse should be taken into consideration. As particularly the "amateur" group in equestrian sport is increasing in numbers, it is therefore advisable when preparing a horse for sale to align oneself to the needs of this customer segment in order to ensure an effective and targeted marketing of horses. PMID:24833979

  11. Target Group Segmentation in the Horse Buyers' Market against the Background of Equestrian Experience.

    PubMed

    Gille, Claudia; Kayser, Maike; Spiller, Achim

    2010-01-01

    Whereas in former times horses were reserved primarily for people involved in agriculture, elite equestrians or the military, nowadays equestrian sport has become an activity for people with a wide variety of backgrounds. However, as more and more people become involved with equestrian sport today, the knowledge concerning animal husbandry in general is diminishing due to an alienation from agricultural themes in modern societies. As a consequence, this development affects both riding ability and the appraisal of horses, especially with respect to the purchase of horses. In order to analyse which factors influence purchase decisions in the horse market in conjunction with equestrian experience, 739 horse riders were surveyed on their purchase behaviour in this study. Using cluster analysis, a typology was generated that provides a differentiated picture of the preferences of the various rider groups. Three clusters were distinguished: the "amateurs", the "experienced" and the "experts". Taking personal horse riding proficiency into account, it could be concluded that especially the "amateur" group required objective criteria for the evaluation of a horse they are considering purchasing. Alongside "measureable" qualities, such as previous showing success or the level of training of the horse, also other attributes such as the simple handling of the horse should be taken into consideration. As particularly the "amateur" group in equestrian sport is increasing in numbers, it is therefore advisable when preparing a horse for sale to align oneself to the needs of this customer segment in order to ensure an effective and targeted marketing of horses.

  12. The neuronal repellent SLIT2 is a target for repression by EZH2 in prostate cancer.

    PubMed

    Yu, J; Cao, Q; Yu, J; Wu, L; Dallol, A; Li, J; Chen, G; Grasso, C; Cao, X; Lonigro, R J; Varambally, S; Mehra, R; Palanisamy, N; Wu, J Y; Latif, F; Chinnaiyan, A M

    2010-09-30

    The neuronal repellent SLIT2 is repressed in a number of cancer types primarily through promoter hypermethylation. SLIT2, however, has not been studied in prostate cancer. Through genome-wide location analysis we identified SLIT2 as a target of polycomb group (PcG) protein EZH2. The EZH2-containing polycomb repressive complexes bound to the SLIT2 promoter inhibiting its expression. SLIT2 was downregulated in a majority of metastatic prostate tumors, showing a negative correlation with EZH2. This repressed expression could be restored by methylation inhibitors or EZH2-suppressing compounds. In addition, a low level of SLIT2 expression was associated with aggressive prostate, breast and lung cancers. Functional assays showed that SLIT2 inhibited prostate cancer cell proliferation and invasion. Thus, this study showed for the first time the epigenetic silencing of SLIT2 in prostate tumors, and supported SLIT2 as a potential biomarker for aggressive solid tumors. Importantly, PcG-mediated repression may serve as a precursor for the silencing of SLIT2 by DNA methylation in cancer.

  13. AGS SUPER NEUTRINO BEAM FACILITY ACCELERATOR AND TARGET SYSTEM DESIGN (NEUTRINO WORKING GROUP REPORT-II).

    SciTech Connect

    DIWAN,M.; MARCIANO,W.; WENG,W.; RAPARIA,D.

    2003-04-21

    This document describes the design of the accelerator and target systems for the AGS Super Neutrino Beam Facility. Under the direction of the Associate Laboratory Director Tom Kirk, BNL has established a Neutrino Working Group to explore the scientific case and facility requirements for a very long baseline neutrino experiment. Results of a study of the physics merit and detector performance was published in BNL-69395 in October 2002, where it was shown that a wide-band neutrino beam generated by a 1 MW proton beam from the AGS, coupled with a half megaton water Cerenkov detector located deep underground in the former Homestake mine in South Dakota would be able to measure the complete set of neutrino oscillation parameters: (1) precise determination of the oscillation parameters {Delta}m{sub 32}{sup 2} and sin{sup 2} 2{theta}{sub 32}; (2) detection of the oscillation of {nu}{sub {mu}}-{nu}{sub e} and measurement of sin{sup 2} 2{theta}{sub 13}; (3) measurement of {Delta}m{sub 21}{sup 2} sin 2{theta}{sub 12} in a {nu}{sub {mu}} {yields} {nu}{sub e} appearance mode, independent of the value of {theta}{sub 13}; (4) verification of matter enhancement and the sign of {Delta}m{sub 32}{sup 2}; and (5) determination of the CP-violation parameter {delta}{sub CP} in the neutrino sector. This report details the performance requirements and conceptual design of the accelerator and the target systems for the production of a neutrino beam by a 1.0 MW proton beam from the AGS. The major components of this facility include a new 1.2 GeV superconducting linac, ramping the AGS at 2.5 Hz, and the new target station for 1.0 MW beam. It also calls for moderate increase, about 30%, of the AGS intensity per pulse. Special care is taken to account for all sources of proton beam loss plus shielding and collimation of stray beam halo particles to ensure equipment reliability and personal safety. A preliminary cost estimate and schedule for the accelerator upgrade and target system are also

  14. The morphogen Decapentaplegic employs a two-tier mechanism to activate target retinal determining genes during ectopic eye formation in Drosophila

    PubMed Central

    Aggarwal, Poonam; Gera, Jayati; Mandal, Lolitika; Mandal, Sudip

    2016-01-01

    Understanding the role of morphogen in activating its target genes, otherwise epigenetically repressed, during change in cell fate specification is a very fascinating yet relatively unexplored domain. Our in vivo loss-of-function genetic analyses reveal that specifically during ectopic eye formation, the morphogen Decapentaplegic (Dpp), in conjunction with the canonical signaling responsible for transcriptional activation of retinal determining (RD) genes, triggers another signaling cascade. Involving dTak1 and JNK, this pathway down-regulates the expression of polycomb group of genes to do away with their repressive role on RD genes. Upon genetic inactivation of members of this newly identified pathway, the canonical Dpp signaling fails to trigger RD gene expression beyond a threshold, critical for ectopic photoreceptor differentiation. Moreover, the drop in ectopic RD gene expression and subsequent reduction in ectopic photoreceptor differentiation resulting from inactivation of dTak1 can be rescued by down-regulating the expression of polycomb group of genes. Our results unravel an otherwise unknown role of morphogen in coordinating simultaneous transcriptional activation and de-repression of target genes implicating its importance in cellular plasticity. PMID:27270790

  15. Polycomb repressive complex PRC1 spatially constrains the mouse embryonic stem cell genome

    PubMed Central

    Mifsud, Borbala; Dimitrova, Emilia; Matheson, Louise; Tavares-Cadete, Filipe; Furlan-Magaril, Mayra; Segonds-Pichon, Anne; Jurkowski, Wiktor; Wingett, Steven W.; Tabbada, Kristina; Andrews, Simon; Herman, Bram; LeProust, Emily; Osborne, Cameron S.; Koseki, Haruhiko; Fraser, Peter; Luscombe, Nicholas M.; Elderkin, Sarah

    2016-01-01

    The Polycomb Repressive Complexes PRC1 and PRC2 maintain embryonic stem cell (ESC) pluripotency by silencing lineage-specifying developmental regulator genes1. Emerging evidence suggests that Polycomb complexes act through controlling spatial genome organisation2–9. We show that PRC1 functions as a master regulator of ESC genome architecture by organizing genes in three-dimensional interaction networks. The strongest spatial network is composed of the four Hox clusters and early developmental transcription factor genes, the majority of which contact poised enhancers. Removal of Polycomb repression leads to disruption of promoter-promoter contacts in the Hox network. In contrast, promoter-enhancer contacts are maintained, accompanied by widespread acquisition of active chromatin signatures at network enhancers and pronounced transcriptional up-regulation of network genes. Thus, PRC1 physically constrains developmental transcription factor genes and their enhancers in a silenced but poised spatial network. We propose that selective release of genes from this spatial network underlies cell fate specification during early embryonic development. PMID:26323060

  16. Structural basis of oncogenic histone H3K27M inhibition of human polycomb repressive complex 2

    PubMed Central

    Justin, Neil; Zhang, Ying; Tarricone, Cataldo; Martin, Stephen R.; Chen, Shuyang; Underwood, Elizabeth; De Marco, Valeria; Haire, Lesley F.; Walker, Philip A.; Reinberg, Danny; Wilson, Jon R.; Gamblin, Steven J.

    2016-01-01

    Polycomb repressive complex 2 (PRC2) silences gene expression through trimethylation of K27 of histone H3 (H3K27me3) via its catalytic SET domain. A missense mutation in the substrate of PRC2, histone H3K27M, is associated with certain pediatric brain cancers and is linked to a global decrease of H3K27me3 in the affected cells thought to be mediated by inhibition of PRC2 activity. We present here the crystal structure of human PRC2 in complex with the inhibitory H3K27M peptide bound to the active site of the SET domain, with the methionine residue located in the pocket that normally accommodates the target lysine residue. The structure and binding studies suggest a mechanism for the oncogenic inhibition of H3K27M. The structure also reveals how binding of repressive marks, like H3K27me3, to the EED subunit of the complex leads to enhancement of the catalytic efficiency of the SET domain and thus the propagation of this repressive histone modification. PMID:27121947

  17. A Small Molecule Inhibitor of Polycomb Repressive Complex 1 Inhibits Ubiquitin Signaling at DNA Double-strand Breaks*

    PubMed Central

    Ismail, Ismail Hassan; McDonald, Darin; Strickfaden, Hilmar; Xu, Zhizhong; Hendzel, Michael J.

    2013-01-01

    Polycomb-repressive complex 1 (PRC1)-mediated histone ubiquitylation plays an important role in aberrant gene silencing in human cancers and is a potential target for cancer therapy. Here we show that 2-pyridine-3-yl-methylene-indan-1,3-dione (PRT4165) is a potent inhibitor of PRC1-mediated H2A ubiquitylation in vivo and in vitro. The drug also inhibits the accumulation of all detectable ubiquitin at sites of DNA double-strand breaks (DSBs), the retention of several DNA damage response proteins in foci that form around DSBs, and the repair of the DSBs. In vitro E3 ubiquitin ligase activity assays revealed that PRT4165 inhibits both RNF2 and RING 1A, which are partially redundant paralogues that together account for the E3 ubiquitin ligase activity found in PRC1 complexes, but not RNF8 nor RNF168. Because ubiquitylation is completely inhibited despite the efficient recruitment of RNF8 to DSBs, our results suggest that PRC1-mediated monoubiquitylation is required for subsequent RNF8- and/or RNF168-mediated polyubiquitylation. Our results demonstrate the unique feature of PRT4165 as a novel chromatin-remodeling compound and provide a new tool for the inhibition of ubiquitylation signaling at DNA double-strand breaks. PMID:23902761

  18. DNMT3A R882 mutants interact with polycomb proteins to block haematopoietic stem and leukaemic cell differentiation

    PubMed Central

    Koya, Junji; Kataoka, Keisuke; Sato, Tomohiko; Bando, Masashige; Kato, Yuki; Tsuruta-Kishino, Takako; Kobayashi, Hiroshi; Narukawa, Kensuke; Miyoshi, Hiroyuki; Shirahige, Katsuhiko; Kurokawa, Mineo

    2016-01-01

    Despite the clinical impact of DNMT3A mutation on acute myeloid leukaemia, the molecular mechanisms regarding how this mutation causes leukaemogenesis in vivo are largely unknown. Here we show that, in murine transplantation experiments, recipients transplanted with DNMT3A mutant-transduced cells exhibit aberrant haematopoietic stem cell (HSC) accumulation. Differentiation-associated genes are downregulated without accompanying changes in methylation status of their promoter-associated CpG islands in DNMT3A mutant-transduced stem/progenitor cells, representing a DNA methylation-independent role of mutated DNMT3A. DNMT3A R882H also promotes monoblastic transformation in vitro in combination with HOXA9. Molecularly, the DNMT3A mutant interacts with polycomb repressive complex 1 (PRC1), causing transcriptional silencing, revealing a DNA methylation-independent role of DNMT3A mutation. Suppression of PRC1 impairs aberrant HSC accumulation and monoblastic transformation. From our data, it is shown that DNMT3A mutants can block the differentiation of HSCs and leukaemic cells via PRC1. This interaction could be targetable in DNMT3A-mutated leukaemias. PMID:27010239

  19. Target Group Segmentation in the Horse Buyers’ Market against the Background of Equestrian Experience

    PubMed Central

    GILLE, Claudia; KAYSER, Maike; SPILLER, Achim

    2011-01-01

    Whereas in former times horses were reserved primarily for people involved in agriculture, elite equestrians or the military, nowadays equestrian sport has become an activity for people with a wide variety of backgrounds. However, as more and more people become involved with equestrian sport today, the knowledge concerning animal husbandry in general is diminishing due to an alienation from agricultural themes in modern societies. As a consequence, this development affects both riding ability and the appraisal of horses, especially with respect to the purchase of horses. In order to analyse which factors influence purchase decisions in the horse market in conjunction with equestrian experience, 739 horse riders were surveyed on their purchase behaviour in this study. Using cluster analysis, a typology was generated that provides a differentiated picture of the preferences of the various rider groups. Three clusters were distinguished: the “amateurs”, the “experienced” and the “experts”. Taking personal horse riding proficiency into account, it could be concluded that especially the “amateur” group required objective criteria for the evaluation of a horse they are considering purchasing. Alongside “measureable” qualities, such as previous showing success or the level of training of the horse, also other attributes such as the simple handling of the horse should be taken into consideration. As particularly the “amateur” group in equestrian sport is increasing in numbers, it is therefore advisable when preparing a horse for sale to align oneself to the needs of this customer segment in order to ensure an effective and targeted marketing of horses. PMID:24833979

  20. The Cockayne syndrome group B DNA repair protein as an anti-cancer target.

    PubMed

    Lu, Y; Mani, S; Kandimalla, E R; Yu, D; Agrawal, S; States, J C; Bregman, D B

    2001-12-01

    Cells from individuals with Cockayne syndrome (CS) have a defect in transcription-coupled DNA repair (TCR), which rapidly corrects certain DNA lesions located on the transcribed strand of active genes. Despite this DNA repair defect, individuals with CS (of which there are two complementation groups, CSA and CSB) do not demonstrate an elevated incidence of cancer. Recently, we demonstrated that disruption of the CSB gene reduces the spontaneous tumor rate in cancer predisposed Ink4a/ARF-/- mice as well as causing their embryo fibroblasts to proliferate more slowly and be more sensitive to UV-induced apoptosis. In the present study we characterized phosphorothioate backbone antisense oligodeoxynucleotides (AOs) that reduced the levels of CSB mRNA in A2780/CP70 ovarian carcinoma cells. The AOs caused the cells to proliferate more slowly and made them more sensitive to either cisplatin or oxaliplatin. The AOs also enhanced the cytotoxicity of hydrogen peroxide and gamma-radiation, both of which can induce oxidative DNA lesions, which are subject to TCR. The AOs did not potentiate the cytotoxicity of topotecan, which induces DNA strand breaks. Chemically modified () AOs (MBOs) targeting CSB were able to potentiate the anti-tumor effect of cisplatin against A2780/CP70 tumor xenografts formed in nude mice. The MBOs enabled a non-toxic (3 mg/kg) dose of cisplatin to have the same degree of anti-tumor efficacy as a more toxic (5 mg/kg) cisplatin dose. Collectively, these results suggest that the CSB gene product may be viewed as an anti-cancer target. PMID:11713576

  1. Cigarette advertising in Mumbai, India: targeting different socioeconomic groups, women, and youth

    PubMed Central

    Bansal, R; John, S; Ling, P

    2005-01-01

    Background: Despite a recent surge in tobacco advertising and the recent advertising ban (pending enforcement at the time of this study), there are few studies describing current cigarette marketing in India. This study sought to assess cigarette companies' marketing strategies in Mumbai, India. Methods: A two week field study was conducted in Mumbai in September 2003, observing, documenting, and collecting cigarette advertising on billboards, storefronts and at point of sale along two major thoroughfares, and performing a content analysis of news, film industry, and women's magazines and three newspapers. Results: Cigarette advertising was ubiquitous in the environment, present in news and in film magazines, but not in women's magazines or the newspapers. The four major advertising campaigns all associated smoking with aspiration; the premium brands targeting the higher socioeconomic status market utilised tangible images of westernisation and affluence whereas the "bingo" (low priced) segment advertisements invited smokers to belong to a league of their own and "rise to the taste" using intangible images. Women were not depicted smoking, but were present in cigarette advertisements—for example, a woman almost always accompanied a man in "the man with the smooth edge" Four Square campaign. Advertisements and product placements at low heights and next to candies at point of sale were easily accessible by children. In view of the iminent enforcement of the ban on tobacco advertisements, cigarette companies are increasing advertising for the existing brand images, launching brand extensions, and brand stretching. Conclusion: Cigarette companies have developed sophisticated campaigns targeting men, women, and children in different socioeconomic groups. Many of these strategies circumvent the Indian tobacco advertising ban. Understanding these marketing strategies is critical to mimimise the exploitation of loopholes in tobacco control legislation. PMID:15923471

  2. The Oncogenic Polycomb Histone Methyltransferase EZH2 Methylates Lysine 120 on Histone H2B and Competes Ubiquitination12

    PubMed Central

    Kogure, Masaharu; Takawa, Masashi; Saloura, Vassiliki; Sone, Kenbun; Piao, Lianhua; Ueda, Koji; Ibrahim, Reem; Tsunoda, Tatsuhiko; Sugiyama, Masanori; Atomi, Yutaka; Nakamura, Yusuke; Hamamoto, Ryuji

    2013-01-01

    The histone methyltransferase enhancer of zeste 2 (EZH2) is known to be a polycomb protein homologous to Drosophila enhancer of zeste and catalyzes the addition of methyl groups to histone H3 at lysine 27 (H3K27). We previously reported that EZH2 was overexpressed in various types of cancer and plays a crucial role in the cell cycle regulation of cancer cells. In the present study, we demonstrated that EZH2 has the function to monomethylate lysine 120 on histone H2B (H2BK120). EZH2-dependent H2BK120 methylation in cancer cells was confirmed with an H2BK120 methylation-specific antibody. Overexpression of EZH2 significantly attenuated the ubiquitination of H2BK120, a key posttranslational modification of histones for transcriptional regulation. Concordantly, knockdown of EZH2 increased the ubiquitination level of H2BK120, suggesting that the methylation of H2BK120 by EZH2 may competitively inhibit the ubiquitination of H2BK120. Subsequent chromatin immunoprecipitation-Seq and microarray analyses identified downstream candidate genes regulated by EZH2 through the methylation of H2BK120. This is the first report to describe a novel substrate of EZH2, H2BK120, unveiling a new aspect of EZH2 functions in human carcinogenesis. PMID:24339737

  3. CpG island erosion, polycomb occupancy and sequence motif enrichment at bivalent promoters in mammalian embryonic stem cells

    PubMed Central

    Mantsoki, Anna; Devailly, Guillaume; Joshi, Anagha

    2015-01-01

    In embryonic stem (ES) cells, developmental regulators have a characteristic bivalent chromatin signature marked by simultaneous presence of both activation (H3K4me3) and repression (H3K27me3) signals and are thought to be in a ‘poised’ state for subsequent activation or silencing during differentiation. We collected eleven pairs (H3K4me3 and H3K27me3) of ChIP sequencing datasets in human ES cells and eight pairs in murine ES cells, and predicted high-confidence (HC) bivalent promoters. Over 85% of H3K27me3 marked promoters were bivalent in human and mouse ES cells. We found that (i) HC bivalent promoters were enriched for developmental factors and were highly likely to be differentially expressed upon transcription factor perturbation; (ii) murine HC bivalent promoters were occupied by both polycomb repressive component classes (PRC1 and PRC2) and grouped into four distinct clusters with different biological functions; (iii) HC bivalent and active promoters were CpG rich while H3K27me3-only promoters lacked CpG islands. Binding enrichment of distinct sets of regulators distinguished bivalent from active promoters. Moreover, a ‘TCCCC’ sequence motif was specifically enriched in bivalent promoters. Finally, this analysis will serve as a resource for future studies to further understand transcriptional regulation during embryonic development. PMID:26582124

  4. Towards an Optimal Design of Target for Tsetse Control: Comparisons of Novel Targets for the Control of Palpalis Group Tsetse in West Africa

    PubMed Central

    Rayaisse, Jean Baptiste; Esterhuizen, Johan; Tirados, Inaki; Kaba, Dramane; Salou, Ernest; Diarrassouba, Abdoulaye; Vale, Glyn A.; Lehane, Michael J.; Torr, Stephen J.; Solano, Philippe

    2011-01-01

    Background Tsetse flies of the Palpalis group are the main vectors of sleeping sickness in Africa. Insecticide impregnated targets are one of the most effective tools for control. However, the cost of these devices still represents a constraint to their wider use. The objective was therefore to improve the cost effectiveness of currently used devices. Methodology/Principal Findings Experiments were performed on three tsetse species, namely Glossina palpalis gambiensis and G. tachinoides in Burkina Faso and G. p. palpalis in Côte d'Ivoire. The 1×1 m2 black blue black target commonly used in W. Africa was used as the standard, and effects of changes in target size, shape, and the use of netting instead of black cloth were measured. Regarding overall target shape, we observed that horizontal targets (i.e. wider than they were high) killed 1.6-5x more G. p. gambiensis and G. tachinoides than vertical ones (i.e. higher than they were wide) (P<0.001). For the three tsetse species including G. p. palpalis, catches were highly correlated with the size of the target. However, beyond the size of 0.75 m, there was no increase in catches. Replacing the black cloth of the target by netting was the most cost efficient for all three species. Conclusion/Significance Reducing the size of the current 1*1 m black-blue-black target to horizontal designs of around 50 cm and replacing black cloth by netting will improve cost effectiveness six-fold for both G. p. gambiensis and G. tachinoides. Studying the visual responses of tsetse to different designs of target has allowed us to design more cost-effective devices for the effective control of sleeping sickness and animal trypanosomiasis in Africa. PMID:21949896

  5. Aspirin's Active Metabolite Salicylic Acid Targets High Mobility Group Box 1 to Modulate Inflammatory Responses.

    PubMed

    Choi, Hyong Woo; Tian, Miaoying; Song, Fei; Venereau, Emilie; Preti, Alessandro; Park, Sang-Wook; Hamilton, Keith; Swapna, G V T; Manohar, Murli; Moreau, Magali; Agresti, Alessandra; Gorzanelli, Andrea; De Marchis, Francesco; Wang, Huang; Antonyak, Marc; Micikas, Robert J; Gentile, Daniel R; Cerione, Richard A; Schroeder, Frank C; Montelione, Gaetano T; Bianchi, Marco E; Klessig, Daniel F

    2015-01-01

    Salicylic acid (SA) and its derivatives have been used for millennia to reduce pain, fever and inflammation. In addition, prophylactic use of acetylsalicylic acid, commonly known as aspirin, reduces the risk of heart attack, stroke and certain cancers. Because aspirin is rapidly de-acetylated by esterases in human plasma, much of aspirin's bioactivity can be attributed to its primary metabolite, SA. Here we demonstrate that human high mobility group box 1 (HMGB1) is a novel SA-binding protein. SA-binding sites on HMGB1 were identified in the HMG-box domains by nuclear magnetic resonance (NMR) spectroscopic studies and confirmed by mutational analysis. Extracellular HMGB1 is a damage-associated molecular pattern molecule (DAMP), with multiple redox states. SA suppresses both the chemoattractant activity of fully reduced HMGB1 and the increased expression of proinflammatory cytokine genes and cyclooxygenase 2 (COX-2) induced by disulfide HMGB1. Natural and synthetic SA derivatives with greater potency for inhibition of HMGB1 were identified, providing proof-of-concept that new molecules with high efficacy against sterile inflammation are attainable. An HMGB1 protein mutated in one of the SA-binding sites identified by NMR chemical shift perturbation studies retained chemoattractant activity, but lost binding of and inhibition by SA and its derivatives, thereby firmly establishing that SA binding to HMGB1 directly suppresses its proinflammatory activities. Identification of HMGB1 as a pharmacological target of SA/aspirin provides new insights into the mechanisms of action of one of the world's longest and most used natural and synthetic drugs. It may also provide an explanation for the protective effects of low-dose aspirin usage. PMID:26101955

  6. Aspirin's Active Metabolite Salicylic Acid Targets High Mobility Group Box 1 to Modulate Inflammatory Responses.

    PubMed

    Choi, Hyong Woo; Tian, Miaoying; Song, Fei; Venereau, Emilie; Preti, Alessandro; Park, Sang-Wook; Hamilton, Keith; Swapna, G V T; Manohar, Murli; Moreau, Magali; Agresti, Alessandra; Gorzanelli, Andrea; De Marchis, Francesco; Wang, Huang; Antonyak, Marc; Micikas, Robert J; Gentile, Daniel R; Cerione, Richard A; Schroeder, Frank C; Montelione, Gaetano T; Bianchi, Marco E; Klessig, Daniel F

    2015-06-18

    Salicylic acid (SA) and its derivatives have been used for millennia to reduce pain, fever and inflammation. In addition, prophylactic use of acetylsalicylic acid, commonly known as aspirin, reduces the risk of heart attack, stroke and certain cancers. Because aspirin is rapidly de-acetylated by esterases in human plasma, much of aspirin's bioactivity can be attributed to its primary metabolite, SA. Here we demonstrate that human high mobility group box 1 (HMGB1) is a novel SA-binding protein. SA-binding sites on HMGB1 were identified in the HMG-box domains by nuclear magnetic resonance (NMR) spectroscopic studies and confirmed by mutational analysis. Extracellular HMGB1 is a damage-associated molecular pattern molecule (DAMP), with multiple redox states. SA suppresses both the chemoattractant activity of fully reduced HMGB1 and the increased expression of proinflammatory cytokine genes and cyclooxygenase 2 (COX-2) induced by disulfide HMGB1. Natural and synthetic SA derivatives with greater potency for inhibition of HMGB1 were identified, providing proof-of-concept that new molecules with high efficacy against sterile inflammation are attainable. An HMGB1 protein mutated in one of the SA-binding sites identified by NMR chemical shift perturbation studies retained chemoattractant activity, but lost binding of and inhibition by SA and its derivatives, thereby firmly establishing that SA binding to HMGB1 directly suppresses its proinflammatory activities. Identification of HMGB1 as a pharmacological target of SA/aspirin provides new insights into the mechanisms of action of one of the world's longest and most used natural and synthetic drugs. It may also provide an explanation for the protective effects of low-dose aspirin usage.

  7. Histone H2A monoubiquitination promotes histone H3 methylation in Polycomb repression.

    PubMed

    Kalb, Reinhard; Latwiel, Sebastian; Baymaz, H Irem; Jansen, Pascal W T C; Müller, Christoph W; Vermeulen, Michiel; Müller, Jürg

    2014-06-01

    A key step in gene repression by Polycomb is trimethylation of histone H3 K27 by PCR2 to form H3K27me3. H3K27me3 provides a binding surface for PRC1. We show that monoubiquitination of histone H2A by PRC1-type complexes to form H2Aub creates a binding site for Jarid2-Aebp2-containing PRC2 and promotes H3K27 trimethylation on H2Aub nucleosomes. Jarid2, Aebp2 and H2Aub thus constitute components of a positive feedback loop establishing H3K27me3 chromatin domains.

  8. Internet-Delivered Targeted Group Intervention for Body Dissatisfaction and Disordered Eating in Adolescent Girls: A Randomized Controlled Trial

    ERIC Educational Resources Information Center

    Heinicke, Brooke E.; Paxton, Susan J.; McLean, Sian A.; Wertheim, Eleanor H.

    2007-01-01

    This study evaluated a targeted intervention designed to alleviate body image and eating problems in adolescent girls that was delivered over the internet so as to increase access to the program. The program consisted of six, 90-minute weekly small group, synchronous on-line sessions and was facilitated by a therapist and manual. Participants were…

  9. Polycomb-Mediated Repression and Sonic Hedgehog Signaling Interact to Regulate Merkel Cell Specification during Skin Development.

    PubMed

    Perdigoto, Carolina N; Dauber, Katherine L; Bar, Carmit; Tsai, Pai-Chi; Valdes, Victor J; Cohen, Idan; Santoriello, Francis J; Zhao, Dejian; Zheng, Deyou; Hsu, Ya-Chieh; Ezhkova, Elena

    2016-07-01

    An increasing amount of evidence indicates that developmental programs are tightly regulated by the complex interplay between signaling pathways, as well as transcriptional and epigenetic processes. Here, we have uncovered coordination between transcriptional and morphogen cues to specify Merkel cells, poorly understood skin cells that mediate light touch sensations. In murine dorsal skin, Merkel cells are part of touch domes, which are skin structures consisting of specialized keratinocytes, Merkel cells, and afferent neurons, and are located exclusively around primary hair follicles. We show that the developing primary hair follicle functions as a niche required for Merkel cell specification. We find that intraepidermal Sonic hedgehog (Shh) signaling, initiated by the production of Shh ligand in the developing hair follicles, is required for Merkel cell specification. The importance of Shh for Merkel cell formation is further reinforced by the fact that Shh overexpression in embryonic epidermal progenitors leads to ectopic Merkel cells. Interestingly, Shh signaling is common to primary, secondary, and tertiary hair follicles, raising the possibility that there are restrictive mechanisms that regulate Merkel cell specification exclusively around primary hair follicles. Indeed, we find that loss of Polycomb repressive complex 2 (PRC2) in the epidermis results in the formation of ectopic Merkel cells that are associated with all hair types. We show that PRC2 loss expands the field of epidermal cells competent to differentiate into Merkel cells through the upregulation of key Merkel-differentiation genes, which are known PRC2 targets. Importantly, PRC2-mediated repression of the Merkel cell differentiation program requires inductive Shh signaling to form mature Merkel cells. Our study exemplifies how the interplay between epigenetic and morphogen cues regulates the complex patterning and formation of the mammalian skin structures. PMID:27414999

  10. Polycomb-Mediated Repression and Sonic Hedgehog Signaling Interact to Regulate Merkel Cell Specification during Skin Development

    PubMed Central

    Bar, Carmit; Tsai, Pai-Chi; Valdes, Victor J.; Cohen, Idan; Santoriello, Francis J.; Zhao, Dejian; Hsu, Ya-Chieh; Ezhkova, Elena

    2016-01-01

    An increasing amount of evidence indicates that developmental programs are tightly regulated by the complex interplay between signaling pathways, as well as transcriptional and epigenetic processes. Here, we have uncovered coordination between transcriptional and morphogen cues to specify Merkel cells, poorly understood skin cells that mediate light touch sensations. In murine dorsal skin, Merkel cells are part of touch domes, which are skin structures consisting of specialized keratinocytes, Merkel cells, and afferent neurons, and are located exclusively around primary hair follicles. We show that the developing primary hair follicle functions as a niche required for Merkel cell specification. We find that intraepidermal Sonic hedgehog (Shh) signaling, initiated by the production of Shh ligand in the developing hair follicles, is required for Merkel cell specification. The importance of Shh for Merkel cell formation is further reinforced by the fact that Shh overexpression in embryonic epidermal progenitors leads to ectopic Merkel cells. Interestingly, Shh signaling is common to primary, secondary, and tertiary hair follicles, raising the possibility that there are restrictive mechanisms that regulate Merkel cell specification exclusively around primary hair follicles. Indeed, we find that loss of Polycomb repressive complex 2 (PRC2) in the epidermis results in the formation of ectopic Merkel cells that are associated with all hair types. We show that PRC2 loss expands the field of epidermal cells competent to differentiate into Merkel cells through the upregulation of key Merkel-differentiation genes, which are known PRC2 targets. Importantly, PRC2-mediated repression of the Merkel cell differentiation program requires inductive Shh signaling to form mature Merkel cells. Our study exemplifies how the interplay between epigenetic and morphogen cues regulates the complex patterning and formation of the mammalian skin structures. PMID:27414999

  11. Customer Systems Group 1996 target summaries. Industrial and agricultural technologies and services

    SciTech Connect

    1995-06-01

    The target summaries give planning information and budgets for EPRI programs, technology development and deployment, member services and partnerships, communication products, and customer technology infrastructure for ten different factions of Industrial and Agricultural Technologies and Services. They are materials fabrication, municipal water and waste water treatment, healthcare, materials production, food, chemicals and petroleum, pulp and paper, textiles, agriculture, and advanced electro-technologies.

  12. Conditional anterograde tracing reveals distinct targeting of individual serotonin cell groups (B5-B9) to the forebrain and brainstem.

    PubMed

    Muzerelle, Aude; Scotto-Lomassese, Sophie; Bernard, Jean François; Soiza-Reilly, Mariano; Gaspar, Patricia

    2016-01-01

    Serotoninergic innervation of the central nervous system is provided by hindbrain raphe nuclei (B1-B9). The extent to which each raphe subdivision has distinct topographic organization of their projections is still unclear. We provide a comprehensive description of the main targets of the rostral serotonin (5-HT) raphe subgroups (B5-B9) in the mouse brain. Adeno-associated viruses that conditionally express GFP under the control of the 5-HT transporter promoter were used to label small groups of 5-HT neurons in the dorsal (B7d), ventral (B7v), lateral (B7l), and caudal (B6) subcomponents of the dorsal raphe (DR) nucleus as well as in the rostral and caudal parts of the median raphe (MR) nucleus (B8 and B5, respectively), and in the supralemniscal (B9) cell group. We illustrate the distinctive and largely non-overlapping projection areas of these cell groups: for instance, DR (B7) projects to basal parts of the forebrain, such as the amygdala, whereas MR (B8) is the main 5-HT source to the hippocampus, septum, and mesopontine tegmental nuclei. Distinct subsets of B7 have preferential brain targets: B7v is the main source of 5-HT for the cortex and amygdala while B7d innervates the hypothalamus. We reveal for the first time the target areas of the B9 cell group, demonstrating projections to the caudate, prefrontal cortex, substantia nigra, locus coeruleus and to the raphe cell groups. The broad topographic organization of the different raphe subnuclei is likely to underlie the different functional roles in which 5-HT has been implicated in the brain. The present mapping study could serve as the basis for genetically driven specific targeting of the different subcomponents of the mouse raphe system.

  13. SWI/SNF mediates polycomb eviction and epigenetic reprogramming of the INK4b-ARF-INK4a locus.

    PubMed

    Kia, Sima Kheradmand; Gorski, Marcin M; Giannakopoulos, Stavros; Verrijzer, C Peter

    2008-05-01

    Stable silencing of the INK4b-ARF-INK4a tumor suppressor locus occurs in a variety of human cancers, including malignant rhabdoid tumors (MRTs). MRTs are extremely aggressive cancers caused by the loss of the hSNF5 subunit of the SWI/SNF chromatin-remodeling complex. We found previously that, in MRT cells, hSNF5 is required for p16(INK4a) induction, mitotic checkpoint activation, and cellular senescence. Here, we investigated how the balance between Polycomb group (PcG) silencing and SWI/SNF activation affects epigenetic control of the INK4b-ARF-INK4a locus in MRT cells. hSNF5 reexpression in MRT cells caused SWI/SNF recruitment and activation of p15(INK4b) and p16(INK4a), but not of p14(ARF). Gene activation by hSNF5 is strictly dependent on the SWI/SNF motor subunit BRG1. SWI/SNF mediates eviction of the PRC1 and PRC2 PcG silencers and extensive chromatin reprogramming. Concomitant with PcG complex removal, the mixed lineage leukemia 1 (MLL1) protein is recruited and active histone marks supplant repressive ones. Strikingly, loss of PcG complexes is accompanied by DNA methyltransferase DNMT3B dissociation and reduced DNA methylation. Thus, various chromatin states can be modulated by SWI/SNF action. Collectively, these findings emphasize the close interconnectivity and dynamics of diverse chromatin modifications in cancer and gene control. PMID:18332116

  14. The Drosophila eve insulator Homie promotes eve expression and protects the adjacent gene from repression by polycomb spreading.

    PubMed

    Fujioka, Miki; Sun, Guizhi; Jaynes, James B

    2013-10-01

    Insulators can block the action of enhancers on promoters and the spreading of repressive chromatin, as well as facilitating specific enhancer-promoter interactions. However, recent studies have called into question whether the activities ascribed to insulators in model transgene assays actually reflect their functions in the genome. The Drosophila even skipped (eve) gene is a Polycomb (Pc) domain with a Pc-group response element (PRE) at one end, flanked by an insulator, an arrangement also seen in other genes. Here, we show that this insulator has three major functions. It blocks the spreading of the eve Pc domain, preventing repression of the adjacent gene, TER94. It prevents activation of TER94 by eve regulatory DNA. It also facilitates normal eve expression. When Homie is deleted in the context of a large transgene that mimics both eve and TER94 regulation, TER94 is repressed. This repression depends on the eve PRE. Ubiquitous TER94 expression is "replaced" by expression in an eve pattern when Homie is deleted, and this effect is reversed when the PRE is also removed. Repression of TER94 is attributable to spreading of the eve Pc domain into the TER94 locus, accompanied by an increase in histone H3 trimethylation at lysine 27. Other PREs can functionally replace the eve PRE, and other insulators can block PRE-dependent repression in this context. The full activity of the eve promoter is also dependent on Homie, and other insulators can promote normal eve enhancer-promoter communication. Our data suggest that this is not due to preventing promoter competition, but is likely the result of the insulator organizing a chromosomal conformation favorable to normal enhancer-promoter interactions. Thus, insulator activities in a native context include enhancer blocking and enhancer-promoter facilitation, as well as preventing the spread of repressive chromatin.

  15. The Bmi-1 polycomb protein antagonizes the (-)-epigallocatechin-3-gallate-dependent suppression of skin cancer cell survival.

    PubMed

    Balasubramanian, Sivaprakasam; Adhikary, Gautam; Eckert, Richard L

    2010-03-01

    The polycomb group (PcG) proteins are epigenetic regulators of gene expression that enhance cell survival. This regulation is achieved via action of two multiprotein PcG complexes--PRC2 (EED) and PRC1 [B-cell-specific Moloney murine leukemia virus integration site 1 (Bmi-1)]. These complexes modulate gene expression by increasing histone methylation and reducing acetylation--leading to a closed chromatin conformation. Activity of these proteins is associated with increased cell proliferation and survival. We show increased expression of key PcG proteins in immortalized keratinocytes and skin cancer cell lines. We examine the role of two key PcG proteins, Bmi-1 and enhancer of zeste homolog 2 (Ezh2), and the impact of the active agent in green tea, (-)-epigallocatechin-3-gallate (EGCG), on the function of these regulators. EGCG treatment of SCC-13 cells reduces Bmi-1 and Ezh2 level and this is associated with reduced cell survival. The reduction in survival is associated with a global reduction in histone H3 lysine 27 trimethylation, a hallmark of PRC2 complex action. This change in PcG protein expression is associated with reduced expression of key proteins that enhance progression through the cell cycle [cyclin-dependent kinase (cdk)1, cdk2, cdk4, cyclin D1, cyclin E, cyclin A and cyclin B1] and increased expression of proteins that inhibit cell cycle progression (p21 and p27). Apoptosis is also enhanced, as evidenced by increased caspase 9, 8 and 3 cleavage and increased poly(adenosine diphosphate ribose) polymerase cleavage. EGCG treatment also increases Bax and suppresses Bcl-xL expression. Vector-mediated enhanced Bmi-1 expression reverses these EGCG-dependent changes. These findings suggest that green tea polyphenols reduce skin tumor cell survival by influencing PcG-mediated epigenetic regulatory mechanisms.

  16. Target gene enrichment in the cyclophyllidean cestodes, the most diverse group of tapeworms.

    PubMed

    Yuan, Hao; Jiang, Jiamei; Jiménez, Francisco Agustín; Hoberg, Eric P; Cook, Joseph A; Galbreath, Kurt E; Li, Chenhong

    2016-09-01

    The Cyclophyllidea is the most diverse order of tapeworms, encompassing species that infect all classes of terrestrial tetrapods including humans and domesticated animals. Available phylogenetic reconstructions based either on morphology or molecular data lack the resolution to allow scientists to either propose a solid taxonomy or infer evolutionary associations. Molecular markers available for the Cyclophyllidea mostly include ribosomal DNA and mitochondrial loci. In this study, we identified 3641 single-copy nuclear coding loci by comparing the genomes of Hymenolepis microstoma, Echinococcus granulosus and Taenia solium. We designed RNA baits based on the sequence of H. microstoma, and applied target enrichment and Illumina sequencing to test the utility of those baits to recover loci useful for phylogenetic analyses. We captured DNA from five species of tapeworms representing two families of cyclophyllideans. We obtained an average of 3284 (90%) of the targets from the test samples and then used captured sequences (2 181 361 bp in total; fragment size ranging from 301 to 6969 bp) to reconstruct a phylogeny for the five test species plus the three species for which genomic data are available. The results were consistent with the current consensus regarding cyclophyllidean relationships. To assess the potential for our method to yield informative genetic variation at intraspecific scales, we extracted 14 074 single nucleotide polymorphisms (SNPs) from alignments of four Arostrilepis macrocirrosa and two A. cooki and successfully inferred their relationships. The results showed that our target gene tools yield data sets that provide robust inferences at a range of taxonomic scales in the Cyclophyllidea. PMID:27037792

  17. Target marketing of tobacco and alcohol-related products to ethnic minority groups in the United States.

    PubMed

    Moore, D J; Williams, J D; Qualls, W J

    1996-01-01

    This paper examines whether increased consumption of tobacco and alcohol products by minority groups is a function of the target marketing campaigns directed at these groups by marketers, and whether such contributes to the perpetuation of racism. First, a description of the tobacco and alcohol consumption rates of blacks and Hispanics compared to whites is presented, including a comparative analysis of the health effects and mortality rates resulting from the consumption of tobacco and alcohol. Second, the paper examines specific marketing strategies of targeting tobacco and alcohol products to ethnic minority consumers. This is followed by a discussion of whether these practices are a deliberate strategy driven by racism or just the pursuit of profit. A framework for answering the question is provided. Finally, the paper assesses the prospects for change in the future, and analyzes specific needs for future research.

  18. Community-Based Long-Term Care Models, Target Groups, and Impacts on Service Use.

    ERIC Educational Resources Information Center

    Capitman, John A.

    1986-01-01

    Describes the intervention approaches, clients groups, and impacts on use of Medicaid and Medicare reimbursed services for five demonstrations included in the national evaluation of community-based long-term care. Only one project produced significant reductions in nursing home use. Unlike other projects, it identified potential clients through…

  19. Whole-Faculty Study Groups: Creating Professional Learning Communities That Target Student Learning. Third Edition

    ERIC Educational Resources Information Center

    Murphy, Carlene U.; Lick, Dale W.

    2004-01-01

    Used by hundreds of schools and school districts across the country, the Whole-Faculty Study Group (WFSG) System is a student-driven, holistic process for facilitating major staff development and schoolwide change. While providing a step-by-step methodology for the development and implementation of successful WFSGs, this newest edition of Murphy…

  20. Most at-risk populations: contextualising HIV prevention programmes targeting marginalised groups in Zanzibar, Tanzania.

    PubMed

    Ahmed, Naheed

    2014-09-01

    According to a 2009 UNAIDS report the HIV/AIDS prevalence rate in Zanzibar, Tanzania, is low in the general population (0.6%), but high among vulnerable groups, specifically sex workers (10.8%), injecting drug users (15.1%), and men who have sex with men (12.3%). In response to this concentrated epidemic, the Government of Zanzibar, international and local non-profit organisations have focused their prevention activities on these marginal populations. Although these efforts are beneficial in terms of disseminating information about HIV/AIDS and referring clients to health clinics, they fail to address how the socio-economic status of these groups places them at a greater risk for contracting and dying from the virus. Furthermore, there is an absence of qualitative research on these populations which is needed to understand the challenges these groups face and to improve the effectiveness of interventions. Through interviews with employees of government agencies and non-profit organisations, medical professionals, vulnerable populations and HIV/AIDS patients, this paper used a political economy of health and syndemic framework to examine how local realities inform and challenge HIV/AIDS programmes in Zanzibar.

  1. Most at-risk populations: contextualising HIV prevention programmes targeting marginalised groups in Zanzibar, Tanzania.

    PubMed

    Ahmed, Naheed

    2014-09-01

    According to a 2009 UNAIDS report the HIV/AIDS prevalence rate in Zanzibar, Tanzania, is low in the general population (0.6%), but high among vulnerable groups, specifically sex workers (10.8%), injecting drug users (15.1%), and men who have sex with men (12.3%). In response to this concentrated epidemic, the Government of Zanzibar, international and local non-profit organisations have focused their prevention activities on these marginal populations. Although these efforts are beneficial in terms of disseminating information about HIV/AIDS and referring clients to health clinics, they fail to address how the socio-economic status of these groups places them at a greater risk for contracting and dying from the virus. Furthermore, there is an absence of qualitative research on these populations which is needed to understand the challenges these groups face and to improve the effectiveness of interventions. Through interviews with employees of government agencies and non-profit organisations, medical professionals, vulnerable populations and HIV/AIDS patients, this paper used a political economy of health and syndemic framework to examine how local realities inform and challenge HIV/AIDS programmes in Zanzibar. PMID:25388975

  2. The spxB gene as a target to identify Lactobacillus casei group species in cheese.

    PubMed

    Savo Sardaro, Maria Luisa; Levante, Alessia; Bernini, Valentina; Gatti, Monica; Neviani, Erasmo; Lazzi, Camilla

    2016-10-01

    This study focused on the spxB gene, which encodes for pyruvate oxidase. The presence of spxB in the genome and its transcription could be a way to produce energy and allow bacterial growth during carbohydrate starvation. In addition, the activity of pyruvate oxidase, which produces hydrogen peroxide, could be a mechanism for interspecies competition. Because this gene seems to provide advantages for the encoding species for adaptation in complex ecosystems, we studied spxB in a large set of cheese isolates belonging to the Lactobacillus casei group. Through this study, we demonstrated that this gene is widely found in the genomes of members of the L. casei group and shows variability useful for taxonomic studies. In particular, the HRM analysis method allowed for a specific discrimination between Lactobacillus rhamnosus, Lactobacillus paracasei and L. casei. Regarding the coding region, the spxB functionality in cheese was shown for the first time by real-time PCR, and by exploiting the heterogeneity between the L. casei group species, we identified the bacterial communities encoding the spxB gene in this ecosystem. This study allowed for monitoring of the active bacterial community involved in different stages of ripening by following the POX pathway. PMID:27375244

  3. Functional Crosstalk Between Lysine Methyltransferases on Histone Substrates: The Case of G9A/GLP and Polycomb Repressive Complex 2

    PubMed Central

    Pontis, Julien

    2015-01-01

    Abstract Significance: Methylation of histone H3 on lysine 9 and 27 (H3K9 and H3K27) are two epigenetic modifications that have been linked to several crucial biological processes, among which are transcriptional silencing and cell differentiation. Recent Advances: Deposition of these marks is catalyzed by H3K9 lysine methyltransferases (KMTs) and polycomb repressive complex 2, respectively. Increasing evidence is emerging in favor of a functional crosstalk between these two major KMT families. Critical Issues: Here, we review the current knowledge on the mechanisms of action and function of these enzymes, with particular emphasis on their interplay in the regulation of chromatin states and biological processes. We outline their crucial roles played in tissue homeostasis, by controlling the fate of embryonic and tissue-specific stem cells, highlighting how their deregulation is often linked to the emergence of a number of malignancies and neurological disorders. Future Directions: Histone methyltransferases are starting to be tested as drug targets. A new generation of highly selective chemical inhibitors is starting to emerge. These hold great promise for a rapid translation of targeting epigenetic drugs into clinical practice for a number of aggressive cancers and neurological disorders. Antioxid. Redox Signal. 22, 1365–1381. PMID:25365549

  4. Reprogramming of Polycomb-Mediated Gene Silencing in Embryonic Stem Cells by the miR-290 Family and the Methyltransferase Ash1l

    PubMed Central

    Kanellopoulou, Chryssa; Gilpatrick, Timothy; Kilaru, Gokhul; Burr, Patrick; Nguyen, Cuong K.; Morawski, Aaron; Lenardo, Michael J.; Muljo, Stefan A.

    2015-01-01

    Summary Members of the miR-290 family are the most abundantly expressed microRNAs (miRNAs) in mouse embryonic stem cells (ESCs). They regulate aspects of differentiation, pluripotency, and proliferation of ESCs, but the molecular program that they control has not been fully delineated. In the absence of Dicer, ESCs fail to express mature miR-290 miRNAs and have selective aberrant overexpression of Hoxa, Hoxb, Hoxc, and Hoxd genes essential for body plan patterning during embryogenesis, but they do not undergo a full differentiation program. Introduction of mature miR-291 into DCR−/− ESCs restores Hox gene silencing. This was attributed to the unexpected regulation of Polycomb-mediated gene targeting by miR-291. We identified the methyltransferase Ash1l as a pivotal target of miR-291 mediating this effect. Collectively, our data shed light on the role of Dicer in ESC homeostasis by revealing a facet of molecular regulation by the miR-290 family. PMID:26549848

  5. Elective Clinical Target Volumes for Conformal Therapy in Anorectal Cancer: A Radiation Therapy Oncology Group Consensus Panel Contouring Atlas

    SciTech Connect

    Myerson, Robert J. Garofalo, Michael C.; El Naqa, Issam; Abrams, Ross A.; Apte, Aditya; Bosch, Walter R.; Das, Prajnan; Gunderson, Leonard L.; Hong, Theodore S.; Kim, J.J. John; Willett, Christopher G.; Kachnic, Lisa A.

    2009-07-01

    Purpose: To develop a Radiation Therapy Oncology Group (RTOG) atlas of the elective clinical target volume (CTV) definitions to be used for planning pelvic intensity-modulated radiotherapy (IMRT) for anal and rectal cancers. Methods and Materials: The Gastrointestinal Committee of the RTOG established a task group (the nine physician co-authors) to develop this atlas. They responded to a questionnaire concerning three elective CTVs (CTVA: internal iliac, presacral, and perirectal nodal regions for both anal and rectal case planning; CTVB: external iliac nodal region for anal case planning and for selected rectal cases; CTVC: inguinal nodal region for anal case planning and for select rectal cases), and to outline these areas on individual computed tomographic images. The imaging files were shared via the Advanced Technology Consortium. A program developed by one of the co-authors (I.E.N.) used binomial maximum-likelihood estimates to generate a 95% group consensus contour. The computer-estimated consensus contours were then reviewed by the group and modified to provide a final contouring consensus atlas. Results: The panel achieved consensus CTV definitions to be used as guidelines for the adjuvant therapy of rectal cancer and definitive therapy for anal cancer. The most important difference from similar atlases for gynecologic or genitourinary cancer is mesorectal coverage. Detailed target volume contouring guidelines and images are discussed. Conclusion: This report serves as a template for the definition of the elective CTVs to be used in IMRT planning for anal and rectal cancers, as part of prospective RTOG trials.

  6. Polycomb repressive complex 2 regulates skeletal growth by suppressing Wnt and TGF-β signalling

    PubMed Central

    Mirzamohammadi, Fatemeh; Papaioannou, Garyfallia; Inloes, Jennifer B.; Rankin, Erinn B.; Xie, Huafeng; Schipani, Ernestina; Orkin, Stuart H.; Kobayashi, Tatsuya

    2016-01-01

    Polycomb repressive complex 2 (PRC2) controls maintenance and lineage determination of stem cells by suppressing genes that regulate cellular differentiation and tissue development. However, the role of PRC2 in lineage-committed somatic cells is mostly unknown. Here we show that Eed deficiency in chondrocytes causes severe kyphosis and a growth defect with decreased chondrocyte proliferation, accelerated hypertrophic differentiation and cell death with reduced Hif1a expression. Eed deficiency also causes induction of multiple signalling pathways in chondrocytes. Wnt signalling overactivation is responsible for the accelerated hypertrophic differentiation and kyphosis, whereas the overactivation of TGF-β signalling is responsible for the reduced proliferation and growth defect. Thus, our study demonstrates that PRC2 has an important regulatory role in lineage-committed tissue cells by suppressing overactivation of multiple signalling pathways. PMID:27329220

  7. Ikaros mediates gene silencing in T cells through Polycomb repressive complex 2

    PubMed Central

    Oravecz, Attila; Apostolov, Apostol; Polak, Katarzyna; Jost, Bernard; Le Gras, Stéphanie; Chan, Susan; Kastner, Philippe

    2015-01-01

    T-cell development is accompanied by epigenetic changes that ensure the silencing of stem cell-related genes and the activation of lymphocyte-specific programmes. How transcription factors influence these changes remains unclear. We show that the Ikaros transcription factor forms a complex with Polycomb repressive complex 2 (PRC2) in CD4−CD8− thymocytes and allows its binding to more than 500 developmentally regulated loci, including those normally activated in haematopoietic stem cells and others induced by the Notch pathway. Loss of Ikaros in CD4−CD8− cells leads to reduced histone H3 lysine 27 trimethylation and ectopic gene expression. Furthermore, Ikaros binding triggers PRC2 recruitment and Ikaros interacts with PRC2 independently of the nucleosome remodelling and deacetylation complex. Our results identify Ikaros as a fundamental regulator of PRC2 function in developing T cells. PMID:26549758

  8. [PRODUCT OF THE BMI1--A KEY COMPONENT OF POLYCOMB--POSITIVELY REGULATES ADIPOCYTE DIFFERENTIATION OF MOUSE MESENCHYMAL STEM CELLS].

    PubMed

    Petrov, N S; Vereschagina, N A; Sushilova, E N; Kropotov, A V; Miheeva, N F; Popov, B V

    2016-01-01

    Bmil is a key component of Polycomb (PcG), which in mammals controls the basic functions of mammalian somatic stem cells (SSC) such as self-renewal and differentiation. Bmi1 supports SSC via transcriptional suppression of genes associated with cell cycle and differentiation. The most studied target genes of Bmi1 are the genes of Ink4 locus, CdkI p16(Ink4a) and p1(Arf), suppression of which due to activating mutations of the BMI1 results in formation of cancer stem cells (CSC) and carcinomas in various tissues. In contrast, inactivation of BMI1 results in cell cycle arrest and cell senescence. Although clinical phenomena of hypo- and hyperactivation of BMI1 are well known, its targets and mechanisms of regulation of tissue specific SSC are still obscure. The goal of this study was to evaluate the regulatory role of BMI1 in adipocyte differentiation (AD) of mouse mesenchymal stem cells (MSC). Induction of AD in mouse MSC of the C3H10T1/2 cell line was associated with an increase in the expression levels of BMI1, the genes of pRb family (RB, p130) and demethylase UTX, but not methyltransferase EZH2, whose products regulate the methylation levels of H3K27. It was observed earlier that H3K27me3 may play the role of the epigenetic switch by promoting AD of human MSC via activating expression of the PPARγ2, the master gene of AD (Hemming et al., 2014). Here we show that inactivation of BMI1 using specific siRNA slows and decreases the levels of AD, but does not abolish it. This is associated with a complete inhibition of the expression of adipogenic marker genes--PPARγ2, ADIPOQ and a decrease in the expression of RB, p130, but not UTX. The results obtained give evidence that the epigenetic mechanism regulating AD differentiation in mouse and human MSC is different.

  9. Isolation and identification of Pseudomonas syringae facilitated by a PCR targeting the whole P. syringae group.

    PubMed

    Guilbaud, Caroline; Morris, Cindy E; Barakat, Mohamed; Ortet, Philippe; Berge, Odile

    2016-01-01

    We present a reliable PCR-based method to avoid the biases related to identification based on the conventional phenotypes currently used in the identification of Pseudomonas syringae sensu lato, a ubiquitous environmental bacterium including plant pathogens. We identified a DNA target suitable for this purpose by applying a comparative genomic pipeline to Pseudomonas genomes. We designed primers and developed PCR conditions that led to a clean and strong PCR product from 97% of the 185 strains of P. syringae strains tested and gave a clear negative result for the 31 non-P. syringae strains tested. The sensitivity of standard PCR was determined with pure strains to be 10(6) bacteria mL(-1) or 0.4 ng of DNA μL(-1). Sensitivity could be improved with the touchdown method. The new PCR-assisted isolation of P. syringae was efficient when deployed on an environmental sample of river water as compared to the isolation based on phenotypes. This innovation eliminates the need for extensive expertise in isolating P. syringae colonies, was simpler, faster and very reliable. It will facilitate discovery of more diversity of P. syringae and research on emergence, dispersion and evolution to understand the varied functions of this environmental bacterium. PMID:26610434

  10. Group I Paks as therapeutic targets in NF2-deficient meningioma

    PubMed Central

    Duron, Sergio G.; Campbell, David A.; Ong, Christy C.; Hoeflich, Klaus P.; Chang, Long-Sheng; Welling, D. Bradley; Yang, Zeng-jie; Chernoff, Jonathan

    2015-01-01

    Neurofibromatosis type 2 (NF2) is an autosomal dominant disorder characterized by the development of multiple tumors in the central nervous system, most notably schwannomas and meningiomas. Mutational inactivation of NF2 is found in 40–60% of sporadic meningiomas, but the molecular mechanisms underlying malignant changes of meningioma cells remain unclear. Because group I p21-activated kinases (Paks) bind to and are inhibited by the NF2-encoded protein Merlin, we assessed the signaling and anti-tumor effects of three group-I specific Pak inhibitors - Frax597, 716 and 1036 - in NF2−/− meningiomas in vitro and in an orthotopic mouse model. We found that these Pak inhibitors suppressed the proliferation and motility of both benign (Ben-Men1) and malignant (KT21-MG1) meningiomas cells. In addition, we found a strong reduction in phosphorylation of Mek and S6, and decreased cyclin D1 expression in both cell lines after treatment with Pak inhibitors. Using intracranial xenografts of luciferase-expressing KT21-MG1 cells, we found that treated mice showed significant tumor suppression for all three Pak inhibitors. Similar effects were observed in Ben-Men1 cells. Tumors dissected from treated animals exhibited an increase in apoptosis without notable change in proliferation. Collectively, these results suggest that Pak inhibitors might be useful agents in treating NF2-deficient meningiomas. PMID:25596744

  11. Yeast Enhancer of Polycomb defines global Esa1-dependent acetylation of chromatin

    PubMed Central

    Boudreault, Alexandre A.; Cronier, Dominique; Selleck, William; Lacoste, Nicolas; Utley, Rhea T.; Allard, Stéphane; Savard, Julie; Lane, William S.; Tan, Song; Côté, Jacques

    2003-01-01

    Drosophila Enhancer of Polycomb, E(Pc), is a suppressor of position-effect variegation and an enhancer of both Polycomb and trithorax mutations. A homologous yeast protein, Epl1, is a subunit of the NuA4 histone acetyltransferase complex. Epl1 depletion causes cells to accumulate in G2/M and global loss of acetylated histones H4 and H2A. In relation to the Drosophila protein, mutation of Epl1 suppresses gene silencing by telomere position effect. Epl1 protein is found in the NuA4 complex and a novel highly active smaller complex named Piccolo NuA4 (picNuA4). The picNuA4 complex contains Esa1, Epl1, and Yng2 as subunits and strongly prefers chromatin over free histones as substrate. Epl1 conserved N-terminal domain bridges Esa1 and Yng2 together, stimulating Esa1 catalytic activity and enabling acetylation of chromatin substrates. A recombinant picNuA4 complex shows characteristics similar to the native complex, including strong chromatin preference. Cells expressing only the N-terminal half of Epl1 lack NuA4 HAT activity, but possess picNuA4 complex and activity. These results indicate that the essential aspect of Esa1 and Epl1 resides in picNuA4 function. We propose that picNuA4 represents a nontargeted histone H4/H2A acetyltransferase activity responsible for global acetylation, whereas the NuA4 complex is recruited to specific genomic loci to perturb locally the dynamic acetylation/deacetylation equilibrium. PMID:12782659

  12. Mariner Transposons Contain a Silencer: Possible Role of the Polycomb Repressive Complex 2

    PubMed Central

    Beauclair, Linda; Moiré, Nathalie; Arensbuger, Peter; Bigot, Yves

    2016-01-01

    Transposable elements are driving forces for establishing genetic innovations such as transcriptional regulatory networks in eukaryotic genomes. Here, we describe a silencer situated in the last 300 bp of the Mos1 transposase open reading frame (ORF) which functions in vertebrate and arthropod cells. Functional silencers are also found at similar locations within three other animal mariner elements, i.e. IS630-Tc1-mariner (ITm) DD34D elements, Himar1, Hsmar1 and Mcmar1. These silencers are able to impact eukaryotic promoters monitoring strong, moderate or low expression as well as those of mariner elements located upstream of the transposase ORF. We report that the silencing involves at least two transcription factors (TFs) that are conserved within animal species, NFAT-5 and Alx1. These cooperatively act with YY1 to trigger the silencing activity. Four other housekeeping transcription factors (TFs), neuron restrictive silencer factor (NRSF), GAGA factor (GAF) and GTGT factor (GTF), were also found to have binding sites within mariner silencers but their impact in modulating the silencer activity remains to be further specified. Interestingly, an NRSF binding site was found to overlap a 30 bp motif coding a highly conserved PHxxYSPDLAPxD peptide in mariner transposases. We also present experimental evidence that silencing is mainly achieved by co-opting the host Polycomb Repressive Complex 2 pathway. However, we observe that when PRC2 is impaired another host silencing pathway potentially takes over to maintain weak silencer activity. Mariner silencers harbour features of Polycomb Response Elements, which are probably a way for mariner elements to self-repress their transcription and mobility in somatic and germinal cells when the required TFs are expressed. At the evolutionary scale, mariner elements, through their exaptation, might have been a source of silencers playing a role in the chromatin configuration in eukaryotic genomes. PMID:26939020

  13. Maintenance of leukemic cell identity by the activity of the Polycomb complex PRC1 in mice

    PubMed Central

    Rossi, Alessandra; Ferrari, Karin J.; Piunti, Andrea; Jammula, SriGanesh; Chiacchiera, Fulvio; Mazzarella, Luca; Scelfo, Andrea; Pelicci, Pier Giuseppe; Pasini, Diego

    2016-01-01

    Leukemia is a complex heterogeneous disease often driven by the expression of oncogenic fusion proteins with different molecular and biochemical properties. Whereas several fusion proteins induce leukemogenesis by activating Hox gene expression (Hox-activating fusions), others impinge on different pathways that do not involve the activation of Hox genes (non–Hox-activating fusions). It has been postulated that one of the main oncogenic properties of the HOXA9 transcription factor is its ability to control the expression of the p16/p19 tumor suppressor locus (Cdkn2a), thereby compensating Polycomb-mediated repression, which is dispensable for leukemias induced by Hox-activating fusions. We show, by genetically depleting the H2A ubiquitin ligase subunits of the Polycomb repressive complex 1 (PRC1), Ring1a and Ring1b, that Hoxa9 activation cannot repress Cdkn2a expression in the absence of PRC1 and its dependent deposition of H2AK119 monoubiquitination (H2AK119Ub). This demonstrates the essential role of PRC1 activity in supporting the oncogenic potential of Hox-activating fusion proteins. By combining genetic tools with genome-wide location and transcription analyses, we further show that PRC1 activity is required for the leukemogenic potential of both Hox-activating and non–Hox-activating fusions, thus preventing the differentiation of leukemic cells independently of the expression of the Cdkn2a locus. Overall, our results genetically demonstrate that PRC1 activity and the deposition of H2AK119Ub are critical factors that maintain the undifferentiated identity of cancer cells, positively sustaining the progression of different types of leukemia. PMID:27730210

  14. Polycomb repressive complex 2-dependent and -independent functions of Jarid2 in transcriptional regulation in Drosophila.

    PubMed

    Herz, Hans-Martin; Mohan, Man; Garrett, Alexander S; Miller, Caitlynn; Casto, David; Zhang, Ying; Seidel, Christopher; Haug, Jeffrey S; Florens, Laurence; Washburn, Michael P; Yamaguchi, Masamitsu; Shiekhattar, Ramin; Shilatifard, Ali

    2012-05-01

    Jarid2 was recently identified as an important component of the mammalian Polycomb repressive complex 2 (PRC2), where it has a major effect on PRC2 recruitment in mouse embryonic stem cells. Although Jarid2 is conserved in Drosophila, it has not previously been implicated in Polycomb (Pc) regulation. Therefore, we purified Drosophila Jarid2 and its associated proteins and found that Jarid2 associates with all of the known canonical PRC2 components, demonstrating a conserved physical interaction with PRC2 in flies and mammals. Furthermore, in vivo studies with Jarid2 mutants in flies demonstrate that among several histone modifications tested, only methylation of histone 3 at K27 (H3K27), the mark implemented by PRC2, was affected. Genome-wide profiling of Jarid2, Su(z)12 (Suppressor of zeste 12), and H3K27me3 occupancy by chromatin immunoprecipitation with sequencing (ChIP-seq) indicates that Jarid2 and Su(z)12 have very similar distribution patterns on chromatin. However, Jarid2 and Su(z)12 occupancy levels at some genes are significantly different, with Jarid2 being present at relatively low levels at many Pc response elements (PREs) of certain Homeobox (Hox) genes, providing a rationale for why Jarid2 was never identified in Pc screens. Gene expression analyses show that Jarid2 and E(z) (Enhancer of zeste, a canonical PRC2 component) are not only required for transcriptional repression but might also function in active transcription. Identification of Jarid2 as a conserved PRC2 interactor in flies provides an opportunity to begin to probe some of its novel functions in Drosophila development.

  15. Toward the identification of methanogenic archaeal groups as targets of methane mitigation in livestock animalsr

    PubMed Central

    St-Pierre, Benoit; Cersosimo, Laura M.; Ishaq, Suzanne L.; Wright, André-Denis G.

    2015-01-01

    In herbivores, enteric methane is a by-product from the digestion of plant biomass by mutualistic gastrointestinal tract (GIT) microbial communities. Methane is a potent greenhouse gas that is not assimilated by the host and is released into the environment where it contributes to climate change. Since enteric methane is exclusively produced by methanogenic archaea, the investigation of mutualistic methanogen communities in the GIT of herbivores has been the subject of ongoing research by a number of research groups. In an effort to uncover trends that would facilitate the development of efficient methane mitigation strategies for livestock species, we have in this review summarized and compared currently available results from published studies on this subject. We also offer our perspectives on the importance of pursuing current research efforts on the sequencing of gut methanogen genomes, as well as investigating their cellular physiology and interactions with other GIT microorganisms. PMID:26284054

  16. Refocusing resolution based on negative refractive-photonic crystal group with Ag defects for target detection and imaging

    NASA Astrophysics Data System (ADS)

    Lian, Yingfei; Zhu, Na; Fang, Yuntuan; Sun, Jiwen; Chen, Junlv; Qian, Huili

    2015-03-01

    Negative refractive-photonic crystal (NR-PC) lenses that can exceed the diffraction limit of focus resolution for imaging and target detection in the near field have gotten more and more special attention in recent years. Three flat lens groups with Ag defects based on NR-PC are designed, and the focusing imaging in the NR-PC three flat lens groups is concluded with the extension of Snell's law, and the influence on the resolution for a target detection dynamic scanning scheme is simulated by using the finite difference time domain method. An optimal-doped structure with Ag defects is achieved by different simulation combinations. The refocusing resolution 0.18834λ is achieved in the optimal structure and there is approximately a 0.06806λ improvement in the refocusing resolution compared to those undoped with Ag (0.2564λ) it also possesses distinct smaller side-lobes than a single flat lens doped with Ag. This means the optimal detecting ability for the three NR-PC flat lens groups with Ag defects is more improved than that for a single undoped and doped with Ag. This is significant for the perfect imaging being achieved for a particle structure.

  17. Molecular Identification of Soil Eukaryotes and Focused Approaches Targeting Protist and Faunal Groups Using High-Throughput Metabarcoding.

    PubMed

    Arjen de Groot, G; Laros, Ivo; Geisen, Stefan

    2016-01-01

    While until recently the application of high-throughput sequencing approaches has mostly been restricted to bacteria and fungi, these methods have now also become available to less often studied (eukaryotic) groups, such as fauna and protists. Such approaches allow routine diversity screening for large numbers of samples via DNA metabarcoding. Given the enormous taxonomic diversity within the eukaryote tree of life, metabarcoding approaches targeting a single specific DNA region do not allow to discriminate members of all eukaryote clades at high taxonomic resolution. Here, we report on protocols that enable studying the diversity of soil eukaryotes and, at high taxonomic resolution, of individual faunal and protist groups therein using a tiered approach: first, the use of a general eukaryotic primer set targeting a wide range of eukaryotes provides a rough impression on the entire diversity of protists and faunal groups. Second, more focused approaches enable deciphering subsets of soil eukaryotes in higher taxonomic detail. We provide primers and protocols for two examples: soil microarthropods and cercozoan protists.

  18. Developing clinical practice guidelines: target audiences, identifying topics for guidelines, guideline group composition and functioning and conflicts of interest.

    PubMed

    Eccles, Martin P; Grimshaw, Jeremy M; Shekelle, Paul; Schünemann, Holger J; Woolf, Steven

    2012-07-04

    Clinical practice guidelines are one of the foundations of efforts to improve health care. In 1999, we authored a paper about methods to develop guidelines. Since it was published, the methods of guideline development have progressed both in terms of methods and necessary procedures and the context for guideline development has changed with the emergence of guideline clearing houses and large scale guideline production organisations (such as the UK National Institute for Health and Clinical Excellence). It therefore seems timely to, in a series of three articles, update and extend our earlier paper. In this first paper we discuss: the target audience(s) for guidelines and their use of guidelines; identifying topics for guidelines; guideline group composition (including consumer involvement) and the processes by which guideline groups function and the important procedural issue of managing conflicts of interest in guideline development.

  19. Distinct Cellular Assembly Stoichiometry of Polycomb Complexes on Chromatin Revealed by Single-molecule Chromatin Immunoprecipitation Imaging.

    PubMed

    Tatavosian, Roubina; Zhen, Chao Yu; Duc, Huy Nguyen; Balas, Maggie M; Johnson, Aaron M; Ren, Xiaojun

    2015-11-20

    Epigenetic complexes play an essential role in regulating chromatin structure, but information about their assembly stoichiometry on chromatin within cells is poorly understood. The cellular assembly stoichiometry is critical for appreciating the initiation, propagation, and maintenance of epigenetic inheritance during normal development and in cancer. By combining genetic engineering, chromatin biochemistry, and single-molecule fluorescence imaging, we developed a novel and sensitive approach termed single-molecule chromatin immunoprecipitation imaging (Sm-ChIPi) to enable investigation of the cellular assembly stoichiometry of epigenetic complexes on chromatin. Sm-ChIPi was validated by using chromatin complexes with known stoichiometry. The stoichiometry of subunits within a polycomb complex and the assembly stoichiometry of polycomb complexes on chromatin have been extensively studied but reached divergent views. Moreover, the cellular assembly stoichiometry of polycomb complexes on chromatin remains unexplored. Using Sm-ChIPi, we demonstrated that within mouse embryonic stem cells, one polycomb repressive complex (PRC) 1 associates with multiple nucleosomes, whereas two PRC2s can bind to a single nucleosome. Furthermore, we obtained direct physical evidence that the nucleoplasmic PRC1 is monomeric, whereas PRC2 can dimerize in the nucleoplasm. We showed that ES cell differentiation induces selective alteration of the assembly stoichiometry of Cbx2 on chromatin but not other PRC1 components. We additionally showed that the PRC2-mediated trimethylation of H3K27 is not required for the assembly stoichiometry of PRC1 on chromatin. Thus, these findings uncover that PRC1 and PRC2 employ distinct mechanisms to assemble on chromatin, and the novel Sm-ChIPi technique could provide single-molecule insight into other epigenetic complexes.

  20. Distinct Cellular Assembly Stoichiometry of Polycomb Complexes on Chromatin Revealed by Single-molecule Chromatin Immunoprecipitation Imaging.

    PubMed

    Tatavosian, Roubina; Zhen, Chao Yu; Duc, Huy Nguyen; Balas, Maggie M; Johnson, Aaron M; Ren, Xiaojun

    2015-11-20

    Epigenetic complexes play an essential role in regulating chromatin structure, but information about their assembly stoichiometry on chromatin within cells is poorly understood. The cellular assembly stoichiometry is critical for appreciating the initiation, propagation, and maintenance of epigenetic inheritance during normal development and in cancer. By combining genetic engineering, chromatin biochemistry, and single-molecule fluorescence imaging, we developed a novel and sensitive approach termed single-molecule chromatin immunoprecipitation imaging (Sm-ChIPi) to enable investigation of the cellular assembly stoichiometry of epigenetic complexes on chromatin. Sm-ChIPi was validated by using chromatin complexes with known stoichiometry. The stoichiometry of subunits within a polycomb complex and the assembly stoichiometry of polycomb complexes on chromatin have been extensively studied but reached divergent views. Moreover, the cellular assembly stoichiometry of polycomb complexes on chromatin remains unexplored. Using Sm-ChIPi, we demonstrated that within mouse embryonic stem cells, one polycomb repressive complex (PRC) 1 associates with multiple nucleosomes, whereas two PRC2s can bind to a single nucleosome. Furthermore, we obtained direct physical evidence that the nucleoplasmic PRC1 is monomeric, whereas PRC2 can dimerize in the nucleoplasm. We showed that ES cell differentiation induces selective alteration of the assembly stoichiometry of Cbx2 on chromatin but not other PRC1 components. We additionally showed that the PRC2-mediated trimethylation of H3K27 is not required for the assembly stoichiometry of PRC1 on chromatin. Thus, these findings uncover that PRC1 and PRC2 employ distinct mechanisms to assemble on chromatin, and the novel Sm-ChIPi technique could provide single-molecule insight into other epigenetic complexes. PMID:26381410

  1. The SAND domain protein ULTRAPETALA1 acts as a trithorax group factor to regulate cell fate in plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During development, trithorax group (trxG) chromatin remodeling complexes counteract repression by Polycomb group (PcG) complexes to sustain active expression of key regulatory genes. Although PcG complexes are well characterized in plants, little is known about trxG activities. Here we demonstrate ...

  2. Regulation of human epidermal stem cell proliferation and senescence requires polycomb- dependent and -independent functions of Cbx4.

    PubMed

    Luis, Nuno Miguel; Morey, Lluis; Mejetta, Stefania; Pascual, Gloria; Janich, Peggy; Kuebler, Bernd; Cozutto, Luca; Roma, Guglielmo; Nascimento, Elisabete; Frye, Michaela; Di Croce, Luciano; Benitah, Salvador Aznar

    2011-09-01

    Human epidermal stem cells transit from a slow cycling to an actively proliferating state to contribute to homeostasis. Both stem cell states differ in their cell cycle profiles but must remain guarded from differentiation and senescence. Here we show that Cbx4, a Polycomb Repressive Complex 1 (PRC1)-associated protein, maintains human epidermal stem cells as slow-cycling and undifferentiated, while protecting them from senescence. Interestingly, abrogating the polycomb activity of Cbx4 impairs its antisenescent function without affecting stem cell differentiation, indicating that differentiation and senescence are independent processes in human epidermis. Conversely, Cbx4 inhibits stem cell activation and differentiation through its SUMO ligase activity. Global transcriptome and chromatin occupancy analyses indicate that Cbx4 regulates modulators of epidermal homeostasis and represses factors such as Ezh2, Dnmt1, and Bmi1 to prevent the active stem cell state. Our results suggest that distinct Polycomb complexes balance epidermal stem cell dormancy and activation, while continually preventing senescence and differentiation. PMID:21885019

  3. Propagation of trimethylated H3K27 regulated by polycomb protein EED is required for embryogenesis, hematopoietic maintenance, and tumor suppression.

    PubMed

    Ueda, Takeshi; Nakata, Yuichiro; Nagamachi, Akiko; Yamasaki, Norimasa; Kanai, Akinori; Sera, Yasuyuki; Sasaki, Masato; Matsui, Hirotaka; Honda, Zen-Ichiro; Oda, Hideaki; Wolff, Linda; Inaba, Toshiya; Honda, Hiroaki

    2016-09-13

    Polycomb repressive complex 2 (PRC2) catalyzes the monomethylation, dimethylation, and trimethylation of histone H3 Lys27 (H3K27) and acts as a central epigenetic regulator that marks the repressive chromatin domain. Embryonic ectoderm development (EED), an essential component of PRC2, interacts with trimethylated H3K27 (H3K27me3) through the aromatic cage structure composed of its three aromatic amino acids, Phe97, Trp364, and Tyr365. This interaction allosterically activates the histone methyltransferase activity of PRC2 and thereby propagates repressive histone marks. In this study, we report the analysis of knock-in mice harboring the myeloid disorder-associated EED Ile363Met (I363M) mutation, analogous to the EED aromatic cage mutants. The I363M homozygotes displayed a remarkable and preferential reduction of H3K27me3 and died at midgestation. The heterozygotes increased the clonogenic capacity and bone marrow repopulating activity of hematopoietic stem/progenitor cells (HSPCs) and were susceptible to leukemia. Lgals3, a PRC2 target gene encoding a multifunctional galactose-binding lectin, was derepressed in I363M heterozygotes, which enhanced the stemness of HSPCs. Thus, our work provides in vivo evidence that the structural integrity of EED to H3K27me3 propagation is critical, especially for embryonic development and hematopoietic homeostasis, and that its perturbation increases the predisposition to hematologic malignancies. PMID:27578866

  4. B-cell-specific Moloney murine leukemia virus integration site 1: potential stratification factor and therapeutic target for epithelial ovarian cancer.

    PubMed

    Zhao, Qianying; Gui, Ting; Qian, Qiuhong; Li, Lei; Shen, Keng

    2016-01-01

    Epithelial ovarian cancer, a vexing challenge for clinical management, still lacks biomarkers for early diagnosis, precise stratification, and prognostic evaluation of patients. B-cell-specific Moloney murine leukemia virus integration site 1 (BMI1), a member of the polycomb group of proteins, engages in diverse cellular processes, including proliferation, differentiation, senescence, and stem cell renewal. In addition, BMI1, as a cancer stem-cell marker, participates in tumorigenesis through various pathways. Rewardingly, recent studies have also revealed a relationship between BMI1 expression and the clinical grade/stage, therapy response, and survival outcome in a majority of human malignancies, including epithelial ovarian cancer. Therefore, BMI1 might serve as a potential stratification factor and treatment target for epithelial ovarian cancer, pending evidence from further investigations. PMID:27578986

  5. B-cell-specific Moloney murine leukemia virus integration site 1: potential stratification factor and therapeutic target for epithelial ovarian cancer

    PubMed Central

    Zhao, Qianying; Gui, Ting; Qian, Qiuhong; Li, Lei; Shen, Keng

    2016-01-01

    Epithelial ovarian cancer, a vexing challenge for clinical management, still lacks biomarkers for early diagnosis, precise stratification, and prognostic evaluation of patients. B-cell-specific Moloney murine leukemia virus integration site 1 (BMI1), a member of the polycomb group of proteins, engages in diverse cellular processes, including proliferation, differentiation, senescence, and stem cell renewal. In addition, BMI1, as a cancer stem-cell marker, participates in tumorigenesis through various pathways. Rewardingly, recent studies have also revealed a relationship between BMI1 expression and the clinical grade/stage, therapy response, and survival outcome in a majority of human malignancies, including epithelial ovarian cancer. Therefore, BMI1 might serve as a potential stratification factor and treatment target for epithelial ovarian cancer, pending evidence from further investigations. PMID:27578986

  6. Characterization of a Broadly Neutralizing Monoclonal Antibody That Targets the Fusion Domain of Group 2 Influenza A Virus Hemagglutinin

    PubMed Central

    Tan, Gene S.; Lee, Peter S.; Hoffman, Ryan M. B.; Mazel-Sanchez, Beryl; Krammer, Florian; Leon, Paul E.; Ward, Andrew B.; Wilson, Ian A.

    2014-01-01

    ABSTRACT Due to continuous changes to its antigenic regions, influenza viruses can evade immune detection and cause a significant amount of morbidity and mortality around the world. Influenza vaccinations can protect against disease but must be annually reformulated to match the current circulating strains. In the development of a broad-spectrum influenza vaccine, the elucidation of conserved epitopes is paramount. To this end, we designed an immunization strategy in mice to boost the humoral response against conserved regions of the hemagglutinin (HA) glycoprotein. Of note, generation and identification of broadly neutralizing antibodies that target group 2 HAs are rare and thus far have yielded only a few monoclonal antibodies (MAbs). Here, we demonstrate that mouse MAb 9H10 has broad and potent in vitro neutralizing activity against H3 and H10 group 2 influenza A subtypes. In the mouse model, MAb 9H10 protects mice against two divergent mouse-adapted H3N2 strains, in both pre- and postexposure administration regimens. In vitro and cell-free assays suggest that MAb 9H10 inhibits viral replication by blocking HA-dependent fusion of the viral and endosomal membranes early in the replication cycle and by disrupting viral particle egress in the late stage of infection. Interestingly, electron microscopy reconstructions of MAb 9H10 bound to the HA reveal that it binds a similar binding footprint to MAbs CR8020 and CR8043. IMPORTANCE The influenza hemagglutinin is the major antigenic target of the humoral immune response. However, due to continuous antigenic changes that occur on the surface of this glycoprotein, influenza viruses can escape the immune system and cause significant disease to the host. Toward the development of broad-spectrum therapeutics and vaccines against influenza virus, elucidation of conserved regions of influenza viruses is crucial. Thus, defining these types of epitopes through the generation and characterization of broadly neutralizing

  7. Group-Specific 16S rRNA-Targeted Oligonucleotide Probes To Identify Thermophilic Bacteria in Marine Hydrothermal Vents

    PubMed Central

    Harmsen, H.; Prieur, D.; Jeanthon, C.

    1997-01-01

    Four 16S rRNA-targeted oligonucleotide probes were designed for the detection of thermophilic members of the domain Bacteria known to thrive in marine hydrothermal systems. We developed and characterized probes encompassing most of the thermophilic members of the genus Bacillus, most species of the genus Thermus, the genera Thermotoga and Thermosipho, and the Aquificales order. The temperature of dissociation of each probe was determined. Probe specificities to the target groups were demonstrated by whole-cell and dot blot hybridization against a collection of target and nontarget rRNAs. Whole-cell hybridizations with the specific probes were performed on cells extracted from hydrothermal vent chimneys. One of the samples contained cells that hybridized to the probe specific to genera Thermotoga and Thermosipho. No positive signals could be detected in the samples tested with the probes whose specificities encompassed either the genus Thermus or the thermophilic members of the genus Bacillus. However, when simultaneous hybridizations with the probe specific to the order Aquificales and a probe specific to the domain Bacteria (R. I. Amann, B. Binder, R. J. Olson, S. W. Chisholm, R. Devereux, and D. A. Stahl, Appl. Environ. Microbiol. 56:1919-1925, 1990) were performed on cells extracted from the top and exterior subsamples of chimneys, positive signals were obtained from morphologically diverse bacteria representing about 40% of the bacterial population. Since specificity studies also revealed that the bacterial probe did not hybridize with the members of the order Aquificales, the detected cells may therefore correspond to a new type of bacteria. One of the observed morphotypes was similar to that of a strictly anaerobic autotrophic sulfur-reducing strain that we isolated from the chimney samples. This work demonstrates that application of whole-cell hybridization with probes specific for different phylogenetic levels is a useful tool for detailed studies of

  8. Combined targeting of high-mobility group box-1 and interleukin-8 to control micrometastasis potential in gastric cancer.

    PubMed

    Chung, Hye Won; Jang, Sunphil; Kim, Hoguen; Lim, Jong-Baeck

    2015-10-01

    Micrometastasis is the major cause of treatment failure in gastric cancer (GC). Because epithelial-to-mesenchymal transition (EMT) is considered to develop prior to macroscopic metastasis, EMT-promoting factors may affect micrometastasis. This study aimed to evaluate the role of extracellular high-mobility group box-1 (HMGB1) in EMT and the treatment effect of combined targeting of HMGB1 and interleukin-8 (IL-8) at early-stage GC progression through interrupting EMT promotion. Extracellular HMGB1 was induced by human recombinant HMGB1 and pCMV-SPORT6-HMGB1 plasmid transfection. EMT activation was evaluated by immunoblotting, immunofluorescence and immunohistochemistry. Increased migration/invasion activities were evaluated by in vitro transwell migration/invasion assay using all histological types of human GC cell lines (N87, MKN28 SNU-1 and KATOIII), N87-xenograft BALB/c nude mice and human paired serum-tissue GC samples. HMGB1-induced soluble factors were measured by chemiluminescent immunoassay. Inhibition effects of tumor growth and EMT activation by combined targeting of HMGB1 and IL-8 were evaluated in N87-xenograft nude mice. Serum HMGB1 increases along the GC carcinogenesis and reaches maximum before macroscopic metastasis. Overexpressed extracellular HMGB1 promoted EMT activation and increased cell motility/invasiveness through ligation to receptor for advanced glycation end products. HMGB1-induced IL-8 overexpression contributed the HMGB1-induced EMT in GC in vitro and in vivo. Blocking HMGB1 caused significant reduction of tumor growth, and addition of human recombinant IL-8 rescues this antitumor effects. Our results imply the role of HMGB1 in EMT through IL-8 mediation, and a potential mechanism of GC micrometastasis. Our observations suggest combination strategy of HMGB1 and IL-8 as a promising diagnostic and therapeutic target to control GC micrometastasis. PMID:25821182

  9. A Group Contingency Plus Self-Management Intervention Targeting At-Risk Secondary Students’ Class-Work and Active Engagement

    PubMed Central

    Trevino-Maack, Sylvia I.; Kamps, Debra; Wills, Howard

    2015-01-01

    The purpose of the present study is to show that an independent group contingency (GC) combined with self-management strategies and randomized-reinforcer components can increase the amount of written work and active classroom responding in high school students. Three remedial reading classes and a total of 15 students participated in this study. Students used self-management strategies during independent reading time to increase the amount of writing in their reading logs. They used self-monitoring strategies to record whether or not they performed expected behaviors in class. A token economy using points and tickets was included in the GC to provide positive reinforcement for target responses. The results were analyzed through visual inspection of graphs and effect size computations and showed that the intervention increased the total amount of written words in the students’ reading logs and overall classroom and individual student academic engagement. PMID:26617432

  10. Outcomes of hepatitis C screening programs targeted at risk groups hidden in the general population: a systematic review

    PubMed Central

    2014-01-01

    Background Effective screening programs are urgently needed to provide undiagnosed hepatitis C virus (HCV)-infected individuals with therapy. This systematic review of characteristics and outcomes of screening programs for HCV focuses on strategies to identify HCV risk groups hidden in the general population. Methods We conducted a comprehensive search of MEDLINE and EMBASE databases for articles published between 1991–2010, including studies that screened the general population using either a newly developed (nonintegrated) screening program or one integrated in existing health care facilities. Look-back studies, prevalence studies, and programs targeting high-risk groups in care (e.g., current drug users) were excluded. Results After reviewing 7052 studies, we identified 67 screening programs: 24 nonintegrated; 41 programs integrated in a variety of health care facilities (e.g., general practitioner); and 2 programs with both integrated and nonintegrated strategies. Together, these programs identified approximately 25,700 HCV-infected individuals. In general, higher HCV prevalence was found in programs in countries with intermediate to high HCV prevalence, in psychiatric clinics, and in programs that used a prescreening selection based on HCV risk factors. Only 6 programs used a comparison group for evaluation purposes, and 1 program used theory about effective promotion for screening. Comparison of the programs and their effectiveness was hampered by lack of reported data on program characteristics, clinical follow-up, and type of diagnostic test. Conclusions A prescreening selection based on risk factors can increase the efficiency of screening in low-prevalence populations, and we need programs with comparison groups to evaluate effectiveness. Also, program characteristics such as type of diagnostic test, screening uptake, and clinical outcomes should be reported systematically. PMID:24450797

  11. Polycomb repressive complex 2 structure with inhibitor reveals a mechanism of activation and drug resistance

    PubMed Central

    Brooun, Alexei; Gajiwala, Ketan S.; Deng, Ya-Li; Liu, Wei; Bolaños, Ben; Bingham, Patrick; He, You-Ai; Diehl, Wade; Grable, Nicole; Kung, Pei-Pei; Sutton, Scott; Maegley, Karen A.; Yu, Xiu; Stewart, Al E.

    2016-01-01

    Polycomb repressive complex 2 (PRC2) mediates gene silencing through chromatin reorganization by methylation of histone H3 lysine 27 (H3K27). Overexpression of the complex and point mutations in the individual subunits of PRC2 have been shown to contribute to tumorigenesis. Several inhibitors of the PRC2 activity have shown efficacy in EZH2-mutated lymphomas and are currently in clinical development, although the molecular basis of inhibitor recognition remains unknown. Here we report the crystal structures of the inhibitor-bound wild-type and Y641N PRC2. The structures illuminate an important role played by a stretch of 17 residues in the N-terminal region of EZH2, we call the activation loop, in the stimulation of the enzyme activity, inhibitor recognition and the potential development of the mutation-mediated drug resistance. The work presented here provides new avenues for the design and development of next-generation PRC2 inhibitors through establishment of a structure-based drug design platform. PMID:27122193

  12. Product binding enforces the genomic specificity of a yeast Polycomb repressive complex

    PubMed Central

    Dumesic, Phillip A.; Homer, Christina M.; Moresco, James J.; Pack, Lindsey R.; Shanle, Erin K.; Coyle, Scott M.; Strahl, Brian D.; Fujimori, Danica G.; Yates, John R.; Madhani, Hiten D.

    2015-01-01

    SUMMARY We characterize the Polycomb system that assembles repressive subtelomeric domains of H3K27 methylation (H3K27me) in the yeast Cryptococcus neoformans. Purification of this PRC2-like protein complex reveals orthologs of animal PRC2 components as well as a chromodomain-containing subunit, Ccc1, which recognizes H3K27me. Whereas removal of either the EZH or EED ortholog eliminates H3K27me, disruption of mark recognition by Ccc1 causes H3K27me to redistribute. Strikingly, the resulting pattern of H3K27me coincides with domains of heterochromatin marked by H3K9me. Indeed, additional removal of the C. neoformans H3K9 methyltransferase Clr4 results in loss of both H3K9me and the redistributed H3K27me marks. These findings indicate that the anchoring of a chromatin-modifying complex to its product suppresses its attraction to a different chromatin type, explaining how enzymes that act on histones, which often harbor product recognition modules, may deposit distinct chromatin domains despite sharing a highly abundant and largely identical substrate—the nucleosome. PMID:25533783

  13. Heart disease education and prevention program targeting immigrant Latinos: using focus group responses to develop effective interventions.

    PubMed

    Moreno, C; Alvarado, M; Balcazar, H; Lane, C; Newman, E; Ortiz, G; Forrest, M

    1997-12-01

    Although research has provided considerable knowledge concerning the positive effects of behavioral change on morbidity and mortality from heart disease and related risk factors, some segments of the population have not benefited equitably from this information. In April 1995, the National Heart, Lung, and Blood Institute (NHLBI) conducted seven focus groups to determine knowledge and attitudes about heart disease and associated risk factors, identify media usage and preferences, and assess publications usage and preferences among Spanish-speaking Latino immigrants residing in the Washington, D.C., metropolitan area. This information was gathered to assist in the development of key messages and strategies for the NHLBI Latino Community Cardiovascular Disease Prevention and Outreach Initiative, Salud para su Corazón--a heart disease prevention and education campaign. Findings from these focus groups indicate that Latinos may not benefit from heart disease prevention messages developed for the general population because of language and cultural differences. The researchers concluded that health education and disease prevention programs targeting the Latino community should develop educational materials and interventions that address language preferences and cultural values. Furthermore, to be effective, these programs should show people how to make positive behavioral changes based on their current circumstances, while remaining sensitive to the fact that Latino immigrants face major life adjustments and many are still greatly influenced by their country of origin.

  14. Selection of tumor antigens as targets for immune attack using immunohistochemistry: II. Blood group-related antigens.

    PubMed

    Zhang, S; Zhang, H S; Cordon-Cardo, C; Reuter, V E; Singhal, A K; Lloyd, K O; Livingston, P O

    1997-09-26

    Blood group-related antigens have been attractive targets for immunotherapy of cancer since their initial identification as cancer-related antigens. However, available information on the relative expression of most of these antigens on human malignant and normal tissues has been insufficient for selecting optimal antigens and tumors for immune attack. In this study, the distribution of the blood group-related antigens TF, Tn, sTn, Le(a), sialyl Le(a), Le(b), Le(x), sialyl Le(x), polyfucosyl Le(x) and Le(y) on 13 types of cancer and 16 normal tissues was compared. Our results show that sTn is strongly expressed on cancers of breast, colon, stomach, ovary, prostate and uterus; Tn on prostate cancer; TF on cancers of breast, colon, ovary, prostate and uterus; Le(y) on the cancers of colon, lung, pancreas and ovary; Le(a) and Le(x) on gastric cancer; and sialyl Le(a) and sialyl Le(x) on colon cancer. The complete absence of these antigens on cancers of neuroectodermal or mesodermal origin including melanoma, sarcoma, neuroblastoma and B cell lymphoma is as striking as their widespread presence on tumors of epithelial origin. Normal tissues were also tested. Tn and Le(b) were only detected on gastric and ovarian epithelia; sTn on Leydig cells of testis in addition to gastric and ovarian epithelia; Le(x) and sialyl Le(x) on polymorphonuclear leukocytes; and TF, Le(a), sialyl Le(a), Le(x), sialyl Le(x), polyfucosyl Le(x) and Le(y) on epithelia from a variety of tissues.

  15. Role for O-glycosylation of RFP in the interaction with enhancer of polycomb.

    PubMed

    Tezel, Gaye; Shimono, Yohei; Murakumo, Yoshiki; Kawai, Kumi; Fukuda, Toshifumi; Iwahashi, Naoko; Takahashi, Masahide

    2002-01-11

    We recently demonstrated that RFP, which belongs to the large B-box RING finger protein family, interacts with Enhancer of Polycomb 1 (EPC1) and functions as a transcriptional repressor in human cultured cells. In this study, we examined the expression of RFP and EPC1 in mouse tissues by immunoblotting as well as their interaction by a pull-down assay. Both RFP and EPC1 proteins are expressed in several mouse tissues including testis, spleen, thymus, adrenal gland, cerebrum, and cerebellum. In addition, they were coprecipitated from the lysate of mouse testis. Pull-down assays using glutathione S-transferase (GST)-fused EPC1 proteins revealed that RFP is associated with the EPcA, EPcB, and carboxy-terminal (CT) regions of EPC1. Although RFP is highly expressed as 58- and 68-kDa proteins in mouse testis, the EPC1 CT region more strongly interacted with the 68-kDa form than the EPcA or EPcB region. Interaction of the 58-kDa form of RFP with each region was weak compared with that of the 68-kDa form with the EPC1 CT region. Because the 68-kDa form of RFP was almost completely digested with O-glycosidase but not with N-glycosidase, this suggested that O-glycosylation of RFP plays a role in its interaction with the EPC1 CT region that may be responsible for transcriptional repression. In addition, the luciferase reporter gene assay showed that expression of the EPcA region strongly impairs the transcriptional repressive activity of RFP.

  16. Characterization of non-canonical Polycomb Repressive Complex 1 subunits during early mouse embryogenesis.

    PubMed

    Eid, André; Torres-Padilla, Maria-Elena

    2016-06-01

    An intense period of chromatin remodeling takes place after fertilization in mammals, which is thought necessary for epigenetic reprogramming to start a new developmental program. While much attention has been given to the role of Polycomb Repressive Complex 2 (PRC2) and to canonical PRC1 complexes during this process, little is known as to whether there is any contribution of non-canonical PRC1 in shaping the chromatin landscape after fertilization. Here, we first describe in detail the temporal dynamics and abundance of H2A ubiquitylation (H2AK119ub), a histone modification catalyzed by PRC1, during pre-implantation mouse development. In addition, we have analyzed the presence of the 2 characteristic subunits of non-canonical PRC1 complexes, RYBP and its homolog YAF-2. Our results indicate that H2AK119ub is inherited from the sperm, rapidly removed from the paternal chromatin after fertilization, but detected again prior to the first mitosis, suggesting that PRC1 activity occurs as early as the zygotic stage. RYBP and YAF-2, together with the non-canonical subunit L3MBTL2, are all present during pre-implantation development but show different temporal dynamics. While RYBP is absent in the zygote, it is strongly induced from the 4-cell stage onwards. YAF-2 is inherited maternally and localizes to the pericentromeric regions in the zygote, is strongly induced between the 2- and 4-cell stages but then remains weak to undetectable subsequently. All together, our data suggest that non-canonical PRC1 is active during pre-implantation development and should be regarded as an additional component during epigenetic reprogramming and in the establishment of cellular plasticity of the early embryo. PMID:27081692

  17. Investigating the Role of a Racially Biased Incident on Changes in Culture and Climate Indicators across Targeted and Non-Targeted Groups

    ERIC Educational Resources Information Center

    Yeung, Fanny P.; Johnston, Marc P.

    2014-01-01

    This study explored the influences of a racially biased incident targeting Asian students at a compositionally diverse public research institution on the U.S. West coast after an unplanned incident that occurred during data collection of the Diverse Learning Environments survey. This occurrence created a unique opportunity to explore how 2 cohorts…

  18. A Safe and Stable Neonatal Vaccine Targeting GAPDH Confers Protection against Group B Streptococcus Infections in Adult Susceptible Mice

    PubMed Central

    Alves, Joana; Madureira, Pedro; Baltazar, Maria Teresa; Barros, Leandro; Oliveira, Liliana; Dinis-Oliveira, Ricardo Jorge; Andrade, Elva Bonifácio; Ribeiro, Adília; Vieira, Luís Mira; Trieu-Cuot, Patrick; Duarte, José Alberto; Carvalho, Félix; Ferreira, Paula

    2015-01-01

    Group B Streptococcus (GBS), a commensal organism, can turn into a life-threatening pathogen in neonates and elderly, or in adults with severe underlying diseases such as diabetes. We developed a vaccine targeting the GBS glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a glycolytic enzyme detected at the bacterial surface, which was proven to be effective in a neonatal mouse model of infection. Since this bacterium has emerged as an important pathogen in non-pregnant adults, here we investigated whether this vaccine also confers protection in an adult susceptible and in a diabetic mouse model of infection. For immunoprotection studies, sham or immunized adult mice were infected with GBS serotype Ia and V strains, the two most prevalent serotypes isolated in adults. Sham and vaccinated mice were also rendered diabetic and infected with a serotype V GBS strain. For toxicological (pre-clinical) studies, adult mice were vaccinated three times, with three concentrations of recombinant GAPDH adjuvanted with Allydrogel, and the toxicity parameters were evaluated twenty-four hours after the last immunization. For the stability tests, the vaccine formulations were maintained at 4°C for 6 and 12 months prior immunization. The results showed that all tested doses of the vaccine, including the stability study formulations, were immunogenic and that the vaccine was innocuous. The organs (brain, blood, heart, and liver) of vaccinated susceptible or diabetic adult mice were significantly less colonized compared to those of control mice. Altogether, these results demonstrate that the GAPDH-based vaccine is safe and stable and protects susceptible and diabetic adult mice against GBS infections. It is therefore a promising candidate as a global vaccine to prevent GBS-induced neonatal and adult diseases. PMID:26673420

  19. Target of rapamycin signaling regulates high mobility group protein association to chromatin, which functions to suppress necrotic cell death

    PubMed Central

    2013-01-01

    Background The target of rapamycin complex 1 (TORC1) is an evolutionarily conserved signal transduction pathway activated by environmental nutrients that regulates gene transcription to control cell growth and proliferation. How TORC1 modulates chromatin structure to control gene expression, however, is largely unknown. Because TORC1 is a major transducer of environmental information, defining this process has critical implications for both understanding environmental effects on epigenetic processes and the role of aberrant TORC1 signaling in many diseases, including cancer, diabetes, and cardiovascular disease. Results To elucidate the role of TORC1 signaling in chromatin regulation, we screened a budding yeast histone H3 and H4 mutant library using the selective TORC1 inhibitor rapamycin to identify histone residues functionally connected to TORC1. Intriguingly, we identified histone H3 lysine 37 (H3K37) as a residue that is essential during periods of limited TORC1 activity. An H3K37A mutation resulted in cell death by necrosis when TORC1 signaling was simultaneously impaired. The induction of necrosis was linked to alterations in high mobility group (HMG) protein binding to chromatin. Furthermore, the necrotic phenotype could be recapitulated in wild-type cells by deregulating the model HMG proteins, Hmo1 or Ixr1, thus implicating a direct role for HMG protein deregulation as a stimulus for inducing necrosis. Conclusions This study identifies histone H3 and H4 residues functionally required for TORC1-dependent cell growth and proliferation that are also candidate epigenetic pathways regulated by TORC1 signaling. It also demonstrates a novel role for H3K37 and TORC1 in regulating the binding of select HMG proteins to chromatin and that HMG protein deregulation can initiate a necrotic cell death response. Overall, the results from this study suggest a possible model by which chromatin anchors HMG proteins during periods of limited TORC1 signaling, such as that

  20. A Safe and Stable Neonatal Vaccine Targeting GAPDH Confers Protection against Group B Streptococcus Infections in Adult Susceptible Mice.

    PubMed

    Alves, Joana; Madureira, Pedro; Baltazar, Maria Teresa; Barros, Leandro; Oliveira, Liliana; Dinis-Oliveira, Ricardo Jorge; Andrade, Elva Bonifácio; Ribeiro, Adília; Vieira, Luís Mira; Trieu-Cuot, Patrick; Duarte, José Alberto; Carvalho, Félix; Ferreira, Paula

    2015-01-01

    Group B Streptococcus (GBS), a commensal organism, can turn into a life-threatening pathogen in neonates and elderly, or in adults with severe underlying diseases such as diabetes. We developed a vaccine targeting the GBS glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a glycolytic enzyme detected at the bacterial surface, which was proven to be effective in a neonatal mouse model of infection. Since this bacterium has emerged as an important pathogen in non-pregnant adults, here we investigated whether this vaccine also confers protection in an adult susceptible and in a diabetic mouse model of infection. For immunoprotection studies, sham or immunized adult mice were infected with GBS serotype Ia and V strains, the two most prevalent serotypes isolated in adults. Sham and vaccinated mice were also rendered diabetic and infected with a serotype V GBS strain. For toxicological (pre-clinical) studies, adult mice were vaccinated three times, with three concentrations of recombinant GAPDH adjuvanted with Allydrogel, and the toxicity parameters were evaluated twenty-four hours after the last immunization. For the stability tests, the vaccine formulations were maintained at 4°C for 6 and 12 months prior immunization. The results showed that all tested doses of the vaccine, including the stability study formulations, were immunogenic and that the vaccine was innocuous. The organs (brain, blood, heart, and liver) of vaccinated susceptible or diabetic adult mice were significantly less colonized compared to those of control mice. Altogether, these results demonstrate that the GAPDH-based vaccine is safe and stable and protects susceptible and diabetic adult mice against GBS infections. It is therefore a promising candidate as a global vaccine to prevent GBS-induced neonatal and adult diseases. PMID:26673420

  1. Neuronal activity controls Bdnf expression via Polycomb de-repression and CREB/CBP/JMJD3 activation in mature neurons

    PubMed Central

    Palomer, Ernest; Carretero, Javier; Benvegnù, Stefano; Dotti, Carlos G.; Martin, Mauricio G.

    2016-01-01

    It has been recently described that in embryonic stem cells, the expression of some important developmentally regulated genes is repressed, but poised for fast activation under the appropriate stimuli. In this work we show that Bdnf promoters are repressed by Polycomb Complex 2 in mature hippocampal neurons, and basal expression is guaranteed by the coexistence with activating histone marks. Neuronal stimulation triggered by N-methyl-D-aspartate application induces the transcription of these promoters by H3K27Me3 demethylation and H3K27Me3 phosphorylation at Serine 28 leading to displacement of EZH2, the catalytic subunit of Polycomb Repressor Complex 2. Our data show that the fast transient expression of Bdnf promoters II and VI after neuronal stimulation is dependent on acetylation of histone H3K27 by CREB-p/CBP. Thus, regulatory mechanisms established during development seem to remain after differentiation controlling genes induced by different stimuli, as would be the case of early memory genes in mature neurons. PMID:27010597

  2. Neuronal activity controls Bdnf expression via Polycomb de-repression and CREB/CBP/JMJD3 activation in mature neurons.

    PubMed

    Palomer, Ernest; Carretero, Javier; Benvegnù, Stefano; Dotti, Carlos G; Martin, Mauricio G

    2016-01-01

    It has been recently described that in embryonic stem cells, the expression of some important developmentally regulated genes is repressed, but poised for fast activation under the appropriate stimuli. In this work we show that Bdnf promoters are repressed by Polycomb Complex 2 in mature hippocampal neurons, and basal expression is guaranteed by the coexistence with activating histone marks. Neuronal stimulation triggered by N-methyl-D-aspartate application induces the transcription of these promoters by H3K27Me3 demethylation and H3K27Me3 phosphorylation at Serine 28 leading to displacement of EZH2, the catalytic subunit of Polycomb Repressor Complex 2. Our data show that the fast transient expression of Bdnf promoters II and VI after neuronal stimulation is dependent on acetylation of histone H3K27 by CREB-p/CBP. Thus, regulatory mechanisms established during development seem to remain after differentiation controlling genes induced by different stimuli, as would be the case of early memory genes in mature neurons. PMID:27010597

  3. Transcriptional Regulation by Trithorax-Group Proteins

    PubMed Central

    Kingston, Robert E.; Tamkun, John W.

    2014-01-01

    The trithorax group of genes (trxG) was identified in mutational screens that examined developmental phenotypes and suppression of Polycomb mutant phenotypes. The protein products of these genes are primarily involved in gene activation, although some can also have repressive effects. There is no central function for these proteins. Some move nucleosomes about on the genome in an ATP-dependent manner, some covalently modify histones such as methylating lysine 4 of histone H3, and some directly interact with the transcription machinery or are a part of that machinery. It is interesting to consider why these specific members of large families of functionally related proteins have strong developmental phenotypes. PMID:25274705

  4. Differentiation in Data Analysis & Probability, PreK-Grade 2: A Content Companion for Ongoing Assessment, Grouping Students, Targeting Instruction, and Adjusting Levels of Cognitive Demand

    ERIC Educational Resources Information Center

    Taylor-Cox, Jennifer

    2008-01-01

    This book applies the author's easy but effective differentiation strategies to the data analysis and probability content standard. Taking the foundational elements of differentiation in this book, it helps you: (1) assess students' math abilities quickly and efficiently; (2) group children by need; (3) target instruction to meet every student's…

  5. Empowering Civil Society To Monitor the Environment: Education for Students, Awareness for the Public, and Functional Literacy for Targeted Groups. WBI Working Papers.

    ERIC Educational Resources Information Center

    Ariasingam, David Lakshmanan

    This paper uses case studies to show that by (1) empowering civil society to monitor the environment through environmental education for primary and secondary students, (2) providing environmental awareness programs for the public, and (3) supporting efforts to improve the functional literacy of targeted groups, the effectiveness and…

  6. Report of the super fixed target beauty facility working group on progress towards the SFT at the SSC

    SciTech Connect

    Brown, H.; Cumalat, J.; Carrigan, R.A.

    1992-12-31

    A low intensity 20 TeV proton beam extracted from the SSC by crystal channeling has been proposed for use in producing B hadrons in a fixed target configuration. This option for doing B physics offers a relatively inexpensive way of obtaining large numbers of reconstructable B decays for the study of rare B decays and CP violation in the B system. This paper reports on the progress during and since the 1990 Snowmass meeting in developing the techniques for the crystal extraction and discusses special advantages that an SSC fixed target spectrometer may have relative to other experimental methods for studying B decays.

  7. Presenting Chained and Discrete Tasks as Non-Targeted Information when Teaching Discrete Academic Skills through Small Group Instruction

    ERIC Educational Resources Information Center

    Falkenstine, Karen Jones; Collins, Belva C.; Schuster, John W.; Kleinert, Harold

    2009-01-01

    Special education teachers often search for effective strategies to teach a variety of skills to students with moderate to severe disabilities through small group instruction. The investigators examined the acquisition of academic skills as well as chained and discrete tasks presented as nontargeted information by a small group of students with…

  8. The cylindrical air holes of the negative-refraction photonic crystal double flat lens group for lightwave target detection and imaging

    NASA Astrophysics Data System (ADS)

    Lu, Jian; Shen, Yang; Shen, TingGen; Lian, YingFei; Wang, FeiFei; Xu, Yang

    2013-06-01

    The influence of the cylindrical air holes of the negative-refraction photonic crystal (NR-PC) double flat lens group on the performance of lightwave target detection and imaging is studied in this paper using the finite-difference time-domain (FDTD) method. Numerical simulations indicate that significant enhancement of the scattering signal can be obtained by using a NR-PC flat lens; consequently, great improvement of the refocusing gain as well as the imaging resolution will be provided. We further research the effects of different positions for target detection by using a NR-PC double flat lens group with cylindrical air holes. Then we use defective air holes instead of perfect ones. By using a dynamic scanning scheme, we find that the distance between two flats could be changed flexibly. And it could improve the lateral resolution of target scanning and enlarge the distance between the target and flat greatly. In conclusion, our investigation optimized the performance of the detection and imaging system, and provided the basis for converting an idealized left-handed material lens into a physically realizable NR-PC double flat lens group.

  9. The Moving Group Targets of the Seeds High-Contrast Imaging Survey of Exoplanets and Disks: Results and Observations from the First Three Years

    NASA Technical Reports Server (NTRS)

    Brandt, Timothy D.; Kuzuhara, Masayuki; McElwain, Michael W.; Schlieder, Joshua E.; Wisniewski, John P.; Turner, Edwin L.; Carson, J.; Matsuo, T.; Biller, B.; Bonnefoy, M.; Dressing, C.; Janson, M.; Knapp, G. R.; Moro-Martin, A.; Thalmann, C.; Kudo, T.; Kusakabe, N.; Hashimoto, J.; Abe, L.; Brandner, W.; Currie, T.; Egner, S.; Feldt, M.; Golota, T.; Goto, M.; Brady, C. A.; Guyon, O.; Hayano, Y.; Hyashi, M.; Hayashi, S.; Henning, T.; Hodapp, W.; Ishi, M.; Iye, M.; Kandori, R.

    2014-01-01

    We present results from the first three years of observations of moving group (MG) targets in the Strategic Exploration of Exoplanets and Disks with Subaru (SEEDS) high-contrast imaging survey of exoplanets and disks using the Subaru telescope. We achieve typical contrasts of (is) approximately10(exp 5) at 1" and (is) approximately 10(exp 6) beyond 2" around 63 proposed members of nearby kinematic MGs. We review each of the kinematic associations to which our targets belong, concluding that five, beta Pictoris ((is) approximately 20 Myr), AB Doradus ((is) approximately 100 Myr), Columba ((is) approximately 30 Myr), Tucana-Horogium ((is) approximately 30 Myr), and TW Hydrae ((is) approximately 10 Myr), are sufficiently well-defined to constrain the ages of individual targets. Somewhat less than half of our targets are high-probability members of one of these MGs. For all of our targets, we combine proposed MG membership with other age indicators where available, including Ca ii HK emission, X-ray activity, and rotation period, to produce a posterior probability distribution of age. SEEDS observations discovered a substellar companion to one of our targets, kappa And, a late B star. We do not detect any other substellar companions, but do find seven new close binary systems, of which one still needs to be confirmed. A detailed analysis of the statistics of this sample, and of the companion mass constraints given our age probability distributions and exoplanet cooling models, will be presented in a forthcoming paper.

  10. The Moving Group Targets of the SEEDS High-contrast Imaging Survey of Exoplanets and Disks: Results and Observations from the First Three Years

    NASA Astrophysics Data System (ADS)

    Brandt, Timothy D.; Kuzuhara, Masayuki; McElwain, Michael W.; Schlieder, Joshua E.; Wisniewski, John P.; Turner, Edwin L.; Carson, J.; Matsuo, T.; Biller, B.; Bonnefoy, M.; Dressing, C.; Janson, M.; Knapp, G. R.; Moro-Martín, A.; Thalmann, C.; Kudo, T.; Kusakabe, N.; Hashimoto, J.; Abe, L.; Brandner, W.; Currie, T.; Egner, S.; Feldt, M.; Golota, T.; Goto, M.; Grady, C. A.; Guyon, O.; Hayano, Y.; Hayashi, M.; Hayashi, S.; Henning, T.; Hodapp, K. W.; Ishii, M.; Iye, M.; Kandori, R.; Kwon, J.; Mede, K.; Miyama, S.; Morino, J.-I.; Nishimura, T.; Pyo, T.-S.; Serabyn, E.; Suenaga, T.; Suto, H.; Suzuki, R.; Takami, M.; Takahashi, Y.; Takato, N.; Terada, H.; Tomono, D.; Watanabe, M.; Yamada, T.; Takami, H.; Usuda, T.; Tamura, M.

    2014-05-01

    We present results from the first three years of observations of moving group (MG) targets in the Strategic Exploration of Exoplanets and Disks with Subaru (SEEDS) high-contrast imaging survey of exoplanets and disks using the Subaru telescope. We achieve typical contrasts of ~105 at 1'' and ~106 beyond 2'' around 63 proposed members of nearby kinematic MGs. We review each of the kinematic associations to which our targets belong, concluding that five, β Pictoris (~20 Myr), AB Doradus (~100 Myr), Columba (~30 Myr), Tucana-Horogium (~30 Myr), and TW Hydrae (~10 Myr), are sufficiently well-defined to constrain the ages of individual targets. Somewhat less than half of our targets are high-probability members of one of these MGs. For all of our targets, we combine proposed MG membership with other age indicators where available, including Ca II HK emission, X-ray activity, and rotation period, to produce a posterior probability distribution of age. SEEDS observations discovered a substellar companion to one of our targets, κ And, a late B star. We do not detect any other substellar companions, but do find seven new close binary systems, of which one still needs to be confirmed. A detailed analysis of the statistics of this sample, and of the companion mass constraints given our age probability distributions and exoplanet cooling models, will be presented in a forthcoming paper.

  11. The moving group targets of the seeds high-contrast imaging survey of exoplanets and disks: Results and observations from the first three years

    SciTech Connect

    Brandt, Timothy D.; Turner, Edwin L.; Janson, M.; Knapp, G. R.; Kuzuhara, Masayuki; McElwain, Michael W.; Schlieder, Joshua E.; Carson, J.; Biller, B.; Bonnefoy, M.; Brandner, W.; Wisniewski, John P.; Hashimoto, J.; Matsuo, T.; Dressing, C.; Moro-Martín, A.; Kudo, T.; Kusakabe, N.; Abe, L.; and others

    2014-05-01

    We present results from the first three years of observations of moving group (MG) targets in the Strategic Exploration of Exoplanets and Disks with Subaru (SEEDS) high-contrast imaging survey of exoplanets and disks using the Subaru telescope. We achieve typical contrasts of ∼10{sup 5} at 1'' and ∼10{sup 6} beyond 2'' around 63 proposed members of nearby kinematic MGs. We review each of the kinematic associations to which our targets belong, concluding that five, β Pictoris (∼20 Myr), AB Doradus (∼100 Myr), Columba (∼30 Myr), Tucana-Horogium (∼30 Myr), and TW Hydrae (∼10 Myr), are sufficiently well-defined to constrain the ages of individual targets. Somewhat less than half of our targets are high-probability members of one of these MGs. For all of our targets, we combine proposed MG membership with other age indicators where available, including Ca II HK emission, X-ray activity, and rotation period, to produce a posterior probability distribution of age. SEEDS observations discovered a substellar companion to one of our targets, κ And, a late B star. We do not detect any other substellar companions, but do find seven new close binary systems, of which one still needs to be confirmed. A detailed analysis of the statistics of this sample, and of the companion mass constraints given our age probability distributions and exoplanet cooling models, will be presented in a forthcoming paper.

  12. Prospective Randomized Double-Blind Pilot Study of Site-Specific Consensus Atlas Implementation for Rectal Cancer Target Volume Delineation in the Cooperative Group Setting

    SciTech Connect

    Fuller, Clifton D.; Nijkamp, Jasper; Duppen, Joop C.; Rasch, Coen R.N.; Thomas, Charles R.; Wang, Samuel J.; Okunieff, Paul; Jones, William E.; Baseman, Daniel; Patel, Shilpen; Demandante, Carlo G.N.; Harris, Anna M.; Smith, Benjamin D.; Katz, Alan W.; McGann, Camille

    2011-02-01

    Purpose: Variations in target volume delineation represent a significant hurdle in clinical trials involving conformal radiotherapy. We sought to determine the effect of a consensus guideline-based visual atlas on contouring the target volumes. Methods and Materials: A representative case was contoured (Scan 1) by 14 physician observers and a reference expert with and without target volume delineation instructions derived from a proposed rectal cancer clinical trial involving conformal radiotherapy. The gross tumor volume (GTV), and two clinical target volumes (CTVA, including the internal iliac, presacral, and perirectal nodes, and CTVB, which included the external iliac nodes) were contoured. The observers were randomly assigned to receipt (Group A) or nonreceipt (Group B) of a consensus guideline and atlas for anorectal cancers and then instructed to recontour the same case/images (Scan 2). Observer variation was analyzed volumetrically using the conformation number (CN, where CN = 1 equals total agreement). Results: Of 14 evaluable contour sets (1 expert and 7 Group A and 6 Group B observers), greater agreement was found for the GTV (mean CN, 0.75) than for the CTVs (mean CN, 0.46-0.65). Atlas exposure for Group A led to significantly increased interobserver agreement for CTVA (mean initial CN, 0.68, after atlas use, 0.76; p = .03) and increased agreement with the expert reference (initial mean CN, 0.58; after atlas use, 0.69; p = .02). For the GTV and CTVB, neither the interobserver nor the expert agreement was altered after atlas exposure. Conclusion: Consensus guideline atlas implementation resulted in a detectable difference in interobserver agreement and a greater approximation of expert volumes for the CTVA but not for the GTV or CTVB in the specified case. Visual atlas inclusion should be considered as a feature in future clinical trials incorporating conformal RT.

  13. A Hybrid Chalcone Combining the Trimethoxyphenyl and Isatinyl Groups Targets Multiple Oncogenic Proteins and Pathways in Hepatocellular Carcinoma Cells

    PubMed Central

    Cao, Lili; Zhang, Lijun; Zhao, Xiang; Zhang, Ye

    2016-01-01

    Small molecule inhibitors that can simultaneously inhibit multiple oncogenic proteins in essential pathways are promising therapeutic chemicals for hepatocellular carcinoma (HCC). To combine the anticancer effects of combretastatins, chalcones and isatins, we synthesized a novel hybrid molecule 3’,4’,5’-trimethoxy-5-chloro-isatinylchalcone (3MCIC). 3MCIC inhibited proliferation of cultured HepG2 cells, causing rounding-up of the cells and massive vacuole accumulation in the cytoplasm. Paxillin and focal adhesion plaques were downregulated by 3MCIC. Surprisingly, unlike the microtubule (MT)-targeting agent CA-4 that inhibits tubulin polymerization, 3MCIC stabilized tubulin polymers both in living cells and in cell lysates. 3MCIC treatment reduced cyclin B1, CDK1, p-CDK1/2, and Rb, but increased p53 and p21. Moreover, 3MCIC caused GSK3β degradation by promoting GSK3β-Ser9 phosphorylation. Nevertheless, 3MCIC inhibited the Wnt/β-catenin pathway by downregulating β-catenin, c-Myc, cyclin D1 and E2F1. 3MCIC treatment not only activated the caspase-3-dependent apoptotic pathway, but also caused massive autophagy evidenced by rapid and drastic changes of LC3 and p62. 3MCIC also promoted cleavage and maturation of the lysosomal protease cathepsin D. Using ligand-affinity chromatography (LAC), target proteins captured onto the Sephacryl S1000-C12-3MCIC resins were isolated and analyzed by mass spectrometry (MS). Some of the LAC-MS identified targets, i.e., septin-2, vimentin, pan-cytokeratin, nucleolin, EF1α1/2, EBP1 (PA2G4), cyclin B1 and GSK3β, were further detected by Western blotting. Moreover, both septin-2 and HIF-1α decreased drastically in 3MCIC-treated HepG2 cells. Our data suggest that 3MCIC is a promising anticancer lead compound with novel targeting mechanisms, and also demonstrate the efficiency of LAC-MS based target identification in anticancer drug development. PMID:27525972

  14. A Hybrid Chalcone Combining the Trimethoxyphenyl and Isatinyl Groups Targets Multiple Oncogenic Proteins and Pathways in Hepatocellular Carcinoma Cells.

    PubMed

    Cao, Lili; Zhang, Lijun; Zhao, Xiang; Zhang, Ye

    2016-01-01

    Small molecule inhibitors that can simultaneously inhibit multiple oncogenic proteins in essential pathways are promising therapeutic chemicals for hepatocellular carcinoma (HCC). To combine the anticancer effects of combretastatins, chalcones and isatins, we synthesized a novel hybrid molecule 3',4',5'-trimethoxy-5-chloro-isatinylchalcone (3MCIC). 3MCIC inhibited proliferation of cultured HepG2 cells, causing rounding-up of the cells and massive vacuole accumulation in the cytoplasm. Paxillin and focal adhesion plaques were downregulated by 3MCIC. Surprisingly, unlike the microtubule (MT)-targeting agent CA-4 that inhibits tubulin polymerization, 3MCIC stabilized tubulin polymers both in living cells and in cell lysates. 3MCIC treatment reduced cyclin B1, CDK1, p-CDK1/2, and Rb, but increased p53 and p21. Moreover, 3MCIC caused GSK3β degradation by promoting GSK3β-Ser9 phosphorylation. Nevertheless, 3MCIC inhibited the Wnt/β-catenin pathway by downregulating β-catenin, c-Myc, cyclin D1 and E2F1. 3MCIC treatment not only activated the caspase-3-dependent apoptotic pathway, but also caused massive autophagy evidenced by rapid and drastic changes of LC3 and p62. 3MCIC also promoted cleavage and maturation of the lysosomal protease cathepsin D. Using ligand-affinity chromatography (LAC), target proteins captured onto the Sephacryl S1000-C12-3MCIC resins were isolated and analyzed by mass spectrometry (MS). Some of the LAC-MS identified targets, i.e., septin-2, vimentin, pan-cytokeratin, nucleolin, EF1α1/2, EBP1 (PA2G4), cyclin B1 and GSK3β, were further detected by Western blotting. Moreover, both septin-2 and HIF-1α decreased drastically in 3MCIC-treated HepG2 cells. Our data suggest that 3MCIC is a promising anticancer lead compound with novel targeting mechanisms, and also demonstrate the efficiency of LAC-MS based target identification in anticancer drug development. PMID:27525972

  15. A Group Contingency plus Self-Management Intervention Targeting At-Risk Secondary Students' Class-Work and Active Engagement

    ERIC Educational Resources Information Center

    Trevino-Maack, Sylvia I.; Kamps, Debra; Wills, Howard

    2015-01-01

    The purpose of the present study is to show that an independent group contingency (GC) combined with self-management strategies and randomized-reinforcer components can increase the amount of written work and active classroom responding in high school students. Three remedial reading classes and a total of 15 students participated in this study.…

  16. Internet Postings Linked to Student Highlight Interest in "Hate Groups": Experts Say Recruitment Efforts Targeting School-Age Youths

    ERIC Educational Resources Information Center

    Cavanagh, Sean

    2005-01-01

    In an Internet forum run by the Libertarian National Socialist Green Party, an organization espousing neo-Nazi views, Jeff Weise made his comments about the group in the year leading up to his deadly armed assault at Red Lake High School in Minnesota. The forum lists 34 postings written by the 16-year-old Native American youth. The commentary Mr.…

  17. Biotechnological applications of mobile group II introns and their reverse transcriptases: gene targeting, RNA-seq, and non-coding RNA analysis

    PubMed Central

    2014-01-01

    Mobile group II introns are bacterial retrotransposons that combine the activities of an autocatalytic intron RNA (a ribozyme) and an intron-encoded reverse transcriptase to insert site-specifically into DNA. They recognize DNA target sites largely by base pairing of sequences within the intron RNA and achieve high DNA target specificity by using the ribozyme active site to couple correct base pairing to RNA-catalyzed intron integration. Algorithms have been developed to program the DNA target site specificity of several mobile group II introns, allowing them to be made into ‘targetrons.’ Targetrons function for gene targeting in a wide variety of bacteria and typically integrate at efficiencies high enough to be screened easily by colony PCR, without the need for selectable markers. Targetrons have found wide application in microbiological research, enabling gene targeting and genetic engineering of bacteria that had been intractable to other methods. Recently, a thermostable targetron has been developed for use in bacterial thermophiles, and new methods have been developed for using targetrons to position recombinase recognition sites, enabling large-scale genome-editing operations, such as deletions, inversions, insertions, and ‘cut-and-pastes’ (that is, translocation of large DNA segments), in a wide range of bacteria at high efficiency. Using targetrons in eukaryotes presents challenges due to the difficulties of nuclear localization and sub-optimal magnesium concentrations, although supplementation with magnesium can increase integration efficiency, and directed evolution is being employed to overcome these barriers. Finally, spurred by new methods for expressing group II intron reverse transcriptases that yield large amounts of highly active protein, thermostable group II intron reverse transcriptases from bacterial thermophiles are being used as research tools for a variety of applications, including qRT-PCR and next-generation RNA sequencing (RNA

  18. Role of Polycomb RYBP in Maintaining the B-1-to-B-2 B-Cell Lineage Switch in Adult Hematopoiesis.

    PubMed

    Calés, Carmela; Pavón, Leticia; Starowicz, Katarzyna; Pérez, Claudia; Bravo, Mónica; Ikawa, Tomokatsu; Koseki, Haruhiko; Vidal, Miguel

    2015-12-28

    Polycomb chromatin modifiers regulate hematopoietic pluripotent stem and progenitor cell self-renewal and expansion. Polycomb complex redundancy and biochemical heterogeneity complicate the unraveling of the functional contributions of distinct components. We have studied the hematopoietic activity of RYBP, a direct interactor and proposed modulator of RING1A/RING1B-dependent histone H2A monoubiquitylation (H2AUb). Using a mouse model to conditionally inactivate Rybp in adult hematopoiesis, we have found that RYBP deletion results in a reversion of B-1-to-B-2 B-cell progenitor ratios, i.e., of the innate (predominantly fetal) to acquired (mostly adult) immunity precursors. Increased numbers of B-1 progenitors correlated with a loss of pre-proB cells, the B-2 progenitors. RYBP-deficient stem and progenitor cell populations (LKS) and isolated common lymphoid progenitors (CLP) gave rise to increased numbers of B-1 progenitors in vitro. Rybp inactivation, however, did not result in changes of global H2AUb and did not interact genetically with Ring1A or Ring1B deletions. These results show that a sustained regulation of the B-1-to-B-2 switch is needed throughout adult life and that RYBP plays an important role in keeping B-2 dominance, most likely independently of its Polycomb affiliation.

  19. Role of Polycomb RYBP in Maintaining the B-1-to-B-2 B-Cell Lineage Switch in Adult Hematopoiesis

    PubMed Central

    Pavón, Leticia; Starowicz, Katarzyna; Pérez, Claudia; Bravo, Mónica; Ikawa, Tomokatsu; Koseki, Haruhiko

    2015-01-01

    Polycomb chromatin modifiers regulate hematopoietic pluripotent stem and progenitor cell self-renewal and expansion. Polycomb complex redundancy and biochemical heterogeneity complicate the unraveling of the functional contributions of distinct components. We have studied the hematopoietic activity of RYBP, a direct interactor and proposed modulator of RING1A/RING1B-dependent histone H2A monoubiquitylation (H2AUb). Using a mouse model to conditionally inactivate Rybp in adult hematopoiesis, we have found that RYBP deletion results in a reversion of B-1-to-B-2 B-cell progenitor ratios, i.e., of the innate (predominantly fetal) to acquired (mostly adult) immunity precursors. Increased numbers of B-1 progenitors correlated with a loss of pre-proB cells, the B-2 progenitors. RYBP-deficient stem and progenitor cell populations (LKS) and isolated common lymphoid progenitors (CLP) gave rise to increased numbers of B-1 progenitors in vitro. Rybp inactivation, however, did not result in changes of global H2AUb and did not interact genetically with Ring1A or Ring1B deletions. These results show that a sustained regulation of the B-1-to-B-2 switch is needed throughout adult life and that RYBP plays an important role in keeping B-2 dominance, most likely independently of its Polycomb affiliation. PMID:26711264

  20. Jarid1b targets genes regulating development and is involved in neural differentiation

    PubMed Central

    Schmitz, Sandra U; Albert, Mareike; Malatesta, Martina; Morey, Lluis; Johansen, Jens V; Bak, Mads; Tommerup, Niels; Abarrategui, Iratxe; Helin, Kristian

    2011-01-01

    H3K4 methylation is associated with active transcription and in combination with H3K27me3 thought to keep genes regulating development in a poised state. The contribution of enzymes regulating trimethylation of lysine 4 at histone 3 (H3K4me3) levels to embryonic stem cell (ESC) self-renewal and differentiation is just starting to emerge. Here, we show that the H3K4me2/3 histone demethylase Jarid1b (Kdm5b/Plu1) is dispensable for ESC self-renewal, but essential for ESC differentiation along the neural lineage. By genome-wide location analysis, we demonstrate that Jarid1b localizes predominantly to transcription start sites of genes encoding developmental regulators, of which more than half are also bound by Polycomb group proteins. Virtually all Jarid1b target genes are associated with H3K4me3 and depletion of Jarid1b in ESCs leads to a global increase of H3K4me3 levels. During neural differentiation, Jarid1b-depleted ESCs fail to efficiently silence lineage-inappropriate genes, specifically stem and germ cell genes. Our results delineate an essential role for Jarid1b-mediated transcriptional control during ESC differentiation. PMID:22020125

  1. Changes in sexual behavior of HIV-infected older adults enrolled in a clinical trial of standalone group psychotherapies targeting depression.

    PubMed

    Lovejoy, Travis I; Heckman, Timothy G; Sikkema, Kathleen J; Hansen, Nathan B; Kochman, Arlene

    2015-01-01

    By 2015, one-half of all HIV-positive persons in the U.S. will be 50-plus years of age, and as many as 30 % of older adults living with HIV/AIDS continue to engage in unprotected sexual intercourse. Contemporary positive prevention models often include mental health treatment as a key component of HIV prevention interventions. This secondary data analysis characterized longitudinal patterns of sexual behavior in HIV-positive older adults enrolled in a randomized controlled trial of group mental health interventions and assessed the efficacy of psychosocial treatments that targeted depression to reduce sexual risk behavior. Participants were 295 HIV-positive adults ≥50 years of age experiencing mild to severe depressive symptoms, randomized to one of three study conditions: a 12-session coping improvement group intervention, a 12-session interpersonal support group intervention, or individual therapy upon request. Approximately one-fifth of participants reported one or more occasions of unprotected anal or vaginal intercourse with HIV-negative sexual partners or persons of unknown HIV serostatus over the study period. Changes in sexual behavior did not vary by intervention condition, indicating that standalone treatments that target and reduce depression may be insufficient to reduce sexual risk behavior in depressed HIV-positive older adults.

  2. Targeting children of substance-using parents with the community-based group intervention TRAMPOLINE: A randomised controlled trial - design, evaluation, recruitment issues

    PubMed Central

    2012-01-01

    Background Children of substance-abusing parents are at risk for developing psychosocial development problems. In Germany it is estimated that approx. 2.65 million children are affected by parental substance abuse or dependence. Only ten percent of them receive treatment when parents are treated. To date, no evaluated programme for children from substance-affected families exists in Germany. The study described in this protocol is designed to test the effectiveness of the group programme TRAMPOLINE for children aged 8-12 years with at least one substance-abusing or -dependent caregiver. The intervention is specifically geared to issues and needs of children from substance-affected families. Methods/Design The effectiveness of the manualised nine-session group programme TRAMPOLINE is tested among N = 218 children from substance-affected families in a multicentre randomised controlled trial. Outpatient counselling facilities across the nation from different settings (rural/urban, Northern/Southern/Eastern/Western regions of the country) will deliver the interventions, as they hold the primary access to the target group in Germany. The control condition is a group programme with the same duration that is not addiction-specific. We expect that participants in the intervention condition will show a significant improvement in the use of adaptive coping strategies (in general and within the family) compared to the control condition as a direct result of the intervention. Data is collected shortly before and after as well as six months after the intervention. Discussion In Germany, the study presented here is the first to develop and evaluate a programme for children of substance-abusing parents. Limitations and strengths are discussed with a special focus on recruitment challenges as they appear to be the most potent threat to feasibility in the difficult-to-access target group at hand (Trial registration: ISRCTN81470784). PMID:22439919

  3. Interobserver Variability in Target Definition for Hepatocellular Carcinoma With and Without Portal Vein Thrombus: Radiation Therapy Oncology Group Consensus Guidelines

    SciTech Connect

    Hong, Theodore S.; Bosch, Walter R.; Krishnan, Sunil; Kim, Tae K.; Mamon, Harvey J.; Ben-Josef, Edgar; Seong, Jinsil; Haddock, Michael G.; Cheng, Jason C.; Feng, Mary U.; Stephans, Kevin L.; Roberge, David; and others

    2014-07-15

    Purpose: Defining hepatocellular carcinoma (HCC) gross tumor volume (GTV) requires multimodal imaging, acquired in different perfusion phases. The purposes of this study were to evaluate the variability in contouring and to establish guidelines and educational recommendations for reproducible HCC contouring for treatment planning. Methods and Materials: Anonymous, multiphasic planning computed tomography scans obtained from 3 patients with HCC were identified and distributed to a panel of 11 gastrointestinal radiation oncologists. Panelists were asked the number of HCC cases they treated in the past year. Case 1 had no vascular involvement, case 2 had extensive portal vein involvement, and case 3 had minor branched portal vein involvement. The agreement between the contoured total GTVs (primary + vascular GTV) was assessed using the generalized kappa statistic. Agreement interpretation was evaluated using Landis and Koch's interpretation of strength of agreement. The S95 contour, defined using the simultaneous truth and performance level estimation (STAPLE) algorithm consensus at the 95% confidence level, was created for each case. Results: Of the 11 panelists, 3 had treated >25 cases in the past year, 2 had treated 10 to 25 cases, 2 had treated 5 to 10 cases, 2 had treated 1 to 5 cases, 1 had treated 0 cases, and 1 did not respond. Near perfect agreement was seen for case 1, and substantial agreement was seen for cases 2 and 3. For case 2, there was significant heterogeneity in the volume identified as tumor thrombus (range 0.58-40.45 cc). For case 3, 2 panelists did not include the branched portal vein thrombus, and 7 panelists contoured thrombus separately from the primary tumor, also showing significant heterogeneity in volume of tumor thrombus (range 4.52-34.27 cc). Conclusions: In a group of experts, excellent agreement was seen in contouring total GTV. Heterogeneity exists in the definition of portal vein thrombus that may impact treatment planning

  4. Polycomb Repressive Complex 2 Regulates MiR-200b in Retinal Endothelial Cells: Potential Relevance in Diabetic Retinopathy

    PubMed Central

    Ruiz, Michael Anthony; Feng, Biao; Chakrabarti, Subrata

    2015-01-01

    Glucose-induced augmented vascular endothelial growth factor (VEGF) production is a key event in diabetic retinopathy. We have previously demonstrated that downregulation of miR-200b increases VEGF, mediating structural and functional changes in the retina in diabetes. However, mechanisms regulating miR-200b in diabetes are not known. Histone methyltransferase complex, Polycomb Repressive Complex 2 (PRC2), has been shown to repress miRNAs in neoplastic process. We hypothesized that, in diabetes, PRC2 represses miR-200b through its histone H3 lysine-27 trimethylation mark. We show that human retinal microvascular endothelial cells exposed to high levels of glucose regulate miR-200b repression through histone methylation and that inhibition of PRC2 increases miR-200b while reducing VEGF. Furthermore, retinal tissue from animal models of diabetes showed increased expression of major PRC2 components, demonstrating in vivo relevance. This research established a repressive relationship between PRC2 and miR-200b, providing evidence of a novel mechanism of miRNA regulation through histone methylation. PMID:25884496

  5. A strand-specific switch in noncoding transcription switches the function of a Polycomb/Trithorax response element

    PubMed Central

    Trupke, Johanna; Okulski, Helena; Altmutter, Christina; Ruge, Frank; Boidol, Bernd; Kubicek, Stefan; Schmauss, Gerald; Aumayr, Karin; Ruf, Marius; Pospisilik, Andrew; Dimond, Andrew; Senergin, Hasene Basak; Vargas, Marcus L.; Simon, Jeffrey A.; Ringrose, Leonie

    2014-01-01

    Polycomb/Trithorax response elements (PRE/TREs) can switch their function reversibly between silencing and activation, by mechanisms that are poorly understood. Here we show that a switch in forward and reverse noncoding transcription from the Drosophila vestigial (vg) PRE/TRE switches the status of the element between silencing (induced by the forward strand) and activation (induced by the reverse strand). In vitro, both ncRNAs inhibit PRC2 histone methyltransferase activity, but in vivo only the reverse strand binds PRC2. Over-expression of the reverse strand evicts PRC2 from chromatin and inhibits its enzymatic activity. We propose that interactions of RNAs with PRC2 are differentially regulated in vivo, allowing regulated inhibition of local PRC2 activity. Genome-wide analysis shows that strand switching of ncRNAs occurs at several hundred PcG binding sites in fly and vertebrate genomes. This work identifies a novel and potentially widespread class of PRE/TREs that switch function by switching the direction of ncRNA transcription. PMID:25108384

  6. Polycomb repressive complex 2 facilitates the nuclear export of the influenza viral genome through the interaction with M1.

    PubMed

    Asaka, Masamitsu N; Kawaguchi, Atsushi; Sakai, Yuri; Mori, Kotaro; Nagata, Kyosuke

    2016-01-01

    The organization of nuclear domains is crucial for biological events including virus infection. Newly synthesized influenza viral genome forms viral ribonucleoprotein (vRNP) complexes and is exported from the nucleus to the cytoplasm through a CRM1-dependent pathway mediated by viral proteins M1 and NS2. However, the spatio-temporal regulation of the progeny vRNP in the nucleus is still unclear. Here we found that polycomb repressive complex 2 (PRC2), which contains a methyltransferase subunit EZH2 and catalyzes histone H3K27me3 for the formation of facultative heterochromatin, is a positive factor for the virus production. Depletion of PRC2 complex showed the nuclear accumulation of vRNP and the reduction of M1-vRNP complex formation. We also found that PRC2 complex directly binds to M1, and facilitates the interaction of M1 with vRNP. In conclusion, we propose that the progeny vRNP could be recruited to facultative heterochromatin and assembled into the export complex mediated by PRC2 complex. PMID:27646999

  7. Polycomb repressive complex 2 facilitates the nuclear export of the influenza viral genome through the interaction with M1

    PubMed Central

    Asaka, Masamitsu N.; Kawaguchi, Atsushi; Sakai, Yuri; Mori, Kotaro; Nagata, Kyosuke

    2016-01-01

    The organization of nuclear domains is crucial for biological events including virus infection. Newly synthesized influenza viral genome forms viral ribonucleoprotein (vRNP) complexes and is exported from the nucleus to the cytoplasm through a CRM1-dependent pathway mediated by viral proteins M1 and NS2. However, the spatio-temporal regulation of the progeny vRNP in the nucleus is still unclear. Here we found that polycomb repressive complex 2 (PRC2), which contains a methyltransferase subunit EZH2 and catalyzes histone H3K27me3 for the formation of facultative heterochromatin, is a positive factor for the virus production. Depletion of PRC2 complex showed the nuclear accumulation of vRNP and the reduction of M1-vRNP complex formation. We also found that PRC2 complex directly binds to M1, and facilitates the interaction of M1 with vRNP. In conclusion, we propose that the progeny vRNP could be recruited to facultative heterochromatin and assembled into the export complex mediated by PRC2 complex. PMID:27646999

  8. LANA-Mediated Recruitment of Host Polycomb Repressive Complexes onto the KSHV Genome during De Novo Infection

    PubMed Central

    Toth, Zsolt; Papp, Bernadett; Brulois, Kevin; Choi, Youn Jung; Gao, Shou-Jiang; Jung, Jae U.

    2016-01-01

    One of the hallmarks of the latent phase of Kaposi’s sarcoma-associated herpesvirus (KSHV) infection is the global repression of lytic viral gene expression. Following de novo KSHV infection, the establishment of latency involves the chromatinization of the incoming viral genomes and recruitment of the host Polycomb repressive complexes (PRC1 and PRC2) to the promoters of lytic genes, which is accompanied by the inhibition of lytic genes. However, the mechanism of how PRCs are recruited to the KSHV episome is still unknown. Utilizing a genetic screen of latent genes in the context of KSHV genome, we identified the latency-associated nuclear antigen (LANA) to be responsible for the genome-wide recruitment of PRCs onto the lytic promoters following infection. We found that LANA initially bound to the KSHV genome right after infection and subsequently recruited PRCs onto the viral lytic promoters, thereby repressing lytic gene expression. Furthermore, both the DNA and chromatin binding activities of LANA were required for the binding of LANA to the KSHV promoters, which was necessary for the recruitment of PRC2 to the lytic promoters during de novo KSHV infection. Consequently, the LANA-knockout KSHV could not recruit PRCs to its viral genome upon de novo infection, resulting in aberrant lytic gene expression and dysregulation of expression of host genes involved in cell cycle and proliferation pathways. In this report, we demonstrate that KSHV LANA recruits host PRCs onto the lytic promoters to suppress lytic gene expression following de novo infection. PMID:27606464

  9. Involvement of Polycomb Repressive Complex 2 in Maturation of Induced Pluripotent Stem Cells during Reprogramming of Mouse and Human Fibroblasts.

    PubMed

    Khazaie, Niusha; Massumi, Mohammad; Wee, Ping; Salimi, Mahdieh; Mohammadnia, Abdulshakour; Yaqubi, Moein

    2016-01-01

    Induced pluripotent stem cells (iPSCs) provide a reliable source for the study of regenerative medicine, drug discovery, and developmental biology. Despite extensive studies on the reprogramming of mouse and human fibroblasts into iPSCs, the efficiency of reprogramming is still low. Here, we used a bioinformatics and systems biology approach to study the two gene regulatory waves governing the reprogramming of mouse and human fibroblasts into iPSCs. Our results revealed that the maturation phase of reprogramming was regulated by a more complex regulatory network of transcription factors compared to the initiation phase. Interestingly, in addition to pluripotency factors, the polycomb repressive complex 2 (PRC2) members Ezh2, Eed, Jarid2, Mtf2, and Suz12 are crucially recruited during the maturation phase of reprogramming. Moreover, we found that during the maturation phase of reprogramming, pluripotency factors, via the expression and induction of PRC2 complex members, could silence the lineage-specific gene expression program and maintain a ground state of pluripotency in human and mouse naïve iPSCs. The findings obtained here provide us a better understanding of the gene regulatory network (GRN) that governs reprogramming, and the maintenance of the naïve state of iPSCs.

  10. Involvement of Polycomb Repressive Complex 2 in Maturation of Induced Pluripotent Stem Cells during Reprogramming of Mouse and Human Fibroblasts

    PubMed Central

    Khazaie, Niusha; Massumi, Mohammad; Wee, Ping; Salimi, Mahdieh; Mohammadnia, Abdulshakour; Yaqubi, Moein

    2016-01-01

    Induced pluripotent stem cells (iPSCs) provide a reliable source for the study of regenerative medicine, drug discovery, and developmental biology. Despite extensive studies on the reprogramming of mouse and human fibroblasts into iPSCs, the efficiency of reprogramming is still low. Here, we used a bioinformatics and systems biology approach to study the two gene regulatory waves governing the reprogramming of mouse and human fibroblasts into iPSCs. Our results revealed that the maturation phase of reprogramming was regulated by a more complex regulatory network of transcription factors compared to the initiation phase. Interestingly, in addition to pluripotency factors, the polycomb repressive complex 2 (PRC2) members Ezh2, Eed, Jarid2, Mtf2, and Suz12 are crucially recruited during the maturation phase of reprogramming. Moreover, we found that during the maturation phase of reprogramming, pluripotency factors, via the expression and induction of PRC2 complex members, could silence the lineage-specific gene expression program and maintain a ground state of pluripotency in human and mouse naïve iPSCs. The findings obtained here provide us a better understanding of the gene regulatory network (GRN) that governs reprogramming, and the maintenance of the naïve state of iPSCs. PMID:26938987

  11. Role of group V phospholipase A2 in zymosan-induced eicosanoid generation and vascular permeability revealed by targeted gene disruption*

    PubMed Central

    Satake, Yoshiyuki; Diaz, Bruno L.; Balestrieri, Barbara; Lam, Bing K.; Kanaoka, Yoshihide; Grusby, Michael J.; Arm, Jonathan P.

    2005-01-01

    SUMMARY Conclusions regarding the contribution of low molecular weight secretory phospholipase A2 (sPLA2) enzymes in eicosanoid generation have relied on data obtained from transfected cells or the use of inhibitors that fail to discriminate between individual members of the large family of mammalian sPLA2 enzymes. To elucidate the role of group V sPLA2, we used targeted gene disruption to generate mice lacking this enzyme. Zymosan-induced generation of leukotriene C4 and prostaglandin E2 was attenuated ~50% in peritoneal macrophages from group V sPLA2-null mice compared to macrophages from wild-type littermates. Furthermore, the early phase of plasma exudation in response to intraperitoneal injection of zymosan and the accompanying in vivo generation of cysteinyl leukotrienes were markedly attenuated in group V sPLA2-null mice compared to wild-type controls. These data provide clear evidence of a role for group V sPLA2 in regulating eicosanoid generation in response to an acute innate stimulus of the immune response both in vitro and in vivo, suggesting a role for this enzyme in innate immunity. PMID:14761945

  12. Targeting Enhancer of Zeste Homolog 2 as a promising strategy for cancer treatment

    PubMed Central

    Marchesi, Irene; Bagella, Luigi

    2016-01-01

    Polycomb group proteins represent a global silencing system involved in development regulation. In specific, they regulate the transition from proliferation to differentiation, contributing to stem-cell maintenance and inhibiting an inappropriate activation of differentiation programs. Enhancer of Zeste Homolog 2 (EZH2) is the catalytic subunit of Polycomb repressive complex 2, which induces transcriptional inhibition through the tri-methylation of histone H3, an epigenetic change associated with gene silencing. EZH2 expression is high in precursor cells while its level decreases in differentiated cells. EZH2 is upregulated in various cancers with high levels associated with metastatic cancer and poor prognosis. Indeed, aberrant expression of EZH2 causes the inhibition of several tumor suppressors and differentiation genes, resulting in an uncontrolled proliferation and tumor formation. This editorial explores the role of Polycomb repressive complex 2 in cancer, focusing in particular on EZH2. The canonical function of EZH2 in gene silencing, the non-canonical activities as the methylation of other proteins and the role in gene transcriptional activation, were summarized. Moreover, mutations of EZH2, responsible for an increased methyltransferase activity in cancer, were recapitulated. Finally, various drugs able to inhibit EZH2 with different mechanism were described, specifically underscoring the effects in several cancers, in order to clarify the role of EZH2 and understand if EZH2 blockade could be a new strategy for developing specific therapies or a way to increase sensitivity of cancer cells to standard therapies. PMID:27081636

  13. Use of 16S rRNA Gene-Targeted Group-Specific Primers for Real-Time PCR Analysis of Predominant Bacteria in Mouse Feces.

    PubMed

    Yang, Yun-Wen; Chen, Mang-Kun; Yang, Bing-Ya; Huang, Xian-Jie; Zhang, Xue-Rui; He, Liang-Qiang; Zhang, Jing; Hua, Zi-Chun

    2015-10-01

    Mouse models are widely used for studying gastrointestinal (GI) tract-related diseases. It is necessary and important to develop a new set of primers to monitor the mouse gut microbiota. In this study, 16S rRNA gene-targeted group-specific primers for Firmicutes, Actinobacteria, Bacteroidetes, Deferribacteres, "Candidatus Saccharibacteria," Verrucomicrobia, Tenericutes, and Proteobacteria were designed and validated for quantification of the predominant bacterial species in mouse feces by real-time PCR. After confirmation of their accuracy and specificity by high-throughput sequencing technologies, these primers were applied to quantify the changes in the fecal samples from a trinitrobenzene sulfonic acid-induced colitis mouse model. Our results showed that this approach efficiently predicted the occurrence of colitis, such as spontaneous chronic inflammatory bowel disease in transgenic mice. The set of primers developed in this study provides a simple and affordable method to monitor changes in the intestinal microbiota at the phylum level. PMID:26187967

  14. The challenge of reducing scientific complexity for different target groups (without losing the essence) - experiences from interdisciplinary audio-visual media production

    NASA Astrophysics Data System (ADS)

    Hezel, Bernd; Broschkowski, Ephraim; Kropp, Jürgen

    2013-04-01

    The Climate Media Factory originates from an interdisciplinary media lab run by the Film and Television University "Konrad Wolf" Potsdam-Babelsberg (HFF) and the Potsdam Institute for Climate Impact Research (PIK). Climate scientists, authors, producers and media scholars work together to develop media products on climate change and sustainability. We strive towards communicating scientific content via different media platforms reconciling the communication needs of scientists and the audience's need to understand the complexity of topics that are relevant in their everyday life. By presenting four audio-visual examples, that have been designed for very different target groups, we show (i) the interdisciplinary challenges during the production process and the lessons learnt and (ii) possibilities to reach the required degree of simplification without the need for dumbing down the content. "We know enough about climate change" is a short animated film that was produced for the German Agency for International Cooperation (GIZ) for training programs and conferences on adaptation in the target countries including Indonesia, Tunisia and Mexico. "Earthbook" is a short animation produced for "The Year of Science" to raise awareness for the topics of sustainability among digital natives. "What is Climate Engineering?". Produced for the Institute for Advanced Sustainability Studies (IASS) the film is meant for an informed and interested public. "Wimmelwelt Energie!" is a prototype of an iPad application for children from 4-6 years of age to help them learn about different forms of energy and related greenhouse gas emissions.

  15. Modern Radiation Therapy for Nodal Non-Hodgkin Lymphoma—Target Definition and Dose Guidelines From the International Lymphoma Radiation Oncology Group

    SciTech Connect

    Illidge, Tim; Specht, Lena; Yahalom, Joachim; Aleman, Berthe; Berthelsen, Anne Kiil; Constine, Louis; Dabaja, Bouthaina; Dharmarajan, Kavita; Ng, Andrea; Ricardi, Umberto; Wirth, Andrew

    2014-05-01

    Radiation therapy (RT) is the most effective single modality for local control of non-Hodgkin lymphoma (NHL) and is an important component of therapy for many patients. Many of the historic concepts of dose and volume have recently been challenged by the advent of modern imaging and RT planning tools. The International Lymphoma Radiation Oncology Group (ILROG) has developed these guidelines after multinational meetings and analysis of available evidence. The guidelines represent an agreed consensus view of the ILROG steering committee on the use of RT in NHL in the modern era. The roles of reduced volume and reduced doses are addressed, integrating modern imaging with 3-dimensional planning and advanced techniques of RT delivery. In the modern era, in which combined-modality treatment with systemic therapy is appropriate, the previously applied extended-field and involved-field RT techniques that targeted nodal regions have now been replaced by limiting the RT to smaller volumes based solely on detectable nodal involvement at presentation. A new concept, involved-site RT, defines the clinical target volume. For indolent NHL, often treated with RT alone, larger fields should be considered. Newer treatment techniques, including intensity modulated RT, breath holding, image guided RT, and 4-dimensional imaging, should be implemented, and their use is expected to decrease significantly the risk for normal tissue damage while still achieving the primary goal of local tumor control.

  16. Characteristics and effectiveness of diabetes self-management educational programs targeted to racial/ethnic minority groups: a systematic review, meta-analysis and meta-regression

    PubMed Central

    2014-01-01

    Background It is not clear to what extent educational programs aimed at promoting diabetes self-management in ethnic minority groups are effective. The aim of this work was to systematically review the effectiveness of educational programs to promote the self-management of racial/ethnic minority groups with type 2 diabetes, and to identify programs’ characteristics associated with greater success. Methods We undertook a systematic literature review. Specific searches were designed and implemented for Medline, EMBASE, CINAHL, ISI Web of Knowledge, Scirus, Current Contents and nine additional sources (from inception to October 2012). We included experimental and quasi-experimental studies assessing the impact of educational programs targeted to racial/ethnic minority groups with type 2 diabetes. We only included interventions conducted in countries members of the OECD. Two reviewers independently screened citations. Structured forms were used to extract information on intervention characteristics, effectiveness, and cost-effectiveness. When possible, we conducted random-effects meta-analyses using standardized mean differences to obtain aggregate estimates of effect size with 95% confidence intervals. Two reviewers independently extracted all the information and critically appraised the studies. Results We identified thirty-seven studies reporting on thirty-nine educational programs. Most of them were conducted in the US, with African American or Latino participants. Most programs obtained some benefits over standard care in improving diabetes knowledge, self-management behaviors and clinical outcomes. A meta-analysis of 20 randomized controlled trials (3,094 patients) indicated that the programs produced a reduction in glycated hemoglobin of -0.31% (95% CI -0.48% to -0.14%). Diabetes knowledge and self-management measures were too heterogeneous to pool. Meta-regressions showed larger reduction in glycated hemoglobin in individual and face to face delivered

  17. Group Grammar

    ERIC Educational Resources Information Center

    Adams, Karen

    2015-01-01

    In this article Karen Adams demonstrates how to incorporate group grammar techniques into a classroom activity. In the activity, students practice using the target grammar to do something they naturally enjoy: learning about each other.

  18. C-terminal extension of calmodulin-like 3 protein from Oryza sativa L.: interaction with a high mobility group target protein.

    PubMed

    Chinpongpanich, Aumnart; Phean-O-Pas, Srivilai; Thongchuang, Mayura; Qu, Li-Jia; Buaboocha, Teerapong

    2015-11-01

    A large number of calmodulin-like (CML) proteins are present in plants, but there is little detailed information on the functions of these proteins in rice (Oryza sativa L.). Here, the CML3 protein from rice (OsCML3) and its truncated form lacking the C-terminal extension (OsCML3m) were found to exhibit a Ca2+-binding property and subsequent conformational change, but the ability to bind the CaM kinase II peptide was only observed for OsCML3m. Changes in their secondary structure upon Ca2+-binding measured by circular dichroism revealed that OsCML3m had a higher helical content than OsCML3. Moreover, OsCML3 was mainly localized in the plasma membrane, whereas OsCML3m was found in the nucleus. The rice high mobility group B1 (OsHMGB1) protein was identified as one of the putative OsCML3 target proteins. Bimolecular fluorescence complementation analysis revealed that OsHMGB1 bound OsCML3, OsCML3m or OsCML3s (cysteine to serine mutation at the prenylation site) in the nucleus presumably through the methionine and phenylalanine-rich hydrophobic patches, confirming that OsHMGB1 is a target protein in planta. The effect of OsCML3 or OsCML3m on the DNA-binding ability of OsHMGB1 was measured using an electrophoretic mobility shift assay. OsCML3m decreased the level of OsHMGB1 binding to pUC19 double-stranded DNA whereas OsCML3 did not. Taken together, OsCML3 probably provides a mechanism for manipulating the DNA-binding ability of OsHMGB1 in the nucleus and its C-terminal extension provides an intracellular Ca2+ regulatory switch. PMID:26423116

  19. C-terminal extension of calmodulin-like 3 protein from Oryza sativa L.: interaction with a high mobility group target protein.

    PubMed

    Chinpongpanich, Aumnart; Phean-O-Pas, Srivilai; Thongchuang, Mayura; Qu, Li-Jia; Buaboocha, Teerapong

    2015-11-01

    A large number of calmodulin-like (CML) proteins are present in plants, but there is little detailed information on the functions of these proteins in rice (Oryza sativa L.). Here, the CML3 protein from rice (OsCML3) and its truncated form lacking the C-terminal extension (OsCML3m) were found to exhibit a Ca2+-binding property and subsequent conformational change, but the ability to bind the CaM kinase II peptide was only observed for OsCML3m. Changes in their secondary structure upon Ca2+-binding measured by circular dichroism revealed that OsCML3m had a higher helical content than OsCML3. Moreover, OsCML3 was mainly localized in the plasma membrane, whereas OsCML3m was found in the nucleus. The rice high mobility group B1 (OsHMGB1) protein was identified as one of the putative OsCML3 target proteins. Bimolecular fluorescence complementation analysis revealed that OsHMGB1 bound OsCML3, OsCML3m or OsCML3s (cysteine to serine mutation at the prenylation site) in the nucleus presumably through the methionine and phenylalanine-rich hydrophobic patches, confirming that OsHMGB1 is a target protein in planta. The effect of OsCML3 or OsCML3m on the DNA-binding ability of OsHMGB1 was measured using an electrophoretic mobility shift assay. OsCML3m decreased the level of OsHMGB1 binding to pUC19 double-stranded DNA whereas OsCML3 did not. Taken together, OsCML3 probably provides a mechanism for manipulating the DNA-binding ability of OsHMGB1 in the nucleus and its C-terminal extension provides an intracellular Ca2+ regulatory switch.

  20. An H3K9/S10 methyl-phospho switch modulates Polycomb and Pol II binding at repressed genes during differentiation.

    PubMed

    Sabbattini, Pierangela; Sjoberg, Marcela; Nikic, Svetlana; Frangini, Alberto; Holmqvist, Per-Henrik; Kunowska, Natalia; Carroll, Tom; Brookes, Emily; Arthur, Simon J; Pombo, Ana; Dillon, Niall

    2014-03-01

    Methylated histones H3K9 and H3K27 are canonical epigenetic silencing modifications in metazoan organisms, but the relationship between the two modifications has not been well characterized. H3K9me3 coexists with H3K27me3 in pluripotent and differentiated cells. However, we find that the functioning of H3K9me3 is altered by H3S10 phosphorylation in differentiated postmitotic osteoblasts and cycling B cells. Deposition of H3K9me3/S10ph at silent genes is partially mediated by the mitogen- and stress-activated kinases (MSK1/2) and the Aurora B kinase. Acquisition of H3K9me3/S10ph during differentiation correlates with loss of paused S5 phosphorylated RNA polymerase II, which is present on Polycomb-regulated genes in embryonic stem cells. Reduction of the levels of H3K9me3/S10ph by kinase inhibition results in increased binding of RNAPIIS5ph and the H3K27 methyltransferase Ezh1 at silent promoters. Our results provide evidence of a novel developmentally regulated methyl-phospho switch that modulates Polycomb regulation in differentiated cells and stabilizes repressed states.

  1. Radiation Therapy Oncology Group Consensus Panel Guidelines for the Delineation of the Clinical Target Volume in the Postoperative Treatment of Pancreatic Head Cancer

    SciTech Connect

    Goodman, Karyn A.; Regine, William F.; Dawson, Laura A.; Ben-Josef, Edgar; Haustermans, Karin; Bosch, Walter R.; Turian, Julius; Abrams, Ross A.

    2012-07-01

    Purpose: To develop contouring guidelines to be used in the Radiation Therapy Oncology Group protocol 0848, a Phase III randomized trial evaluating the benefit of adjuvant chemoradiation in patients with resected head of pancreas cancer. Methods and Materials: A consensus committee of six radiation oncologists with expertise in gastrointestinal radiotherapy developed stepwise contouring guidelines and an atlas for the delineation of the clinical target volume (CTV) in the postoperative treatment of pancreas cancer, based on identifiable regions of interest and margin expansions. Areas at risk for subclinical disease to be included in the CTV were defined, including nodal regions, anastomoses, and the preoperative primary tumor location. Regions of interest that could be reproducibly contoured on postoperative imaging after a pancreaticoduodenectomy were identified. Standardized expansion margins to encompass areas at risk were developed after multiple iterations to determine the optimal margin expansions. Results: New contouring recommendations based on CT anatomy were established. Written guidelines for the delineation of the postoperative CTV and normal tissues, as well as a Web-based atlas, were developed. Conclusions: The postoperative abdomen has been a difficult area for effective radiotherapy. These new guidelines will help physicians create fields that better encompass areas at risk and minimize dose to normal tissues.

  2. Toll-like receptor 4 and high-mobility group box-1 are involved in ictogenesis and can be targeted to reduce seizures.

    PubMed

    Maroso, Mattia; Balosso, Silvia; Ravizza, Teresa; Liu, Jaron; Aronica, Eleonora; Iyer, Anand M; Rossetti, Carlo; Molteni, Monica; Casalgrandi, Maura; Manfredi, Angelo A; Bianchi, Marco E; Vezzani, Annamaria

    2010-04-01

    Brain inflammation is a major factor in epilepsy, but the impact of specific inflammatory mediators on neuronal excitability is incompletely understood. Using models of acute and chronic seizures in C57BL/6 mice, we discovered a proconvulsant pathway involving high-mobility group box-1 (HMGB1) release from neurons and glia and its interaction with Toll-like receptor 4 (TLR4), a key receptor of innate immunity. Antagonists of HMGB1 and TLR4 retard seizure precipitation and decrease acute and chronic seizure recurrence. TLR4-defective C3H/HeJ mice are resistant to kainate-induced seizures. The proconvulsant effects of HMGB1, like those of interleukin-1beta (IL-1beta), are partly mediated by ifenprodil-sensitive N-methyl-d-aspartate (NMDA) receptors. Increased expression of HMGB1 and TLR4 in human epileptogenic tissue, like that observed in the mouse model of chronic seizures, suggests a role for the HMGB1-TLR4 axis in human epilepsy. Thus, HMGB1-TLR4 signaling may contribute to generating and perpetuating seizures in humans and might be targeted to attain anticonvulsant effects in epilepsies that are currently resistant to drugs. PMID:20348922

  3. MicroRNA-142-3p inhibits hypoxia/reoxygenation-induced apoptosis and fibrosis of cardiomyocytes by targeting high mobility group box 1

    PubMed Central

    Wang, Yi; Ouyang, Min; Wang, Qiong; Jian, Zaijin

    2016-01-01

    Myocardial ischemia/reperfusion (I/R) injury may cause the apoptosis of cardiomyocytes as well as cardiac fibrosis, which is characterized as the transdifferentiation of fibroblasts to myofibroblasts and collagen deposition. MicroRNAs (miRNAs or miRs) have been demonstrated to be involved in myocardial I/R injury. However, the underlying molecular mechanism remains largely unclear. In the present study, mouse cardiomyocyte M6200 cells were treated with hypoxia/reoxygenation (H/R). Our data indicated that H/R treatment led to cell apoptosis, the increased expression of fibrosis-related proteins, namely collagen I, II, III, and fibronectin, as well as the downregulation of miR-142-3p in M6200 cells. Overexpression of miR-142-3p suppressed the H/R-induced apoptosis and fibrosis of M6200 cells. Bioinformatics analysis and a Dual-Luciferase reporter assay further identified high mobility group box 1 (HMGB1) as a direct target gene of miR-142-3p, and miR-142-3p negatively regulated the protein level of HMGB1 in M6200 cells. Furthermore, knockdown of HMGB1 enhanced cell proliferation whereas it inhibited the apoptosis and fibrosis of M6200 cells. In addition, TGF-β1/Smad3 signaling was suggested to be involved in the miR-142-3p/HMGB1-mediated apoptosis and fibrosis of M6200 cells treated with H/R. Taken together, the findings of the present study demonstrate that miR-142-3p inhibits H/R-induced apoptosis and fibrosis of cardiomyocytes, partly at least, by the direct inhibition of HMGB1 expression. Therefore, these findings have increased our understanding of the pathogenesis of H/R-induced myocardial injury.

  4. Identification of Pou5f1, Sox2, and Nanog downstream target genes with statistical confidence by applying a novel algorithm to time course microarray and genome-wide chromatin immunoprecipitation data

    PubMed Central

    Sharov, Alexei A; Masui, Shinji; Sharova, Lioudmila V; Piao, Yulan; Aiba, Kazuhiro; Matoba, Ryo; Xin, Li; Niwa, Hitoshi; Ko, Minoru SH

    2008-01-01

    Background Target genes of a transcription factor (TF) Pou5f1 (Oct3/4 or Oct4), which is essential for pluripotency maintenance and self-renewal of embryonic stem (ES) cells, have previously been identified based on their response to Pou5f1 manipulation and occurrence of Chromatin-immunoprecipitation (ChIP)-binding sites in promoters. However, many responding genes with binding sites may not be direct targets because response may be mediated by other genes and ChIP-binding site may not be functional in terms of transcription regulation. Results To reduce the number of false positives, we propose to separate responding genes into groups according to direction, magnitude, and time of response, and to apply the false discovery rate (FDR) criterion to each group individually. Using this novel algorithm with stringent statistical criteria (FDR < 0.2) to a compendium of published and new microarray data (3, 6, 12, and 24 hr after Pou5f1 suppression) and published ChIP data, we identified 420 tentative target genes (TTGs) for Pou5f1. The majority of TTGs (372) were down-regulated after Pou5f1 suppression, indicating that the Pou5f1 functions as an activator of gene expression when it binds to promoters. Interestingly, many activated genes are potent suppressors of transcription, which include polycomb genes, zinc finger TFs, chromatin remodeling factors, and suppressors of signaling. Similar analysis showed that Sox2 and Nanog also function mostly as transcription activators in cooperation with Pou5f1. Conclusion We have identified the most reliable sets of direct target genes for key pluripotency genes – Pou5f1, Sox2, and Nanog, and found that they predominantly function as activators of downstream gene expression. Thus, most genes related to cell differentiation are suppressed indirectly. PMID:18522731

  5. Fragment based group QSAR and molecular dynamics mechanistic studies on arylthioindole derivatives targeting the α-β interfacial site of human tubulin

    PubMed Central

    2014-01-01

    Background A number of microtubule disassembly blocking agents and inhibitors of tubulin polymerization have been elements of great interest in anti-cancer therapy, some of them even entering into the clinical trials. One such class of tubulin assembly inhibitors is of arylthioindole derivatives which results in effective microtubule disorganization responsible for cell apoptosis by interacting with the colchicine binding site of the β-unit of tubulin close to the interface with the α unit. We modelled the human tubulin β unit (chain D) protein and performed docking studies to elucidate the detailed binding mode of actions associated with their inhibition. The activity enhancing structural aspects were evaluated using a fragment-based Group QSAR (G-QSAR) model and was validated statistically to determine its robustness. A combinatorial library was generated keeping the arylthioindole moiety as the template and their activities were predicted. Results The G-QSAR model obtained was statistically significant with r2 value of 0.85, cross validated correlation coefficient q2 value of 0.71 and pred_r2 (r2 value for test set) value of 0.89. A high F test value of 65.76 suggests robustness of the model. Screening of the combinatorial library on the basis of predicted activity values yielded two compounds HPI (predicted pIC50 = 6.042) and MSI (predicted pIC50 = 6.001) whose interactions with the D chain of modelled human tubulin protein were evaluated in detail. A toxicity evaluation resulted in MSI being less toxic in comparison to HPI. Conclusions The study provides an insight into the crucial structural requirements and the necessary chemical substitutions required for the arylthioindole moiety to exhibit enhanced inhibitory activity against human tubulin. The two reported compounds HPI and MSI showed promising anti cancer activities and thus can be considered as potent leads against cancer. The toxicity evaluation of these compounds suggests that MSI is a promising

  6. MicroRNA-31 Is a Transcriptional Target of Histone Deacetylase Inhibitors and a Regulator of Cellular Senescence*

    PubMed Central

    Cho, Joon-Ho; Dimri, Manjari; Dimri, Goberdhan P.

    2015-01-01

    MicroRNAs (miRNAs) have emerged as important regulators of tumorigenesis. Several miRNAs, which can function either as oncomiRs or tumor suppressive miRs are deregulated in cancer cells. The microRNA-31 (miR-31) has been shown to be overexpressed in metastatic breast cancer. It promotes multiple oncogenic phenotypes, including proliferation, motility, and invasion of cancer cells. Using a breast cancer-related miRNA array analysis, we identified miR-31 as a novel target of histone deacetylase inhibitors (HDACi) in breast cancer cells. Specifically, we show that sodium butyrate (NaB) and panobinostat (LBH589), two broad-spectrum HDAC inhibitors up-regulate hsa-miR-31 (miR-31). The up-regulation of miR-31 was accompanied by repression of the polycomb group (PcG) protein BMI1 and induction of cellular senescence. We further show that inhibition of miR-31 overcomes the senescence-inducing effect of HDACi, and restores expression of the PcG protein BMI1. Interestingly, BMI1 also acts as a repressor of miR-31 transcription, suggesting a cross-negative feedback loop between the expression of miR-31 and BMI1. Our data suggest that miR-31 is an important physiological target of HDACi, and that it is an important regulator of senescence relevant to cancer. These studies further suggest that manipulation of miR-31 expression can be used to modulate senescence-related pathological conditions such as cancer, and the aging process. PMID:25737447

  7. Polycomb segment myeloid malignancies.

    PubMed

    Saunthararajah, Yogen; Maciejewski, Jaroslaw

    2012-02-01

    An unexpected revelation of cancer genome studies has been frequent abnormality in genes for factors that modify chromatin, underscored in this issue of Blood by reports from Score et al and Kroeze et al of inactivating mutations and chromosome loss in SUZ12, EED and JARID2 in myelodysplastic syndrome (MDS) and myeloproliferative disease (MPD).

  8. Cultural targeting and tailoring of shared decision making technology: a theoretical framework for improving the effectiveness of patient decision aids in culturally diverse groups.

    PubMed

    Alden, Dana L; Friend, John; Schapira, Marilyn; Stiggelbout, Anne

    2014-03-01

    Patient decision aids are known to positively impact outcomes critical to shared decision making (SDM), such as gist knowledge and decision preparedness. However, research on the potential improvement of these and other important outcomes through cultural targeting and tailoring of decision aids is very limited. This is the case despite extensive evidence supporting use of cultural targeting and tailoring to improve the effectiveness of health communications. Building on prominent psychological theory, we propose a two-stage framework incorporating cultural concepts into the design process for screening and treatment decision aids. The first phase recommends use of cultural constructs, such as collectivism and individualism, to differentially target patients whose cultures are known to vary on these dimensions. Decision aid targeting is operationalized through use of symbols and values that appeal to members of the given culture. Content dimensions within decision aids that appear particularly appropriate for targeting include surface level visual characteristics, language, beliefs, attitudes and values. The second phase of the framework is based on evidence that individuals vary in terms of how strongly cultural norms influence their approach to problem solving and decision making. In particular, the framework hypothesizes that differences in terms of access to cultural mindsets (e.g., access to interdependent versus independent self) can be measured up front and used to tailor decision aids. Thus, the second phase in the framework emphasizes the importance of not only targeting decision aid content, but also tailoring the information to the individual based on measurement of how strongly he/she is connected to dominant cultural mindsets. Overall, the framework provides a theory-based guide for researchers and practitioners who are interested in using cultural targeting and tailoring to develop and test decision aids that move beyond a "one-size fits all" approach

  9. Cultural targeting and tailoring of shared decision making technology: a theoretical framework for improving the effectiveness of patient decision aids in culturally diverse groups.

    PubMed

    Alden, Dana L; Friend, John; Schapira, Marilyn; Stiggelbout, Anne

    2014-03-01

    Patient decision aids are known to positively impact outcomes critical to shared decision making (SDM), such as gist knowledge and decision preparedness. However, research on the potential improvement of these and other important outcomes through cultural targeting and tailoring of decision aids is very limited. This is the case despite extensive evidence supporting use of cultural targeting and tailoring to improve the effectiveness of health communications. Building on prominent psychological theory, we propose a two-stage framework incorporating cultural concepts into the design process for screening and treatment decision aids. The first phase recommends use of cultural constructs, such as collectivism and individualism, to differentially target patients whose cultures are known to vary on these dimensions. Decision aid targeting is operationalized through use of symbols and values that appeal to members of the given culture. Content dimensions within decision aids that appear particularly appropriate for targeting include surface level visual characteristics, language, beliefs, attitudes and values. The second phase of the framework is based on evidence that individuals vary in terms of how strongly cultural norms influence their approach to problem solving and decision making. In particular, the framework hypothesizes that differences in terms of access to cultural mindsets (e.g., access to interdependent versus independent self) can be measured up front and used to tailor decision aids. Thus, the second phase in the framework emphasizes the importance of not only targeting decision aid content, but also tailoring the information to the individual based on measurement of how strongly he/she is connected to dominant cultural mindsets. Overall, the framework provides a theory-based guide for researchers and practitioners who are interested in using cultural targeting and tailoring to develop and test decision aids that move beyond a "one-size fits all" approach

  10. EZH2 in Bladder Cancer, a Promising Therapeutic Target

    PubMed Central

    Martínez-Fernández, Mónica; Rubio, Carolina; Segovia, Cristina; López-Calderón, Fernando F.; Dueñas, Marta; Paramio, Jesús M.

    2015-01-01

    Bladder Cancer (BC) represents a current clinical and social challenge. The recent studies aimed to describe the genomic landscape of BC have underscored the relevance of epigenetic alterations in the pathogenesis of these tumors. Among the epigenetic alterations, histone modifications occupied a central role not only in cancer, but also in normal organism homeostasis and development. EZH2 (Enhancer of Zeste Homolog 2) belongs to the Polycomb repressive complex 2 as its catalytic subunit, which through the trimethylation of H3 (Histone 3) on K27 (Lysine 27), produces gene silencing. EZH2 is frequently overexpressed in multiple tumor types, including BC, and plays multiple roles besides the well-recognized histone mark generation. In this review, we summarize the present knowledge on the oncogenic roles of EZH2 and its potential use as a therapeutic target, with special emphasis on BC pathogenesis and management. PMID:26580594

  11. A genome-wide identification and characterization of mircoRNAs and their targets in 'Suli' pear (Pyrus pyrifolia white pear group).

    PubMed

    Niu, Qingfeng; Qian, Minjie; Liu, Guoqin; Yang, Fengxia; Teng, Yuanwen

    2013-12-01

    MicroRNAs (miRNAs) are a class of small non-coding RNA molecules that are endogenous regulators of gene expression. miRNAs play a crucial role in cells via degradation of target mRNAs or by inhibition of target protein translation. In the present study, 186 new potentially conserved pear miRNAs belonging to 37 families were identified. The length of mature miRNAs ranged from 19 to 24 nt, and most of the miRNAs (154 out of 186) were 21 nt in length. The length of pre-miRNAs in pear was also found to vary from 62 to 282 nt with an average of 105 ± 43 nt. The potential miRNAs belonged to 29 clusters involving 20 different miRNA families. Using these potential miRNAs, we further scoured of the pear genome and found 326 potential target genes, which included transcription factors, stress responsive genes, and the genes involved in transmembrane transport and signal transduction. Gene ontology analysis of these potential targets suggested that 47 biological processes were potentially regulated by miRNAs, including oxidation-reduction, stress response, transport, etc. KEGG pathway analysis showed that the identified miRNAs were found in 15 metabolism networks which were related to starch and sucrose metabolism, and ascorbate and aldarate metabolism, among others. Our study will help in the further understanding of the essential role of miRNAs in growth and development and stress response of pear.

  12. A recommended practical approach to the management of target therapy and angiogenesis inhibitors cardiotoxicity: an opinion paper of the working group on drug cardiotoxicity and cardioprotection, Italian Society of Cardiology

    PubMed Central

    Maurea, Nicola; Spallarossa, Paolo; Cadeddu, Christian; Madonna, Rosalinda; Mele, Donato; Monte, Ines; Novo, Giuseppina; Pagliaro, Pasquale; Pepe, Alessia; Tocchetti, Carlo G.; Zito, Concetta; Mercuro, Giuseppe

    2016-01-01

    The US National Cancer Institute estimates that cardiotoxicity (CTX) from target therapy refers mostly to four groups of drugs: epidermal growth factor receptor 2 inhibitors, angiogenic inhibitors, directed Abelson murine leukemia viral oncogene homolog inhibitors, and proteasome inhibitors. The main cardiotoxic side-effects related to antiepidermal growth factor receptor 2 therapy are left ventricular systolic dysfunction and heart failure. Angiogenesis inhibitors are associated with hypertension, left ventricular dysfunction/heart failure, myocardial ischemia, QT prolongation, and thrombosis. Moreover, other agents may be related to CTX induced by treatment. In this study, we review the guidelines for a practical approach for the management of CTX in patients under anticancer target therapy. PMID:27183530

  13. Tyrosine kinome sequencing of pediatric acute lymphoblastic leukemia: a report from the Children's Oncology Group TARGET Project | Office of Cancer Genomics

    Cancer.gov

    TARGET researchers sequenced the tyrosine kinome and downstream signaling genes in 45 high-risk pediatric ALL cases with activated kinase signaling, including Ph-like ALL, to establish the incidence of tyrosine kinase mutations in this cohort. The study confirmed previously identified somatic mutations in JAK and FLT3, but did not find novel alterations in any additional tyrosine kinases or downstream genes. The mechanism of kinase signaling activation in this high-risk subgroup of pediatric ALL remains largely unknown.

  14. A novel quantitation approach for maximizing detectable targets for offensive/volatile odorants with diverse functional groups by thermal desorption-gas chromatography-mass spectrometry

    PubMed Central

    Kim, Yong-Hyun; Kim, Ki-Hyun

    2016-01-01

    A multitude of analytical systems are needed to analyze diverse odorants with various functionalities. In this study, an experimental method was developed to assess the maximum covering range of odorants using a single experimental setup consisting of a thermal desorber-gas chromatography-mass spectrometry system. To this end, a total of 20 offensive odorants (aldehyde, ketone, ester, alcohol, aromatic, sulfide, amine, and carboxyl) were selected and tested by a single system. The analytical results of standards and environmental samples were evaluated in a number of respects. In the analysis of the standards, all targets were quantified via Carbopack (C + B + X) tube sampling while operating the thermal desorber at −25 °C. The method detection limits of 18 targets (exception of 2 out of the 20 targets: acetaldehyde and methanethiol) were excellent (mean 0.04 ± 0.03 ppb) in terms of their odor threshold values (74.7 ± 140 ~ 624 ± 1,729 ppb). The analysis of organic fertilizer plant samples at a pig farm (slurry treatment facility, compost facility, and ambient air) confirmed the presence of 18 odorants from 0.03 ppb (dimethyldisulfide, ambient sample) to 522 ppb (methyl ethyl ketone, slurry treatment facility). As such, our method allowed simultaneous quantitation of most key odorants with sufficient reliability and sensitivity. PMID:27404037

  15. A novel quantitation approach for maximizing detectable targets for offensive/volatile odorants with diverse functional groups by thermal desorption-gas chromatography-mass spectrometry

    NASA Astrophysics Data System (ADS)

    Kim, Yong-Hyun; Kim, Ki-Hyun

    2016-07-01

    A multitude of analytical systems are needed to analyze diverse odorants with various functionalities. In this study, an experimental method was developed to assess the maximum covering range of odorants using a single experimental setup consisting of a thermal desorber-gas chromatography-mass spectrometry system. To this end, a total of 20 offensive odorants (aldehyde, ketone, ester, alcohol, aromatic, sulfide, amine, and carboxyl) were selected and tested by a single system. The analytical results of standards and environmental samples were evaluated in a number of respects. In the analysis of the standards, all targets were quantified via Carbopack (C + B + X) tube sampling while operating the thermal desorber at ‑25 °C. The method detection limits of 18 targets (exception of 2 out of the 20 targets: acetaldehyde and methanethiol) were excellent (mean 0.04 ± 0.03 ppb) in terms of their odor threshold values (74.7 ± 140 ~ 624 ± 1,729 ppb). The analysis of organic fertilizer plant samples at a pig farm (slurry treatment facility, compost facility, and ambient air) confirmed the presence of 18 odorants from 0.03 ppb (dimethyldisulfide, ambient sample) to 522 ppb (methyl ethyl ketone, slurry treatment facility). As such, our method allowed simultaneous quantitation of most key odorants with sufficient reliability and sensitivity.

  16. A novel quantitation approach for maximizing detectable targets for offensive/volatile odorants with diverse functional groups by thermal desorption-gas chromatography-mass spectrometry.

    PubMed

    Kim, Yong-Hyun; Kim, Ki-Hyun

    2016-01-01

    A multitude of analytical systems are needed to analyze diverse odorants with various functionalities. In this study, an experimental method was developed to assess the maximum covering range of odorants using a single experimental setup consisting of a thermal desorber-gas chromatography-mass spectrometry system. To this end, a total of 20 offensive odorants (aldehyde, ketone, ester, alcohol, aromatic, sulfide, amine, and carboxyl) were selected and tested by a single system. The analytical results of standards and environmental samples were evaluated in a number of respects. In the analysis of the standards, all targets were quantified via Carbopack (C + B + X) tube sampling while operating the thermal desorber at -25 °C. The method detection limits of 18 targets (exception of 2 out of the 20 targets: acetaldehyde and methanethiol) were excellent (mean 0.04 ± 0.03 ppb) in terms of their odor threshold values (74.7 ± 140 ~ 624 ± 1,729 ppb). The analysis of organic fertilizer plant samples at a pig farm (slurry treatment facility, compost facility, and ambient air) confirmed the presence of 18 odorants from 0.03 ppb (dimethyldisulfide, ambient sample) to 522 ppb (methyl ethyl ketone, slurry treatment facility). As such, our method allowed simultaneous quantitation of most key odorants with sufficient reliability and sensitivity. PMID:27404037

  17. Efficacy and Toxicity of Mammalian Target Rapamycin Inhibitors in Patients with Metastatic Renal Cell Carcinoma with Renal Insufficiency: The Korean Cancer Study Group GU 14-08

    PubMed Central

    Kim, Ki Hyang; Kim, Joo Hoon; Lee, Ji Young; Kim, Hyo Song; Heo, Su Jin; Kim, Ji Hyung; Kim, Ho Young; Rha, Sun Young

    2016-01-01

    Purpose We evaluated the efficacy and toxicity of mammalian target rapamycin inhibitors in Korean patients with metastatic renal cell carcinoma (mRCC) with chronic renal insufficiency not requiring dialysis. Materials and Methods Korean patients with mRCC and chronic renal insufficiency not requiring dialysis treated with everolimus or temsirolimus between January 2008 and December 2014 were included. Patient characteristics, clinical outcomes, and toxicities were evaluated. Overall survival (OS) and progression-free survival (PFS) durations were evaluated according to the degree of renal impairment. Results Eighteen patients were considered eligible for the study (median age, 59 years). The median glomerular filtration rate was 51.5 mL/min/1.73 m2. The best response was partial response in six patients and stable disease in 11 patients. The median PFS and OS durations were 8 months (95% confidence interval [CI], 0 to 20.4) and 32 months (95% CI, 27.5 to 36.5), respectively. The most common non-hematologic and grade 3/4 adverse events included stomatitis, fatigue, flu-like symptoms, and anorexia as well as elevated creatinine level. Conclusion Mammalian target rapamycin inhibitors were efficacious and did not increase toxicity in Korean patients with mRCC and chronic renal insufficiency not requiring dialysis. PMID:26875195

  18. Can a Targeted, Group-Based CBT Intervention Reduce Depression and Anxiety and Improve Self-Concept in Primary-Age Children?

    ERIC Educational Resources Information Center

    O'Callaghan, Paul; Cunningham, Enda

    2015-01-01

    This pilot study examined the impact of a 10 session, group-based, early-intervention cognitive behavioural therapy (CBT) programme (Cool Connections) on anxiety, depression and self-concept in nine 8-11 year old pupils in Northern Ireland. The intervention was facilitated by a teacher, education welfare officer and two classroom assistants, with…

  19. Vocational Guidance Needs for Various Target Groups of Young People under the Age of 28 in France. National Report. CEDEFOP Panorama. First Edition.

    ERIC Educational Resources Information Center

    Froissart, Catherine; And Others

    A field survey examined the vocational guidance needs of two groups of people 25 years or younger in France: youths undergoing initial training in vocational-technical education (VTE) and young job seekers who are potential candidates for achieving level V vocational qualifications. Interviews were conducted with youths from two different regions…

  20. Effectiveness of Simultaneous Prompting in Small Group: The Opportunity of Acquiring Non-Target Skills through Observational Learning and Instructive Feedback

    ERIC Educational Resources Information Center

    Gursel, Oguz; Tekin-Iftar, Elif; Bozkurt, Funda

    2006-01-01

    A multiple probe study across behaviors, replicated across students, assessed the effectiveness of simultaneous prompting (SP) in a small group teaching arrangement on teaching (a) to show the provinces, rivers, and border countries of Turkey on a map and (b) to expressively identify the names of the symbols which are usually used in math.…

  1. Targeting binge eating through components of dialectical behavior therapy: preliminary outcomes for individually supported diary card self-monitoring versus group-based DBT.

    PubMed

    Klein, Angela S; Skinner, Jeremy B; Hawley, Kristin M

    2013-12-01

    The current study examined two condensed adaptations of dialectical behavior therapy (DBT) for binge eating. Women with full- or sub-threshold variants of either binge eating disorder or bulimia nervosa were randomly assigned to individually supported self-monitoring using adapted DBT diary cards (DC) or group-based DBT, each 15 sessions over 16 weeks. DC sessions focused on problem-solving diary card completion issues, praising diary card completion, and supporting nonjudgmental awareness of eating-related habits and urges, but not formally teaching DBT skills. Group-based DBT included eating mindfulness, progressing through graded exposure; mindfulness, emotion regulation, and distress tolerance skills; and coaching calls between sessions. Both treatments evidenced large and significant improvements in binge eating, bulimic symptoms, and interoceptive awareness. For group-based DBT, ineffectiveness, drive for thinness, body dissatisfaction, and perfectionism also decreased significantly, with medium to large effect sizes. For DC, results were not significant but large in effect size for body dissatisfaction and medium in effect size for ineffectiveness and drive for thinness. Retention for both treatments was higher than recent trends for eating disorder treatment in fee-for-service practice and for similar clinic settings, but favored DC, with the greater attrition of group-based DBT primarily attributed to its more intensive and time-consuming nature, and dropout overall associated with less pretreatment impairment and greater interoceptive awareness. This preliminary investigation suggests that with both abbreviated DBT-based treatments, substantial improvement in core binge eating symptoms is possible, enhancing potential avenues for implementation beyond more time-intensive DBT.

  2. Polycomb repressor complex 1 promotes gene silencing through H2AK119 mono-ubiquitination in acinar-to-ductal metaplasia and pancreatic cancer cells

    PubMed Central

    Reinhard, Tobias; Popp, Anna; Schäffer, Isabell; Raulefs, Susanne; Kong, Bo; Esposito, Irene

    2016-01-01

    Acinar-to-ductal metaplasia (ADM) occurring in cerulein-mediated pancreatitis or in oncogenic Kras-driven pancreatic cancer development is accompanied by extensive changes in the transcriptional program. In this process, acinar cells shut down the expression of acinar specific differentiation genes and re-express genes usually found in embryonic pancreatic progenitor cells. Previous studies have demonstrated that a loss of acinar-specific transcription factors sensitizes the cells towards oncogenic transformation, ultimately resulting in cancer development. However, the mechanism behind the transcriptional silencing of acinar cell fate genes in ADM and pancreatic cancer is largely unknown. Here, we analyzed whether elevated levels of the polycomb repressor complex 1 (PRC1) components Bmi1 and Ring1b and their catalyzed histone modification H2AK119ub in ADMs and tumor cells, are responsible for the mediation of acinar gene silencing. Therefore, we performed chromatin-immunoprecipitation in in vitro generated ADMs and isolated murine tumor cells against the repressive histone modifications H3K27me3 and H2AK119ub. We established that the acinar transcription factor complex Ptf1-L is epigenetically silenced in ADMs as well as in pancreatic tumor cells. For the first time, this work presents a possible mechanism of acinar gene silencing, which is an important prerequisite in the initiation and maintenance of a dedifferentiated cell state in ADMs and tumor cells. PMID:26716510

  3. The Saccharomyces cerevisiae Piccolo NuA4 histone acetyltransferase complex requires the Enhancer of Polycomb A domain and chromodomain to acetylate nucleosomes.

    PubMed

    Selleck, William; Fortin, Israël; Sermwittayawong, Decha; Côté, Jacques; Tan, Song

    2005-07-01

    Chromatin modification complexes are key gene regulatory factors which posttranslationally modify the histone component of chromatin with epigenetic marks. To address what features of chromatin modification complexes are responsible for the specific recognition of nucleosomes compared to naked histones, we have performed a functional dissection of the Esa1-containing Saccharomyces cerevisiae Piccolo NuA4 histone acetyltransferase complex. Our studies define the Piccolo determinants sufficient to assemble its three subunits into a complex as well as Piccolo determinants sufficient to specifically acetylate a chromatin template. We find that the conserved Enhancer of Polycomb A (EPcA) homology region of the Epl1 component and the N-terminal 165 amino acids of the Yng2 component of Piccolo are sufficient with Esa1 to specifically act on nucleosomes. We also find that the Esa1 chromodomain plays a critical role in Piccolo's ability to distinguish between histones and nucleosomes. In particular, specific point mutations in the chromodomain putative hydrophobic cage which strongly hinder growth in yeast greatly reduce histone acetyltransferase activity on nucleosome substrates, independent of histone methylation or other modifications. However, the chromodomain is not required for Piccolo to bind to nucleosomes, suggesting a role for the chromodomain in a catalysis step after nucleosome binding.

  4. The Saccharomyces cerevisiae Piccolo NuA4 Histone Acetyltransferase Complex Requires the Enhancer of Polycomb A Domain and Chromodomain To Acetylate Nucleosomes

    PubMed Central

    Selleck, William; Fortin, Israël; Sermwittayawong, Decha; Côté, Jacques; Tan, Song

    2005-01-01

    Chromatin modification complexes are key gene regulatory factors which posttranslationally modify the histone component of chromatin with epigenetic marks. To address what features of chromatin modification complexes are responsible for the specific recognition of nucleosomes compared to naked histones, we have performed a functional dissection of the Esa1-containing Saccharomyces cerevisiae Piccolo NuA4 histone acetyltransferase complex. Our studies define the Piccolo determinants sufficient to assemble its three subunits into a complex as well as Piccolo determinants sufficient to specifically acetylate a chromatin template. We find that the conserved Enhancer of Polycomb A (EPcA) homology region of the Epl1 component and the N-terminal 165 amino acids of the Yng2 component of Piccolo are sufficient with Esa1 to specifically act on nucleosomes. We also find that the Esa1 chromodomain plays a critical role in Piccolo's ability to distinguish between histones and nucleosomes. In particular, specific point mutations in the chromodomain putative hydrophobic cage which strongly hinder growth in yeast greatly reduce histone acetyltransferase activity on nucleosome substrates, independent of histone methylation or other modifications. However, the chromodomain is not required for Piccolo to bind to nucleosomes, suggesting a role for the chromodomain in a catalysis step after nucleosome binding. PMID:15964809

  5. miR-155 activates cytokine gene expression in Th17 cells by regulating the DNA-binding protein Jarid2 to relieve polycomb-mediated repression.

    PubMed

    Escobar, Thelma M; Kanellopoulou, Chrysi; Kugler, David G; Kilaru, Gokhul; Nguyen, Cuong K; Nagarajan, Vijayaraj; Bhairavabhotla, Ravikiran K; Northrup, Daniel; Zahr, Rami; Burr, Patrick; Liu, Xiuhuai; Zhao, Keji; Sher, Alan; Jankovic, Dragana; Zhu, Jinfang; Muljo, Stefan A

    2014-06-19

    Specification of the T helper 17 (Th17) cell lineage requires a well-defined set of transcription factors, but how these integrate with posttranscriptional and epigenetic programs to regulate gene expression is poorly understood. Here we found defective Th17 cell cytokine expression in miR-155-deficient CD4+ T cells in vitro and in vivo. Mir155 was bound by Th17 cell transcription factors and was highly expressed during Th17 cell differentiation. miR-155-deficient Th17 and T regulatory (Treg) cells expressed increased amounts of Jarid2, a DNA-binding protein that recruits the Polycomb Repressive Complex 2 (PRC2) to chromatin. PRC2 binding to chromatin and H3K27 histone methylation was increased in miR-155-deficient cells, coinciding with failure to express Il22, Il10, Il9, and Atf3. Defects in Th17 cell cytokine expression and Treg cell homeostasis in the absence of Mir155 could be partially suppressed by Jarid2 deletion. Thus, miR-155 contributes to Th17 cell function by suppressing the inhibitory effects of Jarid2.

  6. High School Students Are a Target Group for Fight against Self-Medication with Antimalarial Drugs: A Pilot Study in University of Kinshasa, Democratic Republic of Congo

    PubMed Central

    Kabongo Kamitalu, Ramsès; Aloni, Michel Ntetani

    2016-01-01

    Aim. To assess the self-medication against malaria infection in population of Congolese students in Kinshasa, Democratic Republic of Congo (DRC). Methods. A cross-sectional study was carried out in University of Kinshasa, Kinshasa, Democratic Republic of Congo. Medical records of all students with malaria admitted to Centre de Santé Universitaire of University of Kinshasa from January 1, 2008, to April 30, 2008, were reviewed retrospectively. Results. The median age of the patients was 25.4 years (range: from 18 to 36 years). The majority of them were male (67.9%). Artemisinin-based combination treatments (ACTs) was the most used self-prescribed antimalarial drugs. However, self-medication was associated with the ingestion of quinine in 19.9% of cases. No case of ingestion of artesunate/artemether in monotherapy was found. All the medicines taken were registered in DRC. In this series, self-prescribed antimalarial was very irrational in terms of dose and duration of treatment. Conclusion. This paper highlights self-medication by a group who should be aware of malaria treatment protocols. The level of self-prescribing quinine is relatively high among students and is disturbing for a molecule reserved for severe disease in Congolese health care policy in management of malaria. PMID:27340411

  7. HYDROGEN ISOTOPE TARGETS

    DOEpatents

    Ashley, R.W.

    1958-08-12

    The design of targets for use in the investigation of nuclear reactions of hydrogen isotopes by bombardment with accelerated particles is described. The target con struction eomprises a backing disc of a metal selected from the group consisting of molybdenunn and tungsten, a eoating of condensed titaniunn on the dise, and a hydrogen isotope selected from the group consisting of deuterium and tritium absorbed in the coatiag. The proeess for preparing these hydrogen isotope targets is described.

  8. Detection of long non-coding RNA in archival tissue: correlation with polycomb protein expression in primary and metastatic breast carcinoma.

    PubMed

    Chisholm, Karen M; Wan, Yue; Li, Rui; Montgomery, Kelli D; Chang, Howard Y; West, Robert B

    2012-01-01

    A major function of long non-coding RNAs (lncRNAs) is regulating gene expression through changes in chromatin state. Experimental evidence suggests that in cancer, they can influence Polycomb Repressive Complexes (PRC) to retarget to an occupancy pattern resembling that of the embryonic state. We have previously demonstrated that the expression level of lncRNA in the HOX locus, including HOTAIR, is a predictor of breast cancer metastasis. In this current project, RNA in situ hybridization of probes to three different lncRNAs (HOTAIR, ncHoxA1, and ncHoxD4), as well a immunohistochemical staining of EZH2, is undertaken in formalin-fixed paraffin-embedded breast cancer tissues in a high throughput tissue microarray format to correlate expression with clinicopathologic features. Though overall EZH2 and HOTAIR expression levels were highly correlated, the subset of cases with strong HOTAIR expression correlated with ER and PR positivity, while the subset of cases with strong EZH2 expression correlated with an increased proliferation rate, ER and PR negativity, HER2 underexpression, and triple negativity. Co-expression of HOTAIR and EZH2 trended with a worse outcome. In matched primary and metastatic cancers, both HOTAIR and EZH2 had increased expression in the metastatic carcinomas. This is the first study to show that RNA in situ hybridization of formalin fixed paraffin-embedded clinical material can be used to measure levels of long non-coding RNAs. This approach offers a method to make observations on lncRNAs that may influence the cancer epigenome in a tissue-based technique.

  9. Drosophila TDP-43 RNA-Binding Protein Facilitates Association of Sister Chromatid Cohesion Proteins with Genes, Enhancers and Polycomb Response Elements

    PubMed Central

    Misulovin, Ziva; Gause, Maria; Rickels, Ryan A; Shilatifard, Ali

    2016-01-01

    The cohesin protein complex mediates sister chromatid cohesion and participates in transcriptional control of genes that regulate growth and development. Substantial reduction of cohesin activity alters transcription of many genes without disrupting chromosome segregation. Drosophila Nipped-B protein loads cohesin onto chromosomes, and together Nipped-B and cohesin occupy essentially all active transcriptional enhancers and a large fraction of active genes. It is unknown why some active genes bind high levels of cohesin and some do not. Here we show that the TBPH and Lark RNA-binding proteins influence association of Nipped-B and cohesin with genes and gene regulatory sequences. In vitro, TBPH and Lark proteins specifically bind RNAs produced by genes occupied by Nipped-B and cohesin. By genomic chromatin immunoprecipitation these RNA-binding proteins also bind to chromosomes at cohesin-binding genes, enhancers, and Polycomb response elements (PREs). RNAi depletion reveals that TBPH facilitates association of Nipped-B and cohesin with genes and regulatory sequences. Lark reduces binding of Nipped-B and cohesin at many promoters and aids their association with several large enhancers. Conversely, Nipped-B facilitates TBPH and Lark association with genes and regulatory sequences, and interacts with TBPH and Lark in affinity chromatography and immunoprecipitation experiments. Blocking transcription does not ablate binding of Nipped-B and the RNA-binding proteins to chromosomes, indicating transcription is not required to maintain binding once established. These findings demonstrate that RNA-binding proteins help govern association of sister chromatid cohesion proteins with genes and enhancers. PMID:27662615

  10. Ubiquitin E3 Ligase Ring1b/Rnf2 of Polycomb Repressive Complex 1 Contributes to Stable Maintenance of Mouse Embryonic Stem Cells

    PubMed Central

    Hulsman, Danielle; Noback, Sonja; Heimerikx, Mike; Kerkhoven, Ron M.; Voncken, J. Willem; Wessels, Lodewyk F. A.; van Lohuizen, Maarten

    2008-01-01

    Background Polycomb repressive complex 1 (PRC1) core member Ring1b/Rnf2, with ubiquitin E3 ligase activity towards histone H2A at lysine 119, is essential for early embryogenesis. To obtain more insight into the role of Ring1b in early development, we studied its function in mouse embryonic stem (ES) cells. Methodology/Principal Findings We investigated the effects of Ring1b ablation on transcriptional regulation using Ring1b conditional knockout ES cells and large-scale gene expression analysis. The absence of Ring1b results in aberrant expression of key developmental genes and deregulation of specific differentiation-related pathways, including TGFbeta signaling, cell cycle regulation and cellular communication. Moreover, ES cell markers, including Zfp42/Rex-1 and Sox2, are downregulated. Importantly, retained expression of ES cell regulators Oct4, Nanog and alkaline phosphatase indicates that Ring1b-deficient ES cells retain important ES cell specific characteristics. Comparative analysis of our expression profiling data with previously published global binding studies shows that the genes that are bound by Ring1b in ES cells have bivalent histone marks, i.e. both active H3K4me3 and repressive H3K27me3, or the active H3K4me3 histone mark alone and are associated with CpG-‘rich’ promoters. However, deletion of Ring1b results in deregulation, mainly derepression, of only a subset of these genes, suggesting that additional silencing mechanisms are involved in repression of the other Ring1b bound genes in ES cells. Conclusions Ring1b is essential to stably maintain an undifferentiated state of mouse ES cells by repressing genes with important roles during differentiation and development. These genes are characterized by high CpG content promoters and bivalent histone marks or the active H3K4me3 histone mark alone. PMID:18493325

  11. Aberrant differential expression of EZH1 and EZH2 in Polycomb repressive complex 2 among B- and T/NK-cell neoplasms.

    PubMed

    Abdalkader, Lamia; Oka, Takashi; Takata, Katsuyoshi; Sato, Hiaki; Murakami, Ichiro; Otte, Arie P; Yoshino, Tadashi

    2016-08-01

    The Polycomb repressive complex-2 members (EZH2, EED, SUZ12 and EZH1) are important regulators of haematopoiesis, cell cycle and differentiation. Over-expression of EZH2 has been linked to cancer metastases and poor prognosis. Detailed information on the expression of other members in normal and neoplastic lymphoid tissue remains to be elucidated. Immunohistochemical and immunofluorescent analyses of 156 samples from haematopoietic neoplasms patients and 27 haematopoietic cell lines were used. B-cell neoplasms showed a significant over-expression of EZH2, EED and SUZ12 in the aggressive subtypes compared to the indolent subtypes and normal tissue (p = 0.000-0.046) while expression of EZH1 was decreased in mantle cell lymphoma compared to normal tissue (p = 0.011). T/NK-cell neoplasms also showed significant over-expression of EZH2, EED and SUZ12 (p = 0.000-0.002) and decreased expression of EZH1 (p = 0.001) compared to normal cells. EZH2 and EZH1 have opposite expression patterns both in normal and neoplastic lymphoid tissues as well as an opposite relation to Ki-67. These results were supported by western blotting analyses. Immunofluorescent staining revealed a difference in the intracellular localisation of EZH1 compared to other members. These evidences suggest that EZH2 and EZH1 are important in the counter-balancing mechanisms controlling proliferation/resting of lymphoid cells. The disruption of the balanced EZH2/EZH1 ratio may play important roles in the pathogenesis of lymphomas. PMID:27311868

  12. GRHL3/GET1 and Trithorax Group Members Collaborate to Activate the Epidermal Progenitor Differentiation Program

    PubMed Central

    Hopkin, Amelia Soto; Gordon, William; Klein, Rachel Herndon; Espitia, Francisco; Daily, Kenneth; Zeller, Michael; Baldi, Pierre; Andersen, Bogi

    2012-01-01

    The antagonistic actions of Polycomb and Trithorax are responsible for proper cell fate determination in mammalian tissues. In the epidermis, a self-renewing epithelium, previous work has shown that release from Polycomb repression only partially explains differentiation gene activation. We now show that Trithorax is also a key regulator of epidermal differentiation, not only through activation of genes repressed by Polycomb in progenitor cells, but also through activation of genes independent of regulation by Polycomb. The differentiation associated transcription factor GRHL3/GET1 recruits the ubiquitously expressed Trithorax complex to a subset of differentiation genes. PMID:22829784

  13. Chromodomain Ligand Optimization via Target-Class Directed Combinatorial Repurposing.

    PubMed

    Barnash, Kimberly D; Lamb, Kelsey N; Stuckey, Jacob I; Norris, Jacqueline L; Cholensky, Stephanie H; Kireev, Dmitri B; Frye, Stephen V; James, Lindsey I

    2016-09-16

    Efforts to develop strategies for small-molecule chemical probe discovery against the readers of the methyl-lysine (Kme) post-translational modification have been met with limited success. Targeted disruption of these protein-protein interactions via peptidomimetic inhibitor optimization is a promising alternative to small-molecule hit discovery; however, recognition of identical peptide motifs by multiple Kme reader proteins presents a unique challenge in the development of selective Kme reader chemical probes. These selectivity challenges are exemplified by the Polycomb repressive complex 1 (PRC1) chemical probe, UNC3866, which demonstrates submicromolar off-target affinity toward the non-PRC1 chromodomains CDYL2 and CDYL. Moreover, since peptidomimetics are challenging subjects for structure-activity relationship (SAR) studies, traditional optimization of UNC3866 would prove costly and time-consuming. Herein, we report a broadly applicable strategy for the affinity-based, target-class screening of chromodomains via the repurposing of UNC3866 in an efficient, combinatorial peptide library. A first-generation library yielded UNC4991, a UNC3866 analogue that exhibits a distinct selectivity profile while maintaining submicromolar affinity toward the CDYL chromodomains. Additionally, in vitro pull-down experiments from HeLa nuclear lysates further demonstrate the selectivity and utility of this compound for future elucidation of CDYL protein function.

  14. New STEM Schools Target Underrepresented Groups

    ERIC Educational Resources Information Center

    Robelen, Erik W.

    2011-01-01

    Few Americans may know about the Grand Challenges for Engineering--from making solar energy affordable to ensuring access to clean water--but the students at a new school on the campus of North Carolina State University are getting to know them firsthand. The set of 21st-century challenges, devised by the National Academy of Engineering, serves as…

  15. Targets and targeting.

    PubMed

    Will, E

    2001-08-01

    Using the vocabulary of ballistics in medicine for emphasis can result in misleading exaggeration and semantic confusion. The dual meaning of target as either aiming point (aim at) or outcome (aim to achieve) creates a muddle in the efforts to comply with quality assurance initiatives. Disentangling the two meanings allows new approaches to the clinical technology required in a modern health care environment. An example can be shown in new strategies for the management of renal anemia with iron and erythropoietin. The potential to shape outcome distributions through validated, preemptive intervention thresholds offers the predictable results required by patients and payers. Using the management of patient cohorts as a platform for outcomes creates no necessary conflict with individualized clinical care. Future guideline statements should include the likely characteristics of compliant outcome populations, as a prompt to clinical goals and as an indication of the necessary cost and effort of compliance with treatment standards. Overemphasis in language is no substitute for considered clinical methodology.

  16. The histone deacetylase inhibitor sodium valproate causes limited transcriptional change in mouse embryonic stem cells but selectively overrides Polycomb-mediated Hoxb silencing

    PubMed Central

    2013-01-01

    Background Histone deacetylase inhibitors (HDACi) cause histone hyperacetylation and H3K4 hypermethylation in various cell types. They find clinical application as anti-epileptics and chemotherapeutic agents, but the pathways through which they operate remain unclear. Surprisingly, changes in gene expression caused by HDACi are often limited in extent and can be positive or negative. Here we have explored the ability of the clinically important HDACi valproic acid (VPA) to alter histone modification and gene expression, both globally and at specific genes, in mouse embryonic stem (ES) cells. Results Microarray expression analysis of ES cells exposed to VPA (1 mM, 8 h), showed that only 2.4% of genes showed a significant, >1.5-fold transcriptional change. Of these, 33% were down-regulated. There was no correlation between gene expression and VPA-induced changes in histone acetylation or H3K4 methylation at gene promoters, which were usually minimal. In contrast, all Hoxb genes showed increased levels of H3K9ac after exposure to VPA, but much less change in other modifications showing bulk increases. VPA-induced changes were lost within 24 h of inhibitor removal. VPA significantly increased the low transcription of Hoxb4 and Hoxb7, but not other Hoxb genes. Expression of Hoxb genes increased in ES cells lacking functional Polycomb silencing complexes PRC1 and PRC2. Surprisingly, VPA caused no further increase in Hoxb transcription in these cells, except for Hoxb1, whose expression increased several fold. Retinoic acid (RA) increased transcription of all Hoxb genes in differentiating ES cells within 24 h, but thereafter transcription remained the same, increased progressively or fell progressively in a locus-specific manner. Conclusions Hoxb genes in ES cells are unusual in being sensitive to VPA, with effects on both cluster-wide and locus-specific processes. VPA increases H3K9ac at all Hoxb loci but significantly overrides PRC-mediated silencing only at Hoxb4 and

  17. Long Non-coding RNA HOTAIR Expression in Diffuse Large B-Cell Lymphoma: In Relation to Polycomb Repressive Complex Pathway Proteins and H3K27 Trimethylation

    PubMed Central

    Oh, Eun Ji; Kim, Soo Hee; Yang, Woo Ick; Ko, Young Hyeh; Yoon, Sun Och

    2016-01-01

    Background A long non-coding RNA hox transcript antisense intergenic RNA (HOTAIR) is involved in epigenetic regulation through chromatin remodeling by recruiting polycomb repressive complex 2 (PRC2) proteins (EZH2, SUZ12, and EED) that induce histone H3 trimethylation at lysine 27 (H3K27me3). Deregulation of c-MYC and interaction between c-MYC and EZH2 are well known in lymphomagenesis; however, little is known about the expression status of HOTAIR in diffuse large B-cell lymphomas (DLBCLs). Methods The expression status of PRC2 (EZH2, SUZ12, and EED), H3K27me3, c-MYC, and BCL2 was analyzed using immunohistochemistry (n = 231), and HOTAIR was investigated by a quantification real-time polymerase chain reaction method (n = 164) in DLBCLs. Results The present study confirmed the positive correlation among PRC2 proteins, H3K27me3, and c-MYC in DLBCLs. Expression level of HOTAIR was also positively correlated to EZH2 (p < .05, respectively). Between c-MYC and HOTAIR, and between c- MYC/BCL2 co-expression and HOTAIR, however, negative correlation was observed in DLBCLs (p < .05, respectively). High level of H3K27me3 was determined as an independent prognostic marker in poor overall survival (hazard ratio, 2.0; p = .023) of DLBCL patients. High expression of HOTAIR, however, was associated with favorable overall survival (p = .004) in the univariate analysis, but the impact was not significant in the multivariate analysis. The favorable outcome of DLBCL with HOTAIR high expression levels may be related to the negative correlation with c- MYC expression or c-MYC/BCL2 co-expression. Conclusions HOTAIR expression could be one of possible mechanisms for inducing H3K27me3 via EZH2-related PRC2 activation, and induced H3K27me3 may be strongly related to aggressive DLBCLs which show poor patient outcome. PMID:27550047

  18. Polycomb Repressor Complex 1 Member, BMI1 Contributes to Urothelial Tumorigenesis through p16-Independent Mechanisms1

    PubMed Central

    De Faveri, Lia E.; Hurst, Carolyn D.; Roulson, Jo-An; Wood, Henry; Sanchez-Carbayo, Marta; Knowles, Margaret A.; Chapman, Emma J.

    2015-01-01

    Urothelial carcinoma (UC) causes significant morbidity and remains the most expensive cancer to treat because of the need for repeated resections and lifelong monitoring for patients with non–muscle-invasive bladder cancer (NMIBC). Novel therapeutics and stratification approaches are needed to improve the outlook for both NMIBC and muscle-invasive bladder cancer. We investigated the expression and effects of B Lymphoma Mo-MLV Insertion Region 1 (BMI1) in UC. BMI1 was found to be overexpressed in most UC cell lines and primary tumors by quantitative real-time polymerase chain reaction and immunohistochemistry. In contrast to some previous reports, no association with tumor stage or grade was observed in two independent tumor panels. Furthermore, upregulation of BMI1 was detected in premalignant bladder lesions, suggesting a role early in tumorigenesis. BMI1 is not located within a common region of genomic amplification in UC. The CDKN2A locus (which encodes the p16 tumor suppressor gene) is a transcriptional target of BMI1 in some cellular contexts. In UC cell lines and primary tissues, no correlation between BMI1 and p16 expression was observed. Retroviral-mediated overexpression of BMI1 immortalized normal human urothelial cells (NHUC) in vitro and was associated with induction of telomerase activity, bypass of senescence, and repression of differentiation. The effects of BMI1 on gene expression were identified by expression microarray analysis of NHUC-BMI1. Metacore analysis of the gene expression profile implicated downstream effects of BMI1 on α4/β1 integrin-mediated adhesion, cytoskeleton remodeling, and CREB1-mediated transcription. PMID:26500029

  19. Perceiving persons and groups.

    PubMed

    Hamilton, D L; Sherman, S J

    1996-04-01

    This article analyzes the similarities and differences in forming impressions of individuals and in developing conceptions of groups. In both cases, the perceiver develops a mental conception of the target (individual or group) on the basis of available information and uses that information to make judgments about that person or group. However, a review of existing evidence reveals differences in the outcomes of impressions formed of individual and group targets, even when those impressions are based on the very same behavioral information. A model is proposed to account for these differences. The model emphasizes the role of differing expectancies of unity and coherence in individual and group targets, which in turn engage different mechanisms for processing information and making judgments. Implications of the model are discussed.

  20. Perceiving persons and groups.

    PubMed

    Hamilton, D L; Sherman, S J

    1996-04-01

    This article analyzes the similarities and differences in forming impressions of individuals and in developing conceptions of groups. In both cases, the perceiver develops a mental conception of the target (individual or group) on the basis of available information and uses that information to make judgments about that person or group. However, a review of existing evidence reveals differences in the outcomes of impressions formed of individual and group targets, even when those impressions are based on the very same behavioral information. A model is proposed to account for these differences. The model emphasizes the role of differing expectancies of unity and coherence in individual and group targets, which in turn engage different mechanisms for processing information and making judgments. Implications of the model are discussed. PMID:8637962

  1. RTOG Sarcoma Radiation Oncologists Reach Consensus on Gross Tumor Volume and Clinical Target Volume on Computed Tomographic Images for Preoperative Radiotherapy of Primary Soft Tissue Sarcoma of Extremity in Radiation Therapy Oncology Group Studies

    SciTech Connect

    Wang Dian; Bosch, Walter; Roberge, David; Finkelstein, Steven E.; Petersen, Ivy; Haddock, Michael; Chen, Yen-Lin E.; Saito, Naoyuki G.; Kirsch, David G.; Hitchcock, Ying J.; Wolfson, Aaron H.; DeLaney, Thomas F.

    2011-11-15

    Objective: To develop a Radiation Therapy Oncology Group (RTOG) atlas delineating gross tumor volume (GTV) and clinical target volume (CTV) to be used for preoperative radiotherapy of primary extremity soft tissue sarcoma (STS). Methods and Materials: A consensus meeting was held during the RTOG meeting in January 2010 to reach agreement about GTV and CTV delineation on computed tomography (CT) images for preoperative radiotherapy of high-grade large extremity STS. Data were presented to address the local extension of STS. Extensive discussion ensued to develop optimal criteria for GTV and CTV delineation on CT images. Results: A consensus was reached on appropriate CT-based GTV and CTV. The GTV is gross tumor defined by T1 contrast-enhanced magnetic resonance images. Fusion of magnetic resonance and images is recommended to delineate the GTV. The CTV for high-grade large STS typically includes the GTV plus 3-cm margins in the longitudinal directions. If this causes the field to extend beyond the compartment, the field can be shortened to include the end of a compartment. The radial margin from the lesion should be 1.5 cm, including any portion of the tumor not confined by an intact fascial barrier, bone, or skin surface. Conclusion: The consensus on GTV and CTV for preoperative radiotherapy of high-grade large extremity STS is available as web-based images and in a descriptive format through the RTOG. This is expected to improve target volume consistency and allow for rigorous evaluation of the benefits and risks of such treatment.

  2. Significant Reduction of Late Toxicities in Patients With Extremity Sarcoma Treated With Image-Guided Radiation Therapy to a Reduced Target Volume: Results of Radiation Therapy Oncology Group RTOG-0630 Trial

    PubMed Central

    Wang, Dian; Zhang, Qiang; Eisenberg, Burton L.; Kane, John M.; Li, X. Allen; Lucas, David; Petersen, Ivy A.; DeLaney, Thomas F.; Freeman, Carolyn R.; Finkelstein, Steven E.; Hitchcock, Ying J.; Bedi, Manpreet; Singh, Anurag K.; Dundas, George; Kirsch, David G.

    2015-01-01

    Purpose We performed a multi-institutional prospective phase II trial to assess late toxicities in patients with extremity soft tissue sarcoma (STS) treated with preoperative image-guided radiation therapy (IGRT) to a reduced target volume. Patients and Methods Patients with extremity STS received IGRT with (cohort A) or without (cohort B) chemotherapy followed by limb-sparing resection. Daily pretreatment images were coregistered with digitally reconstructed radiographs so that the patient position could be adjusted before each treatment. All patients received IGRT to reduced tumor volumes according to strict protocol guidelines. Late toxicities were assessed at 2 years. Results In all, 98 patients were accrued (cohort A, 12; cohort B, 86). Cohort A was closed prematurely because of poor accrual and is not reported. Seventy-nine eligible patients from cohort B form the basis of this report. At a median follow-up of 3.6 years, five patients did not have surgery because of disease progression. There were five local treatment failures, all of which were in field. Of the 57 patients assessed for late toxicities at 2 years, 10.5% experienced at least one grade ≥ 2 toxicity as compared with 37% of patients in the National Cancer Institute of Canada SR2 (CAN-NCIC-SR2: Phase III Randomized Study of Pre- vs Postoperative Radiotherapy in Curable Extremity Soft Tissue Sarcoma) trial receiving preoperative radiation therapy without IGRT (P < .001). Conclusion The significant reduction of late toxicities in patients with extremity STS who were treated with preoperative IGRT and absence of marginal-field recurrences suggest that the target volumes used in the Radiation Therapy Oncology Group RTOG-0630 (A Phase II Trial of Image-Guided Preoperative Radiotherapy for Primary Soft Tissue Sarcomas of the Extremity) study are appropriate for preoperative IGRT for extremity STS. PMID:25667281

  3. Sputter target

    DOEpatents

    Gates, Willard G.; Hale, Gerald J.

    1980-01-01

    The disclosure relates to an improved sputter target for use in the deposition of hard coatings. An exemplary target is given wherein titanium diboride is brazed to a tantalum backing plate using a gold-palladium-nickel braze alloy.

  4. Profile and quantification of human stratum corneum ceramides by normal-phase liquid chromatography coupled with dynamic multiple reaction monitoring of mass spectrometry: development of targeted lipidomic method and application to human stratum corneum of different age groups.

    PubMed

    Jia, Zhi-Xin; Zhang, Jin-Lan; Shen, Chun-Ping; Ma, Lin

    2016-09-01

    Skin, the largest organ of the human body, serves as the primary barrier to the external environment. Ceramides are one of the main constituents of stratum corneum (SC), playing an important role in skin barrier function. Therefore, comprehensive profiling and quantification of SC ceramide is important. Herein, a new targeted lipidomic method for human SC ceramide profiling and quantification is presented and tested. Normal-phase high-performance liquid chromatography coupled with dynamic multiple reaction monitoring mass spectrometry (NP-HPLC-dMRM-MS) was used to separate ceramides into subclasses and then characterize different ceramides within each subclass on the basis of their characteristics. In total, 483 ceramides were quantified in a single run within 20 min, covering 12 subclasses as well as some glycosylated ceramides not previously reported. Each subclass had typical standard substances (if available) that served to establish representative standard curves and were used for related substances with no standards. Linearity range, limit of quantification (LOQ), limit of detection (LOD), precision, accuracy, stability, and matrix effects were validated. dMRM increased sensitivity and accuracy greatly compared with common MRM (cMRM). This method was successfully applied to the study of human SC from different age groups. A total of 193 potential biomarkers were found to indicate age differences between children and adults. This method is an innovative approach for high-throughput quantification of SC ceramide. Graphical Abstract Method establishment (MRM spectra by the established method) and method application (score scatter plots of authentic samples). PMID:27473427

  5. The group A streptococcal collagen-like protein-1, Scl1, mediates biofilm formation by targeting the extra domain A-containing variant of cellular fibronectin expressed in wounded tissue.

    PubMed

    Oliver-Kozup, Heaven; Martin, Karen H; Schwegler-Berry, Diane; Green, Brett J; Betts, Courtney; Shinde, Arti V; Van De Water, Livingston; Lukomski, Slawomir

    2013-02-01

    Wounds are known to serve as portals of entry for group A Streptococcus (GAS). Subsequent tissue colonization is mediated by interactions between GAS surface proteins and host extracellular matrix components. We recently reported that the streptococcal collagen-like protein-1, Scl1, selectively binds the cellular form of fibronectin (cFn) and also contributes to GAS biofilm formation on abiotic surfaces. One structural feature of cFn, which is predominantly expressed in response to tissue injury, is the presence of a spliced variant containing extra domain A (EDA/EIIIA). We now report that GAS biofilm formation is mediated by the Scl1 interaction with EDA-containing cFn. Recombinant Scl1 proteins that bound cFn also bound recombinant EDA within the C-C' loop region recognized by the α(9)β(1) integrin. The extracellular 2-D matrix derived from human dermal fibroblasts supports GAS adherence and biofilm formation. Altogether, this work identifies and characterizes a novel molecular mechanism by which GAS utilizes Scl1 to specifically target an extracellular matrix component that is predominantly expressed at the site of injury in order to secure host tissue colonization.

  6. Training Groups, Encounter Groups, Sensitivity Groups and Group Psychotherapy

    PubMed Central

    Gottschalk, Louis A.; Pattison, E. Mansell; Schafer, Donald W.

    1971-01-01

    Descriptions and comparison of group therapies and the new group procedures (training groups and sensitivity groups—an outgrowth of the so-called Laboratory Movement methods of the mid-1930's) have been provided for the better understanding of non-psychiatric physicians. A group leader must have proper training and must help his group in its search for its avowed goals, whether he is a group therapist, a sensitivity trainer, or anyone else interested in utilizing group processes. Those goals are either the therapeutic benefit of the individual, as defined in group psychotherapy, or a better understanding of how one functions in groups, as in T-groups or the other group processes in the area of sensitive living. All group situations contain powerful tools which must be handled with proper respect. When so handled by experienced leaders, the individuals involved can achieve their goals in these group experiences. PMID:18730582

  7. Group Counseling

    ERIC Educational Resources Information Center

    Mahler, Clarence A.

    1971-01-01

    This article reviews the major concerns of group counseling and differentiates among group guidance, group counseling, and group therapy. It also evaluates the research status of group counseling and presents implications for the future of this approach. Comment by Carl E. Thoresen follows. (Author)

  8. Marketing of Group Counseling Services.

    ERIC Educational Resources Information Center

    Wilson, F. Robert; And Others

    1987-01-01

    Provides social marketing guidelines for attracting members of appropriate target groups and encouraging their participation in group activities. Includes examination of the personal and social framework of the group counselor, elements of social marketing theory, a case study illustrating difficulties encountered by novice group counselors in…

  9. LIQUID TARGET

    DOEpatents

    Martin, M.D.; Salsig, W.W. Jr.

    1959-01-13

    A liquid handling apparatus is presented for a liquid material which is to be irradiated. The apparatus consists essentially of a reservoir for the liquid, a target element, a drain tank and a drain lock chamber. The target is in the form of a looped tube, the upper end of which is adapted to be disposed in a beam of atomic particles. The lower end of the target tube is in communication with the liquid in the reservoir and a means is provided to continuously circulate the liquid material to be irradiated through the target tube. Means to heat the reservoir tank is provided in the event that a metal is to be used as the target material. The apparatus is provided with suitable valves and shielding to provide maximum safety in operation.

  10. Group X

    SciTech Connect

    Fields, Susannah

    2007-08-16

    This project is currently under contract for research through the Department of Homeland Security until 2011. The group I was responsible for studying has to remain confidential so as not to affect the current project. All dates, reference links and authors, and other distinguishing characteristics of the original group have been removed from this report. All references to the name of this group or the individual splinter groups has been changed to 'Group X'. I have been collecting texts from a variety of sources intended for the use of recruiting and radicalizing members for Group X splinter groups for the purpose of researching the motivation and intent of leaders of those groups and their influence over the likelihood of group radicalization. This work included visiting many Group X websites to find information on splinter group leaders and finding their statements to new and old members. This proved difficult because the splinter groups of Group X are united in beliefs, but differ in public opinion. They are eager to tear each other down, prove their superiority, and yet remain anonymous. After a few weeks of intense searching, a list of eight recruiting texts and eight radicalizing texts from a variety of Group X leaders were compiled.

  11. Group Flow and Group Genius

    ERIC Educational Resources Information Center

    Sawyer, Keith

    2015-01-01

    Keith Sawyer views the spontaneous collaboration of group creativity and improvisation actions as "group flow," which organizations can use to function at optimum levels. Sawyer establishes ideal conditions for group flow: group goals, close listening, complete concentration, being in control, blending egos, equal participation, knowing…

  12. Group collaboration in recognition memory.

    PubMed

    Clark, S E; Hori, A; Putnam, A; Martin, T P

    2000-11-01

    Group collaboration was examined in item and associative recognition. The present study distinguishes between group effects versus collaborative processes and defines the latter as interactive information exchange among group members. By that definition, many group effects do not involve collaboration. For example, group performance can exceed individual performance by pooling the increased resources of the group. Specifically, a group advantage can be obtained by deferring to a majority vote or to the group's best member. For both item and associative recognition, a group advantage was obtained that could not be accounted for by resource pooling. Collaborative facilitation was shown reliably in recognizing targets but not for rejecting distractors. PMID:11185784

  13. Isopermutation group

    SciTech Connect

    Muktibodh, A. S.

    2015-03-10

    The concept of ‘Isotopy’ as formulated by Ruggero Maria Santilli [1, 2, 3] plays a vital role in the development of Iso mathematics. Santilli defined iso-fields of characteristic zero. In this paper we extend this definition to define Iso-Galois fields [4] which are essentially of non-zero characteristic. Isotopically isomorphic realizations of a group define isopermutation group which gives a clear cut distinction between automorphic groups and isotopic groups.

  14. Hot Groups.

    ERIC Educational Resources Information Center

    Vail, Kathleen

    1996-01-01

    Collaborators sparked by creative ideas and obsessed by a common task may not realize they're part of a "hot group"--a term coined by business professors Harold J. Leavitt and Jean Lipman-Blumen. Spawned by group decision making and employee empowerment, hot groups can flourish in education settings. They're typically small, short lived, and goal…

  15. Runx1 regulation of Pu.1 corepressor/coactivator exchange identifies specific molecular targets for leukemia differentiation therapy.

    PubMed

    Gu, Xiaorong; Hu, Zhenbo; Ebrahem, Quteba; Crabb, John S; Mahfouz, Reda Z; Radivoyevitch, Tomas; Crabb, John W; Saunthararajah, Yogen

    2014-05-23

    Gene activation requires cooperative assembly of multiprotein transcription factor-coregulator complexes. Disruption to cooperative assemblage could underlie repression of tumor suppressor genes in leukemia cells. Mechanisms of cooperation and its disruption were therefore examined for PU.1 and RUNX1, transcription factors that cooperate to activate hematopoietic differentiation genes. PU.1 is highly expressed in leukemia cells, whereas RUNX1 is frequently inactivated by mutation or translocation. Thus, coregulator interactions of Pu.1 were examined by immunoprecipitation coupled with tandem mass spectrometry/Western blot in wild-type and Runx1-deficient hematopoietic cells. In wild-type cells, the NuAT and Baf families of coactivators coimmunoprecipitated with Pu.1. Runx1 deficiency produced a striking switch to Pu.1 interaction with the Dnmt1, Sin3A, Nurd, CoRest, and B-Wich corepressor families. Corepressors of the Polycomb family, which are frequently inactivated by mutation or deletion in myeloid leukemia, did not interact with Pu.1. The most significant gene ontology association of Runx1-Pu.1 co-bound genes was with macrophages, therefore, functional consequences of altered corepressor/coactivator exchange were examined at Mcsfr, a key macrophage differentiation gene. In chromatin immunoprecipitation analyses, high level Pu.1 binding to the Mcsfr promoter was not decreased by Runx1 deficiency. However, the Pu.1-driven shift from histone repression to activation marks at this locus, and terminal macrophage differentiation, were substantially diminished. DNMT1 inhibition, but not Polycomb inhibition, in RUNX1-translocated leukemia cells induced terminal differentiation. Thus, RUNX1 and PU.1 cooperate to exchange corepressors for coactivators, and the specific corepressors recruited to PU.1 as a consequence of RUNX1 deficiency could be rational targets for leukemia differentiation therapy.

  16. Galaxy groups

    SciTech Connect

    Brent Tully, R.

    2015-02-01

    Galaxy groups can be characterized by the radius of decoupling from cosmic expansion, the radius of the caustic of second turnaround, and the velocity dispersion of galaxies within this latter radius. These parameters can be a challenge to measure, especially for small groups with few members. In this study, results are gathered pertaining to particularly well-studied groups over four decades in group mass. Scaling relations anticipated from theory are demonstrated and coefficients of the relationships are specified. There is an update of the relationship between light and mass for groups, confirming that groups with mass of a few times 10{sup 12}M{sub ⊙} are the most lit up while groups with more and less mass are darker. It is demonstrated that there is an interesting one-to-one correlation between the number of dwarf satellites in a group and the group mass. There is the suggestion that small variations in the slope of the luminosity function in groups are caused by the degree of depletion of intermediate luminosity systems rather than variations in the number per unit mass of dwarfs. Finally, returning to the characteristic radii of groups, the ratio of first to second turnaround depends on the dark matter and dark energy content of the universe and a crude estimate can be made from the current observations of Ω{sub matter}∼0.15 in a flat topology, with a 68% probability of being less than 0.44.

  17. GROUP INEQUALITY

    PubMed Central

    Bowles, Samuel; Loury, Glenn C.; Sethi, Rajiv

    2014-01-01

    We explore the combined effect of segregation in social networks, peer effects, and the relative size of a historically disadvantaged group on the incentives to invest in market-rewarded skills and the dynamics of inequality between social groups. We identify conditions under which group inequality will persist in the absence of differences in ability, credit constraints, or labor market discrimination. Under these conditions, group inequality may be amplified even if initial group differences are negligible. Increases in social integration may destabilize an unequal state and make group equality possible, but the distributional and human capital effects of this depend on the demographic composition of the population. When the size of the initially disadvantaged group is sufficiently small, integration can lower the long-run costs of human capital investment in both groups and result in an increase the aggregate skill share. In contrast, when the initially disadvantaged group is large, integration can induce a fall in the aggregate skill share as the costs of human capital investment rise in both groups. We consider applications to concrete cases and policy implications. PMID:25554727

  18. Tackling Targets.

    ERIC Educational Resources Information Center

    Further Education Unit, London (England).

    This document is designed to help British training and enterprise councils (TECs) and further education (FE) colleges develop and implement strategies for achieving the National Targets for Education and Training (NTET), which were developed by the Confederation of British Industry in 1992 and endorsed by the British government. The findings from…

  19. Molecular Profiling to Optimize Treatment in Non-Small Cell Lung Cancer: A Review of Potential Molecular Targets for Radiation Therapy by the Translational Research Program of the Radiation Therapy Oncology Group

    SciTech Connect

    Ausborn, Natalie L.; Le, Quynh Thu; Bradley, Jeffrey D.; Choy, Hak; Dicker, Adam P.; Saha, Debabrata; Simko, Jeff; Story, Michael D.; Torossian, Artour; Lu, Bo

    2012-07-15

    Therapeutic decisions in non-small cell lung cancer (NSCLC) have been mainly based on disease stage, performance status, and co-morbidities, and rarely on histological or molecular classification. Rather than applying broad treatments to unselected patients that may result in survival increase of only weeks to months, research efforts should be, and are being, focused on identifying predictive markers for molecularly targeted therapy and determining genomic signatures that predict survival and response to specific therapies. The availability of such targeted biologics requires their use to be matched to tumors of corresponding molecular vulnerability for maximum efficacy. Molecular markers such as epidermal growth factor receptor (EGFR), K-ras, vascular endothelial growth factor (VEGF), mammalian target of rapamycin (mTOR), and anaplastic lymphoma kinase (ALK) represent potential parameters guide treatment decisions. Ultimately, identifying patients who will respond to specific therapies will allow optimal efficacy with minimal toxicity, which will result in more judicious and effective application of expensive targeted therapy as the new paradigm of personalized medicine develops.

  20. Regulation of stem cell pluripotency and differentiation involves a mutual regulatory circuit of the NANOG, OCT4, and SOX2 pluripotency transcription factors with polycomb repressive complexes and stem cell microRNAs.

    PubMed

    Kashyap, Vasundhra; Rezende, Naira C; Scotland, Kymora B; Shaffer, Sebastian M; Persson, Jenny Liao; Gudas, Lorraine J; Mongan, Nigel P

    2009-09-01

    Coordinated transcription factor networks have emerged as the master regulatory mechanisms of stem cell pluripotency and differentiation. Many stem cell-specific transcription factors, including the pluripotency transcription factors, OCT4, NANOG, and SOX2 function in combinatorial complexes to regulate the expression of loci, which are involved in embryonic stem (ES) cell pluripotency and cellular differentiation. This review will address how these pathways form a reciprocal regulatory circuit whereby the equilibrium between stem cell self-renewal, proliferation, and differentiation is in perpetual balance. We will discuss how distinct epigenetic repressive pathways involving polycomb complexes, DNA methylation, and microRNAs cooperate to reduce transcriptional noise and to prevent stochastic and aberrant induction of differentiation. We will provide a brief overview of how these networks cooperate to modulate differentiation along hematopoietic and neuronal lineages. Finally, we will describe how aberrant functioning of components of the stem cell regulatory network may contribute to malignant transformation of adult stem cells and the establishment of a "cancer stem cell" phenotype and thereby underlie multiple types of human malignancies.

  1. Target assembly

    DOEpatents

    Lewis, Richard A.

    1980-01-01

    A target for a proton beam which is capable of generating neutrons for absorption in a breeding blanket includes a plurality of solid pins formed of a neutron emissive target material disposed parallel to the path of the beam and which are arranged axially in a plurality of layers so that pins in each layer are offset with respect to pins in all other layers, enough layers being used so that each proton in the beam will strike at least one pin with means being provided to cool the pins. For a 300 mA, 1 GeV beam (300 MW), stainless steel pins, 12 inches long and 0.23 inches in diameter are arranged in triangular array in six layers with one sixth of the pins in each layer, the number of pins being such that the entire cross sectional area of the beam is covered by the pins with minimum overlap of pins.

  2. Group dynamics.

    PubMed

    Scandiffio, A L

    1990-12-01

    Group dynamics play a significant role within any organization, culture, or unit. The important thing to remember with any of these structures is that they are made up of people--people with different ideas, motivations, background, and sometimes different agendas. Most groups, formal or informal, look for a leader in an effort to maintain cohesiveness of the unit. At times, that cultural bond must be developed; once developed, it must be nurtured. There are also times that one of the group no longer finds the culture comfortable and begins to act out behaviorally. It is these times that become trying for the leader as she or he attempts to remain objective when that which was once in the building phase of group cohesiveness starts to fall apart. At all times, the manager must continue to view the employee creating the disturbance as an integral part of the group. It is at this time that it is beneficial to perceive the employee exhibiting problem behaviors as a special employee, as one who needs the benefit of your experience and skills, as one who is still part of the group. It is also during this time that the manager should focus upon her or his own views in the area of power, communication, and the corporate culture of the unit that one has established before attempting to understand another's point of view. Once we understand our own motivation and accept ourselves, it is then that we may move on to offer assistance to another. Once we understand our insecurities recognizing staff dysfunction as a symptom of system dysfunction will not be so threatening to the concept of the manager that we perceive ourselves to be. It takes a secure person to admit that she or he favors staff before deciding to do something to change things. The important thing to know is that it can be done. The favored staff can find a new way of relating to others, the special employee can find new modes of behavior (and even find self-esteem in the process), the group can find new ways

  3. Accelerator target

    DOEpatents

    Schlyer, D.J.; Ferrieri, R.A.; Koehler, C.

    1999-06-29

    A target includes a body having a depression in a front side for holding a sample for irradiation by a particle beam to produce a radioisotope. Cooling fins are disposed on a backside of the body opposite the depression. A foil is joined to the body front side to cover the depression and sample therein. A perforate grid is joined to the body atop the foil for supporting the foil and for transmitting the particle beam therethrough. A coolant is circulated over the fins to cool the body during the particle beam irradiation of the sample in the depression. 5 figs.

  4. Accelerator target

    DOEpatents

    Schlyer, David J.; Ferrieri, Richard A.; Koehler, Conrad

    1999-01-01

    A target includes a body having a depression in a front side for holding a sample for irradiation by a particle beam to produce a radioisotope. Cooling fins are disposed on a backside of the body opposite the depression. A foil is joined to the body front side to cover the depression and sample therein. A perforate grid is joined to the body atop the foil for supporting the foil and for transmitting the particle beam therethrough. A coolant is circulated over the fins to cool the body during the particle beam irradiation of the sample in the depression.

  5. New polycomb group protein enhancer of zeste homolog (EZH) 2-derived peptide with the potential to induce cancer-reactive cytotoxic T lymphocytes in prostate cancer patients with HLA-A3 supertype alleles.

    PubMed

    Minami, Takafumi; Minami, Tomoko; Shimizu, Nobutaka; Yamamoto, Yutaka; De Velasco, Marco A; Nozawa, Masahiro; Yoshimura, Kazuhiro; Harashima, Nanae; Harada, Mamoru; Uemura, Hirotsugu

    2015-05-01

    Analyses on reactivity of anti-cancer cytotoxic T lymphocytes (CTLs) and clinical application of peptide-based anti-cancer vaccine have been mainly focused on patients with HLA-A2 or -A24 alleles. In this study, we identified an enhancer of zeste homolog (EZH) 2-derived peptide applicable for anti-cancer vaccine for prostate cancer patients with HLA-A3 supertype alleles. Five EZH2-derived peptides that were prepared based on the binding motif to the HLA-A3 supertype alleles (HLA-A11, -A31, and -A33) were functionally screened for their potential to induce peptide-specific CTLs from peripheral blood mononuclear cells (PBMCs) of HLA-A3 supertype allele(+) prostate cancer patients. As a result, EZH2733-741 peptide was found to efficiently induce peptide-specific CTLs. The EZH2733-741 peptide-stimulated and purified CD8(+) T cells from PBMCs of HLA-A3 supertype allele(+) prostate cancer patients showed higher cytotoxicity against HLA-A3 supertype allele-expressing LNCaP prostate cancer cells than against parental LNCaP cells. This cytotoxicity against HLA-A3 supertype allele-expressing LNCaP cells was partially but significantly inhibited by the addition of EZH2733-741 peptide-pulsed competitive cells. These results indicate that the EZH2733-741 peptide could be a promising candidate for peptide-based immunotherapy for HLA-A3 supertype allele(+) prostate cancer patients.

  6. Characterization of polybacterial clinical samples using a set of group-specific broad-range primers targeting the 16S rRNA gene followed by DNA sequencing and RipSeq analysis

    PubMed Central

    Lekang, Katrine; Langeland, Nina; Wiker, Harald G.

    2011-01-01

    The standard use of a single universal broad-range PCR in direct 16S rDNA sequencing from polybacterial samples leaves the minor constituents at risk of remaining undetected because all bacterial DNA will be competing for the same reagents. In this article we introduce a set of three broad-range group-specific 16S rDNA PCRs that together cover the clinically relevant bacteria and apply them in the investigation of 25 polybacterial clinical samples. Mixed DNA chromatograms from samples containing more than one species per primer group were analysed using RipSeq Mixed (iSentio, Norway), a web-based application for the interpretation of chromatograms containing up to three different species. The group-specific PCRs reduced complexity in the resulting DNA chromatograms and made the assay more sensitive in situations with unequal species concentrations. Together this allowed for identification of a significantly higher number of bacterial species than did standard direct sequencing with a single universal primer pair and RipSeq analysis (95 vs 51). The method could improve microbiological diagnostics for important groups of patients and can be established in any laboratory with experience in direct 16S rDNA sequencing. PMID:21436365

  7. Group Learning.

    ERIC Educational Resources Information Center

    Black, Susan

    1992-01-01

    Research suggests that cooperative learning works best when students are first taught group-processing skills, such as leadership, decision making, communication, trust building, and conflict management. Inadequate teacher training and boring assignments can torpedo cooperative learning efforts. Administrators should reassure teachers with…

  8. Foveal target repetitions reduce crowding.

    PubMed

    Sayim, Bilge; Greenwood, John A; Cavanagh, Patrick

    2014-01-01

    Crowding is the limitation of peripheral vision by clutter. Objects that are easily identified when presented in isolation are hard to identify when presented flanked by similar close-by objects. It is often assumed that the signal of a crowded target is irretrievably lost because it is combined with the signals of the flankers. Here, we asked whether a target signal can be enhanced (or retrieved) by items presented far outside the crowding region. We investigated whether remote items matching a peripheral, crowded target enhanced discrimination compared to remote items not matching the target. In Experiment 1, we presented the remote item at different locations in the visual field and found that, when presented in the fovea, a matching remote item improved target discrimination compared to a nonmatching remote item. In Experiment 2, we varied stimulus onset asynchronies between target and remote items and found a strong effect when the remote item was presented simultaneously with the target. The effect diminished (or was absent) with increasing temporal separation. In Experiment 3, we asked whether semantic knowledge of a target was sufficient to improve target discrimination and found that this was not the case. We conclude that crowded target signals are not irretrievably lost. Rather, their accurate recognition is facilitated in the presence of remote items that match the target. We suggest that long-range grouping mechanisms underlie this "uncrowding" effect.

  9. Design of HIV-1 integrase inhibitors targeting the catalytic domain as well as its interaction with LEDGF/p75: a scaffold hopping approach using salicylate and catechol groups.

    PubMed

    Fan, Xing; Zhang, Feng-Hua; Al-Safi, Rasha I; Zeng, Li-Fan; Shabaik, Yumna; Debnath, Bikash; Sanchez, Tino W; Odde, Srinivas; Neamati, Nouri; Long, Ya-Qiu

    2011-08-15

    HIV-1 integrase (IN) is a validated therapeutic target for antiviral drug design. However, the emergence of viral strains resistant to clinically studied IN inhibitors demands the discovery of novel inhibitors that are structurally as well mechanistically different. Herein, we describe the design and discovery of novel IN inhibitors targeting the catalytic domain as well as its interaction with LEDGF/p75, which is essential for the HIV-1 integration as an IN cofactor. By merging the pharmacophores of salicylate and catechol, the 2,3-dihydroxybenzamide (5a) was identified as a new scaffold to inhibit the strand transfer reaction efficiently. Further structural modifications on the 2,3-dihydroxybenzamide scaffold revealed that the heteroaromatic functionality attached on the carboxamide portion and the piperidin-1-ylsulfonyl substituted at the phenyl ring are beneficial for the activity, resulting in a low micromolar IN inhibitor (5p, IC(50)=5 μM) with more than 40-fold selectivity for the strand transfer over the 3'-processing reaction. More significantly, this active scaffold remarkably inhibited the interaction between IN and LEDGF/p75 cofactor. The prototype example, N-(cyclohexylmethyl)-2,3-dihydroxy-5-(piperidin-1-ylsulfonyl) benzamide (5u) inhibited the IN-LEDGF/p75 interaction with an IC(50) value of 8 μM. Using molecular modeling, the mechanism of action was hypothesized to involve the chelation of the divalent metal ions inside the IN active site. Furthermore, the inhibitor of IN-LEDGF/p75 interaction was properly bound to the LEDGF/p75 binding site on IN. This work provides a new and efficient approach to evolve novel HIV-1 IN inhibitors from rational integration and optimization of previously reported inhibitors.

  10. Design of HIV-1 Integrase Inhibitors Targeting the Catalytic Domain as Well as Its Interaction with LEDGF/p75: A Scaffold Hopping Approach Using Salicylate and Catechol Groups

    PubMed Central

    Fan, Xing; Zhang, Feng-Hua; Al-Safi, Rasha I.; Zeng, Li-Fan; Shabaik, Yumna; Debnath, Bikash; Sanchez, Tino W.; Odde, Srinivas; Neamati, Nouri; Long, Ya-Qiu

    2011-01-01

    HIV-1 integrase (IN) is a validated therapeutic target for antiviral agents. However, the emergence of viral strains resistant to clinically studied IN inhibitors demands new structure and new mechanism IN inhibitors. Herein, we describe the design and discovery of novel IN inhibitors targeting the catalytic domain as well as its interaction with LEDGF/p75, which is essential for the HIV-1 integration as an IN cofactor. By merging the pharmacophores of salicylate and catechol, the 2,3-dihydroxybenzamide (5a) was identified as a new scaffold to inhibit the strand transfer reaction efficiently. Further structural modifications on the 2,3-dihydroxybenzamide scaffold revealed that the heteroaromatic functionality attached on the carboxamide portion and the piperidin-1-ylsulfonyl substituted at the phenyl ring are beneficial for the activity, resulting in a low micromolar IN inhibitor (5p, IC50 = 5 μM) with more than 40-fold selectivity for the strand transfer over the 3′-processing reaction. More significantly, this active scaffold remarkably inhibited the interaction between IN and LEDGF/p75 cofactor. The prototype example, N-(cyclohexylmethyl)-2,3-dihydroxy-5-(piperidin-1-ylsulfonyl) benzamide (5u) inhibited the IN-LEDGF/p75 interaction with an IC50 value of 8 μM. Based on the molecular modeling, the mechanism of action was hypothesized to involve the chelation of the divalent metal ions inside the IN active site. And the inhibitor of IN-LEDGF/p75 interaction was properly bound to the LEDGF/p75 binding site in IN protein. This work provided a new and efficient approach to evolve novel HIV-1 IN inhibitors from rational integration and optimization of previously reported inhibitors. PMID:21778063

  11. Moving targets

    SciTech Connect

    Not Available

    1993-09-01

    This article discusses the conversion of the Westinghouse Corporation's defence arm, Electronic Systems Group, to marketing products for U.S. police rather than for U.S. defense. The uses of electronic defense technology in law enforcement are addressed. Examples of applications include hand held biosensors for detection of drugs and chemicals, remote computers in patrol cars, and a scaled down AWACS radar aircraft.

  12. Convergent evolution of chromatin modification by structurally distinct enzymes: comparative enzymology of histone H3 Lys²⁷ methylation by human polycomb repressive complex 2 and vSET.

    PubMed

    Swalm, Brooke M; Hallenbeck, Kenneth K; Majer, Christina R; Jin, Lei; Scott, Margaret Porter; Moyer, Mikel P; Copeland, Robert A; Wigle, Tim J

    2013-07-15

    H3K27 (histone H3 Lys27) methylation is an important epigenetic modification that regulates gene transcription. In humans, EZH (enhancer of zeste homologue) 1 and EZH2 are the only enzymes capable of catalysing methylation of H3K27. There is great interest in understanding structure-function relationships for EZH2, as genetic alterations in this enzyme are thought to play a causal role in a number of human cancers. EZH2 is challenging to study because it is only active in the context of the multi-subunit PRC2 (polycomb repressive complex 2). vSET is a viral lysine methyltransferase that represents the smallest protein unit capable of catalysing H3K27 methylation. The crystal structure of this minimal catalytic protein has been solved and researchers have suggested that vSET might prove useful as an EZH2 surrogate for the development of active site-directed inhibitors. To test this proposition, we conducted comparative enzymatic analysis of human EZH2 and vSET and report that, although both enzymes share similar preferences for methylation of H3K27, they diverge in terms of their permissiveness for catalysing methylation of alternative histone lysine sites, their relative preferences for utilization of multimeric macromolecular substrates, their active site primary sequences and, most importantly, their sensitivity to inhibition by drug-like small molecules. The cumulative data led us to suggest that EZH2 and vSET have very distinct active site structures, despite the commonality of the reaction catalysed by the two enzymes. Hence, the EZH2 and vSET pair of enzymes represent an example of convergent evolution in which distinct structural solutions have developed to solve a common catalytic need.

  13. Calcium-myristoyl Tug is a new mechanism for intramolecular tuning of calcium sensitivity and target enzyme interaction for guanylyl cyclase-activating protein 1: dynamic connection between N-fatty acyl group and EF-hand controls calcium sensitivity.

    PubMed

    Peshenko, Igor V; Olshevskaya, Elena V; Lim, Sunghyuk; Ames, James B; Dizhoor, Alexander M

    2012-04-20

    Guanylyl cyclase-activating protein 1 (GCAP1), a myristoylated Ca(2+) sensor in vision, regulates retinal guanylyl cyclase (RetGC). We show that protein-myristoyl group interactions control Ca(2+) sensitivity, apparent affinity for RetGC, and maximal level of cyclase activation. Mutating residues near the myristoyl moiety affected the affinity of Ca(2+) binding to EF-hand 4. Inserting Phe residues in the cavity around the myristoyl group increased both the affinity of GCAP1 for RetGC and maximal activation of the cyclase. NMR spectra show that the myristoyl group in the L80F/L176F/V180F mutant remained sequestered inside GCAP1 in both Ca(2+)-bound and Mg(2+)-bound states. This mutant displayed much higher affinity for the cyclase but reduced Ca(2+) sensitivity of the cyclase regulation. The L176F substitution improved affinity of myristoylated and non-acylated GCAP1 for the cyclase but simultaneously reduced the affinity of Ca(2+) binding to EF-hand 4 and Ca(2+) sensitivity of the cyclase regulation by acylated GCAP1. The replacement of amino acids near both ends of the myristoyl moiety (Leu(80) and Val(180)) minimally affected regulatory properties of GCAP1. N-Lauryl- and N-myristoyl-GCAP1 activated RetGC in a similar fashion. Thus, protein interactions with the central region of the fatty acyl chain optimize GCAP1 binding to RetGC and maximize activation of the cyclase. We propose a dynamic connection (or "tug") between the fatty acyl group and EF-hand 4 via the C-terminal helix that attenuates the efficiency of RetGC activation in exchange for optimal Ca(2+) sensitivity.

  14. Local Group

    NASA Astrophysics Data System (ADS)

    Mateo, M.; Murdin, P.

    2000-11-01

    Not long after EDWIN HUBBLE established that galaxies are `island universes' similar to our home galaxy, the MILKY WAY, he realized that a few of these external galaxies are considerably closer to us than any others. In 1936 he first coined the term `Local Group' in his famous book The Realm of the Nebulae to identify our nearest galactic neighbors. More than 60 yr later, the galaxies of the Loca...

  15. Underrepresented groups

    NASA Technical Reports Server (NTRS)

    Peters, David A.

    1990-01-01

    The problem with the shortage of under represented groups in science and engineering is absolutely crucial, especially considering that U.S. will experience a shortage of 560,000 science and engineering personnel by the year 2010. Most studies by the National Science Foundation also concluded that projected shortages cannot be alleviated without significant increases in the involvement of Blacks, Hispanics, Native Americans, handicapped persons, and women.

  16. Diverse patterns of genomic targeting by transcriptional regulators in Drosophila melanogaster

    PubMed Central

    Slattery, Matthew; Ma, Lijia; Spokony, Rebecca F.; Arthur, Robert K.; Kheradpour, Pouya; Kundaje, Anshul; Nègre, Nicolas; Crofts, Alex; Ptashkin, Ryan; Zieba, Jennifer; Ostapenko, Alexander; Suchy, Sarah; Victorsen, Alec; Jameel, Nader; Grundstad, A. Jason; Gao, Wenxuan; Moran, Jennifer R.; Rehm, E. Jay; Grossman, Robert L.; Kellis, Manolis; White, Kevin P.

    2014-01-01

    Annotation of regulatory elements and identification of the transcription-related factors (TRFs) targeting these elements are key steps in understanding how cells interpret their genetic blueprint and their environment during development, and how that process goes awry in the case of disease. One goal of the modENCODE (model organism ENCyclopedia of DNA Elements) Project is to survey a diverse sampling of TRFs, both DNA-binding and non-DNA-binding factors, to provide a framework for the subsequent study of the mechanisms by which transcriptional regulators target the genome. Here we provide an updated map of the Drosophila melanogaster regulatory genome based on the location of 84 TRFs at various stages of development. This regulatory map reveals a variety of genomic targeting patterns, including factors with strong preferences toward proximal promoter binding, factors that target intergenic and intronic DNA, and factors with distinct chromatin state preferences. The data also highlight the stringency of the Polycomb regulatory network, and show association of the Trithorax-like (Trl) protein with hotspots of DNA binding throughout development. Furthermore, the data identify more than 5800 instances in which TRFs target DNA regions with demonstrated enhancer activity. Regions of high TRF co-occupancy are more likely to be associated with open enhancers used across cell types, while lower TRF occupancy regions are associated with complex enhancers that are also regulated at the epigenetic level. Together these data serve as a resource for the research community in the continued effort to dissect transcriptional regulatory mechanisms directing Drosophila development. PMID:24985916

  17. Targeting EZH2-mediated methylation of H3K27 inhibits proliferation and migration of Synovial Sarcoma in vitro.

    PubMed

    Shen, Jacson K; Cote, Gregory M; Gao, Yan; Choy, Edwin; Mankin, Henry J; Hornicek, Francis J; Duan, Zhenfeng

    2016-01-01

    Synovial sarcoma is an aggressive soft tissue sarcoma genetically defined by the fusion oncogene SS18-SSX. It is hypothesized that either SS18-SSX disrupts SWI/SNF complex inhibition of the polycomb complex 2 (PRC2) methyltransferase Enhancer of Zeste Homologue 2 (EZH2), or that SS18-SSX is able to directly recruit PRC2 to aberrantly silence target genes. This is of potential therapeutic value as several EZH2 small molecule inhibitors are entering early phase clinical trials. In this study, we first confirmed EZH2 expression in the 76% of human synovial sarcoma samples. We subsequently investigated EZH2 as a therapeutic target in synovial sarcoma in vitro. Knockdown of EZH2 by shRNA or siRNA resulted in inhibition of cell growth and migration across a series of synovial sarcoma cell lines. The EZH2 selective small-molecule inhibitor EPZ005687 similarly suppressed cell proliferation and migration. These data support the hypothesis that targeting EZH2 may be a promising therapeutic strategy in the treatment of synovial sarcoma; clinical trials are initiating enrollment currently. PMID:27125524

  18. A Comprehensive Single Institutional Review of 2 Years in a Designated Fast-Track Sarcoma Diagnostic Clinic Linked with a Sarcoma Specialist Advisory Group: Meeting the Target but Failing the Task?

    PubMed Central

    Davidson, Dochka; Wong, Han Hsi; Horan, Gail; Bearcroft, Philip W. P.; Grant, Ian; Grimer, Robert; Hopper, Melanie A.; Hatcher, Helen; Earl, Helena

    2016-01-01

    Background. National guidelines prompted the implementation of a designated two-week wait referral pathway to facilitate the early diagnosis of sarcomas, to improve treatment outcomes. Methods. Patients referred to the Cambridge Sarcoma Diagnostic Clinic between January 2013 and December 2014 were identified through the electronic appointments system. Information was retrospectively retrieved about patient characteristics and details of the diagnostic pathway. Results. 17.3% of patients referred (69/397) were diagnosed with a malignancy. Of these, 59.3% (41/69) had primary sarcomas, 17.4% (12/69) had metastatic cancer, and 23.2% (16/69) had a different primary malignancy. 15% of the 41 sarcomas were <5 cm, 34% in the 5–10 cm range, and 51% >10 cm. Sarcomas diagnosed through this clinic represented 13% (41/315) of sarcomas managed at the centre during the same 2 years. Conclusion. While we achieved the target of 10% (41/397) sarcoma diagnosis rate in the rapid access clinic, only 15% of these were <5 cm better prognosis lesions. This calls into question the “real world” impact of such diagnostic clinics on early diagnosis of sarcomas. In order to enhance generic cancer diagnostic skills, training in these diagnostic clinics could be usefully integrated into national training curricula for both surgical and nonsurgical oncologists. PMID:27340367

  19. Grouping principles in direct competition.

    PubMed

    Schmidt, Filipp; Schmidt, Thomas

    2013-08-01

    We (1) introduce a primed flanker task as an objective method to measure perceptual grouping, and (2) use it to directly compare the efficiency of different grouping cues in rapid visuomotor processing. In two experiments, centrally presented primes were succeeded by flanking targets with varying stimulus-onset asynchronies (SOAs). Primes and targets were grouped by the same or by different grouping cues (Exp. 1: brightness/shape, Exp. 2: brightness/size) and were consistent or inconsistent with respect to the required response. Subjective grouping strength was varied to identify its influence on overall response times, error rates, and priming effects, that served as a measure of visual feedforward processing. Our results show that stronger grouping in the targets enhanced overall response times while stronger grouping in the primes enhanced priming effects in motor responses. Also, we obtained differences between rapid visuomotor processing and the subjective impression with cues of brightness and shape but not with cues of brightness and size. Our findings establish the primed flanker task as an objective method to study the speeded visuomotor processing of grouping cues, making it a useful method for the comparative study of feedforward-transmitted base groupings (Roelfsema & Houtkamp, 2011). PMID:23764184

  20. Cardiovascular group

    NASA Technical Reports Server (NTRS)

    Blomqvist, Gunnar

    1989-01-01

    As a starting point, the group defined a primary goal of maintaining in flight a level of systemic oxygen transport capacity comparable to each individual's preflight upright baseline. The goal of maintaining capacity at preflight levels would seem to be a reasonable objective for several different reasons, including the maintenance of good health in general and the preservation of sufficient cardiovascular reserve capacity to meet operational demands. It is also important not to introduce confounding variables in whatever other physiological studies are being performed. A change in the level of fitness is likely to be a significant confounding variable in the study of many organ systems. The principal component of the in-flight cardiovascular exercise program should be large-muscle activity such as treadmill exercise. It is desirable that at least one session per week be monitored to assure maintenance of proper functional levels and to provide guidance for any adjustments of the exercise prescription. Appropriate measurements include evaluation of the heart-rate/workload or the heart-rate/oxygen-uptake relationship. Respiratory gas analysis is helpful by providing better opportunities to document relative workload levels from analysis of the interrelationships among VO2, VCO2, and ventilation. The committee felt that there is no clear evidence that any particular in-flight exercise regimen is protective against orthostatic hypotension during the early readaptation phase. Some group members suggested that maintenance of the lower body muscle mass and muscle tone may be helpful. There is also evidence that late in-flight interventions to reexpand blood volume to preflight levels are helpful in preventing or minimizing postflight orthostatic hypotension.

  1. Group evaporation

    NASA Technical Reports Server (NTRS)

    Shen, Hayley H.

    1991-01-01

    Liquid fuel combustion process is greatly affected by the rate of droplet evaporation. The heat and mass exchanges between gas and liquid couple the dynamics of both phases in all aspects: mass, momentum, and energy. Correct prediction of the evaporation rate is therefore a key issue in engineering design of liquid combustion devices. Current analytical tools for characterizing the behavior of these devices are based on results from a single isolated droplet. Numerous experimental studies have challenged the applicability of these results in a dense spray. To account for the droplets' interaction in a dense spray, a number of theories have been developed in the past decade. Herein, two tasks are examined. One was to study how to implement the existing theoretical results, and the other was to explore the possibility of experimental verifications. The current theoretical results of group evaporation are given for a monodispersed cluster subject to adiabatic conditions. The time evolution of the fluid mechanic and thermodynamic behavior in this cluster is derived. The results given are not in the form of a subscale model for CFD codes.

  2. Event parameters - fixed target

    SciTech Connect

    Poskanzer, A.; Ritter, H.G.; Ludewigt, B.; Foley, K.; Borenstein, S.; Platner, E.; Love, W.; Keane, D.; Plasil, F.

    1984-06-15

    This subgroup has focussed on detectors for fixed target experiments which have full azimuthal coverage. The general scope of the working group was to consider (1) the configuration of an idealized detector, and (2) various configurations of practical detectors that could be implemented on a relatively short time scale. The second category includes possible upgrades and modifications of existing experimental facilities. Beams of both 15 GeV/A sulphur at the AGS and 200 GeV/A oxygen at the SPS were considered.

  3. Direct targeted glycation of the free sulfhydryl group of cysteine residue (Cys-34) of BSA. Mapping of the glycation sites of the anti-tumor Thomsen-Friedenreich neoglycoconjugate vaccine prepared by Michael addition reaction.

    PubMed

    Demian, Wael L L; Kottari, Naresh; Shiao, Tze Chieh; Randell, Edward; Roy, René; Banoub, Joseph H

    2014-12-01

    We present in this manuscript the characterization of the exact glycation sites of the Thomsen-Friedenreich antigen-BSA vaccine (TF antigen:BSA) prepared using a Michael addition reaction between the saccharide antigen as an electrophilic acceptor and the nucleophilic thiol and L-Lysine ε-amino groups of BSA using different ligation conditions. Matrix laser desorption ionization time-of-flight mass spectrometry of the neoglycoconjugates prepared with TF antigen:protein ratios of 2:1 and 8:1, allowed to observe, respectively, the protonated molecules for each neoglycoconjugates: [M + H](+) at m/z 67,599 and 70,905. The measurements of these molecular weights allowed us to confirm exactly the carbohydrate:protein ratios of these two synthetic vaccines. These were found to be closely formed by a TF antigen:BSA ratios of 2:1 and 8:1, respectively. Trypsin digestion and liquid chromatography coupled with electrospray ionization mass spectrometry allowed us to identify the series of released glycopeptide and peptide fragments. De novo sequencing affected by low-energy collision dissociation tandem mass spectrometry was then employed to unravel the precise glycation sites of these neoglycoconjugate vaccines. Finally, we identified, respectively, three diagnostic and characteristic glycated peptides for the synthetic glycoconjugate possessing a TF antigen:BSA ratio 2:1, whereas we have identified for the synthetic glycoconjugate having a TF:BSA ratio 8:1 a series of 14 glycated peptides. The net increase in the occupancy sites of these neoglycoconjugates was caused by the large number of glycoforms produced during the chemical ligation of the synthetic carbohydrate antigen onto the protein carrier.

  4. Direct targeted glycation of the free sulfhydryl group of cysteine residue (Cys-34) of BSA. Mapping of the glycation sites of the anti-tumor Thomsen-Friedenreich neoglycoconjugate vaccine prepared by Michael addition reaction.

    PubMed

    Demian, Wael L L; Kottari, Naresh; Shiao, Tze Chieh; Randell, Edward; Roy, René; Banoub, Joseph H

    2014-12-01

    We present in this manuscript the characterization of the exact glycation sites of the Thomsen-Friedenreich antigen-BSA vaccine (TF antigen:BSA) prepared using a Michael addition reaction between the saccharide antigen as an electrophilic acceptor and the nucleophilic thiol and L-Lysine ε-amino groups of BSA using different ligation conditions. Matrix laser desorption ionization time-of-flight mass spectrometry of the neoglycoconjugates prepared with TF antigen:protein ratios of 2:1 and 8:1, allowed to observe, respectively, the protonated molecules for each neoglycoconjugates: [M + H](+) at m/z 67,599 and 70,905. The measurements of these molecular weights allowed us to confirm exactly the carbohydrate:protein ratios of these two synthetic vaccines. These were found to be closely formed by a TF antigen:BSA ratios of 2:1 and 8:1, respectively. Trypsin digestion and liquid chromatography coupled with electrospray ionization mass spectrometry allowed us to identify the series of released glycopeptide and peptide fragments. De novo sequencing affected by low-energy collision dissociation tandem mass spectrometry was then employed to unravel the precise glycation sites of these neoglycoconjugate vaccines. Finally, we identified, respectively, three diagnostic and characteristic glycated peptides for the synthetic glycoconjugate possessing a TF antigen:BSA ratio 2:1, whereas we have identified for the synthetic glycoconjugate having a TF:BSA ratio 8:1 a series of 14 glycated peptides. The net increase in the occupancy sites of these neoglycoconjugates was caused by the large number of glycoforms produced during the chemical ligation of the synthetic carbohydrate antigen onto the protein carrier. PMID:25476939

  5. Cbx7 is epigenetically silenced in glioblastoma and inhibits cell migration by targeting YAP/TAZ-dependent transcription

    PubMed Central

    Nawaz, Zahid; Patil, Vikas; Arora, Anjali; Hegde, Alangar S.; Arivazhagan, Arimappamagan; Santosh, Vani; Somasundaram, Kumaravel

    2016-01-01

    Glioblastomas (GBM) are the most malignant form of astrocytomas which are difficult to treat and portend a grave clinical course and poor prognosis. In this study, we identified Chromobox homolog 7 (Cbx7), a member of Polycomb Repressive Complex 1 (PRC1), as a downregulated gene in GBM owing to its promoter hypermethylation. Bisulphite sequencing and methylation inhibitor treatment established the hypermethylation of Cbx7 in GBM. Exogenous overexpression of Cbx7 induced cell death, inhibited cell proliferation, colony formation and migration/invasion of the glioma cells. GSEA of Cbx7 regulated genes identified Cbx7 as a repressor of transcription co-activators YAP/TAZ, the inhibitory targets of the Hippo signalling pathway. In good correlation, the exogenous expression of Cbx7 repressed the YAP/TAZ-dependent transcription and downregulated CTGF, a bonafide YAP/TAZ target. We also observed reduced levels of phospho-JNK in Cbx7 expressing cells. Additionally, CTGF silencing and pharmacological inhibition of JNK also inhibited glioma cell migration. Further, Cbx7 failed to inhibit cell migration significantly in the presence of exogenously overexpressed CTGF or constitutively active JNK. Thus, our study identifies Cbx7 as an inhibitor of glioma cell migration through its inhibitory effect on YAP/TAZ-CTGF-JNK signalling axis and underscores the importance of epigenetic inactivation of Cbx7 in gliomagenesis. PMID:27291091

  6. Acquisition of a single EZH2 D1 domain mutation confers acquired resistance to EZH2-targeted inhibitors

    PubMed Central

    Baker, Theresa; Nerle, Sujata; Pritchard, Justin; Zhao, Boyang; Rivera, Victor M.

    2015-01-01

    Although targeted therapies have revolutionized cancer treatment, overcoming acquired resistance remains a major clinical challenge. EZH2 inhibitors (EZH2i), EPZ-6438 and GSK126, are currently in the early stages of clinical evaluation and the first encouraging signs of efficacy have recently emerged in the clinic. To anticipate mechanisms of resistance to EZH2i, we used a forward genetic platform combining a mutagenesis screen with next generation sequencing technology and identified a hotspot of secondary mutations in the EZH2 D1 domain (Y111 and I109). Y111D mutation within the WT or A677G EZH2 allele conferred robust resistance to both EPZ-6438 and GSK126, but it only drove a partial resistance within the Y641F allele. EZH2 mutants required histone methyltransferase (HMT) catalytic activity and the polycomb repressive complex 2 (PRC2) components, SUZ12 and EED, to drive drug resistance. Furthermore, D1 domain mutations not only blocked the ability of EZH2i to bind to WT and A677G mutant, but also abrogated drug binding to the Y641F mutant. These data provide the first cellular validation of the mechanistic model underpinning the oncogenic function of WT and mutant EZH2. Importantly, our findings suggest that acquired-resistance to EZH2i may arise in WT and mutant EZH2 patients through a single mutation that remains targetable by second generation EZH2i. PMID:26360609

  7. Jarid2 Is Implicated in the Initial Xist-Induced Targeting of PRC2 to the Inactive X Chromosome.

    PubMed

    da Rocha, Simão Teixeira; Boeva, Valentina; Escamilla-Del-Arenal, Martin; Ancelin, Katia; Granier, Camille; Matias, Neuza Reis; Sanulli, Serena; Chow, Jen; Schulz, Edda; Picard, Christel; Kaneko, Syuzo; Helin, Kristian; Reinberg, Danny; Stewart, A Francis; Wutz, Anton; Margueron, Raphaël; Heard, Edith

    2014-01-23

    During X chromosome inactivation (XCI), the Polycomb Repressive Complex 2 (PRC2) is thought to participate in the early maintenance of the inactive state. Although Xist RNA is essential for the recruitment of PRC2 to the X chromosome, the precise mechanism remains unclear. Here, we demonstrate that the PRC2 cofactor Jarid2 is an important mediator of Xist-induced PRC2 targeting. The region containing the conserved B and F repeats of Xist is critical for Jarid2 recruitment via its unique N-terminal domain. Xist-induced Jarid2 recruitment occurs chromosome-wide independently of a functional PRC2 complex, unlike at other parts of the genome, such as CG-rich regions, where Jarid2 and PRC2 binding are interdependent. Conversely, we show that Jarid2 loss prevents efficient PRC2 and H3K27me3 enrichment to Xist-coated chromatin. Jarid2 thus represents an important intermediate between PRC2 and Xist RNA for the initial targeting of the PRC2 complex to the X chromosome during onset of XCI.

  8. Molecular Genetic Analysis of Drosophila Ash2, a Member of the Trithorax Group Required for Imaginal Disc Pattern Formation

    PubMed Central

    Adamson, A. L.; Shearn, A.

    1996-01-01

    The ash2 gene is a member of the trithorax group of genes whose products function to maintain active transcription of homeotic selector genes. Mutations in ash2 cause the homeotic transformations expected for a gene in this group but, in addition, cause a variety of pattern formation defects that are not necessarily expected. The ash2 gene is located in cytogenetic region 96A17-19 flanked by slowpoke and tolloid and is included in a cosmid that contains part of slowpoke. The ash2 transcript is 2.0 kb and is present throughout development. The ASH2 protein predicted from the nucleotide sequence of the open reading frame has a putative double zinc-finger domain, called a PHD finger, that is present not only in the products of other trithorax group genes such as TRX and ASH1, but also in the product of a Polycomb group gene, PCL. Polyclonal antibodies directed against ASH2 detect the protein in imaginal discs and in the nuclei of salivary gland and fat body cells. On immunoblots these affinity-purified antibodies detect a 70-kDa protein in larvae and a 53-kDa protein in pupae. PMID:8889525

  9. Targeted therapy for sarcomas

    PubMed Central

    Forscher, Charles; Mita, Monica; Figlin, Robert

    2014-01-01

    Sarcomas are tumors of mesenchymal origin that make up approximately 1% of human cancers. They may arise as primary tumors in either bone or soft tissue, with approximately 11,280 soft tissue tumors and 2,650 bone tumors diagnosed each year in the United States. There are at least 50 different subtypes of soft tissue sarcoma, with new ones described with ever-increasing frequency. One way to look at sarcomas is to divide them into categories on the basis of their genetic make-up. One group of sarcomas has an identifiable, relatively simple genetic signature, such as the X:18 translocation seen in synovial sarcoma or the 11:22 translocation seen in Ewing’s sarcoma. These specific abnormalities often lead to the presence of fusion proteins, such as EWS-FLI1 in Ewing’s sarcoma, which are helpful as diagnostic tools and may become therapeutic targets in the future. Another group of sarcomas is characterized by complex genetic abnormalities as seen in leiomyosarcoma, osteosarcoma, and undifferentiated sarcoma. It is important to keep these distinctions in mind when contemplating the development of targeted agents for sarcomas. Different abnormalities in sarcoma could be divided by tumor subtype or by the molecular or pathway abnormality. However, some existing drugs or drugs in development may interfere with or alter more than one of the presented pathways. PMID:24669185

  10. Effects of target typicality on categorical search

    PubMed Central

    Maxfield, Justin T.; Stalder, Westri D.; Zelinsky, Gregory J.

    2014-01-01

    The role of target typicality in a categorical visual search task was investigated by cueing observers with a target name, followed by a five-item target present/absent search array in which the target images were rated in a pretest to be high, medium, or low in typicality with respect to the basic-level target cue. Contrary to previous work, we found that search guidance was better for high-typicality targets compared to low-typicality targets, as measured by both the proportion of immediate target fixations and the time to fixate the target. Consistent with previous work, we also found an effect of typicality on target verification times, the time between target fixation and the search judgment; as target typicality decreased, verification times increased. To model these typicality effects, we trained Support Vector Machine (SVM) classifiers on the target categories, and tested these on the corresponding specific targets used in the search task. This analysis revealed significant differences in classifier confidence between the high-, medium-, and low-typicality groups, paralleling the behavioral results. Collectively, these findings suggest that target typicality broadly affects both search guidance and verification, and that differences in typicality can be predicted by distance from an SVM classification boundary. PMID:25274990

  11. Lamin A/C sustains PcG protein architecture, maintaining transcriptional repression at target genes

    PubMed Central

    Cesarini, Elisa; Mozzetta, Chiara; Marullo, Fabrizia; Gregoretti, Francesco; Gargiulo, Annagiusi; Columbaro, Marta; Cortesi, Alice; Antonelli, Laura; Di Pelino, Simona; Squarzoni, Stefano; Palacios, Daniela; Zippo, Alessio; Bodega, Beatrice; Oliva, Gennaro

    2015-01-01

    Beyond its role in providing structure to the nuclear envelope, lamin A/C is involved in transcriptional regulation. However, its cross talk with epigenetic factors—and how this cross talk influences physiological processes—is still unexplored. Key epigenetic regulators of development and differentiation are the Polycomb group (PcG) of proteins, organized in the nucleus as microscopically visible foci. Here, we show that lamin A/C is evolutionarily required for correct PcG protein nuclear compartmentalization. Confocal microscopy supported by new algorithms for image analysis reveals that lamin A/C knock-down leads to PcG protein foci disassembly and PcG protein dispersion. This causes detachment from chromatin and defects in PcG protein–mediated higher-order structures, thereby leading to impaired PcG protein repressive functions. Using myogenic differentiation as a model, we found that reduced levels of lamin A/C at the onset of differentiation led to an anticipation of the myogenic program because of an alteration of PcG protein–mediated transcriptional repression. Collectively, our results indicate that lamin A/C can modulate transcription through the regulation of PcG protein epigenetic factors. PMID:26553927

  12. Peptide targeted copper-64 radiopharmaceuticals.

    PubMed

    Ma, Michelle T; Donnelly, Paul S

    2011-01-01

    Peptide targeted ⁶⁴Cu-labelled diagnostic agents for positron emission tomography are viable candidates for molecular imaging of cancer. In a clinical setting, optimal image quality relies on selective tumor uptake of the ⁶⁴Cu-labelled radiotracer. The three components of the radiotracer construct--the chelate group, linker and targeting peptide--all influence the biodistribution of the ⁶⁴Cu-labelled radiotracer in vivo. Low or moderate Cu complex stability in vivo results in transmetallation of ⁶⁴Cu to endogenous proteins, giving rise to high background activity. The length and the nature of the linker group affect the affinity of the ⁶⁴Cu-labelled radiotracer for the target receptor. Variations in the peptide sequence can impact on the metabolic stability and therefore the bioavailability and tumor retention of the ⁶⁴Cu-labelled radiotracer in vivo. Lastly, the hydrophilicity of the construct can influence radiotracer metabolism and clearance pathways. Recent advances in the field of peptide targeted ⁶⁴Cu-labelled radiopharmaceuticals involve GRPR-targeted and αvβ3 integrin receptor-targeted constructs. These constructs are based on the bombesin peptide sequence and the RGD recognition motif respectively. These examples are reviewed as case studies in the optimisation of ⁶⁴Cu radiotracer design.

  13. Evaluation of LSCA Services to Special Target Groups: Final Report.

    ERIC Educational Resources Information Center

    Black, D.V.; And Others

    To perform a complete and useful evaluation of the impact of federal funding, under Titles I, II, and IV of the Library Services and Construction Act (LSCA), on public library services to the disadvantaged, handicapped, and institutionalized, two convergent lines of study were undertaken: the study of project plans and achievements and the study…

  14. The More Knowledgeable Peer, Target Language Use, and Group Participation

    ERIC Educational Resources Information Center

    Huong, Le Pham Hoai

    2007-01-01

    Vygotsky proposed the concept of the zone of proximal development (ZPD) but did not elaborate the concept of "peer," leaving open the question of how capable a peer should be and how practice or outcome might differ according to a peer's level of capability. These issues were investigated in a sociocultural study of first-year Vietnamese…

  15. Targeted therapies for cancer

    MedlinePlus

    ... page: //medlineplus.gov/ency/patientinstructions/000902.htm Targeted therapies for cancer To use the sharing features on ... cells so they cannot spread. How Does Targeted Therapy Work? Targeted therapy drugs work in a few ...

  16. Liquid Hydrogen: Target, Detector

    SciTech Connect

    Mulholland, G.T.; Harigel, G.G.

    2004-06-23

    In 1952 D. Glaser demonstrated that a radioactive source's radiation could boil 135 deg. C superheated-diethyl ether in a 3-mm O glass vessel and recorded bubble track growth on high-speed film in a 2-cm3 chamber. This Bubble Chamber (BC) promised improved particle track time and spatial resolution and cycling rate. Hildebrand and Nagle, U of Chicago, reported Liquid Hydrogen minimum ionizing particle boiling in August 1953. John Wood created the 3.7-cm O Liquid Hydrogen BC at LBL in January 1954. By 1959 the Lawrence Berkley Laboratory (LBL) Alvarez group's '72-inch' BC had tracks in liquid hydrogen. Within 10 years bubble chamber volumes increased by a factor of a million and spread to every laboratory with a substantial high-energy physics program. The BC, particle accelerators and special separated particle beams created a new era of High Energy Physics (HEP) experimentation. The BC became the largest most complex cryogenic installation at the world's HEP laboratories for decades. The invention and worldwide development, deployment and characteristics of these cryogenic dynamic target/detectors and related hydrogen targets are described.

  17. Cloned IGH VDJ targets as tools for personalized minimal residual disease monitoring in mature lymphoid malignancies; a feasibility study in mantle cell lymphoma by the Groupe Ouest Est d'Etude des Leucémies et Autres Maladies du Sang.

    PubMed

    Gimenez, Estelle; Chauvet, Martine; Rabin, Laetitia; Puteaud, Isabelle; Duley, Samuel; Hamaidia, Sieme; Bruder, Juliana; Rolland-Neyret, Valérie; Le Gouill, Steven; Tournilhac, Olivier; Voog, Eric; Maisonneuve, Hervé; Jacob, Marie C; Leroux, Dominique; Béné, Marie C; Formisano-Tréziny, Christine; Gabert, Jean; Gressin, Rémy; Callanan, Mary B

    2012-07-01

    Molecular minimal residual disease (MRD) analysis is fast emerging as an essential clinical decision-making tool for the treatment and follow-up of mature B cell malignancies. Current EuroMRD consensus IGH real-time quantitative polymerase chain reaction RQ-PCR assays rely on flow cytometric assessment of diagnostic tumour burdens to construct 'normalized', patient-specific, diagnostic DNA-based MRD quantification standards. Here, we propose a new 'hybrid' assay that relies on plasmid-based quantification of patient-specific IGH VDJ targets by consensus IGH real time (RQ)-PCR, combined with EuroMRD guidelines, for MRD monitoring in lymphoid malignancies. This assay was evaluated for MRD assessment in a total of 273 samples from 29 mantle cell lymphoma (MCL) patients treated within a Groupe Ouest Est d'Etude des Leucémies et Autres Maladies du Sang (GOELAMS) Phase II trial and was feasible, reliable and consistently comparable to gold-standard MRD techniques (99% concordance across all samples including 32 samples within the quantitative range) when analysed in parallel (117 samples). Integrating clinical prognostic parameters and MRD status in peripheral blood at the post-induction stage was predictive of progression-free survival (P = 0·034) thus demonstrating the clinical utility of the approach. Plasmid-based standards for the quantification of IGH VDJ targets are therefore confirmed to offer new opportunities for further standardization and clinical evaluation of MRD-guided management of patients with mature B cell malignancies.

  18. Group Dynamics in Automatic Imitation

    PubMed Central

    Wilson, Neil; Reddy, Geetha; Catmur, Caroline

    2016-01-01

    Imitation–matching the configural body movements of another individual–plays a crucial part in social interaction. We investigated whether automatic imitation is not only influenced by who we imitate (ingroup vs. outgroup member) but also by the nature of an expected interaction situation (competitive vs. cooperative). In line with assumptions from Social Identity Theory), we predicted that both social group membership and the expected situation impact on the level of automatic imitation. We adopted a 2 (group membership target: ingroup, outgroup) x 2 (situation: cooperative, competitive) design. The dependent variable was the degree to which participants imitated the target in a reaction time automatic imitation task. 99 female students from two British Universities participated. We found a significant two-way interaction on the imitation effect. When interacting in expectation of cooperation, imitation was stronger for an ingroup target compared to an outgroup target. However, this was not the case in the competitive condition where imitation did not differ between ingroup and outgroup target. This demonstrates that the goal structure of an expected interaction will determine the extent to which intergroup relations influence imitation, supporting a social identity approach. PMID:27657926

  19. Jarid2/Jumonji coordinates control of PRC2 enzymatic activity and target gene occupancy in pluripotent cells.

    PubMed

    Peng, Jamy C; Valouev, Anton; Swigut, Tomek; Zhang, Junmei; Zhao, Yingming; Sidow, Arend; Wysocka, Joanna

    2009-12-24

    Polycomb Repressive Complex 2 (PRC2) regulates key developmental genes in embryonic stem (ES) cells and during development. Here we show that Jarid2/Jumonji, a protein enriched in pluripotent cells and a founding member of the Jumonji C (JmjC) domain protein family, is a PRC2 subunit in ES cells. Genome-wide ChIP-seq analyses of Jarid2, Ezh2, and Suz12 binding reveal that Jarid2 and PRC2 occupy the same genomic regions. We further show that Jarid2 promotes PRC2 recruitment to the target genes while inhibiting PRC2 histone methyltransferase activity, suggesting that it acts as a "molecular rheostat" that finely calibrates PRC2 functions at developmental genes. Using Xenopus laevis as a model we demonstrate that Jarid2 knockdown impairs the induction of gastrulation genes in blastula embryos and results in failure of differentiation. Our findings illuminate a mechanism of histone methylation regulation in pluripotent cells and during early cell-fate transitions.

  20. Direct targeting of SUZ12/ROCK2 by miR-200b/c inhibits cholangiocarcinoma tumourigenesis and metastasis

    PubMed Central

    Peng, F; Jiang, J; Yu, Y; Tian, R; Guo, X; Li, X; Shen, M; Xu, M; Zhu, F; Shi, C; Hu, J; Wang, M; Qin, R

    2013-01-01

    Background: The multidrug resistance and distant metastasis of cholangiocarcinoma result in high postoperative recurrence and low long-term survival rates. It has been demonstrated that the ectopic expression of miR-200 suppresses the multidrug resistance and metastasis of cancer. However, the expression and function of miR-200 in cholangiocarcinoma has not yet been described. Methods: In this study, we identified dysregulated microRNAs (miRNAs, miR) in cholangiocarcinoma tissue by microarray analysis, and subsequent real-time PCR and northern blot analyses validated the expression of candidate miR. We performed functional analyses and investigated the relationship between miR-200b/c expression and the properties of cholangiocarcinoma cells. A dual luciferase assay was applied to examine the effect of miRNAs on the 3′-UTR of target genes, and we demonstrated the function of the target gene by siRNA transfection identifying the downstream pathway via western blotting. Results: We found significantly downregulated expression of four miR-200 family members (miR-200a/b/c/429) and then confirmed that ectopic miR-200b/200c inhibits the migration and invasion of cholangiocarcinoma cells both in vitro and in vivo. We found that miR-200b/c influenced the tumourigenesis of cholangiocarcinoma cells including their tumour-initiating capacity, sphere formation, and drug resistance. We further found that miR-200b/c regulated migration and invasion capacities by directly targeting rho-kinase 2 and regulated tumorigenic properties by directly targeting SUZ12 (a subunit of a polycomb repressor complex). Conclusion: Our study shows that miR-200b/c has a critical role in the regulation of the tumorigenic and metastatic capacity of cholangiocarcinoma and reveals the probable underlying mechanisms. PMID:24169343

  1. Fostering group identification and creativity in diverse groups: the role of individuation and self-verification.

    PubMed

    Swann, William B; Kwan, Virginia S Y; Polzer, Jeffrey T; Milton, Laurie P

    2003-11-01

    A longitudinal study examined the interplay of identity negotiation processes and diversity in small groups of master's of business administration (MBA) students. When perceivers formed relatively positive impressions of other group members, higher diversity predicted more individuation of targets. When perceivers formed relatively neutral impressions of other group members, however, higher diversity predicted less individuation of targets. Individuation at the outset of the semester predicted self-verification effects several weeks later, and self-verification, in turn, predicted group identification and creative task performance. The authors conclude that contrary to self-categorization theory, fostering individuation and self-verification in diverse groups may maximize group identification and productivity.

  2. Experience with IPNS targets

    SciTech Connect

    Carpenter, J.M.; Hins, A.G.

    1993-12-31

    Three targets have operated in the IPNS Neutron Scattering Facility. The first, a depleted Uranium target, served from 1981 until it was replaced in 1988 by the Enriched Uranium Booster Target. The Booster Target had operated for nearly three years when it suffered a cladding leak and was replaced with the retired depleted Uranium target. That target reached its end-of-life after less than one year`s further operation, and was replaced with an identical one newly assembled from spare components, which is still operating satisfactorily. This paper reviews the operating history of the IPNS targets and the findings reached during analysis of the failures. Similarities with ISIS target experience, preliminary conclusions and plans for providing spares and improved targets are discussed. We present some preliminary results from the hot cell examination of the failed depleted Uranium target.

  3. 28 CFR 55.17 - Targeting.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... REGARDING LANGUAGE MINORITY GROUPS Minority Language Materials and Assistance § 55.17 Targeting. The term...). “Targeting” refers to a system in which the minority language materials or assistance required by the Act are... targeting system will normally fulfill the Act's minority language requirements if it is designed...

  4. 28 CFR 55.17 - Targeting.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... REGARDING LANGUAGE MINORITY GROUPS Minority Language Materials and Assistance § 55.17 Targeting. The term...). “Targeting” refers to a system in which the minority language materials or assistance required by the Act are... targeting system will normally fulfill the Act's minority language requirements if it is designed...

  5. 28 CFR 55.17 - Targeting.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... REGARDING LANGUAGE MINORITY GROUPS Minority Language Materials and Assistance § 55.17 Targeting. The term...). “Targeting” refers to a system in which the minority language materials or assistance required by the Act are... targeting system will normally fulfill the Act's minority language requirements if it is designed...

  6. 28 CFR 55.17 - Targeting.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... REGARDING LANGUAGE MINORITY GROUPS Minority Language Materials and Assistance § 55.17 Targeting. The term...). “Targeting” refers to a system in which the minority language materials or assistance required by the Act are... targeting system will normally fulfill the Act's minority language requirements if it is designed...

  7. 28 CFR 55.17 - Targeting.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... REGARDING LANGUAGE MINORITY GROUPS Minority Language Materials and Assistance § 55.17 Targeting. The term...). “Targeting” refers to a system in which the minority language materials or assistance required by the Act are... targeting system will normally fulfill the Act's minority language requirements if it is designed...

  8. Electrically charged targets

    DOEpatents

    Goodman, Ronald K.; Hunt, Angus L.

    1984-01-01

    Electrically chargeable laser targets and method for forming such charged targets in order to improve their guidance along a predetermined desired trajectory. This is accomplished by the incorporation of a small amount of an additive to the target material which will increase the electrical conductivity thereof, and thereby enhance the charge placed upon the target material for guidance thereof by electrostatic or magnetic steering mechanisms, without adversely affecting the target when illuminated by laser energy.

  9. Polarized internal target apparatus

    DOEpatents

    Holt, Roy J.

    1986-01-01

    A polarized internal target apparatus with a polarized gas target of improved polarization and density achieved by mixing target gas atoms with a small amount of alkali metal gas atoms, and passing a high intensity polarized light source into the mixture to cause the alkali metal gas atoms to become polarized which interact in spin exchange collisions with target gas atoms yielding polarized target gas atoms.

  10. Polarized internal target apparatus

    DOEpatents

    Holt, R.J.

    1984-10-10

    A polarized internal target apparatus with a polarized gas target of improved polarization and density (achieved by mixing target gas atoms with a small amount of alkali metal gas atoms, and passing a high intensity polarized light source into the mixture to cause the alkali metal gas atoms to become polarized which interact in spin exchange collisions with target gas atoms yielding polarized target gas atoms) is described.

  11. Group Work Publication-1991.

    ERIC Educational Resources Information Center

    Zimpfer, David G.

    1992-01-01

    Lists 21 new publications in group work, of which 9 are reviewed. Those discussed include publications on group counseling and psychotherapy, structured groups, support groups, psychodrama, and social group work. (Author/NB)

  12. Group Cohesion in Experiential Growth Groups

    ERIC Educational Resources Information Center

    Steen, Sam; Vasserman-Stokes, Elaina; Vannatta, Rachel

    2014-01-01

    This article explores the effect of web-based journaling on changes in group cohesion within experiential growth groups. Master's students were divided into 2 groups. Both used a web-based platform to journal after each session; however, only 1 of the groups was able to read each other's journals. Quantitative data collected before and…

  13. Fixed target facility at the SSC

    SciTech Connect

    Loken, S.C.; Morfin, J.G.

    1985-01-01

    The question of whether a facility for fixed target physics should be provided at the SSC must be answered before the final technical design of the SSC can be completed, particularly if the eventual form of extraction would influence the magnet design. To this end, an enthusiastic group of experimentalists, theoreticians and accelerator specialists have studied this point. The accelerator physics issues were addressed by a group led by E. Colton whose report is contained in these proceedings. The physics addressable by fixed target was considered by many of the Physics area working groups and in particular by the Structure Function Group. This report is the summary of the working group which considered various SSC fixed target experiments and determined which types of beams and detectors would be required. 13 references, 5 figures.

  14. Adaptive group coordination and role differentiation.

    PubMed

    Roberts, Michael E; Goldstone, Robert L

    2011-01-01

    Many real world situations (potluck dinners, academic departments, sports teams, corporate divisions, committees, seminar classes, etc.) involve actors adjusting their contributions in order to achieve a mutually satisfactory group goal, a win-win result. However, the majority of human group research has involved situations where groups perform poorly because task constraints promote either individual maximization behavior or diffusion of responsibility, and even successful tasks generally involve the propagation of one correct solution through a group. Here we introduce a group task that requires complementary actions among participants in order to reach a shared goal. Without communication, group members submit numbers in an attempt to collectively sum to a randomly selected target number. After receiving group feedback, members adjust their submitted numbers until the target number is reached. For all groups, performance improves with task experience, and group reactivity decreases over rounds. Our empirical results provide evidence for adaptive coordination in human groups, and as the coordination costs increase with group size, large groups adapt through spontaneous role differentiation and self-consistency among members. We suggest several agent-based models with different rules for agent reactions, and we show that the empirical results are best fit by a flexible, adaptive agent strategy in which agents decrease their reactions when the group feedback changes. The task offers a simple experimental platform for studying the general problem of group coordination while maximizing group returns, and we distinguish the task from several games in behavioral game theory. PMID:21811595

  15. SEEDS Moving Group Status Update

    NASA Technical Reports Server (NTRS)

    McElwain, Michael

    2011-01-01

    I will summarize the current status of the SEEDS Moving Group category and describe the importance of this sub-sample for the entire SEEDS survey. This presentation will include analysis of the sensitivity for the Moving Groups with general a comparison to other the other sub-categories. I will discuss the future impact of the Subaru SCExAO system for these targets and the advantage of using a specialized integral field spectrograph. Finally, I will present the impact of a pupil grid mask in order to produce fiducial spots in the focal plane that can be used for both photometry and astrometry.

  16. Magnetically attached sputter targets

    DOEpatents

    Makowiecki, D.M.; McKernan, M.A.

    1994-02-15

    An improved method and assembly for attaching sputtering targets to cathode assemblies of sputtering systems which includes a magnetically permeable material is described. The magnetically permeable material is imbedded in a target base that is brazed, welded, or soldered to the sputter target, or is mechanically retained in the target material. Target attachment to the cathode is achieved by virtue of the permanent magnets and/or the pole pieces in the cathode assembly that create magnetic flux lines adjacent to the backing plate, which strongly attract the magnetically permeable material in the target assembly. 11 figures.

  17. Magnetically attached sputter targets

    DOEpatents

    Makowiecki, Daniel M.; McKernan, Mark A.

    1994-01-01

    An improved method and assembly for attaching sputtering targets to cathode assemblies of sputtering systems which includes a magnetically permeable material. The magnetically permeable material is imbedded in a target base that is brazed, welded, or soldered to the sputter target, or is mechanically retained in the target material. Target attachment to the cathode is achieved by virtue of the permanent magnets and/or the pole pieces in the cathode assembly that create magnetic flux lines adjacent to the backing plate, which strongly attract the magnetically permeable material in the target assembly.

  18. Reducing Prejudice With Labels: Shared Group Memberships Attenuate Implicit Bias and Expand Implicit Group Boundaries.

    PubMed

    Scroggins, W Anthony; Mackie, Diane M; Allen, Thomas J; Sherman, Jeffrey W

    2016-02-01

    In three experiments, we used a novel Implicit Association Test procedure to investigate the impact of group memberships on implicit bias and implicit group boundaries. Results from Experiment 1 indicated that categorizing targets using a shared category reduced implicit bias by increasing the extent to which positivity was associated with Blacks. Results from Experiment 2 revealed that shared group membership, but not mere positivity of a group membership, was necessary to reduce implicit bias. Quadruple process model analyses indicated that changes in implicit bias caused by shared group membership are due to changes in the way that targets are evaluated, not to changes in the regulation of evaluative bias. Results from Experiment 3 showed that categorizing Black targets into shared group memberships expanded implicit group boundaries. PMID:26667477

  19. Reducing Prejudice With Labels: Shared Group Memberships Attenuate Implicit Bias and Expand Implicit Group Boundaries.

    PubMed

    Scroggins, W Anthony; Mackie, Diane M; Allen, Thomas J; Sherman, Jeffrey W

    2016-02-01

    In three experiments, we used a novel Implicit Association Test procedure to investigate the impact of group memberships on implicit bias and implicit group boundaries. Results from Experiment 1 indicated that categorizing targets using a shared category reduced implicit bias by increasing the extent to which positivity was associated with Blacks. Results from Experiment 2 revealed that shared group membership, but not mere positivity of a group membership, was necessary to reduce implicit bias. Quadruple process model analyses indicated that changes in implicit bias caused by shared group membership are due to changes in the way that targets are evaluated, not to changes in the regulation of evaluative bias. Results from Experiment 3 showed that categorizing Black targets into shared group memberships expanded implicit group boundaries.

  20. FLIR target screening

    NASA Technical Reports Server (NTRS)

    Aggarwal, R.

    1982-01-01

    Methods for the segmentation and recognition of individual targets sensed with forward looking infrared detectors are discussed. Particular attention is given to an adaptive multi-scenario target screener.

  1. High Power Cryogenic Targets

    SciTech Connect

    Gregory Smith

    2011-08-01

    The development of high power cryogenic targets for use in parity violating electron scattering has been a crucial ingredient in the success of those experiments. As we chase the precision frontier, the demands and requirements for these targets have grown accordingly. We discuss the state of the art, and describe recent developments and strategies in the design of the next generation of these targets.

  2. An actionable climate target

    NASA Astrophysics Data System (ADS)

    Geden, Oliver

    2016-05-01

    The Paris Agreement introduced three mitigation targets. In the future, the main focus should not be on temperature targets such as 2 or 1.5 °C, but on the target with the greatest potential to effectively guide policy: net zero emissions.

  3. Plasma sheath driven targets

    NASA Astrophysics Data System (ADS)

    Brownell, J. H.; Freeman, B. L.

    1980-02-01

    Plasma focus driven target implosions are simulated using hydrodynamic-burn codes. Support is given to the idea that the use of a target in a plasma focus should allow 'impedance matching' between the fuel and gun, permitting larger fusion yields from a focus-target geometry than the scaling laws for a conventional plasma focus would predict.

  4. Interagency mechanical operations group numerical systems group

    SciTech Connect

    1997-09-01

    This report consists of the minutes of the May 20-21, 1971 meeting of the Interagency Mechanical Operations Group (IMOG) Numerical Systems Group. This group looks at issues related to numerical control in the machining industry. Items discussed related to the use of CAD and CAM, EIA standards, data links, and numerical control.

  5. Group Dynamic Processes in Email Groups

    ERIC Educational Resources Information Center

    Alpay, Esat

    2005-01-01

    Discussion is given on the relevance of group dynamic processes in promoting decision-making in email discussion groups. General theories on social facilitation and social loafing are considered in the context of email groups, as well as the applicability of psychodynamic and interaction-based models. It is argued that such theories may indeed…

  6. Facilitating Reminiscence Groups: Perceptions of Group Leaders

    ERIC Educational Resources Information Center

    Christensen, Teresa M.; Hulse-Killacky, Diana; Salgado, Roy A.; Thornton, Mark D.; Miller, Jason L.

    2006-01-01

    This article presents the results of a two-year qualitative investigation in which group leaders provided their perceptions of the process of facilitating reminiscence groups with elderly persons in a residential care facility. Group Culture emerged as the dominant construct. Findings from this study can serve guide leaders who are interested in…

  7. Perceiving individuals and groups: expectancies, dispositional inferences, and causal attributions.

    PubMed

    Susskind, J; Maurer, K; Thakkar, V; Hamilton, D L; Sherman, J W

    1999-02-01

    Two experiments investigated differences in forming impressions of individual and group targets. Experiment 1 showed that when forming an impression of an individual, perceivers made more extreme trait judgments, made those judgments more quickly and with greater confidence, and recalled more information than when the impression target was a group. Experiment 2 showed that when participants were forming an impression of an individual, expectancy-inconsistent behaviors spontaneously triggered causal attributions to resolve the inconsistency; this was not the case when the impression target was a group. Results are interpreted as reflecting perceivers' a priori assumptions of unity and coherence in individual versus group targets.

  8. Perceiving individuals and groups: expectancies, dispositional inferences, and causal attributions.

    PubMed

    Susskind, J; Maurer, K; Thakkar, V; Hamilton, D L; Sherman, J W

    1999-02-01

    Two experiments investigated differences in forming impressions of individual and group targets. Experiment 1 showed that when forming an impression of an individual, perceivers made more extreme trait judgments, made those judgments more quickly and with greater confidence, and recalled more information than when the impression target was a group. Experiment 2 showed that when participants were forming an impression of an individual, expectancy-inconsistent behaviors spontaneously triggered causal attributions to resolve the inconsistency; this was not the case when the impression target was a group. Results are interpreted as reflecting perceivers' a priori assumptions of unity and coherence in individual versus group targets. PMID:10074704

  9. CASP9 Target Classification

    PubMed Central

    Kinch, Lisa N.; Shi, Shuoyong; Cheng, Hua; Cong, Qian; Pei, Jimin; Mariani, Valerio; Schwede, Torsten; Grishin, Nick V.

    2011-01-01

    The Critical Assessment of Protein Structure Prediction round 9 (CASP9) aimed to evaluate predictions for 129 experimentally determined protein structures. To assess tertiary structure predictions, these target structures were divided into domain-based evaluation units that were then classified into two assessment categories: template based modeling (TBM) and template free modeling (FM). CASP9 targets were split into domains of structurally compact evolutionary modules. For the targets with more than one defined domain, the decision to split structures into domains for evaluation was based on server performance. Target domains were categorized based on their evolutionary relatedness to existing templates as well as their difficulty levels indicated by server performance. Those target domains with sequence-related templates and high server prediction performance were classified as TMB, while those targets without identifiable templates and low server performance were classified as FM. However, using these generalizations for classification resulted in a blurred boundary between CASP9 assessment categories. Thus, the FM category included those domains without sequence detectable templates (25 target domains) as well as some domains with difficult to detect templates whose predictions were as poor as those without templates (5 target domains). Several interesting examples are discussed, including targets with sequence related templates that exhibit unusual structural differences, targets with homologous or analogous structure templates that are not detectable by sequence, and targets with new folds. PMID:21997778

  10. Wake Shield Target Protection

    SciTech Connect

    Valmianski, Emanuil I.; Petzoldt, Ronald W.; Alexander, Neil B.

    2003-05-15

    The heat flux from both gas convection and chamber radiation on a direct drive target must be limited to avoid target damage from excessive D-T temperature increase. One of the possibilities of protecting the target is a wake shield flying in front of the target. A shield will also reduce drag force on the target, thereby facilitating target tracking and position prediction. A Direct Simulation Monte Carlo (DSMC) code was used to calculate convection heat loads as boundary conditions input into ANSYS thermal calculations. These were used for studying the quality of target protection depending on various shapes of shields, target-shield distance, and protective properties of the shield moving relative to the target. The results show that the shield can reduce the convective heat flux by a factor of 2 to 5 depending on pressure, temperature, and velocity. The protective effect of a shield moving relative to the target is greater than the protective properties of a fixed shield. However, the protective effect of a shield moving under the drag force is not sufficient for bringing the heat load on the target down to the necessary limit. Some other ways of diminishing heat flux using a protective shield are discussed.

  11. Target size matters: target errors contribute to the generalization of implicit visuomotor learning.

    PubMed

    Reichenthal, Maayan; Avraham, Guy; Karniel, Amir; Shmuelof, Lior

    2016-08-01

    The process of sensorimotor adaptation is considered to be driven by errors. While sensory prediction errors, defined as the difference between the planned and the actual movement of the cursor, drive implicit learning processes, target errors (e.g., the distance of the cursor from the target) are thought to drive explicit learning mechanisms. This distinction was mainly studied in the context of arm reaching tasks where the position and the size of the target were constant. We hypothesize that in a dynamic reaching environment, where subjects have to hit moving targets and the targets' dynamic characteristics affect task success, implicit processes will benefit from target errors as well. We examine the effect of target errors on learning of an unnoticed perturbation during unconstrained reaching movements. Subjects played a Pong game, in which they had to hit a moving ball by moving a paddle controlled by their hand. During the game, the movement of the paddle was gradually rotated with respect to the hand, reaching a final rotation of 25°. Subjects were assigned to one of two groups: The high-target error group played the Pong with a small ball, and the low-target error group played with a big ball. Before and after the Pong game, subjects performed open-loop reaching movements toward static targets with no visual feedback. While both groups adapted to the rotation, the postrotation reaching movements were directionally biased only in the small-ball group. This result provides evidence that implicit adaptation is sensitive to target errors.

  12. Bar coded retroreflective target

    SciTech Connect

    Vann, C.S.

    2000-01-25

    This small, inexpensive, non-contact laser sensor can detect the location of a retroreflective target in a relatively large volume and up to six degrees of position. The tracker's laser beam is formed into a plane of light which is swept across the space of interest. When the beam illuminates the retroreflector, some of the light returns to the tracker. The intensity, angle, and time of the return beam is measured to calculate the three dimensional location of the target. With three retroreflectors on the target, the locations of three points on the target are measured, enabling the calculation of all six degrees of target position. Until now, devices for three-dimensional tracking of objects in a large volume have been heavy, large, and very expensive. Because of the simplicity and unique characteristics of this tracker, it is capable of three-dimensional tracking of one to several objects in a large volume, yet it is compact, light-weight, and relatively inexpensive. Alternatively, a tracker produces a diverging laser beam which is directed towards a fixed position, and senses when a retroreflective target enters the fixed field of view. An optically bar coded target can be read by the tracker to provide information about the target. The target can be formed of a ball lens with a bar code on one end. As the target moves through the field, the ball lens causes the laser beam to scan across the bar code.

  13. Bar coded retroreflective target

    DOEpatents

    Vann, Charles S.

    2000-01-01

    This small, inexpensive, non-contact laser sensor can detect the location of a retroreflective target in a relatively large volume and up to six degrees of position. The tracker's laser beam is formed into a plane of light which is swept across the space of interest. When the beam illuminates the retroreflector, some of the light returns to the tracker. The intensity, angle, and time of the return beam is measured to calculate the three dimensional location of the target. With three retroreflectors on the target, the locations of three points on the target are measured, enabling the calculation of all six degrees of target position. Until now, devices for three-dimensional tracking of objects in a large volume have been heavy, large, and very expensive. Because of the simplicity and unique characteristics of this tracker, it is capable of three-dimensional tracking of one to several objects in a large volume, yet it is compact, light-weight, and relatively inexpensive. Alternatively, a tracker produces a diverging laser beam which is directed towards a fixed position, and senses when a retroreflective target enters the fixed field of view. An optically bar coded target can be read by the tracker to provide information about the target. The target can be formed of a ball lens with a bar code on one end. As the target moves through the field, the ball lens causes the laser beam to scan across the bar code.

  14. Lay Conceptions of Sexual Minority Groups.

    PubMed

    Burke, Sara E; LaFrance, Marianne

    2016-04-01

    Bisexual people are often implored to "pick a side," implying that bisexuality is both more controllable and less desirable than heterosexuality or homosexuality. Bisexual people's status as a social group perceived to fall between a traditionally advantaged group and a traditionally disadvantaged group may have the potential to clarify lay conceptions of sexual orientation. We examined participants' views of groups varying in sexual orientation by randomly assigning participants (including heterosexual men and women as well as gay men and lesbian women) from four samples to evaluate heterosexual, bisexual, or homosexual targets (N = 1379). Results provided strong evidence for the previously untested theoretical argument that bisexuality is perceived as less stable than heterosexuality or homosexuality. In addition, participants low in Personal Need for Structure rated female (but not male) bisexuality as relatively stable, suggesting that a preference for simple, binary thinking can partially explain a negative conception of an ostensibly "intermediate" identity. Bisexual targets were perceived as falling between heterosexual and homosexual targets in terms of gender nonconformity, and less decisive, less monogamous, and lacking in positive traits that were associated with homosexual targets. In sum, views of bisexual people were both more negative than and qualitatively different from views of gay men and lesbian women. We discuss the results as an illustration of the complex ways that perceivers' attitudes can differ depending on which target groups they are considering, suggesting that intergroup bias cannot be fully understood without attending to social categories viewed as intermediate. PMID:26597649

  15. Inertial Confinement fusion targets

    NASA Technical Reports Server (NTRS)

    Hendricks, C. D.

    1982-01-01

    Inertial confinement fusion (ICF) targets are made as simple flat discs, as hollow shells or as complicated multilayer structures. Many techniques were devised for producing the targets. Glass and metal shells are made by using drop and bubble techniques. Solid hydrogen shells are also produced by adapting old methods to the solution of modern problems. Some of these techniques, problems, and solutions are discussed. In addition, the applications of many of the techniques to fabrication of ICF targets is presented.

  16. Integrin Targeted MR Imaging.

    PubMed

    Tan, Mingqian; Lu, Zheng-Rong

    2011-01-19

    Magnetic resonance imaging (MRI) is a powerful medical diagnostic imaging modality for integrin targeted imaging, which uses the magnetic resonance of tissue water protons to display tissue anatomic structures with high spatial resolution. Contrast agents are often used in MRI to highlight specific regions of the body and make them easier to visualize. There are four main classes of MRI contrast agents based on their different contrast mechanisms, including T(1), T(2), chemical exchange saturation transfer (CEST) agents, and heteronuclear contrast agents. Integrins are an important family of heterodimeric transmembrane glycoproteins that function as mediators of cell-cell and cell-extracellular matrix interactions. The overexpressed integrins can be used as the molecular targets for designing suitable integrin targeted contrast agents for MR molecular imaging. Integrin targeted contrast agent includes a targeting agent specific to a target integrin, a paramagnetic agent and a linker connecting the targeting agent with the paramagnetic agent. Proper selection of targeting agents is critical for targeted MRI contrast agents to effectively bind to integrins for in vivo imaging. An ideal integrin targeted MR contrast agent should be non-toxic, provide strong contrast enhancement at the target sites and can be completely excreted from the body after MR imaging. An overview of integrin targeted MR contrast agents based on small molecular and macromolecular Gd(III) complexes, lipid nanoparticles and superparamagnetic nanoparticles is provided for MR molecular imaging. By using proper delivery systems for loading sufficient Gd(III) chelates or superparamagnetic nanoparticles, effective molecular imaging of integrins with MRI has been demonstrated in animal models.

  17. Automatic Target Recognizer Database Requirements

    NASA Astrophysics Data System (ADS)

    Power, David R.

    1987-09-01

    Data representative of imaging sensors and scenarios which form the inputs for automatic target recognizers (ATRs) is critical to their development, testing and performance evaluation. The Data Base Committee of the Automatic Target Recognizer Working Group provides a forum and produces products to assist collection, distribution and use of data for development of military ATR systems. Examples discussed in the paper include digital image data exchange format specifications. Requirements for ground and image truth data have been the subject of surveys. Such inputs are intended as recommendations for consideration by imagery data collection activities whose products are potentially useful for ATR development. Other topics concerning collection, reduction, use and exchange of imaging sensor data are outlined but not discussed in detail.

  18. Hox Targets and Cellular Functions

    PubMed Central

    Sánchez-Herrero, Ernesto

    2013-01-01

    Hox genes are a group of genes that specify structures along the anteroposterior axis in bilaterians. Although in many cases they do so by modifying a homologous structure with a different (or no) Hox input, there are also examples of Hox genes constructing new organs with no homology in other regions of the body. Hox genes determine structures though the regulation of targets implementing cellular functions and by coordinating cell behavior. The genetic organization to construct or modify a certain organ involves both a genetic cascade through intermediate transcription factors and a direct regulation of targets carrying out cellular functions. In this review I discuss new data from genome-wide techniques, as well as previous genetic and developmental information, to describe some examples of Hox regulation of different cell functions. I also discuss the organization of genetic cascades leading to the development of new organs, mainly using Drosophila melanogaster as the model to analyze Hox function. PMID:24490109

  19. Group Work: How to Use Groups Effectively

    ERIC Educational Resources Information Center

    Burke, Alison

    2011-01-01

    Many students cringe and groan when told that they will need to work in a group. However, group work has been found to be good for students and good for teachers. Employers want college graduates to have developed teamwork skills. Additionally, students who participate in collaborative learning get better grades, are more satisfied with their…

  20. Targeting the tumor microenvironment

    SciTech Connect

    Kenny, P.A.; Lee, G.Y.; Bissell, M.J.

    2006-11-07

    Despite some notable successes cancer remains, for the most part, a seemingly intractable problem. There is, however, a growing appreciation that targeting the tumor epithelium in isolation is not sufficient as there is an intricate mutually sustaining synergy between the tumor epithelial cells and their surrounding stroma. As the details of this dialogue emerge, new therapeutic targets have been proposed. The FDA has already approved drugs targeting microenvironmental components such as VEGF and aromatase and many more agents are in the pipeline. In this article, we describe some of the 'druggable' targets and processes within the tumor microenvironment and review the approaches being taken to disrupt these interactions.

  1. Infrared target array development

    NASA Astrophysics Data System (ADS)

    Scott, E. A.

    1980-04-01

    The US Army Yuma Proving Ground (USAYPG) was requested to develop and acquire a series of infrared targets with controllable thermal signatures to support the test and evaluation of the Target Acquisition Designation System/Pilot Night Vision System (TADS/PNVS) subsystems of the Advanced Attack Helicopter (AAH) Fire Control System. Prior to this development effort, no capability beyond the use of real-scene targets existed at USAYPG to provide thermally active targets with characteristic signatures in the infrared band. Three targets were acquired: (1) a detection target; (2) a recognition target; and (3) a laser scoring board. It is concluded that design goals were met and the system was delivered in time to perform its function. The system provides sufficient thermal realism and has advanced the state-of-the-art of infrared imaging system test and evaluation. It is recommended that the Field Equivalent Bar Target (FEBT) system be validated as a potential test standard and that environmentally 'hardened' targets be acquired for continued thermal sight testing.

  2. MSUD Family Support Group

    MedlinePlus

    ... Group The MSUD Family Support Group is a non-profit 501 (c)(3) organization for those with MSUD ... Family Support Group is a 501(c)(3) non-profit organization with no paid staff. Funds are needed ...

  3. Leadership in Small Groups: A Reward-Cost Analysis.

    ERIC Educational Resources Information Center

    Nydegger, Rudy V.

    By utilizing reinforcing and punishing light cues the verbal output and leadership status of Target Ss in a four-person group was manipulated. There were three conditions: Control (no light cues used); Agree, where Non-Target Ss were reinforced for agreeing with the Target, and punished for all other verbalizations; and Disagree, where Non-Target…

  4. Enhanced antitumor effect of novel dual-targeted paclitaxel liposomes

    NASA Astrophysics Data System (ADS)

    Meng, Shuyan; Su, Bo; Li, Wei; Ding, Yongmei; Tang, Liang; Zhou, Wei; Song, Yin; Li, Heyan; Zhou, Caicun

    2010-10-01

    A novel dual-targeted peptide containing an alpha V integrins specific ligand and a neuropilin-1 specific motif was developed which showed an increased specific targeting affinity to tumors. Active dual-targeted liposomes were then produced with this peptide and exhibited greater binding activity than single-targeted liposomes in vitro. Paclitaxel entrapped in this formulation greatly increased the uptake of paclitaxel in the targeting cells and significantly suppressed the growth of HUVEC and A549 cells compared with general paclitaxel injections (Taxol) and single-targeted paclitaxel liposomes. The treatment of tumor xenograft models with dual-targeted paclitaxel liposomes also resulted in better tumor growth inhibition than any other treatment groups. Therefore, the dual-targeted paclitaxel liposomes prepared in the present study might be a more promising drug for cancer treatment. Furthermore, the dual-targeting approach may produce synergistic effects that can be applied in the development of new targeted drug delivery systems.

  5. Grouping Factors and the Reverse Contrast Illusion.

    PubMed

    Economou, Elias; Zdravković, Sunčica; Gilchrist, Alan

    2015-12-01

    In simultaneous lightness contrast, two identical gray target squares lying on backgrounds of different intensities appear different in lightness. Traditionally, this illusion was explained by lateral inhibitory mechanisms operating retinotopically. More recently, spatial filtering models have been preferred. We report tests of an anchoring theory account in which the illusion is attributed to grouping rules used by the visual system to compute lightness. We parametrically varied the belongingness of two gray target bars to their respective backgrounds so that they either appeared to group with a set of bars flanking them, or they appeared to group with their respective backgrounds. In all variations, the retinal adjacency of the gray squares and their backgrounds was essentially unchanged. We report data from seven experiments showing that manipulation of the grouping rules governs the size and direction of the simultaneous lightness contrast illusion. These results support the idea that simultaneous lightness contrast is the product of anchoring within perceptual groups. PMID:26562863

  6. Target visibility for multiple maneuvering target tracking

    NASA Astrophysics Data System (ADS)

    Sabordo, Madeleine G.; Aboutanios, Elias

    2015-05-01

    We present a recursion of the probability of target visibility and its applications to analysis of track life and termination in the context of Global Nearest Neighbour (GNN) approach and Probability Hypothesis Density (PHD) filter. In the presence of uncertainties brought about by clutter; decisions to retain a track, terminate it or initialise a new track are based on probability, rather than on distance criterion or estimation error. The visibility concept is introduced into a conventional data-association-oriented multitarget tracker, the GNN; and a random finite set based-tracker, the PHD filter, to take into account instances when targets become invisible or occluded by obstacles. We employ the natural logarithmof the Dynamic Error Spectrum to assess the performance of the trackers with and without probability of visibility incorporated. Simulation results show that the performance of the GNN tracker with visibility concept incorporated is significantly enhanced.

  7. Perceptual grouping determines haptic contextual modulation.

    PubMed

    Overvliet, K E; Sayim, B

    2016-09-01

    Since the early phenomenological demonstrations of Gestalt principles, one of the major challenges of Gestalt psychology has been to quantify these principles. Here, we show that contextual modulation, i.e. the influence of context on target perception, can be used as a tool to quantify perceptual grouping in the haptic domain, similar to the visual domain. We investigated the influence of target-flanker grouping on performance in haptic vernier offset discrimination. We hypothesized that when, despite the apparent differences between vision and haptics, similar grouping principles are operational, a similar pattern of flanker interference would be observed in the haptic as in the visual domain. Participants discriminated the offset of a haptic vernier. The vernier was flanked by different flanker configurations: no flankers, single flanking lines, 10 flanking lines, rectangles and single perpendicular lines, varying the degree to which the vernier grouped with the flankers. Additionally, we used two different flanker widths (same width as and narrower than the target), again to vary target-flanker grouping. Our results show a clear effect of flankers: performance was much better when the vernier was presented alone compared to when it was presented with flankers. In the majority of flanker configurations, grouping between the target and the flankers determined the strength of interference, similar to the visual domain. However, in the same width rectangular flanker condition we found aberrant results. We discuss the results of our study in light of similarities and differences between vision and haptics and the interaction between different grouping principles. We conclude that in haptics, similar organization principles apply as in visual perception and argue that grouping and Gestalt are key organization principles not only of vision, but of the perceptual system in general.

  8. Intelligent [F-18] fluoride target system

    NASA Astrophysics Data System (ADS)

    Hichwa, R. D.; Aykac, M.; Bilgen, D.; Watkins, G. L.

    1999-06-01

    An automated target filling system has been developed for [F-18]F- production from [O-18]water. The system consists of a pair of standard syringe dispensing pumps, valve manifolds, pressure and flow sensors, RS-232 serial I/O modules, high pressure silver targets and X-windows software. Operations are controlled through a graphical interface and can be manipulated individually, in groups for specific functions, or as complex processes either manually or automatically. Major functional operations include: 1) system test, 2) target fill, 3) target empty, and 4) target clean up. Fault conditions if present are identified and flagged. Alternate (duplicate) pathways are automatically used if a nonfatal failure mode is detected. Results from the testing procedures are logged to a file for documented adherence to SOPs and trend assessment of performance.

  9. Intercepting moving targets: does memory from practice in a specific condition of target displacement affect movement timing?

    PubMed

    de Azevedo Neto, Raymundo Machado; Teixeira, Luis Augusto

    2011-05-01

    This investigation aimed at assessing the extent to which memory from practice in a specific condition of target displacement modulates temporal errors and movement timing of interceptive movements. We compared two groups practicing with certainty of future target velocity either in unchanged target velocity or in target velocity decrease. Following practice, both experimental groups were probed in the situations of unchanged target velocity and target velocity decrease either under the context of certainty or uncertainty about target velocity. Results from practice showed similar improvement of temporal accuracy between groups, revealing that target velocity decrease did not disturb temporal movement organization when fully predictable. Analysis of temporal errors in the probing trials indicated that both groups had higher timing accuracy in velocity decrease in comparison with unchanged velocity. Effect of practice was detected by increased temporal accuracy of the velocity decrease group in situations of decreased velocity; a trend consistent with the expected effect of practice was observed for temporal errors in the unchanged velocity group and in movement initiation at a descriptive level. An additional point of theoretical interest was the fast adaptation in both groups to a target velocity pattern different from that practiced. These points are discussed under the perspective of integration of vision and motor control by means of an internal forward model of external motion.

  10. Gene targeting in livestock.

    PubMed

    Thomson, A J; Marques, M M; McWhir, J

    2003-01-01

    The development of nuclear transfer from tissue culture cells in livestock made it possible in principle to produce animals with subtle, directed genetic changes by in vitro modification of nuclear donor cells. In the short period since nuclear transfer was first performed, gene targeting in livestock has become a reality. Although gene targeting has immediate potential in biotechnology, it is unclear whether there are practical agricultural applications, at present. The first livestock targeting experiments have been directed at engineering animals either to render their organs immunologically compatible for human transplantation, or for improving the commercial production of recombinant proteins in the transgenic mammary gland. All successful examples of targeting have involved target loci that are expressed in the nuclear donor cell line. Two important barriers to the further development of this technology are adapting protocols for non-expressed genes and modifying procedures to enhance the lifespan of targeted cells in vitro. This review provides data that illustrate the difficulty in targeting non-expressed genes and discusses some of the practical issues associated with providing targeted nuclear donor cells that are competent for nuclear transfer.

  11. Knowing Your Learning Target

    ERIC Educational Resources Information Center

    Moss, Connie M.; Brookhart, Susan M.; Long, Beverly A.

    2011-01-01

    No matter what we decide students need to learn, not much will happen until students understand what they are supposed to learn during a lesson and set their sights on learning it. Crafting learning targets for each lesson and deliberately sharing them with students is one way to give students the direction they need. Targets that tell students…

  12. The Tracking and Ability Grouping Debate. Volume 2, Number 8.

    ERIC Educational Resources Information Center

    Loveless, Tom

    Tracking and ability grouping are common practices that are often harshly criticized. Both practices group students of similar achievement levels for instruction, but they differ in how this task is accomplished. Elementary schools typically use ability grouping in reading instruction, with instruction targeted to the reading level of each group.…

  13. Methodology for target discrimination.

    PubMed

    McNolty, F; Clow, R

    1980-03-15

    The objective is to distinguish the true target from point-target imitators and from extended-target clutter in the exoatmospheric regime. Matched filters are carefully studied from the viewpoint of SNR enhancement and pulse recognition. The matched filter structure takes into account photon noise, modulation noise, generation-recombination (GR) noise, contact noise, and various thermal noise sources. A multicolor radiant-intensity structure for target discrimination is developed by analyzing the uncertainties in such target irradiance parameters as range, temperature, projected area, and emissivity. Bias terms, variances, and other statistical descriptors are derived. Certain statistical discrimination techniques are discussed that exploit the radiant-intensity format. Helstrom's method for processing radar signals is adapted to a fourchannel pulse-recognition system for which degradation due to arrival time delays and mismatched filters is discussed.

  14. Advanced Targeted Nanomedicine

    PubMed Central

    Arachchige, Mohan C M; Reshetnyak, Yana K.; Andreev, Oleg A.

    2015-01-01

    Targeted drug delivery has been the major topic in drug formulation and delivery. As nanomedicine emerges to create nano scale therapeutics and diagnostics, it is still essential to embed targeting capability to these novel systems to make them useful. Here we discuss various targeting approaches for delivery of therapeutic and diagnostic nano materials in view of search for more universal methods to target diseased tissues. Many diseases are accompanied with hypoxia and acidosis. Coating nanoparticles with pH Low Insertion Peptides (pHLIPs) increases efficiency of targeting acidic diseased tissues. It has been showing promising results to create future nanotheranostics for cancer and other diseases which are dominating in the present world. PMID:25615945

  15. Interpersonal perception and metaperception in nonoverlapping social groups.

    PubMed

    Malloy, T E; Albright, L; Kenny, D A; Agatstein, F; Winquist, L

    1997-02-01

    Consensus, self-other agreement, and meta-accuracy were studied within and across nonoverlapping social groups. Thirty-one target persons were judged on the Big Five factors by 9 informants: 3 family members, 3 friends, and 3 coworkers. Although well acquainted within groups, informants were unacquainted between groups. A social relations analysis conducted within each social group showed reliable consensus on the Big Five personality factors. A model specified to estimate the consistency of a target person's effect on perceptions by others across social groups showed weaker agreement across groups. That is, targets were perceived consensually within groups, but these consensual perceptions differed between groups. The data suggest that personality and identity are context specific; however, there was some evidence of agreement in perceptions across groups.

  16. Infrared Target Array Development

    NASA Astrophysics Data System (ADS)

    McIntire, Thomas O.; Scott, Edward A.

    1982-03-01

    A "life size" thermal target array has been developed to facilitate in-flight testing of airborne weapon systems containing night vision subsystems. This in-flight testing to measure the performance of the night vision subsystem and its effect on overall weapon system performance is essential to the test and evaluation process of the particular weapon under test. This measurement of subsystem performance is called the Modulation Transfer Function, or MTF. In addition, a laser designator subsystem is frequently incorporated in a precision guided munition weapon system. In the test and evaluation of the designator, such quantities as beam quality (energy distribution), beam divergence, and beam wander are of interest. The thermal targets may be used to evaluate armored weapon systems. The capability of providing carefully controlled and variable thermal signatures in a field test environment is considered unique. The thermal target array consists of three targets: A six bar recognition target, a two bar detection target, and a laser designator scoring board (cross-hair). The image dimensions of 2.3 meters by 2.3 meters were derived from an optimized threat envelope. The thermal signatures of the targets are controllable to within 0.3 C about a differential setpoint. This differential setpoint is measured between the active element and the target background (or "ambient"). Several differential temperature settings are available to the test officer: 1.25°C, 3°C, 5°C, 7.5°C, and 10°C. This paper reviews the thermal array test objectives, target array fabrication, methodology of target utilization, and representative results.

  17. Target marketing strategies for occupational therapy entrepreneurs.

    PubMed

    Kautzmann, L N; Kautzmann, F N; Navarro, F H

    1989-01-01

    Understanding marketing techniques is one of the skills needed by successful entre renews. Target marketing is an effective method for occupational therapy entrepreneurs to use in determining when and where to enter the marketplace. The two components of target marketing, market segmentation and the development of marketing mix strategies for each identified market segment, are described. The Profife of Attitudes Toward Health Care (PATH) method of psychographic market segmentation of health care consumers is presented. Occupational therapy marketing mix strategies for each PATH consumer group are delineated and compatible groupings of market segments are suggested.

  18. SETI science working group report

    NASA Technical Reports Server (NTRS)

    Drake, F.; Wolfe, J. H.; Seeger, C. L.

    1984-01-01

    This report covers the initial activities and deliberations of a continuing working group asked to assist the SETI Program Office at NASA. Seven chapters present the group's consensus on objectives, strategies, and plans for instrumental R&D and for a microwave search for extraterrestrial in intelligence (SETI) projected for the end of this decade. Thirteen appendixes reflect the views of their individual authors. Included are discussions of the 8-million-channel spectrum analyzer architecture and the proof-of-concept device under development; signal detection, recognition, and identification on-line in the presence of noise and radio interference; the 1-10 GHz sky survey and the 1-3 GHz targeted search envisaged; and the mutual interests of SETI and radio astronomy. The report ends with a selective, annotated SETI reading list of pro and contra SETI publications.

  19. Liposarcoma: Multimodality Management and Future Targeted Therapies.

    PubMed

    Crago, Aimee M; Dickson, Mark A

    2016-10-01

    There are 3 biologic groups of liposarcoma: well-differentiated and dedifferentiated liposarcoma, myxoid/round cell liposarcoma, and pleomorphic liposarcoma. In all 3 groups, complete surgical resection is central in treatment aimed at cure and is based on grade. Radiation can reduce risk of local recurrence in high-grade lesions or minimize surgical morbidity in the myxoid/round cell liposarcoma group. The groups differ in chemosensitivity, so adjuvant chemotherapy is selectively used in histologies with metastatic potential but not in the resistant subtype dedifferentiated liposarcoma. Improved understanding of the genetic aberrations that lead to liposarcoma initiation is allowing for the rapid development of targeted therapies for liposarcoma. PMID:27591497

  20. Nuclear target development

    SciTech Connect

    Greene, J.P.; Thomas, G.E.

    1995-08-01

    The Physics Division operates a target development laboratory that produces thin foil targets needed for experiments performed at the ATLAS and Dynamitron accelerators. Targets are not only produced for the Physics Division but also for other divisions and occasionally for other laboratories and universities. In the past year, numerous targets were fabricated by vacuum evaporation either as self-supporting foils or on various substrates. Targets produced included Ag, Au, {sup 10,11}B, {sup 138}Ba, Be, {sup 12}C, {sup 40}Ca, {sup 116}Cd, {sup 155,160}Gd, {sup 76}Ge, In, LID, {sup 6}LiH, Melamine, Mg, {sup 142,150}Nd, {sup 58}Ni, {sup 206,208}Pb, {sup 194}Pt, {sup 28}Si, {sup 144,148}Sm, {sup 120,122,124}Sn, Ta, {sup 130}Te, ThF{sub 4}, {sup 46,50}Ti, TiH, U, UF{sub 4}, {sup 182}W and {sup 170}Yb. Polypropylene and aluminized polypropylene, along with metallized Mylar were produced for experiments at ATLAS. A number of targets of {sup 11}B of various thickness were made for the DEP 2-MeV Van de Graff accelerator. An increased output of foils fabricated using our small rolling mill included targets of Au, C, {sup 50}Cr, Cu, {sup 155,160}Gd, Mg, {sup 58}Ni, {sup 208}Pb, {sup 105,110}Pd. Sc, Ti, and {sup 64,66}Zn.

  1. STIS target acquisition

    NASA Technical Reports Server (NTRS)

    Kraemer, Steve; Downes, Ron; Katsanis, Rocio; Crenshaw, Mike; McGrath, Melissa; Robinson, Rich

    1997-01-01

    We describe the STIS autonomous target acquisition capabilities. We also present the results of dedicated tests executed as part of Cycle 7 calibration, following post-launch improvements to the Space Telescope Imaging Spectrograph (STIS) flight software. The residual pointing error from the acquisitions are < 0.5 CCD pixels, which is better than preflight estimates. Execution of peakups show clear improvement of target centering for slits of width 0.1 sec or smaller. These results may be used by Guest Observers in planning target acquisitions for their STIS programs.

  2. USGS aerial resolution targets.

    USGS Publications Warehouse

    Salamonowicz, P.H.

    1982-01-01

    It is necessary to measure the achievable resolution of any airborne sensor that is to be used for metric purposes. Laboratory calibration facilities may be inadequate or inappropriate for determining the resolution of non-photographic sensors such as optical-mechanical scanners, television imaging tubes, and linear arrays. However, large target arrays imaged in the field can be used in testing such systems. The USGS has constructed an array of resolution targets in order to permit field testing of a variety of airborne sensing systems. The target array permits any interested organization with an airborne sensing system to accurately determine the operational resolution of its system. -from Author

  3. Nras in melanoma: targeting the undruggable target.

    PubMed

    Mandalà, Mario; Merelli, Barbara; Massi, Daniela

    2014-11-01

    RAS belongs to the guanosine 5'-triphosphate (GTP)-binding proteins' family, and oncogenic mutations in codons 12, 13, or 61 of RAS family occur in approximately one third of all human cancers with N-RAS mutations found in about 15-20% of melanomas. The importance of RAS signaling as a potential target in cancer is emphasized not only by the prevalence of RAS mutations, but also by the high number of RAS activators and effectors identified in mammalian cells that places the RAS proteins at the crossroads of several, important signaling networks. Ras proteins are crucial crossroads of signaling pathways that link the activation of cell surface receptors with a wide variety of cellular processes leading to the control of proliferation, apoptosis and differentiation. Furthermore, oncogenic ras proteins interfere with metabolism of tumor cells, microenvironment's remodeling, evasion of the immune response, and finally contributes to the metastatic process. After 40 years of basic, translational and clinical research, much is now known about the molecular mechanisms by which these monomeric guanosine triphosphatase-binding proteins promote cellular malignancy, and it is clear that they regulate signaling pathways involved in the control of cell proliferation, survival, and invasiveness. In this review we summarize the biological role of RAS in cancer by focusing our attention on the biological rational and strategies to target RAS in melanoma.

  4. Mitochondria-targeted antioxidants.

    PubMed

    Oyewole, Anne O; Birch-Machin, Mark A

    2015-12-01

    Redox homeostasis is maintained by the antioxidant defense system, which is responsible for eliminating a wide range of oxidants, including reactive oxygen species (ROS), lipid peroxides, and metals. Mitochondria-localized antioxidants are widely studied because the mitochondria, the major producers of intracellular ROS, have been linked to the cause of aging and other chronic diseases. Mitochondria-targeted antioxidants have shown great potential because they cross the mitochondrial phospholipid bilayer and eliminate ROS at the heart of the source. Growing evidence has identified mitochondria-targeted antioxidants, such as MitoQ and tiron, as potentially effective antioxidant therapies against the damage caused by enhanced ROS generation. This literature review summarizes the current knowledge on mitochondria-targeted antioxidants and their contribution to the body's antioxidant defense system. In addition to addressing the concerns surrounding current antioxidant strategies, including difficulties in targeting antioxidant treatment to sites of pathologic oxidative damage, we discuss promising therapeutic agents and new strategic approaches.

  5. Multiple shell fusion targets

    DOEpatents

    Lindl, J.D.; Bangerter, R.O.

    1975-10-31

    Multiple shell fusion targets for use with electron beam and ion beam implosion systems are described. The multiple shell targets are of the low-power type and use a separate relatively low Z, low density ablator at large radius for the outer shell, which reduces the focusing and power requirements of the implosion system while maintaining reasonable aspect ratios. The targets use a high Z, high density pusher shell placed at a much smaller radius in order to obtain an aspect ratio small enough to protect against fluid instability. Velocity multiplication between these shells further lowers the power requirements. Careful tuning of the power profile and intershell density results in a low entropy implosion which allows breakeven at low powers. For example, with ion beams as a power source, breakeven at 10-20 Terrawatts with 10 MeV alpha particles for imploding a multiple shell target can be accomplished.

  6. Target Heart Rate Calculator

    MedlinePlus

    ... My Saved Articles » My ACS » + - Text Size Target Heart Rate Calculator Compute your best workout Enter your age ... is your age? years. How to Check Your Heart Rate Right after you stop exercising, take your pulse: ...

  7. Liposomes for cardiovascular targeting.

    PubMed

    Levchenko, Tatyana S; Hartner, William C; Torchilin, Vladimir P

    2012-04-01

    Liposome-based pharmaceuticals used within the cardiovascular system are reviewed in this article. The delivery of diagnostic and therapeutic agents by plain liposomes and liposomes with surface-attached targeting antibodies or polyethylene glycol to prolong their circulation time and accumulation at vascular injuries, ischemic zones or sites of thrombi are also discussed. An overview of the advantages and disadvantages of liposome-mediated in vitro, ex vivo and in vivo targeting is presented, including discussion of the targeting of liposomes to pathological sites on the blood vessel wall and a description of liposomes that can be internalized by endothelial cells. Diagnostic liposomes used to target myocardial infarction and the relative importance of liposome size, targetability of immunoliposomes and prolonged circulation time on the efficiency of sealing hypoxia-induced plasma membrane damage to cardiocytes are discussed as a promising approach for therapy. The progress in the use of targeted liposomal plasmids for the transfection of hypoxic cardiomyocytes and myocardium is presented. Stent-mediated liposomal-based drug delivery is also reviewed briefly. PMID:22834079

  8. The GROOP Effect: Groups Mimic Group Actions

    ERIC Educational Resources Information Center

    Tsai, Jessica Chia-Chin; Sebanz, Natalie; Knoblich, Gunther

    2011-01-01

    Research on perception-action links has focused on an interpersonal level, demonstrating effects of observing individual actions on performance. The present study investigated perception-action matching at an inter-group level. Pairs of participants responded to hand movements that were performed by two individuals who used one hand each or they…

  9. Stress and nurses' horizontal mobbing: moderating effects of group identity and group support.

    PubMed

    Topa, Gabriela; Moriano, Juan A

    2013-01-01

    Horizontal mobbing is a process of systematic and repeated aggression towards a worker by coworkers. Among others, stress has been pointed out as one of the antecedents that favors the onset of horizontal mobbing, whereas group support to the target could act as a buffer. Moreover, the social identity approach emphasizes that group identity is an antecedent of group support. This study explores the interaction of group support and group identity in the explanation of horizontal mobbing in a sample (N = 388) of registered nurses and licensed practical nurses employed at two large hospitals in Madrid and Navarre (Spain). The results show that stress is positively associated to horizontal mobbing, whereas group support and group identity were negative predictors of horizontal mobbing. Furthermore, the combination of low group identity and low group support precipitated HM among nurses. PMID:23664419

  10. Gestalt Interactional Groups

    ERIC Educational Resources Information Center

    Harman, Robert L.; Franklin, Richard W.

    1975-01-01

    Gestalt therapy in groups is not limited to individual work in the presence of an audience. Describes several ways to involve gestalt groups interactionally. Interactions described focus on learning by doing and discovering, and are noninterpretive. (Author/EJT)

  11. What Makes Groups Tick.

    ERIC Educational Resources Information Center

    Allcorn, Seth

    1985-01-01

    By reviewing this analysis of the behavior of both groups and individuals in groups, human resources managers can learn to tell whether committees, task forces, and departments may be encouraging or inhibiting the work they set out to do. (Author)

  12. Nilpotent -local finite groups

    NASA Astrophysics Data System (ADS)

    Cantarero, José; Scherer, Jérôme; Viruel, Antonio

    2014-10-01

    We provide characterizations of -nilpotency for fusion systems and -local finite groups that are inspired by known result for finite groups. In particular, we generalize criteria by Atiyah, Brunetti, Frobenius, Quillen, Stammbach and Tate.

  13. Bioorthogonal Oxime Ligation Mediated In Vivo Cancer Targeting

    PubMed Central

    Tang, Li; Yin, Qian; Xu, Yunxiang; Zhou, Qin; Cai, Kaimin; Yen, Jonathan; Dobrucki, Lawrence W.

    2015-01-01

    Current cancer targeting relying on specific biological interaction between cell surface antigen and respective antibody or its analogue has proven to be effective in the treatment of different cancers; however, this strategy has its own limitations, such as heterogeneity of cancer cells and immunogenicity of the biomacromolecule binding ligands. Bioorthogonal chemical conjugation has emerged as an attractive alternative to biological interaction for in vivo cancer targeting. Here, we report an in vivo cancer targeting strategy mediated by bioorthogonal oxime ligation. Oxyamine group, the artificial target, is introduced onto 4T1 murine breast cancer cells through liposome delivery and fusion. Poly(ethylene glycol) -polylactide (PEG-PLA) nanoparticle (NP) is surface-functionalized with aldehyde groups as targeting ligands. The improved in vivo cancer targeting of PEG-PLA NPs is achieved through specific and efficient chemical reaction between the oxyamine and aldehyde groups. PMID:26146536

  14. Internet minimal group paradigm.

    PubMed

    Amichai-Hamburger, Yair

    2005-04-01

    Over many years, social psychologists have sought to understand what causes individuals to form themselves into groups. Initially, it was believed that groups were formed when people bonded around a common goal. Later, it was found that, when individuals were divided into groups on a random basis, this in itself was sufficient for them to feel part of a group and show a preference for their own group over others. Since the environment in cyberspace is different from that of the offline world, for example, there is no physical proximity between participants; it may be assumed that it would be difficult to achieve feelings of affiliation among potential or actual group members. This pioneer study seeks to discover which components are requisite to the creation of a group identity among individuals surfing the Internet. For this experiment, 24 people were divided into two Internet chat groups according to their intuitive preference in a decision-making task. It was found that group members perceived their own group performance as superior on a cognitive task as compared with that of the other group. These results demonstrate that for surfers, the Internet experience is very real and even a trivial allocation of people to a group is likely to create a situation of ingroup favoritism. PMID:15938653

  15. Practice and Group Learning

    ERIC Educational Resources Information Center

    Hager, Paul

    2014-01-01

    Although learning has always been a central topic for philosophy of education, little attention has been paid to the notion of group learning. This article outlines and discusses some plausible examples of group learning. Drawing on these examples, various principles and issues that surround the notion of group learning are identified and…

  16. Infant Group Care Risks.

    ERIC Educational Resources Information Center

    Kendall, Earline D.

    Children under 3 years of age who are in group care face special health risks. The U.S. Centers for Disease Control indicate the existence of a causal relationship between infant group day care and certain diseases that are spread through contact at day care centers. Children in group care who are still in diapers are especially vulnerable to…

  17. Internet Discussion Groups.

    ERIC Educational Resources Information Center

    Bull, Glen; Bull, Gina; Sigmon, Tim

    1997-01-01

    Discusses newsgroups, listservs, and Web-based discussion groups. Highlights include major categories of international USENET discussion groups; newsgroups versus mailing lists; newsreaders; news servers; newsgroup subscriptions; newsgroups versus Web discussion groups; linking newsgroups, mailing lists, and the Web; and setting up a news host. A…

  18. Integrated Play Groups

    ERIC Educational Resources Information Center

    Glovak, Sandra

    2007-01-01

    As an occupational therapist running social play groups with sensory integration for children on the autism spectrum, the author frequently doubted the wisdom of combining several children on the spectrum into a group. In fact, as the owner of a clinic she said, "No more!" The groups seemed like a waste of parents' time and money, and she refused…

  19. Working Group 7 Summary

    SciTech Connect

    Nagaitsev S.; Berg J.

    2012-06-10

    The primary subject of working group 7 at the 2012 Advanced Accelerator Concepts Workshop was muon accelerators for a muon collider or neutrino factory. Additionally, this working group included topics that did not fit well into other working groups. Two subjects were discussed by more than one speaker: lattices to create a perfectly integrable nonlinear lattice, and a Penning trap to create antihydrogen.

  20. Parent Group Spotlight

    ERIC Educational Resources Information Center

    Parenting for High Potential, 2014

    2014-01-01

    This issue's "Parent Group Spotlight" features Deborah Simon, president of West Sound Gifted, Talented & Twice-Exceptional (WSGT2e), who started a parent group in Washington in 2013. In just one year, this small, but mighty group has held community forums, attended school board meetings, and helped influence local gifted programming.…